Key Determinants of Successful Cardiopulmonary Resuscitation (CPR)
Quality Chest Compressions (100-120/min with 2-2.4” Depth and Full Chest Recoil Between Compressions
Early Defibrillation
American Heart Association Guidelines Recommend Maintaining a Chest Compression Fraction of ≥60% (Meaning on Average, Chest Compressions Should Be Withheld<40% of the Intra-Arrest Time ( J Emerg Med, 2018) [MEDLINE]
There May Be Additional Benefit with Maintaining a Chest Compression Fraction of ≥80% (Circulation, 2009) [MEDLINE] (Resuscitation, 2011) [MEDLINE]
Multiple Interventions May Interrupt Chest Compressions: some of which have unclear benefit
Administration of Resuscitation Medications
Endotracheal Intubation: supraglottic airway insertion can be quicker than endotracheal intubation, don’t interfere with chest compressions, and have a loer complication than endotracheal intubation
Vascular Access Attempts: intraosseous access can be quicker than intravenous access and doesn’t interfere with chest compressions
In Cardiopulmonary Arrest, Systemic and Pulmonary Vascular Perfusion is Very Low Despite Optimal Cardiopulmonary Resuscitation (CPR)
Therefore, Ventilation/Perfusion Relationships Can Be Maintained with Low Minute Ventilation
Hyperventilation Should Be Avoided During CPR, as Increased Intrathoracic Pressure and Gastric Distention Can Impede Effective Chest Compressions (Circulation, 2015) [MEDLINE]
Airway Management Techniques During Cardiopulmonary Resuscitation
Laryngeal Mask Airway (LMA) or Other Similar Supraglottic Airway Device
Clinical Efficacy of Endotracheal Intubation in Out-of-Hospital Cardiac Arrest
Randomized Trial of Bag-Mask Ventilation vs Endotracheal Intubation During Cardiopulmonary Resuscitation in Out-of-Hospital Cardiac Arrest (JAMA 2018) [MEDLINE]: n= 2043
Bag-Mask Ventilation and Endotracheal Intubation were Equivalent in Terms of 28-Day Neurologic Outcome for Out-of-Hospital Cardiac Arrest
AIRWAYS-2 Randomized Trial of Supraglottic Airway Device vs Tracheal Intubation in Out-of-Hospital Cardiac Arrest ( JAMA, 2018) [MEDLINE]: n = 9296
Supraglottic Airway Device and Endotracheal Intubation Were Equivalent in Terms of 30-Day Outcome in Out-of-Hospital Cardiac Arrest
Trial of Laryngeal Tube Insertion vs Endotracheal Intubation in Out-of-Hospital Cardiac Arrest (JAMA, 2018) [MEDLINE]: n= 3000
Laryngeal Tube Insertion was Superior to Endotracheal Intubation in Terms of 72 hr Mortality Rate in Out-of-Hospital Cardiac Arrest
Recommendations (American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care, 2015) (Circulation, 2015) [MEDLINE]
Use the Maximal Feasible Inspired Oxygen Concentration During CPR (Class IIb, LOE C-EO)
Method of Oxygenation/Ventilation
Inadequate Evidence to Demonstrate a Difference in Survival or Favorable Neurologic Outcome with the Use of Bag-Mask Ventilation, as Compared to Endotracheal Intubation During CPR
Either a Bag-Mask Device or an Advanced Airway May Be Used for Oxygenation/Ventilation During CPR in Both the In-Hospital and Out-of-Hospital Settings (Class IIb, LOE C-LD)
For Healthcare Providers Trained in Their Use, Either an Supraglottic Airway Device or an Endotracheal Tube May Be Used as the Initial Advanced Airway During CPR (Class IIb, LOE C-LD)
Confirmation of Endotracheal Tube Placement
Continuous Waveform Capnography is Recommended in Addition to Clinical Assessment as the Most Reliable Method of Confirming and Monitoring Correct Endotracheal Tube Placement (Class I, LOE C-LD)
If Continuous Waveform Capnometry is Not Available, a Nonwaveform CO2 Detector, Esophageal Detector Device, or Ultrasound Used by an Experienced Operator is a Reasonable Alternative (Class IIa, LOE C-LD)
Ventilation After Advanced Airway Placement
After Placement of Advanced Airway, it is Reasonable to Deliver 1 Breath Every 6 sec (10 Breaths/min) While Continuous Chest Compressions are Being Performed (Class IIb, LOE C-LD)
May Be Complicated by Gastric Rupture in Some Cases (Am J Emerg Med, 1993) [MEDLINE]
Back Blows
Chest Thrusts
Clinical Efficacy
Efficacy of a Single Maneuver is 50% at Best, with the Highest Efficacy Observed When Using Multiple Maneuvers (Crit Care Med, 1979) [MEDLINE]
Recommendations for Responsive Patient (2010 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care) (Circulation, 2010) [MEDLINE] (2015 American Heart Association Guidelines Update for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care) (Circulation, 2015) [MEDLINE]
In a Patient with Severe Airway Obstruction by a Foreign Body, Multiple Rapid-Sequence Abdominal Thrusts Followed by Chest Thrusts is Recommended
If the Abdomen Cannot Be Encircled or the Patient is in the Late Stages of Pregnancy, Chest Thrusts are the Initial Recommended Maneuver
Recommendations for Unresponsive Patient (2010 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care) (Circulation, 2010) [MEDLINE]
Blind Finger Sweep is Not Recommended, Unless Solid Material Becomes Visible in the Upper Airway During the Course of CPR
Cardiopulmonary Resuscitation (CPR): since chest compressions may produce higher airway pressures than abdominal thrusts in unresponsive patients (Resuscitation, 2000) [MEDLINE]
Airway Maneuvers (Measures to Decrease Soft Tissue Upper Airway Obstruction and Establish Upper Airway Patency)
Head-Tilt Chin-Lift Maneuver
Background
Head-Tilt Chin-Lift is Frequently the First Maneuver to Utilized in a Patient without a Concern About Possible Cervical Cord Spinal Injury
Technique
Use 2 Hands to Apply Downward Pressure to the Forehead and Use Tips of Index and Middle Fingers to Extend Neck by Lifting Jaw Forward at the Mentum: this maneuver moves the tongue anteriorly out of the posterior pharynx (JACEP, 1976) [MEDLINE]
Jaw-Thrust Maneuver
Background
Jaw Thrust Maneuver Can Be Utilized in a Patient Even if There is a Concern About Possible Cervical Spinal Cord Injury
However, Since Airway Maneuvers are Usually Associated with at Least Some Movement of the Cervical Spine, Caution Must Be Exercised in Any Patient in Whom There is a Concern About Potential Cervical Spinal Cord Injury (Spine; Phila Pa 1976) [MEDLINE] (Anesth Analg, 2000) [MEDLINE]
Technique
With Hands on Parieto-Occipital Skull, Thrusting Jaw Forward (Importantly, without Extending the Neck) Moves the Tongue Anteriorly Out of the Posterior Pharynx (ORL J Otorhinolaryngol Relat Spec, 2005) [MEDLINE]
Airway Adjuncts (Measures to Maintain Upper Airway Patency)
General Comments
After Establishment of Upper Airway Patency by the Above Upper Airway Maneuvers, Airway Adjuncts Serve to Maintain Patency
Oropharyngeal Airway
Design
Oropharyngeal Airway is a Tube-Like Plastic Device Which Prevents the Tongue and Oropharyngeal Soft Tissues from Obstructing the Upper Airway
Clinical Use
Oropharyngeal Airway Should Only Be Used in a Patient Under Deep Sedation (Due to the Risk of Vomiting and/or Aspiration)
Sizing
When Held Next to the Patients Face with the Flat End in Line with the Patient’s Mouth, the Tip of a Properly-Sized Oropharyngeal Airway Should Just Reach the Angle of the Mandible
Insertion
Insert the Oropharyngeal Airway Upside Down to Avoid Pushing the Tongue Posteriorly into the Oropharynx
Then Carefully Rotate the Oropharyngeal Airway 180 Degrees While Advancing It into the Posterior Pharynx
Adverse Effects/Complications
Capture of Lips/Tongue Between the Oropharyngeal Airway and Teeth (Causing Injury)
Oropharyngeal Mucosal Injury (May Occur During Rotation): may cause bleeding in a patient with coagulopathy
Inadvertent Displacement of the Tongue into the Posterior Pharynx (Worsening Upper Airway Obstruction)
Use of Incorrectly Size Oropharyngeal Airway
Too Large Oropharyngeal Airway: may push the epiglottis into the airway, worsening upper airway obstruction
Too Small Oropharyngeal Airway: may be ineffective and/or become lost in the oropharynx
Vomiting (with/without Aspiration): may occur in a patient who is not adequately sedated prior to oropharyngeal device insertion
Nasopharyngeal Airway (Nasal Trumpet)
Design
Nasopharyngeal Airway is a Soft Rubber or Plastic Tube Which is Passed Through the Nose into the Posterior Pharynx
Clinical Use
Nasopharyngeal Airway May Be Used in a Patient with Clenched Jaw or Inability to Tolerate an Oropharyngeal Airway (Due to Inadequate Sedation)
Sizing
Nasopharyngeal Airway Comes Sizing is Based on the Internal Diameter: with the larger internal diameter = longer length
Small Adult: 6-7 cm
Medium Adult: 7-8 cm
Large Adult: 8-9 cm
Size Should Be Selected Based on Length of the Nasopharyngeal Airway (Emerg Med J, 2005) [MEDLINE]
When Holding the Nasopharyngeal Airway Next to Patient’s Mandible with the Flared End at the Patient’s Mouth, the Distal Tip of a Properly-Sized Nasopharyngeal Airway Should Just Reach the Angle of the Patient’s Mandible
Insertion
Lubricate the Nasopharyngeal Airway (with Water-Soluble Lubricant or Lidocaine Jelly) and Insert Along the Floor of the Nares into the Posterior Pharynx (Following a Downward Angle of Approximately 15 Degrees): note that the contact time for lidocaine jelly is insufficient to provide anesthesia during the insertion, but it may provide anesthesia after the nasopharyngeal airway is already in place
Adverse Effects/Complications
Inadvertent Intracranial Nasopharyngeal Airway Incursion: has been rarely described in patients with basilar skull fractures
Nasopharyngeal Mucosal Injury: may cause epistaxis in up to 30% of cases (Anaesthesia, 1993) [MEDLINE]
Epistaxis May Be Severe in a Patient with Coagulopathy
Use of Excessively Long Nasopharyngeal Airway (Which May Extend into the Esophagus and Cause Gastric Distention During Subsequent Bag-Valve-Mask Ventilation)
Pre-Intubation Assessment
American Society of Anesthesiologists (ASA) Physical Status Classification
ASA 1: Normal Healthy Patient
Example: varicose veins in otherwise healthy patient
ASA 2: Mild Systemic Disease That Does Not Impair Normal Activity
ASA 4: Severe Systemic Disease That is a Constant Threat to Life
Example: CHF, major organ insufficiency, etc
ASA 5: Moribund Patient Who is Not Expected to Survive for 24 hrs With or Without Surgery
Example: intracranial hemorrhage in coma, etc
ASA 6: Declared Brain Dead with Plan for Organ Donation
Assessment for Physiologic Factors Which May Increase the Risk of Intubation
Physiologic Risk Factors Which Increase the Risk of Cardiovascular Compromise During or After Airway Management, Regardless of Anatomic Difficulty with Endotracheal Intubation (West J Emerg Med. 2015;16(7):1109 [MEDLINE]
Study of Diagnostic Validity of Multivariate Airway Scoring Systems to Predict Difficult Laryngoscopy (J Intl Med Res, 2016) [MEDLINE]
All Three Scoring Systems Demonstrated Inconclusive Zones Which Limit Their Clinical Utility in Predicting Difficult Intubations
Naguib Airway Assessment Method
Commonly Utilized in Operative Settings
Uses Measurements in an Equation to Predict Difficult Intubation
Positive = Difficult Laryngoscopy
Negative = Easy Laryngoscopy
LEMON Airway Assessment Method
Look
Dentition: assess for dentures, prominent maxillary incisors, broken/loose teeth, and crowns
Incisor Size
Scars
Tongue Size
Evaluate Using the 3-3-2 Rule
At Least 3 Fingers Between the Incisors
At Least 3 Fingers for the Thyromental Distance: distance from thyroid prominence to the point of chin (mentum) with the neck extended
Thyromental Distance is Considered Important Because During Direct Laryngoscopy, the Tongue is Displaced by the Laryngoscope into the Thyromental Space: a short thyromental distance indicates less space for the tongue to be displaced by the laryngoscope blade
At Least 2 Fingers for the Hyomental Distance: distance between hyoid bone (just above thyroid cartilage) and point of chin (mentum)
Mallampati Airway Class/Score: assessed in upright patient with mouth wide open and tongue out -> allows assessment of oral size and anatomy of tongue and oropharynx
Class I: hard palate, soft palate, entire uvula, fauces, and pillars visible
Class II: hard palate, soft palate, part of uvula, and fauces visible
Class III: hard palate, soft palate, and base of uvula visible -> predicts difficult mask ventilation and difficult intubation
Class IV: only hard palate visible -> predicts difficult mask ventilation and difficult intubation
Obstruction of Airway
Neck Mobility: assess for next extension
Neck Extension May Be Limited with History of C-Spine Surgery
Neck Extension May Be limited Due to Rheumatoid Arthritis (RA) (see Rheumatoid Arthritis): neck extension during intubation in some patients with RA may result in atlanto-axial subluxation, resulting in spinal cord injury
Clinical Efficacy
Prospective Validation of the LEMON Score in the Emergency Department (Am J Emerg Med, 2015) [MEDLINE]
Type of Laryngoscope: 84% direct larynogoscope, 16% video laryngoscope
Difficult Intubation: 5.4% with direct larynogoscope, 7.4% with video laryngoscope
Sensitivity: 85.7% with direct laryngoscope, 94.9% with video laryngoscope
Specificity: 47.6% with direct laryngoscope, 40.3% with video laryngoscope
Negative Predictive Value: 98.2% with direct laryngoscope, 9% with video laryngoscope
MACHOCHA Airway Assessment Score
Scoring System (Am J Respir Crit Care Med, 2013) [MEDLINE]
MACOCHA Score Can Be Used to Predict Intubation Failure in Non-Anesthesiologist Trainees ( J Crit Care, 2015) [MEDLINE]
Bag-Valve-Mask (BVM) Ventilation
General Comments
Proper Bag-Valve-Mask Ventilation Allows for Adequate Oxygenation and Ventilation, Giving the Provider Time to Prepare for a Well-Controlled Endotracheal Intubation (see Endotracheal Intubation)
Requirements for Effective Bag-Valve-Mask Ventilation
Proper Mask Seal
Upper Airway Patency
Ability to Provide the Proper Respiratory Rate, Tidal Volume, and Cadence to Achieve Ventilation
Types of Ventilation Bags
Self-Inflating Ventilation Bag (Ambu Bag)
Technique
Bag Has a Recoil Mechanism, Allowing Self-Inflation: does not require an oxygen flow to reinflate
Ambu Bag Has a One-Way Valve to Prevent Rebreathing: however, with a tight mask seal, some spontaneously breathing patients may be able to generate adequate inspiratory pressure to overcome the one-way valve
Oxygen Flows to the Patient When the Bag is Squeezed
Range of Oxygen Delivery: 95-100% FIO2 (with reservoir)
Considerations
Allows Assisted Ventilation in Combination with Supplemental Oxygen: assisted ventilation is useful for patient who may be hypoxemic in combination with hypercapnic (i.e. in type II hypoxemic, hypercapnic respiratory failure)
Should Not Use to Provide Blow By
Requires a Reservoir to Achieve Higher FIO2
Flow-Inflating Ventilation Bag (Anesthesia Bag)
Technique
Flow-Inflating Bag Provides a Constant Flow of Oxygen (When Connected to an Oxygen Source): bag requires a constant oxygen flow to remain inflated
Range of Oxygen Delivery: up to 100% FIO2
Considerations
Allows Assisted Ventilation in Combination with Supplemental Oxygen: assisted ventilation is useful for patient who may be hypoxemic in combination with hypercapnic (i.e. in type II hypoxemic, hypercapnic respiratory failure)
May Use to Provide Blow By
Requires Expertise to Use Effectively (Pediatr Emerg Care, 1997) [MEDLINE]
Technique
General Comments
Position the Mask So that the Top of the Mask is on the Bridge of the Nose and the Bottom of the Mask Covers the Mandibular Alveolar Ridge
Operator Should Not Rest Wrists or the Upper Part of the Mask on the Patients Eyes (to Avoid Inducing a Vagal Response or Causing Corneal Damage
Mask Size
Ensure that Airway Adjunct and Corners of the Mouth are Within the Mask and Allow a Proper Seal
Requires Only a Single Provider to Perform Both Mask Sealing and Bag Ventilation
Place Hand with Thumb Web Resting Against the Mask Connector Tube and Three Fingers Along the Mandible (Using Fingers to Advance the Mandible Forward)
Double-Handed Bag-Valve-Mask Ventilation Technique: generally considered the more effective method (Anesthesiology, 2010) [MEDLINE]
Requires a Second Person to Perform Bag Ventilation
Place Thumb and Index Finger on the Top of Mask and Other Three Fingers Along the Mandible (Using Fingers to Advance the Mandible Forward)
Alternately, the Provider Can Place Their Thenar Eminences on the Top of the Mask and the Other Four Fingers Along the Mandible (Using Fingers to Advance the Mandible Forward): this method may be less fatiguing and provide superior ventilation (Clin Anesth, 2013) [MEDLINE]
Respiratory Rate
Generally, the Respiratory Rate During Bag Ventilation Should Correspond to the Patient’s Expected Acid-Base Status (with Caution to Avoid High Respiratory Rates in the Setting of Hemodynamic Compromise)
During Cardiopulmonary Resuscitation (CPR), Respiratory Rate Should Be <10-12 Breaths/min to Avoid Creating Unnecessary Auto-PEEP Which May Increased Intrathoracic Pressure, Resulting in Decreased Venous Return to the Right Side of the Heart and Decreased Cardiac Output ( Circulation, 2004) [MEDLINE] (Crit Care Med, 2004) [MEDLINE]
During CPR, the Standard Compression:Ventilation Ratio of 30:2 Would Result in a Respiratory Rate of Approximately 8 Breaths/min
Tidal Volume
Generally, a Tidal Volume of 8-10 mL/kg is Adequate
During CPR, Tidal Volume of 5-6 mL/kg is Adequate, Due to Presence of Decreased Cardiac Output (Circulation, 1989) [MEDLINE]
Cricoid Pressure (Sellick’s Maneuver)
Definition
Cricoid Pressure Applied During Bag-Valve-Mask Ventilation Decrease Gastric Insufflation
Cricoid Pressure Applied During Rapid Sequence Intubation Theoretically Decreases Emesis with Aspiration
Maintain Cricoid Pressure Until the Endotracheal Tube Cuff is Inflated
Cautions
Cricoid Pressure is Frequently Applied Improperly and Inconsistently
Cricoid Pressure May Impair Lower Esophageal Sphincter Function
Cricoid Pressure May Result in Esophageal Injury
Cricoid Pressure May Result in Undesirable Movement of the Cervical Spine in Patients with Cervical Spinal Cord Injury
Cricoid Pressure May Contribute to Airway Obstruction, Even When Using a Video Laryngoscope (Ann Emerg Med, 2006) [MEDLINE] (Ann Emerg Med, 2013) [MEDLINE]
Clinical Efficacy
Review of Cricoid Pressure to Prevent Aspiration During Endotracheal Intubation (Emerg Med J, 2005) [MEDLINE]
There is Little Evidence that Cricoid Pressure Decreases the Incidence of Aspiration During Rapid Sequence Intubation
Cochrane Database Systematic Review of Cricoid Pressure During Rapid Sequence Endotracheal Intubation (Cochrane Database Syst Rev, 2015) [MEDLINE]
No Randomized Trials are Available to Evaluate the Efficacy of Cricoid Pressure During Rapid Sequence Endotracheal Intubation
Non-Randomized Trials Suggest that Cricoid Pressure is Not Required to Safely Perform Rapid Sequence Endotracheal Intubation
Recommendations
While Cricoid Pressure May Decrease Gastric Insufflation During Bag-Valve-Mask Ventilation, it is No Longer Recommended for Use During Rapid Sequence Endotracheal Intubation
Difficult Mask Ventilation
General Comments
Difficult Mask Ventilation Occurs in Approximately 5% of Adults (Anesthesiology, 2000) [MEDLINE] and (Anesthesiology, 2006) [MEDLINE]
Difficult Mask Ventilation is Associated with Difficult Intubation
Difficult Intubation Occurs in 30% of Patients with Difficult Mask Ventilation, as Compared to Only 8% of Patients without Difficult Mask Ventilation (Anesthesiology, 2000) [MEDLINE]
Difficult Mask Ventilation is Associated with a “Can’t Intubate, Can’t Ventilate” Scenario
Predictors of Difficult Mask Ventilation: the presence of two of these factors had a 72% sensitivity and 73% specificity (Anesthesiology, 2000) [MEDLINE] and (Anesthesiology, 2006) [MEDLINE]
Age >55 y/o: age is associated with increased pharyngeal resistance to airflow (from choanae to epiglottis) in men, but not in women
BMI >26 kg/m2: obesity is associated with decreased posterior airway space behind the base of the tongue, impaired airway patency during sleep, and is a risk factor for OSA
Lack of Teeth
Presence of Beard
History of Snoring
Limited Mandibular Protrusion
Etiology of Difficult Mask Ventilation (Respir Care, 2015) [MEDLINE]
Management of Difficult Bag-Valve-Mask Ventilation the Edentulous Patient
Reinsert False Teeth in the Edentulous Patient to Improve Mask Seal (Anesth Analg, 2007) [MEDLINE]
Changing Location of the Lower Edge of the Mask to Between the Lower Lip and the Alveolar Ridge May Improve Mask Seal in the Edentulous Patient (Anesthesiology, 2010) [MEDLINE]
Preparation for Intubation
Hemodynamic Optimization
Since Sedative Medications and Positive-Pressure Ventilation Can Both Induce Hypotension During and/or Soon After Endotracheal Intubation, Attention Should Be Paid to Intravenous Volume Resuscitation Prior to Intubation
In Most Cases, Preemptive Intravenous Volume Resuscitation and Vasopressors Can Be Utilized Prior to and/or During Endotracheal Intubation to Mitigate or Completely Avoid the Occurrence of Intubation-Associated Hypotension
Body Positioning for Intubation
Body Positions
Sniffing Position: classical position used for intubation
Atlanto-Occipital Extension with Head Elevation of 3-7 cm
Ramped Position
Use of Towels/Blankets to Elevate the Head and Upper Torso, Creating Horizontal Alignment of the External Auditory Meatus with the Sternal Notch
Clinical Efficacy
Comparison of Sniff and Ramped Positions for Laryngoscopic Intubation in Morbidly Obese Patients (Obes Surg, 2004) [MEDLINE]: randomized trial (n = 60)
Sniffing Position was Achieved by Placing a Firm 7 cm Cushion Under the Patient’s Head: this raised the occiput a standard distance from the table
Ramped Position was Achieved by Placing Blankets Under the Upper Body and Head to Horizontally Align the External Auditory Meatus with the Sternal Notch
Ramped Position Significantly Improved the Laryngeal View, as Compared to the Standard Sniffing Position
Study of Head-Elevated Position During Endotracheal Intubation in Decreasing Airway-Related Complications (Anesth Analg, 2016) [MEDLINE]: retrospective study (n = 528)
Back-Up, Head-Elevated Position During Endotracheal Intubation Decreased Airway-Related Complications (Aspiration, Difficult Intubation, Hypoxemia, Esophageal Intubation), as Compared to Supine Positioning
Preparation of the Endotracheal Tube (ETT)
Purposes of the Endotracheal Tube
Maintenance of Airway Patency in in Patient Who Cannot Do So Independently
Maintenance of Upper Airway Patency During Positive-Pressure Mechanical Ventilation
While Negative-Pressure Ventilation May Induce Upper Airway Collapse (Requiring an Endotracheal Tube to Maintain Airway Patency with Large Negative Airway Pressures), Maintenance of Airway Patency During Positive-Pressure Ventilation is Also Critically Important
Pulmonary Toilet
Maintenance of the Ability to Therapeutically Clear Airways (i.e. Suctioning of Secretions and Blood)
Choice of Endotracheal Tube
Standard Endotracheal Tube
Subglottic Suction Port Endotracheal Tube
Subglottic Suction Port Endotracheal Tubes are Designed to Allow Suctioning of Secretions from Above the Endotracheal Tube Cuff and Theoretically Decrease the Risk of Ventilator-Associated Pneumonia (VAP) (see Hospital-Acquired Pneumonia and Ventilator-Associated Pneumonia, [[Hospital-Acquired Pneumonia and Ventilator-Associated Pneumonia]])
Silver-Coated Endotracheal Tube
Silver Coating is Designed to Decrease Bacterial Growth and Theoretically Decrease the Risk of Ventilator-Associated Pneumonia (VAP) (see Hospital-Acquired Pneumonia and Ventilator-Associated Pneumonia, [[Hospital-Acquired Pneumonia and Ventilator-Associated Pneumonia]])
Structure of the Endotracheal Tube
Anatomic Relationships of the Endotracheal Tube
Physical Preparation of the Endotracheal Tube
Push Top Endotracheal Tube Connector Piece Firmly into the Endotracheal Tube: this is important since insertion of this piece deeper into the endotracheal tube after intubation can be difficult in some cases
Determine if Stylet Will Be Utilized (and if it Should Be Loaded in the Endotracheal Tube)
Standard Aluminum Stylet
Gum Elastic Bougie with Bent Tip
Stiff Metal Stylet (Glidescope Stylet, etc)
Check Endotracheal Tube Cuff Balloon for Integrity: keep the 10 mL syringe available for cuff inflation after intubation
Lubricate Endotracheal Tube Cuff: avoid lubricating endotracheal tube above the cuff, as this can make handling of the tube difficult during intubation
Assure that a Colorimetric Carbon Dioxide Detector is Present
Confirmation of Functioning Suction Set-Up
Yankauer Suction Set-Up Should Be Tested for Function: in some cases with large volumes of anticipated orla material, a second suction set-up should be prepared
Preparation of Backup Airway Management Devices and Personnel with Airway Expertise
Prior to Intubation, Other Airway Devices (Including Bronchoscope, Laryngeal Mask Airway, etc) and Personnel Should Be Readily Available, Should Difficulty Be Encountered During Intubation
Pre-Intubation Airway Assessment is Crucial to Predict the Risk of a Difficult Airway Prior to Intubation, Triggering More Robust Advance Preparation
However, Since a Difficult Intubation Can Be Encountered Unexpectedly in Some Cases, Routine Preparation of Other Equipment is Always Advisable
Confirmation of Adequate Intravenous Access and Intravenous Fluids
Ensure that Patient Has at Least Two Functional Intravenous Lines in Place
Adequate Intravenous Access is Critical to Deliver Sedative and Paralytic Medications Which are Standardly Used to Facilitate Endotracheal Intubation
Loss of Functional Intravenous Lines During the Course of Endotracheal Intubation Can Significantly Delay the Performance of Rapid Sequence Intubation, Resulting in Undesired Prolonged Bag-Valve-Mask Ventilation and Gastric Insufflation
Intravenous Fluids and Vasopressors Should Be Available to Manage Post-Intubation Hypotension
Confirmation of Preparation of Sedative and Paralytic Medications for Intubation
In Addition to Below, Additional Sedatives (Propofol Drip, etc) May Be Desired to Manage Sedation After Intubation: this is critical when a short-acting sedative (such as etomidate) is used in conjunction with a long-acting paralytic agent (such as rocuronium, etc)
Intubation Techniques
Rapid Sequence Intubation (RSI)
Definition and Background
Definition of Rapid Sequence Intubation: period of preoxygenation, folllowed by the nearly simultaneous administration of a sedative and paralytic agent to facilitate rapid and effective endotracheal intubation (with a minimal risk of aspiration)
RSI is the Most Common Emergency Intubation Technique in a Patient Who is Not Anticipated to Have a Difficult Airway: approximately 85% of first endotracheal intubation attempts in emergency departments are performed using RSI (Ann Emerg Med, 2015) [MEDLINE]
Clinical Efficacy
RSI Has Been Demonstrated to Decrease Procedure-Related Complications and Increase the Probability of First-Pass Endotracheal Intubation Success (Crit Care Med, 2012) [MEDLINE] (Ann Am Thorac Soc, 2015) [MEDLINE] (Int J Emerg Med, 2017)[MEDLINE]
RSI Has Been Demonstrated to Have High First-Pass Endotracheal Intubation Success Rates (90%) with Video Laryngoscopy in Patients with Anticipated Difficult Airways: 11% of non-arrest patients had a predicted difficult airway in this study and none required a surgical airway ( J Emerg Med, 2017) [MEDLINE]
Physiologic Basis of Rapid Sequence Intubation
RSI is Based Upon the Observation that, After Preoxygenation, an Average 70 kg Adult Will Maintain SaO2 >90% for 8 min During Apnea (Anesthesiology, 1997) [MEDLINE]
Importantly, Even with Adequate Preoxygenation, this Period of Time is <3 min in Critically Ill, Obese, and Third Trimester Pregnant Patients
This Period of Time is <4 min in Children
Preoxygenation (with the Highest Possible Oxygen Concentration for a Minimum of 3 min) Replaces Nitrogen and Other Gases in the Functional Residual Capacity, Creating an Oxygen Reservoir Which is Depleted During the Subsequent RSI Apneic Period (Anesth Analg, 2017) [MEDLINE]
Importantly, in its Pure Form, RSI Utilizes an Apneic Period Following Administration of Pharmacologic Sedation/Paralytic (Up to the Point of Endotracheal Tube Placement): bag ventilation is avoided during this period, if possible, to avoid gastric insufflation (which may result in aspiration)
Cautions
Since RSI Utilizes the Monitoring of Oxygen Saturation During Apnea, Finger Probe Pulse Oximetry May Lag Behind that of the Central Arterial Circulation in Critically Ill Patients (Can J Anaesth, 1992) [MEDLINE]: for this reason, pulse oximetry must be used with judicious caution during RSI
In Patients with Right-to-Left Shunt (Usually Intrapulmonary Shunt Resulting from Pneumonia, ARDS, etc), Standard Attempts at Preoxygenation May Be Ineffective: these patients may require positive-pressure ventilation with PEEP to promote alveolar recruitment and facilitate adequate preoxygenation
Bag-Valve Mask Ventilation, Noninvasive Positive-Pressure Ventilation, or High-Flow Nasal Cannula Can Be Used to Facilitate Prexoygenation in this Setting
Relative Contraindications to Rapid-Sequence Intubation
Anticipated Difficult Intubation (Especially if Rescue is Anticipated to Be Difficult or Impossible)
Inability to Tolerate Apneic Period During RSI (Due to Severe Hypoxemia, Acidosis, etc)
Seven P’s of Rapid Sequence Intubation
Preparation: 10 min before intubation
Preoxygenation: 5 min before intubation
Pre-Intubation Optimization: 3 min before intubation
Paralysis with Induction: induction
Protection: 30 sec after induction
Placement (Intubation): 45 sec after induction
Post-Intubation Management: 60 sec after induction
Preoxygenation and Continuous Passive Oxygenation During Apnea (“Apneic Oxygenation”)
Preoxygenation (with the Highest Possible Oxygen Concentration for a Minimum of 3 min) Replaces Nitrogen and Other Gases in the Functional Residual Capacity of the Lung, Creating an Oxygen Reservoir Which is Subsequently Depleted During the Subsequent Rapid Sequence Intubation Apneic Period (Anesth Analg, 2017) [MEDLINE]
Since RSI Utilizes the Monitoring of Oxygen Saturation Using Finger Probe Pulse Oximetry During Apnea, Pulse Oximetry Readings May Lag Behind that of the Central Arterial Circulation in Critically Ill Patients (Can J Anaesth, 1992) [MEDLINE]
For This Reason, Pulse Oximetry Must Be Used Judiciously During RSI
In Patients with Right-to-Left Shunt (Usually Intrapulmonary Shunt Resulting from Pneumonia, ARDS, etc), Standard Attempts at Preoxygenation May Be Ineffective
These Patients May Require Positive-Pressure Ventilation with PEEP to Promote Alveolar Recruitment and Facilitate Adequate Preoxygenation
Bag-Valve Mask Ventilation, Noninvasive Positive-Pressure Ventilation (NIPPV), or High-Flow Nasal Cannula (OptiFlow, etc) Can Be Used to Facilitate Prexoygenation in this Setting
Methods to Increase the Reservoir Size
Use of Bag-Valve-Mask Ventilation or Noninvasive Positive-Pressure Ventilation, Both of Which Increase the Mean Airway Pressure
Use of 20 Degree Head-Up Patient Positioning, Which Decreases Dependent Atelectasis (Anaesthesia, 2005) [MEDLINE]
Preoxygenation Techniques Based on Patient Type
Patient with Adequate Spontaneous Ventilation and Cooperative
Bag-Valve-Mask Ventilation with Oxygen at 15 L/min
Squeezing the Bag is Not Necessary, But a Tight Mask Seal Must Be Maintained to Ensure a High FIO2
If the Time is Critically Short and the Bag is Squeezed, Eight Vital Capacity Breaths Can Achieve Adequate Preoxygenation in <1 min
Patient with Adequate Spontaneous Ventilation and Uncooperative/Intolerant of Bag-Valve-Mask Ventilation
Non-Rebreather Mask with Flush Rate Oxygen (≥50 L/min): note that standard 15 L/minflow rates are inadequate for preoxygenation due to entrainment of room air (and decrease in the effective FIO2)
High-Flow Nasal Cannula: can also be considered
Patient with Inadequate Spontaneous Ventilation
Bag-Valve-Mask Ventilation with Oxygen at 15 L/min (Synchronized with Patient’s Respiratory Efforts): avoid pressure >20 cm H2O to minimize the degree of gastric insufflation
Continuous Passive Oxygenation Can Be Used During the RSI Apneic Period for Patients Who Cannot Tolerate the Apneic Period without Developing Hypoxemia
Continuous Passive Oxygenation Slows Depletion of the Oxygen Reservoir Created During Preoxygenation
Apneic Oxygenation Can Potentially Induce Worsening Hypercapnia in Patients with Chronic Hypoventilation (in this Setting, Predominantly Due to the Worsening of V/Q Mismatch)
The Resulting Hypercapnia Can Be Deleterious in Specific Patient Populations, Such as Those with Increased Intracranial Pressure, Metabolic Acidosis, or Pulmonary Hypertension
Continuous Passive Oxygenation Techniques
High-Flow Nasal Cannula (HFNC)
Standard Nasal Cannula (at a High Flow Rate): at flow rate ≥15 L/min
Clinical Efficacy-Preoxygenation and Continuous Passive Oxygenation During Apnea (“Apneic Oxygenation”)
Study of Nasopharyngeal Apneic Oxygenation Using the Four Breath Technique in Surgical Patients (Anaesthesia, 2006) [MEDLINE]
Apneic Oxygenation (Following Preoxygenation Using the Four Breath Technique) Delayed the Onset of Oxygen Desaturation During Apnea
Study of Apneic Oxygenation in During Simulated Laryngoscopy in Obese Patients (J Clin Anesth, 2010) [MEDLINE]
Nasal Apneic Oxygenation Improved the Frequency/Duration of SpO2 ≥95% and Increased the Minimal SpO2 During Prolonged Laryngoscopy in Obese Patients
Transnasal Humidified Rapid-Insufflation Ventilatory Exchange (THRIVE) Increases Apnea Time During Endotracheal Intubation (Anaesthesia, 2015) [MEDLINE]
High-Nasal Cannula Oxygenation (During Preoxygenation and Continuing as Post-Oxygenation During Intravenous Induction of Anaesthesia and Neuromuscular Blockade Until Airway was Secured) Increases the Apnea Time During Endotracheal Intubation
Proposed Mechanism: combines the benefits of classical apneic oxygenation with continuous positive airway pressure and gaseous exchange through flow-dependent deadspace flushing
French PREOXYFLOW Multicenter Randomized Trial of High-Flow Nasal Cannula in Hypoxemic Patients Undergoing Intubation (Intensive Care Med, 2015) [MEDLINE]: multicenter, randomized opne-labelled, controlled trial in 6 French ICU’s (n = 124)
In Terms of the Lowest Level of Oxygen Desaturation, High-Flow Nasal Cannula (Maintained Throughout the Procedure) was Comparable to High-Flow Face Mask Preoxygenation (Removed at End of General Anesthesia Induction)
No Differences were Observed in Difficult Intubations, Ventilator-Free Days, intubation-Related Events, or Mortality Rate
Trial of High-Flow Nasal Cannula During Endotracheal Intubation in ICU Patients (Crit Care Med, 2015) [MEDLINE]: n = 101
High-Flow Nasal Cannula Oxygen Significantly Improved Preoxygenation and Reduced the Prevalence of Severe Hypoxemia, as Compared to Non-Rebreathing Bag Reservoir Facemask Oxygen
Australian Study of Apneic Oxygenation in Helicopter Emergency Service (Ann Emerg Med, 2015) [MEDLINE]
Apneic Oxygenation Decreased the Incidence of Oxygen Desaturation in Patients Undergoing Rapid Sequence Intubation
Study of Apneic Oxygenation in Adult Patients the Emergency Department (Acad Emerg Med, 2016) [MEDLINE]
Apneic Oxygenation Increased First-Pass Intubation Success without Hypoxemia
Randomized Trial of Apneic Oxygenation During Intubation in Critically Ill Adult Patients in the Medical ICU (Am J Respir Crit Care Med, 2016) [MEDLINE]: n= 150
Apneic Oxygenation Had No Effect on the Lowest Oxygen Saturation in Critically Ill Patients
German Randomized Trial of Flow Nasal Cannula Versus Bag-Valve-Mask for Preoxygenation Before Intubation in Subjects With Hypoxemic Respiratory Failure (Respir Care, 2016) [MEDLINE]: n = 40
No Significant Difference in the Mean Lowest Oxygen Saturation During intubation Between the High-Flow Nasal Cannula Group and the Bag-Valve-Mask-Ventilation Group in Patients with Mild-Moderate Hypoxemic Respiratory Failure
However, On Continuous Monitoring, There was a Significant Decrease in Oxygen Saturation During the Apnea Phase Before Intubation in the Bag-Valve-Mask-Ventilation Group, which was Not Observed in the High-Flow Nasal Cannula Group
French OPTINIV Trial of High-Flow Nasal Cannula Combined with Noninvasive Positive-Pressure Ventilation vs Noninvasive Positive-Pressure Ventilation Alone for Preoxygenation Prior to Intubation (Intensive Care Med, 2016) [MEDLINE]: single-center, blinded, randomized trial
Use of Combined High-Flow Nasal Cannula and Noninvasive Positive-Pressure Ventilation for Preoxygenation Prior to Intubation was More Effective in Decreasing Oxygen Desaturation, as Compared to Noninvasive Positive-Pressure Ventilation Alone
Trial of Apneic Oxygenation During Rapid Sequence Intubation in the Emergency Department (Acad Emerg Med, 2016) [MEDLINE]
Apneic Oxygenation During RSI Increased the First Pass Success (without Hypoxemia) Rate: defined as successful intubation with SaO2 remaining ≥90%
Randomized Trial of Apneic Oxygenation During Intubation in a Medical ICU (Am J Respir Crit Care Med, 2016) [MEDLINE]: n = 150
Apneic Oxygenation with High-Flow Nasal Cannula (15 L/min) During Intubation Did Not Increase the Lowest SaO2, as Compared to Usual Care
Systematic Review and Meta-Analysis of Support Techniques to Prevent Oxygen Desaturation in Critically Ill Patients Requiring Endotracheal Intubation ( J Crit Care, 2017) [MEDLINE]
Apneic Oxygenation was Significantly Associated with Higher Minimum Oxygen Saturation During Intubation, as Compared to No Apneic Oxygenation: but there were no significant differences in severe hypoxemia and intubation related-complications
Further Study is Required to Evaluate the Role of Noninvasive Positive-Pressure Ventilation (NIPPV) and High-Flow Nasal Cannula (HFNC)
Systematic Review/Meta-Analysis of Apneic Oxygenation During Emergency Intubation (Am J Emerg Med, 2017) [MEDLINE]
Apneic Oxygenation Significantly Decreased the Incidence of Hypoxemia During Emergency Intubation
Systematic Review/Meta-Analysis of Apneic Oxygenation (J Crit Care, 2017) [MEDLINE]
In Patients Being Intubated for Any Indication Other than Respiratory Failure, Apneic Oxygenation at Any Flow Rate >15 L/min Decreased the Incidence of Desaturation (<90%) and Critical Desaturation (<80%)
Further Trials are Required, Given the Degree of Heterogeneity in Outcomes and Subgroup Analyses
Systematic Review/Meta-Analysis of Apneic Oxygenation (Ann Emerg Med, 2017 [MEDLINE]
Apneic Oxygenation Increased Peri-Intubation Oxygen Saturation, Decreased the Rate of Hypoxemia, and Increased First-Pass Success Rate
Randomized ENDAO Trial of Apneic Oxygenation During RSI in the Emergency Department (Acad Emerg Med, 2017) [MEDLINE]: n = 200
Apneic Oxygenation Had No Effect on the Lowest Mean Oxygen Saturation
However, All Patients were Intubated within 120 sec in this Trial, Likely Diluting Out Any Effect that Apneic Oxygenation Might Have Had
Study of Risk Factors for and Prediction of Hypoxemia During Endotracheal Intubation of Critically Ill Adults (Ann Am Thorac Soc, 2018) [MEDLINE]: n = 426
Predictors of Severe Hypoxemia During Endotracheal Intubation of Critically Ill Adult
Hypoxemic Respiratory Failure as Indication for Intubation (Odds Ratio 2.70; 95% CI: 1.58-4.60)
Lower Oxygen Saturation at Induction (Odds Ratio 0.92 Per 1% Increase; 95% CI: 0.89-0.96 Per 1% Increase)
Younger Age (Odds Ratio 0.97 Per 1-Year Increase in Age; 95% CI: 0.95-0.99 Per 1-Year Increase in Age)
Higher Body Mass Index (Odds Ratio 1.03 Per 1 kg/m2; 95% CI: 1.00-1.06 Per 1 kg/m2)
Race (Odds Ratio 4.58 for White vs Black; 95% CI, 1.97-10.67; Odds Ratio 4.47 for Other vs Black; 95% CI: 1.19-16.84)
Operator with <100 Prior Intubations (Odds Ratio 2.83; 95% CI: 1.37-5.85)
Comprehensive Systematic Review of Randomized Trials for Endotracheal Intubation in Critically Ill Patients (Crit Care, 2018) [MEDLINE]: n = 22 trials
Analyzed 1 Trial Using Pre-Procedure Checklist, 6 Trials of Preoxygenation or Apneic Oxygenation, 3 Trials of Sedatives, 1 Trial of Neuromuscular Blocking Agents, 1 Trial of Patient Positioning, 9 Trials of Video Laryngoscopy, and 1 Trial of Post-Intubation Lung Recruitment
Preoxygenation with Noninvasive Positive-Pressure Ventilation and/or High-Flow Nasal Cannula Before Endotracheal Intubation was Beneficial
Post-Intubation Lung Recruitment Maneuvers May Increase Post-Intubation Oxygenation
No Effect was Found for Use of a Pre-Intubation Checklist, Apneic Oxygenation (on Oxygenation and Hemodynamics), Video Laryngoscopy (on Number and Length of Intubation Attempts), Sedatives and Neuromuscular Blockers (on Hemodynamics)
Video Laryngoscopy was Associated with Severe Adverse Effects in Multiple Trials
Ramped Position Increased the Number of Intubation Attempts
Thiopental Had Negative Hemodynamic Effects
Multicenter, Randomized PreVent Trial of Bag-Valve-Mask Ventilation During Endotracheal Intubation in Critically Ill Patients (NEJM, 2019) [MEDLINE]: n = 401 (7 intensive care units in the US)
Bag-Valve-Mask Ventilation During Endotracheal Intubation Resulted in Improved Oxygenation, as Compared to Apnea Between Induction and Laryngoscopy
Operator-Reported Aspiration Occurred During 2.5% of Intubations in the Bag-Valve-Mask Ventilation Group and During 4.0% in the No-Ventilation Group (P = 0.41)
Incidence of New Opacity on Chest X-Ray in the 48 hrs After Endotracheal Intubation was 16.4% in the Bag-Valve-Mask Ventilation Group and 14.8% in the No-Ventilation Group (P = 0.73)
Randomized PROTRACH Trial of Nasal High-Flow Preoxygenation for Endotracheal Intubation in the Critically Ill Patient (Intensive Care Med, 2019) [MEDLINE]: n = 192 randomized, n = 184 in intent-to-treat analysis
Compared with Standard Bag-Valve-Mask Oxygenation, Preoxygenation with High-Flow Nasal Cannula Did Not improve the Lowest Oxygen Saturation During Intubation in the Non-Severely Hypoxemic Patients, But Led to a Decrease in Intubation-Related Adverse Events
Cricoid Pressure (Sellick’s Maneuver)
Definition
Cricoid Pressure Applied During Bag-Valve-Mask Ventilation Decrease Gastric Insufflation
Cricoid Pressure Applied During Rapid Sequence Intubation (and Maintained Until the Endotracheal Tube Cuff is Inflated) Theoretically Decreases Emesis with Aspiration
Cautions
Cricoid Pressure is Frequently Applied Improperly and Inconsistently
Cricoid Pressure May Impair Lower Esophageal Sphincter Function
Cricoid Pressure May Result in Esophageal Injury
Cricoid Pressure May Result in Undesirable Movement of the Cervical Spine in Patients with Cervical Spinal Cord Injury
Cricoid Pressure May Contribute to Airway Obstruction, Even When Using a Video Laryngoscope (Ann Emerg Med, 2006) [MEDLINE] (Ann Emerg Med, 2013) [MEDLINE]
Clinical Efficacy
Review of Cricoid Pressure to Prevent Aspiration During Endotracheal Intubation (Emerg Med J, 2005) [MEDLINE]
There is Little Evidence that Cricoid Pressure Decreases the Incidence of Aspiration During Rapid Sequence Intubation
Cadaver Study of Airway Maneuvers During Laryngoscopy (Ann Emerg Med, 2006) [MEDLINE]
Bimanual Laryngoscopy Improved the Laryngoscopic View, as Compared to Cricoid Pressure, BURP, and No Manipulation
Cricoid Pressure and BURP Frequently Worsen the Laryngoscopic View
Anatomic MRI Study of the Effects of Cricoid Pressure During Endotracheal Intubation (Anesth Analg, 2009) [MEDLINE]
Cricoid Pressure Results in Compression of the Postcricoid Hypopharynx (Hypopharynx and Cricoid Ring Move Together as an Anatomic Unit)
The Location and Movement of the Esophagus is Irrelevant to the Efficiency of Cricoid Pressure in Regard to Prevention of Gastric Regurgitation into the Pharynx
Compression of the Esophagus Occurs with Midline and Lateral Displacement of the Cricoid Cartilage Relative to the Underlying Vertebral Body
Intubation Bundles Can Decrease the Incidence of Post-Intubation Adverse Effects/Complications in the Intensive Care Unit (Intensive Care Med, 2010) [MEDLINE]: n = 244
Bundle Components
Capnography
Cricoid Pressure
Intravenous Fluid Loading
Preoxygenation with Noninvasive Positive-Pressure Ventilation
Preparation and Early Administration of Sedation
Presence of Two Operators
Protective Ventilation
Rapid Sequence Induction
Vasopressor Use (If Required)
Observational Study of Identification of the Cricothyroid Membrane in Female Subjects Using Palpation (Anesth Analg, 2012) [MEDLINE]
Misidentification of the Cricothyroid Membrane in Female Patients is Common and its Localization is Less Precise in Those Who are Obese
Cochrane Database Systematic Review of Cricoid Pressure During Rapid Sequence Endotracheal Intubation (Cochrane Database Syst Rev, 2015) [MEDLINE]
No Randomized Trials are Available to Evaluate the Efficacy of Cricoid Pressure During Rapid Sequence Endotracheal Intubation
Non-Randomized Trials Suggest that Cricoid Pressure is Not Required to Safely Perform Rapid Sequence Endotracheal Intubation
Randomized IRIS Trial of Cricoid Pressure in Operating Room Rapid Sequence Intubation (JAMA Surg, 2019) [MEDLINE]: n = 3472
Cricoid Pressure Had No Clinical Benefit in Preventing Aspiration, as Compared to Sham Cricoid Procedure
Secondary End Points (Pneumonia, Length of Stay, Mortality) Were Similar Between the Two Groups
Intubation Time was Longer in the Cricoid Pressure Group
Recommendations
While Cricoid Pressure May Decrease Gastric Insufflation During Bag-Valve-Mask Ventilation, it is No Longer Recommended for Use During Rapid Sequence Endotracheal Intubation
Backward-Upward-Rightward (BURP) Maneuver
Definition:
Backward-Upward-Rightward Movement of Larynx by Manipulating the Thyroid Cartilage
Clinical Efficacy
Cadaver Study of Airway Maneuvers During Laryngoscopy (Ann Emerg Med, 2006) [MEDLINE]
Bimanual Laryngoscopy Improved the Laryngoscopic View, as Compared to Cricoid Pressure, BURP, and No Manipulation
Cricoid Pressure and BURP Frequently Worsen the Laryngoscopic View
Mandibular Advancement
May Improve the Laryngoscopic View
Clinical Efficacy
Mandibular Advancement May Improve the Laryngoscopic View During Intubation Performed by Inexperienced Operators (Anesthesiology, 2004) [MEDLINE]
Gum Elastic Bougie
Clinical Efficacy
Randomized Trial of Gum Elastic Bougie vs Endotracheal Tube and Stylet in Difficult Emergency Intubation in the Emergency Department (JAMA, 2018) [MEDLINE]
Gum Elastic Bougie Increased First-Pass Success Rate in Emergency Difficult Intubation, as Compared to Endotracheal Tube and Stylet
Induction and Paralytic Medications for Rapid Sequence Intubation
Video Laryngoscopy is Being Increasingly Used (27% of Cases) as the First Emergency Adult Endotracheal Intubation Attempt Method in Emergency Departments: presumably replacing direct laryngoscopy (Ann Emerg Med, 2015) [MEDLINE]
Advantages
Video Laryngoscope Provides a Superior View, as Compared to Direct Laryngoscopy
Video Laryngoscope Results in Less Cervical Spinal Motion, as Compared to Direct Laryngoscopy: beneficial in patients with unsecured cervical spinal cord injury (J Emerg Med, 2013) [MEDLINE]
Clinical Efficacy
Systematic Review/Meta-Analysis of Video Laryngoscopic vs Direct Laryngoscopic Endotracheal Intubation (Intensive Care Med, 2014) [MEDLINE]: 9 trials (n = 2133) comparing direct laryngoscopic vs video laryngoscopic intubaton in the ICU
Compared to Direct Laryngoscopy, Video Laryngoscopy Reduced the Risk of Difficult Orotracheal Intubation [OR 0.29 (95% confidence interval (CI) 0.20-0.44, p < 0.001)], Cormack 3/4 Grade Airways [OR 0.26 (95% CI 0.17-0.41, p < 0.001)], and Esophageal Intubation [0.14 (95% CI 0.02-0.81, p = 0.03)]
Compared to Direct Laryngoscopy, Video Laryngoscopy Increased the First-Attempt Success Rate [OR 2.07 (95% CI 1.35-3.16, p < 0.001)]
No Statistically Significant Difference was Found for Severe Hypoxemia, Severe Cardiovascular Collapse, or Airway Injury
Randomized Trial of Glidescope Video Laryngoscopy (Crit Care Med, 2015) [MEDLINE]
Glidescope Video Laryngoscopy Improved First-Pass Intubation Success Rates for Urgent Endotracheal Intubation Performed by Pulmonary and Critical Care Medicine Fellow, as Compared to Direct Laryngoscopy
Emergency Department Study of Combined Rapid Sequence Intubation and Video Laryngoscopy ( J Emerg Med, 2017) [MEDLINE]
Approximately 11% of Patients (n = 50) Had a Predicted Difficult Airway
Rapid Sequence Intubation was Demonstrated to Have High First-Pass Endotracheal Intubation Success Rates (90%) with Video Laryngoscopy in Patients with Anticipated Difficult Airways
None of the Patients with Difficult Airway Required Placement of a Surgical Airway
Cormack-Lehane (C-L) View of Glottis
Grade I: full view of glottis
Grade II: partial glottic view
Grade III: minimal glottic view
Grade IV: no view of glottis
Lighted Stylet (Trachlight, etc)
Lighted Stylet Can Be Used for Management of the Difficult Anterior Airway, Where Airway Anatomy is Not Distorted
Device Transilluminates the Glottis Through the Soft Tissues of the Neck
Device Requires Training to Become Proficient with its Use: typically 10-20 intubations are required before proficiency is attained
Hemodynamic Responses with Lighted Stylet are Similar to that with Direct/Video Laryngoscopy
Advantages
Ability to Intubate When the Glottis Cannot Be Visualized Using Direct Laryngoscopy
Decreased Pharyngeal Trauma, as Compared to Direct Laryngoscopy
Produces Less Cervical Spinal Motion than Direct/Video Laryngoscopy: beneficial in patients with cervical spinal cord injury
Disadvantages
Cannot Be Used with Any Airway Anatomic Distortion (Such as Trauma, Tumor, Airway Foreign Body, etc)
Optical Style Uses a Fiberoptic or Video Camera in the Distal End of a Metal Stylet
Stylet Can Be Rigid, Flexible, and/or Directable (Similar to a Bronchoscope)
Disadvantages
Less Useful in the Presence of Any Obstructing Debris in the Airway (Such as Blood, Vomit, Secretions, etc)
Delayed Sequence Intubation (DSI)
Clinical Efficacy
Prospective Trial of Delayed Sequence Intubation in Patients with Delirium (Ann Emerg Med, 2015) [MEDLINE]
Dissociative Dose of Ketamine, Allowing Preoxygenation with High-Flow Nonrebreather Mask or Noninvasive Positive-Pressure Ventilation (NIPPV), Followed by Rapid Sequence Intubation was Safe and Effective
“Awake” Direct Laryngoscopic Intubation
Definition
Definition of Awake Intubation: use of topical anesthesia with light sedation (but without the use of a paralytic agent)
Awake Fiberoptic Intubation is Successful in 88-100% of Difficult Airway Patients (Category B3-B Evidence) (American Society of Anesthesiologists Task Force on Management of the Difficult Airway; Anesthesiology, 2013) [MEDLINE]
Extension of Apnea Time During Endotracheal Intubation
Clinical Efficacy
High-Flow Nasal Cannula May Be Used to Facilitate Oxygenation During Fiberoptic Intubation (Chest, 2015) [MEDLINE]
Nasotracheal Intubation
Disadvantages
Higher Incidence of Maxillary Sinusitis
Confirmation of Endotracheal Tube (ETT) Placement
Auscultation
Technique
Auscultation Over Bilateral Lung Fields and Auscultation Over the Epigastric Area: note that auscultation over the lung field alone is inadequate to confirm endotracheal tube placement (epigastric auscultation is additionally required to confirm a lack of breath sounds in that location)
Clinical Efficacy
Auscultation Alone Mistakenly Identifies Location of the Endotracheal Tube in 16% of Cases (Anesth Analg, 1986) [MEDLINE]
Observation of Chest Wall Movement is an Unreliable Means of Confirming Endotracheal Tube Placement, as Chest Wall Movement May Occur in Esophageal Intubation (Anaesth Intensive Care, 1980) [MEDLINE]
Single-View (Antero-Posterior) CXR Cannot Reliably Confirm Endotracheal Intubation: although it is usually obtained to determine the location of the distal tip of the endotracheal tube
Condensation in Endotracheal Tube (“Fogging”)
Clinical Efficacy
Observation of Condensation (Fogging) in the Endotracheal Tube is an Unreliable Means of Confirming Endotracheal Tube Placement, as Condensation Occurs in the Endotracheal Tube in 83% of Esophageal Intubations (Ann Emerg Med, 1998) [MEDLINE]
Endotracheal Introducer (Eschmann Introducer or Gum Elastic Bougie)
Technique
Bougie is Inserted and Advanced, Feeling the “Clicks” of the Tracheal Rings
Sensitivity of Ring Clicks in the Detection of Endotracheal Intubation: 95%
End-Tidal Carbon Dioxide Detection
General Comments
End-Tidal Carbon Dioxide Detection is Most Accurate Means of Confirming Endotracheal Tube Placement in the Non-Cardiac Arrest Patient: end-tidal carbon dioxide detection is a standard of care practice to confirm appropriate endotracheal intubation
In the Setting of Cardiac Arrest (without a Detectable Pulse), Gas Exchange in the Lungs is Markedly Decreased and Carbon Dioxide May Not Be Detectable Despite Appropriate Endotracheal Tube Positioning in the Trachea (Crit Care Med, 1985) [MEDLINE]
However, the Detection of Carbon Dioxide Which Persists for 6 Breaths in the Cardiac Arrest Patient Indicates Appropriate Endotracheal Tube Positioning in the Trachea
Colorimetric Carbon Dioxide Indicator
Principle/Technique: colorimetric carbon dioxide indicators (Easy Cap II, etc) use litmus paper that tidally changes (breath by breath) from purple to yellow in the presence of exhaled carbon dioxide
ETCO2 <0.5%: purple
ETCO2 0.5-2%: tan
ETCO2 >2%: yellow
False-Positive Results: yellow color change without successful endotracheal intubation
Difficult Intubation with Prolonged Bag Ventilation: air previously pushed into the stomach during bag ventilation may cause yellow color change during the first few breaths
However, if Color Remains Yellow After >4-5 breaths, this Indicates Endotracheal Intubation (Anesth Analg, 1989) [MEDLINE]
Epinephrine (see Epinephrine, [[Epinephrine]]): acidic medication which can cause (non-tidal) yellow color change
Lidocaine (see Lidocaine, [[Lidocaine]]): acidic medication which can cause (non-tidal) yellow color change
Regurgitation of Gastric Contents During Intubation: gastric acid can cause (non-tidal) yellow color change
False-Negative Results: lack of yellow color change even with successful endotracheal intubation
Acute Pulmonary Embolism (PE) (see Acute Pulmonary Embolism, [[Acute Pulmonary Embolism]]): due to decreased pulmonary blood flow and decreased delivery of carbon dioxide to the lungs
Airway Obstruction: indicator may not turn yellow, due to poor carbon dioxide exchange across the obstructed airway (Emerg Med J, 2003) [MEDLINE]
Cardiac Arrest (see Cardiac Arrest, [[Cardiac Arrest]]): due to decreased pulmonary blood flow and decreased delivery of carbon dioxide to the lungs
If Chest Compressions are Adequate (with Adequate Blood Flow to the Lungs), Indicator Will Likely Turn Yellow
Indicator Has Only 69% Sensitivity for Endotracheal Intubation When Used During Cardiopulmonary Resuscitation (Ann Emerg Med, 1992) [MEDLINE]
Clinical Efficacy
Sensitivity of End-Tidal Carbon Dioxide Detection Approaches 100% in Non-Cardiac Arrest Patients
Sensitivity of End-Tidal Carbon Dioxide Detection is Variable in Cardiac Arrest Patients: ranges from 62-100% in various studies (depending on the modality used and the duration of cardiac arrest)
In Non-Cardiac Arrest, Infrared Capnometry and Infrared Capnography Have a 100% Sensitivity/100% Specificity in Detecting Endotracheal Intubation (Intensive Care Med. 2002) [MEDLINE]
In Cardiac Arrest, Infrared Capnometry Has a 88% Sensitivity/100% Specificity in Detecting Endotracheal Intubation (Intensive Care Med. 2002) [MEDLINE]
Waveform Capnography (see Capnography, [[Capnography]])
Principle/Technique: end-tidal carbon dioxide monitor attached to the end of the endotracheal tube uses infrared absorption to detect carbon dioxide
Displays Either Waveform Capnography or Digital Readout
Clinical Efficacy
Sensitivity of End-Tidal Carbon Dioxide Detection Approaches 100% in Non-Cardiac Arrest Patients
Sensitivity of End-Tidal Carbon Dioxide Detection is Variable in Cardiac Arrest Patients: ranges from 62-100% in various studies (depending on the modality used and the duration of cardiac arrest)
In Non-Cardiac Arrest, Infrared Capnometry and Infrared Capnography Have a 100% Sensitivity/100% Specificity in Detecting Endotracheal Intubation (Intensive Care Med. 2002) [MEDLINE]
In Cardiac Arrest, Infrared Capnometry Has a 88% Sensitivity/100% Specificity in Detecting Endotracheal Intubation (Intensive Care Med. 2002) [MEDLINE]
Esophageal Detector Device
Technique
Uses Suction Applied with Syringes (or Bulb Suction Device) to Distinguish the Trachea from Esophagus
Trachea is Rigid and Allows Free Flow of Air into the Device
Esophagus is Collapsible and Does Not Allow Free Flow of Air When Suction is Applied
Transtracheal Ultrasound
Technique
Advantages
Technique Can Be Performed Quickly and Offers Real-Time Information
Technique is Independent of Pulmonary Blood Flow and Does Not Require Lung Ventilation
Clinical Efficacy
Systematic Review/Meta-Analysis of Transtracheal Ultrasound for Confirmation of Endotracheal Tube Placement (Can J Anaesth, 2015) [MEDLINE]: n = 11 studies
Transtracheal Ultrasound is a Useful Tool to Confirm Endotracheal Tube Placement with Acceptable Sensitivity/Specificity: it can be used as a preliminary test in emergency situations before final confirmation by capnography
Sensitivity: 98%
Specificity: 98%
Systematic Review/Meta-Analysis of Transtracheal Ultrasound for Confirmation of Endotracheal Tube Placement (Resuscitation, 2015) [MEDLINE]
Transtracheal Ultrasound is a Useful Tool to Confirm Endotracheal Tube Placement
Sensitivity: 93%
Specificity: 97%
Combination of Tracheal (to Determine Endotracheal Tube Position) and Pleural Ultrasound (to Detect Lung Sliding) is Superior to Auscultation in Determining Endotracheal Tube Location (Anesthesiology, 2016) [MEDLINE]: small, randomized trial
Exclusion of Mainstem Bronchial Endotracheal Tube Placement
Bronchoscopy May Be Used to Confirm Endotracheal Tube Placement
Chest X-Ray (CXR) (see Chest X-Ray, [[Chest X-Ray]])
Technique
CXR May Be Used to Confirm Endotracheal Tube Placement
Depth of Endotracheal Tube Insertion
Technique
Depth of Endotracheal Tube Insertion May Be Used to Confirm Endotracheal Tube Placement
Measurement at Teeth/Gums is Preferred, Since These are Fixed Landmarks
Clinical Efficacy
Endotracheal Tube is Usually Inserted to a Depth of 20-21 cm in Females and 22-23 cm in Males (BMJ, 2010) [MEDLINE]
Transtracheal Ultrasound
Clinical Efficacy
Transtracheal Ultrasound May Be Used to Confirm Ventilation Via Detection of Lung Sliding (Acta Anaesthesiol Scand, 2011) [MEDLINE]: lung sliding observed in only one lung indicates mainstem bronchial intubation
Combination of Tracheal (to Determine Endotracheal Tube Position) and Pleural Ultrasound (to Detect Lung Sliding) is Superior to Auscultation in Determining Endotracheal Tube Location (Anesthesiology, 2016) [MEDLINE]: small, randomized trial
Exchange of Endotracheal Tube
Reasons for Exchange of Endotracheal Tube
Endotracheal Tube Cuff Leak
Discrepancy Between Endotracheal Tube Size and Tracheal Diameter (Especially in a Patient with Tracheomalacia)
Pilot Balloon Line or Cuff Leak: some cases of severed pilot balloon lines can be remedied with a pilot balloon line repair kit (assuming the leak is at/near the pilot balloon itself, allowing the pilot balloon line to be cut and repaired)
Mucous Plugging Due to Inadequate Saline Lavage and Suctioning of the Endotracheal Tube
Example: in postoperative patients with tracheal resection, suctioning is frequently discouraged to avoid disruption of the anastomosis -> these patients can rapidly develop concretions within the endotracheal tube within a matter of days, leading to life-threatening endotracheal tube obstruction with inability to ventilate
Gradual Development of Endotracheal Tube Obstruction is Manifested by an Increasing Peak Airway Pressure-Plateau Pressure Difference
Risks of Endotracheal Tube Exchange
Airway Trauma: since intubation itself contributes to at least some degree of laryngeal and tracheal mucosal injury (even in the best of circumstances), reintubations can be expected to increase the risk of this trauma to some extent
Gum Elastic Bougie (Plastic Stylet): a plastic intubating stylet is the most commonly used method to change a dysfunctional endotracheal tube in a patient whose airway is not anticipated to be difficult
While Endotracheal Tube Change Can Be Performed Blindly (without Concomitant Airway Visualization) in Many Cases, Use of a Direct Laryngoscope/Video Laryngoscope is Highly Recommended in Case the Operator is Unable to Pass the New Endotracheal Tube Through the Vocal Cords
Endotracheal Tube Changer: a plastic hollow-bore tube changer (with adapters to allow either supplemental oxygen therapy or bag ventilation) is preferred in a patient whose airway is anticipated to be difficult
While Endotracheal Tube Change Can Be Performed Blindly (without Concomitant Airway Visualization) in Many Cases, Use of a Direct Laryngoscope/Video Laryngoscope is Highly Recommended in Case the Operator is Unable to Pass the New Endotracheal Tube Through the Vocal Cords
Removal of the Endotracheal Tube with Reintubation by Any of the Methods Described Above: this method can be used by experienced operators in a patient whose airway is not anticipated ot be difficult
Endotracheal Tube (ETT) Movement with Head Positioning
ETT Tip Movement Follows Direction of Chin Movement
Neck Flexion (Chin Downward): ETT tip moves downward
Neck Extension (Chin Upward): ETT tip moves upward
Inability to Intubate
General Comments
Supraglottic Airways Can Be Placed into the Pharynx and Utilized to Provide Oxygenation, Ventilation, and Anesthetic Gas Administration without the Need for Endotracheal Intubation
Use for Respiratory Failure in the Prehospital Setting
Use in Operating Room with/without General Anesthesia
Use of General Airway Management
Use for Emergency Airway Management When Endotracheal Intubation is Unsuccessful
Use as a Conduit for Endotracheal Intubation
Use in the Hospital Setting s Part of the Emergency Airway Algorithm
Use for Emergency Airway Management When Endotracheal Intubation is Unsuccessful
Use as a Conduit for Endotracheal Intubation
Types of Supraglottic Airways
Laryngeal Mask Airway (LMA)
Other Supraglottic Devices
Combitube
Laryngeal Tube
Pharyngeal Tube
Laryngeal Mask Airway (LMA)
Rationale
Laryngeal Mask Airway Rests in the Hypopharynx (Facing the Glottis) Forming a Seal Over the Laryngeal Inlet to Allow Mask Ventilation
Laryngeal Mask Airway is Generally Less Stimulating than Endotracheal Intubation
Laryngeal Mask Airway Does Not Fully Protect Against Aspiration
Laryngeal Mask Airway Does Not Prevent Laryngospasm
Indications
Temporary Ventilation During a Surgical Procedure
During Emergency Airway Management When an Endotracheal Tube is Not Initially Desired or Cannot Be Successfully Placed by Laryngoscopy (Can J Anaesth, 2005) [MEDLINE]
Clinical Efficacy
Laryngeal Mask Airway Can Be Placed by Emergency Medical Response Personnel in the Field with Subsequent Exchange for an Endotracheal Tube During Transport or in the Emergency Department (Prehosp Emerg Care, 2007) [MEDLINE]
Laryngeal Mask Airway Placement During Out-of-Hospital Cardiac Arrest was Safer than Bag-Valve-Mask Ventilation (Am J Emerg Med, 2015) [MEDLINE]
Laryngeal Mask Airway Placed During Out-of-Hospital Cardiac Arrest Resulted in Improved 72 hr Survival, as Compared to Endotracheal Intubation (JAMA, 2018) [MEDLINE]
In the AIRWAYS-2 Trial, Laryngeal Mask Airway Placed During Out-of-Hospital Cardiac Arrest Did Not Impact the 30-Day Mortality Rate (JAMA, 2018) [MEDLINE]
Contraindications to Use of Laryngeal Mask Airway
Esophageal Varices (see Esophageal Varices, [[Esophageal Varices]]): due to risk of hemorrhage or perforation
Gag Reflex (Due to Risk of Emesis/Aspiration)
Gag Reflex Can Be Removed by Using Pharmacologic Paralysis
Gastroesophageal Reflux Disease (GERD) (see Gastroesophageal Reflux Disease, [[Gastroesophageal Reflux Disease]]): since LMA’s do not offer the same degree of protection against aspiration as endotracheal intubation, they generally should not be used in patients with significant gastroesophageal reflux (except in emergency situations)
However, LMA with a Gastric Decompression Port May Be Preferred in this Population
Mild GERD is Probably Not a Contraindication to LMA Use
Obesity with BMI >35 kg/m2, Limited Access to Airway During Surgery, Surgery Expected to Last >90 min, and/or Use of Lithotomy Position During Surgery
When Used for Airway Management During Surgery, Obesity Increases the Amount of Time Required for LMA Insertion (Cochrane Database Syst Rev, 2013) [MEDLINE]: probably not clinically important (although the failure rate of LMA’s is approximately 3-5%)
When Used for Airway Management During Surgery, Obesity Increases the Risk of Gastric Insufflation
When Used for Airway Management During Surgery, Obesity Increases the Peak Inspiratory Pressure (PIP)
When Used for Airway Management During Surgery, Obesity Increases the Risk of Mask Leak, Although it Does Not Appear to Affer Ventilation (Cochrane Database Syst Rev, 2013) [MEDLINE]
When Used for Airway Management During Surgery in Obese Patients, LMA Significantly Improves Oxygenation During and After Surgery: suggests improved pulmonary performance
Oropharyngeal Trauma with Risk of Perforation
Proximal Esophageal Trauma with Risk of Perforation
Upper Airway Foreign Body (see Airway Foreign Body, [[Airway Foreign Body]]): since foreign body can be inadvertently moved into the trachea, resulting in tracheal obstruction
Determinants of Proper Laryngeal Mask Airway Sizing
Patient Anatomy
Laryngeal Mask Airway Size: the usual adult LMA sizes are 3/4/5/6 (most LMA’s are available in full sizes, some are available in half sizes too)
Cuff Inflation
General Sizing
Adult Female (Up to 100 kg): usually size 4
Adult Male (Up to 100 kg): usually size 5
Cuff Volume: appropriate cuff volume is usually provided by the manufacturer (note: cuff overinflation should be avoided to prevent worsening mask seal and/or injury the oropharyngeal mucosa)
Size 4 LMA: approximate cuff volume 30 mL (if larger cuff volume is required to maintain an adequate seal, a larger LMA should be placed or the patient should be endotracheally intubated)
Size 5 LMA: approximate cuff volume 40 mL (if larger cuff volume is required to maintain an adequate seal, a larger LMA should be placed or the patient should be endotracheally intubated)
Laryngeal Mask Airway Insertion
Anesthesia
Adequate Anesthesia (General Anesthesia, Intravenous Sedation) is Required Prior to LMA Inseriton to Avoid Gagging, Coughing, Laryngospasm, Breath Holding, and Straining
However, Some Patients Can Tolerate Placement with Topical Anesthesia Alone
Pharmacologic Neuromuscular Blockade Can Be Utilized to Facilitate LMA Placement: decreases the incidence of gagging, laryngospasm, and coughing
Use of Bronchoscopy for Laryngeal Mask Airway Placement
Bronchoscope Can Be Utilized to Verify Correct Placement of the LMA
Features Which Indicate Correct Laryngeal Mask Airway Placement
Ability to Ventilate without Difficulty: as determined by tidal volume, peak airway pressure <20 cm H20, and chest rise
Normal Capnography
No Leak (with Peak Airway Pressure <20 cm H2O)
Other Aspects
With Correct LMA Positioning, Cuff Inflation May Result in Outward Movement of the LMA and Slight Swelling in the Neck
Technique for LMA Fastrach Insertion
Deflate the LMA Cuff Completely and Lubricate Both Sides with Water-Soluble Lubricant
Standing at the Head of the Bed, with LMA in Dominant Hand, Place Mask on the Palate and Advance Along Palate Until Resistance is Felt
In Proper Position, the Handle Will Have a Slight Upward Angle (and Will Not Be Horizontal)
Inflate LMA Fastrach Cuff to Maintain Seal (Pressure <40 cm H2O)
Check for Proper Ventilation with Bag-Valve and Capnography
Technique for Air-Q Insertion
Similar to Placement of the LMA Classic, Except that the Air-Q Does Not Need to Ride Against the Palate During Insertion: cuff is stiff, so that it does not need to touch the pharyngeal structures during insertion
Inflate Air-Q Cuff to Maintain Seal (Pressure <40 cm H2O)
Difficulties Associated with Laryngeal Mask Airway Placement and Function
Epiglottis Entrapment (Tip of Epiglottis Flipped Over by the Laryngeal Mask)
Management
“Up-Down” Technique: withdraw LMA 2-4 cm without deflating the cuff and then reinsert
Patient Maintaining Upper Airway Tone (Which Prevents Proper Seating of the Mask in the Larynx)
Management
Increase Anesthesia/Sedation
Inadequate Laryngeal Mask Seal
Etiology
Folded Over LMA Cuff
Improper LMA Size
Since Larger Size LMA’s Generally Provide a Better Seal with Lower Cuff Inflation Volumes and Pressures, as Compared to Smaller Size LMA’s, Replacing with a Larger LMA May Remedy the Problem
Inadequate Air in the LMA Cuff
High Peak Airway Pressure
Management
Add Air to Cuff (If Necessary)
Replace with Same or Larger LMA
Transition to Endotracheal Intubation: if unable to maintain adequate seal
Poor Patient Anatomy Contributing to Difficult LMA Placement
Management
Rotational Placement of LMA (with Partially-Inflated Cuff) May Facilitate Placement in Difficult Cases
Placement with the Aid of Ultrasound or Bronchoscopy
Intubating Via the Laryngeal Mask Airway
General Comments
While Intubation Through an Intubating Laryngeal Mask Airway Can Be Achieved Blindly, May Providers Utilize a Bronchoscope to Intubate by this Technique
Endotracheal Tube is Loaded Onto the Bronchoscope and the Bronchoscope/Tube are Passed Through the LMA Channel
Technique for Intubation Via Laryngeal Mask Airway Fastrach
General Comments
LMA Fastrach Contains a Bar Which Elevates the Epiglottis as the Endotracheal Tube Passes Through the Aperture
LMA Fastrach Has a Ramp in the Intubating Channel Which Directs the Endotracheal Tube Anteriorly and Centrally to Facilitate Movement into the Trachea (and Minimize Damage to Glottis)
LMA Fastrach May Use Either a Standard Endotracheal Tube or a Proprietary Non-Kinking Endotracheal Tube
If Standard Endotracheal Tube is Used, Warm it Beforehand (to Increase Flexibility) and Insert it onto a Bronchoscope, then Insert the Bronchoscope/Endotracheal Tube Asssembly into the LMA with the Curvature Reversed (To Facilitate the Tip Exiting the LMA at a Shallow Angle and Entering the Trachea)
At 15 cm Depth, an Endotracheal Tube Emerges from the LMA and Lifts the Epiglottis Elevating Bar
Proprietary Endotracheal Tube
Vertical Black Line Should Face the Operator (This Aligns the Bevel with the Vocal Cords)
Horizontal Black Line Marks the 15 cm Insertion Depth (at Which the Tube Exits the LMA)
Perform a “Skillet Lift” Using the LMA Fastrach Handle to Align the Cuff with the Glottic Opening
Gently Advance the Endotracheal Tube: if resistance is encountered, glottic alignment is not correct
When Endotracheal Placement is Confirmed, Deflate the LMA Fastrach Cuff to Relieve the Mucosal Pressure
After Intubation, Carefully Remove the LMA Fastrach
LMA Fastrach May Remain in Place for Several Hours Prior to Removal
Technique for Intubation Via the Air-Q
General Comments
Large Adult Size Air-Q Can Accomodate a 8.5 Endotracheal Tube
Air-Q Has a Mild Curvature and is Designed to Utilize a Standard Endotracheal Tube: it does not require a specialized non-kinking endotracheal tube
Lubricate the Endotracheal Tube with Water-Soluble Lubricant
Remove the 15 mm Bag Connector and Insert the Endotracheal Tube into the Lumen
Move Endotracheal Tube Up and Down in the Lumen to Lubricate the Channel
Advance the Endotracheal Tube into the Trachea
May Need to Gently Insert/Withdraw the Air-Q to Facilitate Endotracheal Tube Passage
Inflate the Endotracheal Tube Cuff
When Endotracheal Placement is Confirmed, Deflate the Air-Q Cuff to Relieve the Mucosal Pressure
After Confirmation of Endotracheal Tube Placement, Remove the Air-Q Using the Removal Stylet: this decreases the risk of damage to the pilot balloon
Air-Q May Remain in Place for Several Hours Prior to Removal
Ventilation Technique
Spontaneous Ventilation
Advantages
Better Tolerance of LMA Malpositioning
Decreases Air Leak Around the LMA
Limits the Development of Gastric Insufflation
Positive-Pressure Ventilation
Pressure-Limited Ventilation (Pressure Support, Pressure Control) is Used More Commonly than Volume-Limited Ventilation, Since the LMA Does Not Seal the Pharynx and There is Leak Around the Device (with Resulting Gastric Insufflation and/or Inadequate Ventilation)
LMA’s are Generally Designed for Use with Peak Airway Pressure <20 cm H2O: higher peak airway pressure may result in LMA leak and/or gastric insufflation
LMA ProSeal was Designed for Use with Somewhat Higher Peak Airway Pressures (<25 cm H2O): cuff has a posterior extension which provides a “double seal”
Advantages
Allows Control of Respiratory Rate and Tidal Volume
Ventilation is Assured During Deeper Levels of Sedation
Adverse Effects/Complications
General Comments
Laryngeal Mask Airway-Associated Complications are Low: occur in approximately 0.15% of cases (Anesth Analg, 1996) [MEDLINE]
High Laryngeal Mask Airway Cuff Pressure May Increase the Risk of Airway Complications (Anesthesiology, 2010) [MEDLINE] (Can J Anaesth, 2013) [MEDLINE]
Laryngeal Mask Airway May Function to Some Extent to Seal Off the Trachea from Aspiration of Regurgitated Gastric Contents
However, Vomiting or Increase in Intragastric Pressure Can Overcome this Protection, Resulting in Aspiration (Br J Anaesth, 2002) [MEDLINE]
Laryngeal Mask Airway Decreases Lower Esophageal Sphincter Tone Via a Reflex Mechanism (Br J Anaesth, 1992) [MEDLINE]: this is similar to the reflex which occurs while swallowing a bolus of food
This Results in Increased Acid Reflux into the Esophagus During Lithotomy and Trendelenburg Positioning (Can J Anaesth, 1999) [MEDLINE]
Prevention
Patient Selection
Assess Risk Factors for Aspiration
Assess Lung/Chest Wall Compliance for Factors that Might Increase Peak Airway Pressure
Procedure Selection (Accounting for Expected Patient Positioning Which Might Contribute to Aspiration)
Maintenance of Adequate Depth of Anesthesia During Laryngeal Mask Airway Insertion and During Surgery
Minimization of Peak Airway Pressure During Mechanical Ventilation to Avoid Gastric Insufflation
Ensure Adequate Reversal of Neuromuscular Blockade Prior to Emergence from General Anesthesia
Use of Laryngeal Mask Airway with Gastric Decompression Port (Anaesthesia, 2011) [MEDLINE]
Incision of the Cricothyroid Membrane with Insertion of a Tube to Establish an Artificial Airway
History
Cricothyroidotomy (Initially Referred to as “High Tracheostomy”) was First Performed by Dr. Chevalier Jackson in 1909: cases were often performed due to upper airway obstruction related to diphtheria
Due to Complications of Tracheal Stenosis, He Later Criticize the Use of Cricothyroidotomy
Epidemiology
The Historical Rate of Cricothyroidotomies Has Been Demonstrated to Decrease Over Time, Attributable to Several Factors (Acad Emerg Med, 1998) [MEDLINE]
Adoption of Rapid Sequence Intubation (RSI)
Decreased Concern Related to the Perfomance of Endotracheal Intubation in Trauma Patients Without Initial Evaluation to Rule Out Cervical Spinal Cord Injury
Establishment of Emergency Medicine Residencies with the Presence of 24 hr Supervising Emergency Medicine Faculty
Rates of Cricothyroidotomy Might Be Expected to Continue to Decline with the Increased Use of Video Laryngoscopy and the Advancement of Other Airway Management Techniques
In a Single-Center Retrospective Study, Cricothyroidotomy Comprised 1% of All Emergency Department Intubations (and 10.9% of All Prehospital Intubations) (J Emerg Med. 2003) [MEDLINE]
Indications
General Indications for Cricothyroidotomy
Inability to Intubate Patient
Contraindication to Intubation
Upper Airway Obstruction: note that cricothyroidotomy will only be effective if the airway obstruction is proximal to the site of the cricothyroidotomy
Specific Etiologies Requiring Cricothyroidotomy (Acad Emerg Med, 1998) [MEDLINE]
Facial Fracture: 32% of cases
Emesis in the Airway: 32% of cases
Failure of Intubation (in the Absence of Clinical Issues): 11% of cases
Traumatic Upper Airway Obstruction: 7% of cases
Relative Contraindications
Childhood (<5-12 y/o): since the childhood airway is funnel-shaped with the narrowest aspect at the cricoid ring rather than at the vocal cords (with an increased risk of developing subglottic stenosis) and procedure can damage the relatively soft cricoid cartilage in children
Coagulopathy (Uncontrolled) (see Coagulopathy, [[Coagulopathy]])
Remote Radiation Therapy (or Other Deformity/Scarring) Which May Alter the Upper Airway Anatomy
Tumor
Intrinsic Airway Tumor
Technique
Cricothyroid Membrane Lies Below the Thyroid Cartilage and Above the Cricoid Cartilage
Laterally on Both Sides of the Cricothyroid Membrane are the Cricothyroideus Muscles
Location of the Cricothyroid Membrane by Palpation Can Be Difficult Even for Experienced Providers with Surgical Airway Experience (Success Rates ≤50%) (Can J Anaesth, 2016) [MEDLINE]: this is especially true in obese patients (Anaesthesia, 2015) [MEDLINE]
Location of the Cricothyroid Membrane by Ultrasound: may be useful, but studies are lacking
Cook Melker Kit Procedure
Components: 6 mL syringe, 18 gauge needle with overlying catheter, a guide wire, a tissue dilator, cuffed cricothyroidotomy tube, and tracheostomy tape
Time Required: 1-4 min (Anaesthesist, 2003) [MEDLINE]
Steps
Stand at the Patient’s Right Side
Immobilize the Larynx by Holding the Thyroid Cartilage with the Left Hand
With Right Hand, Insert Needle (Pointed at a Downward 45 Degree Angle) into the Cricothyroid Membrane with Syringe Filled with Saline, Aspirating as You Go: watch for air bubbles into the syringe, indicating that you are in the trachea
Remove Syringe and Pass Wire Through the Needle
Remove Needle
Make a 1-2 cm Horizontal Incision Through the Skin and Cricothyroid Membrane: take care to not incise too deep (which may injury the posterior tracheal wall) or with the blade oriented superiorly (which may injure the vocal cords)
Thread the Dilator/Tube Assembly Over the Wire into the Airway
Remove the Dilator and Wire
Secure Airway Tube with Tracheostomy Tape and Attach to Either Bag Ventilation or Mechanical Ventilator
Complications
Early Adverse Effects/Complications
Bleeding: usually occurs and can be controlled with direct pressure/packing
Cricoid Cartilage Fracture
Infection
Passage of Tube into Extratracheal Location
Posterior Tracheal Wall Perforation
Thyroid Cartilage Fracture
Tracheal Ring Fracture
Unintentional Tracheostomy
Late Adverse Effects/Complications
Subglottic Stenosis
Voice Changes
Adverse Effects/Complications of Endotracheal Intubation
General Comments
Significant Morbidity/Mortality (as Well as Medical Malpractice) is Related to Adverse Events/Complications of Airway Management and Endotracheal Intubation
Inadequate Ventilation, Esophageal Intubation, and Difficult Endotracheal Intubation are the Most Common Mechanisms of Respiratory Adverse Events/Complications Associated with Endotracheal Intubation/Mechanical Ventilation by Anesthesiologists (Anesthesiology, 1991) [MEDLINE]
US Review of Airway Complications in Patients Undergoing General Anesthesia (Anesthesiology, 2009) [MEDLINE]: mortality rate of 1.1 per million
British National Health Service Review of Major Airway Complications in Patients Undergoing General Anesthesia (Br J Anaesth. 2011) [MEDLINE]: 46 events per million (associated mortality of 5.6 per million)
British National Health Service Review of Major Airway Complications Noted that 25% of Reported Airway Events Occurred in the Intensive Care Unit or Emergency Department (and 61% of Those Events Resulted in Permanent Patient Harm or Death) (Br J Anaesth, 2011) [MEDLINE]
Risk Factors for Adverse Events/Complications of Airway Management and Endotracheal Intubation
Multiple Intubation Attempts
In Emergency Endotracheal Intubations Performed in Critically Ill Patients Suffering Deterioration, As Compared to ≤2 Attempts, Repeated Attempts (≥3) were Significantly Associated with Increased Incidence of Hypoxemia (11.8% vs 70%), Regurgitation of Gastric Contents (1.9% vs 22%), Aspiration of Gastric Contents (0.8% vs 13%), Bradycardia (1.6% vs 21%), and Cardiac Arrest (0.7% vs 11%; P<0.001) (Anesth Analg, 2004) [MEDLINE]
In Emergency Department Intubations, ≥3 Intubation Attempts were Associated with a Significantly Increased Rate of Adverse Events (35% vs 9%) (Ann Emerg Med, 2012) [MEDLINE]
Patients Requiring 1 Intubation Attempts Had a 14.2% Adverse Event Rate, Patients Requiring 2 Intubation Attempts Had a 47.2% Adverse Event Rate, and Patients Requiring 3 Intubation Attempts in the Emergency Department Had a 63.6% Adverse Event Rate (Acad Emerg Med, 2013) [MEDLINE]
Intubation Bundles Can Decrease the Incidence of Post-Intubation Adverse Effects/Complications in the Intensive Care Unit (Intensive Care Med, 2010) [MEDLINE]: n = 244
Bundle Components
Capnography
Cricoid Pressure
Intravenous Fluid Loading
Preoxygenation with Noninvasive Positive-Pressure Ventilation
Preparation and Early Administration of Sedation
Presence of Two Operators
Protective Ventilation
Rapid Sequence Induction
Vasopressor Use (If Required)
Immediate Adverse Effects/Complications of Endotracheal Intubation and Invasive Mechanical Ventilation (Manifest During or Immediately Following Endotracheal Intubation)
Cardiac Arrest (see Cardiac Arrest) In Emergency Endotracheal Intubations Performed in Critically Ill Patients Suffering Deterioration, the Rate of Cardiac Arrest was 1 in 50 and was Associated with Hypoxemia in 83% of Cases (and 63% of the Cases of Hypoxemia were Associated with Inadvertent Esophageal Intubation) (Anesth Analg, 2004) [MEDLINE]
Early Post-Intubation Cardiac Arrest Occurred in Approximately 2% of Emergency Department Intubations and was Associated with Preintubation Systolic Hypotension (PLoS One, 2014) [MEDLINE]
Pulseless Electrical Activity (PEA) (see Pulseless Electrical Activity) Typically Occurs Due to Initiation of Positive-Pressure Ventilation in a Patient with Shock
Pulseless Electrical Activity was the Most Common Rhythm in Post-Intubation Early Cardiac Arrest (Occurred in 78.1% of Cases) (PLoS One, 2014) [MEDLINE]
Large Airway Mucous Plugging, Resulting in Obstructive Atelectasis
Diagnosis
Bronchoscopy (see Bronchoscopy): useful to rapidly assess for large airway mucous plugging
Clinical
Increased Peak Airway Pressure (PIP) on Mechanical Ventilator
Unilaterally Absent Breath Sounds: on the obstructed side
Auto-Positive End-Expiratory Airway Pressure (Auto-PEEP or Intrinsic PEEP) (see PEEP+Auto-PEEP) (Am Rev Respir Dis, 1982) [MEDLINE]
Risk Factors for the Development of Auto-PEEP
High Minute Ventilation (VE)
High Minute Ventilation (VE) May Due to Any/All of the Following
High Set Respiratory Rate (RR) on the Ventilator
High Patient-Driven Respiratory Rate (RR) (Due to Fever, Sepsis, Pain, Agitation, Anxiety, etc)
High Set Tidal Volume (VT) on the Ventilator
High Patient-Driven Tidal (VT) (Due to Fever, Sepsis, Pain, Agitation, Anxiety, etc)
High Inspiratory/Expiratory (I/E) Ratio
While the “Normal” I/E Ratio for a Normal Spontaneously-Ventilating Patient is 1:2, a “High” I/E Ratio Cannot Be Numerically Defined for All Patients, Since Patients with Significant Airway Resistance (i.e. Airway Obstruction Due to Status Asthmaticus, etc) May Develop Auto-PEEP Even at a Relatively “Normal” I/E Ratio
Time-Constant Inequality of Lung Units
Some Lung Units (Especially in the Setting of Airway Obstruction) Empty Heterogeneously, Resulting in the Development of Auto-PEEP Even at Relatively Low Minute Ventilation (VE)
Expiratory Flow Resistance (Due to Small Endotracheal Tube, Ventilator Tubing, etc): impairs exhalation
Airway Obstruction with Expiratory Flow Limitation (Due to Asthma, COPD, etc): impairs exhalation
Altered Respiratory System Compliance (Due to Expiratory Muscle Activity): impairs exhalation
Altered Respiratory System Compliance May Also Interfere with the Accurate Measurement of Auto-PEEP (Am J Respir Crit Care Med, 1995) [MEDLINE]
Physiologic/Clinical Effects of Auto-PEEP
Next Ventilator Breath is Triggered Before the Airway Pressure Returns to Baseline (i.e. Zero)
Decreased Venous Return to the Right Side of the Heart, Resulting in Decreased Cardiac Output
Increased Risk of Barotrauma: see below
Patient is Required to Overcome the Residual Positive Airway Pressure to Generate a Negative Pressure Deflection to Trigger the Next Ventilator Breath, Increasing the Work of Breathing
Introduction of Errors in the Estimation of the Mean Alveolar Pressure and Static Lung Compliance (Am J Respir Crit Care Med, 1996) [MEDLINE]
Diagnosis of Auto-PEEP
Auscultation (or Palpation) of Continued Expiratory Airflow at the Point When the Next Ventilator Breath is Initiated
Physical Exam Has a Positive Predictive Value of 95% and a Negative Predictive Value of 58% in Detecting the Presence of Auto-PEEP, Suggesting that it is Useful to Diagnose Auto-PEEP, But Not to Rule Out Auto-PEEP (Am J Respir Crit Care Med, 1999) [MEDLINE]
Observation of Pressure Waveform Not Returning to Baseline Between Breaths
Expiratory Hold (0.5-1.0 sec) on Ventilator (i.e. Occlusion of Exhalation Port on Ventilator)
Increase the Inspiratory Flow Rate and/or Decrease the Respiratory Rate (RR) to Decrease the Inspiratory/Expiratory (I/E) Ratio (to 1:3, 1:4, 1:5, etc)
This Served to Lengthen the Expiratory Time, Allowing a Longer Period to Expel the Gas in the Lung
In Rare Cases, Transient Removal of the Patient from the Ventilator Can Allow Gas Emptying from the Lungs
“Permissive Hypercapnia” (Decrease the Respiratory Rate and/or Tidal Volume to Purposely Underventilate the Patient): allowing the pCO2 to increase to as much as 70-100 mm Hg
History
Permissive Hypercapnia was First Utilized in Status Asthmaticus
Rationale
Decrease in Tidal Volume (VT) Will Decrease the Total Volume of Gas Which Must Be Exhaled During Expiration
Decrease in the Respiratory Rate (RR) Will Allow a Longer Expiratory Time
Contraindications
Contraindicated in Presence of Increased Intracranial Pressure (see Increased Intracranial Pressure, [[Increased Intracranial Pressure]])
Technique
Maintenance of pH >7.2 Can Be Achieved with Either Sodium Bicarbonate (or Tris-Hydroxymethyl Aminomethane, THAM) Administration: however, sodium bicarbonate administration may be ineffective in increasing the pH in this setting
Many Patients Require Deep Sedation (and Paralysis, if Necessary) to Maintain a Low Minute Ventilation (VE)
Measures to Decrease the Metabolic Rate (Decreasing Carbon Dioxide Production and Therefore, the Ventilatory Demand)
Decrease Carbohydrate Intake
Treat Anxiety/Agitation with Sedation (and Paralysis, if Necessary)
Treat Fever
Treat Shivering
Measures to Decrease the Expiratory Flow Resistance
Use Larger Diameter Endotracheal Tube
Frequent Suctioning
Use Synchronized Intermittent Mandatory Ventilation (SIMV) Mode, Instead of Assist Control: prevents breath stacking
Application of Extrinsic PEEP (Nearly Up to the Level of the Intrinsic PEEP): this may decrease the amount of auto-PEEP
Mechanisms
Decreases Dynamic Airway Compression
Counteracts the Critical Closing Pressure that Causes Small Airway Collapse in Asthma/COPD
Technique
Add PEEP to the Point Just Below Where the PIP and Plateau Pressures Start to Increase
Use Extrinsic PEEP in an Amount Less than Approximately 80% of the Amount of Auto-PEEP
Clinical Efficacy
The Efficacy of Applied PEEP in Decreasing Auto-PEEP Depends on the Level of PEEP Used and Whether Flow Limitation is Present
Applying PEEP to Lungs Without Flow Limitation Simply Distends Them Further and is Ineffective
Barotrauma
Definitions
Barotrauma: alveolar injury due to high pressure during mechanical ventilation
Volutrauma alveolar injury due to overdistention of the lung during mechanical ventilation
Epidemiology
Mechanical Ventilation Itself Increases the Risk of Barotrauma
Development of Auto-PEEP During Mechanical Ventilation Further Increases the Risk of Barotrauma
Noninvasive Positive-Pressure Ventilation Probably Has a Similar Mechanism of Barotrauma as Invasive Mechanical Ventilation, But the Rate of Barotrauma is Lower (Due to Use of Lower Pressures) (Rev Bras Ter Intensiva, 2008) [MEDLINE]
Incidence of Barotrauma in ARDS is Approximately 10% (NEJM, 2000) [MEDLINE] (Intensive Care Med, 2002) [MEDLINE] (NEJM, 2004) [MEDLINE]
Physiology
Ventilator Factors Which May Cause Alveolar Overdistention, Resulting in Alveolar Rupture
Positive-Pressure Ventilation Itself
All Patients on Mechanical Ventilation are at Risk for Barotrauma, Since Positive-Pressure Ventilation Increases the Transalveolar Pressure (Alveolar Pressure – Adjacent Interstitial Space Pressure)
High Tidal Volume
Inappropriately High Tidal Volume Set During Bag-Valve-Mask Ventilation
Inappropriately High Tidal Volume Set on Ventilator (During Volume-Cycled Ventilation)
Inadvertent Right (or Left) Mainstem Intubation with Inappropriately High Tidal Volume Applied to a Single Lung
High Plateau Pressure (Pplat)
Plateau Pressure is the Pressure Applied to the Small Airways and Alveoli
While There is No Safe Plateau Pressure Under Which Barotrauma Does Not Occur, the Greatest Risk of Barotrauma Occurs with Plateau Pressure ≥35 cm H2O or Static Compliance <30 mL/cm H2O (Intensive Care Med, 2002) [MEDLINE]
High Peak Inspiratory Pressure (PIP)
There is No Absolute Safe Threshold for PIP Under Which Barotrauma Does Not Occur
PIP is Probably Less Associated with the Risk of Barotrauma than the Plateau Pressure, Although Some Data are Conflicting (Crit Care Med, 1983) [MEDLINE] (Chest, 1994) [MEDLINE] (Am J Respir Crit Care Med, 2002) [MEDLINE]
High Positive End-Expiratory Pressure (PEEP)
High PEEP Probably Only Contributes to an Increased Risk of Barotrauma When Open Lung Ventilation (High PEEP or Recruitment Maneuvers, Usually with Lung Protective Measure Such as Low Tidal Volume with Plateau Pressure ≤30 cm H2O) Strategies are Ineffective in Recruiting Atelectatic Lung Units in ARDS or When Lung Protective Ventilation (Low Tidal Volume with Plateau Pressure ≤30 cm H2O) is Not Utilized
Mode of Ventilation (Volume-Cycled vs Pressure-Cycled): does not appear to be associated with the risk of barotrauma (PLoS One, 2011) [MEDLINE] (Cochrane Database Syst Rev, 2015) [MEDLINE]
Disease Factors Which May Cause Alveolar Overdistention, Resulting in Alveolar Rupture
Acute Respiratory Distress Syndrome (ARDS): due to decreased lung compliance, resulting in increased alveolar pressure (Am J Respir Crit Care Med, 1995) [MEDLINE] (Intensive Care Med, 2004) [MEDLINE]
Asthma (see Asthma, [[Asthma]]): due to dynamic hyperinflation, resulting in increased alveolar pressure (Intensive Care Med, 2004) [MEDLINE]
Chronic Obstructive Pulmonary Disease (COPD) (see Chronic Obstructive Pulmonary Disease, [[Chronic Obstructive Pulmonary Disease]]): due to dynamic hyperinflation, resulting in increased alveolar pressure
Interstitial Lung Disease (ILD) (see Interstitial Lung Disease, [[Interstitial Lung Disease]]): due to decreased lung compliance, resulting in increased alveolar pressure (Intensive Care Med, 2004) [MEDLINE]
Langerhans Cell Histiocytosis (see Langerhans Cell Histiocytosis, [[Langerhans Cell Histiocytosis]]): due to cystic lung disease, resulting in escape of air
Necrotizing Pneumonia (see Necrotizing Pneumonia and Pulmonary Gangrene, [[Necrotizing Pneumonia and Pulmonary Gangrene]]): due to cavitating lung disease, resulting in escape of air
Pneumocystis Jirovecii Pneumonia (see Pneumocystis Jirovecii, [[Pneumocystis Jirovecii]]): due to cavitating lung disease, resulting in escape of air
Other Factors Which May Cause Alveolar Overdistention, Resulting in Alveolar Rupture
Bronchoscopy During Mechanical Ventilation: may result in prolonged increase in plateau pressure
High Tidal Volume During Bag-Valve-Mask Ventilation: may result in prolonged increase in plateau pressure
High Tidal Volume Ventilation in Pneumonectomy Patient: may result in prolonged increase in plateau pressure
Right Mainstem Bronchial Intubation: may result in prolonged increase in plateau pressure
Severe Central Airway Obstruction: may result in prolonged increase in plateau pressure
Anatomic Path of Air Dissection
Air from Torn Alveolus Enters the Perivascular Interstitium, Dissecting Along the Bronchovascular Sheath into the Pulmonary Hila and Subsequently Into the Mediastinum, Causing Pneumomediastinum (in the Setting of Blunt Trauma to the Lung, This Tracking of Air Has Been Termed the “Macklin Effect”) (see Pneumomediastinum, [[Pneumomediastinum]]) (Chest, 2001) [MEDLINE]
From Pneumomediastinum, Air Can Dissect Upward into the Soft Tissues of the Neck (Causing Subcutaneous Emphysema), into the Pleural Spaces (Causing Pneumothorax on Either Side), Inferiorly into the Peritoneum (Causing Pneumoperitoneum), or Rarely, into the Pericardium (Causing Pneumopericardium)
Diagnosis
Bronchoscopy (see Bronchoscopy, [[Bronchoscopy]]): useful to rapidly identify and treat large airway mucous plugging and identify endotracheal tube tip location
Chest X-Ray (CXR)/Chest CT (see Chest X-Ray, [[Chest X-Ray]] and Chest Computed Tomography, [[Chest Computed Tomography]]): useful to exclude pneumothorax and diagnose atelectasis
Thoracic Ultrasound (see Thoracic Ultrasound, [[Thoracic Ultrasound]]): useful to exclude pneumothorax
Clinical Harbingers of Possible Barotrauma
Bleb (intrapleural Air Collection) (see Bullae, [[Bullae]]): this represents a form of interstitial emphysema
Venous Air Embolism (see Air Embolism, [[Air Embolism]]) (Am Rev Respir Dis, 1993) [MEDLINE]
Epidemiology
Uncommon Manifestation of Barotrauma
Prevention
General Comments: while both barotrauma and volutrauma likely contribute to alveolar injury, limiting alveolar pressure appears to be the most effective measure to prevent barotrauma
Avoid Dynamic Hyperinflation (in Asthma and COPD): hyperinflation is progressive (dynamic) since air accumulates in the lung with each breath as a result of a failure to achieve complete exhalation before the onset of the next breath
Treatment of Bronchospasm (see Obstructive Lung Disease, [[Obstructive Lung Disease]]): usually with bronchodilators, corticosteroids, etc
Use Low Tidal Volume Ventilation: reduces amount of air in each breath which needs to be exhaled
Use Short Inspiratory Time/Longer Expiratory Time: allows adequate time for expiration
Use Lower Respiratory Rate (Even Using Permissive Hypercapnia in Some Cases)
Maintain Low Plateau Pressure (Pplat ≤30 cm H2O): being cautious to avoid Pplat >35 cm H2O
Targeting Even Lower Plateau Pressures May Further Reduce the Risk of Barotrauma (Am J Respir Crit Care Med, 1999) [MEDLINE]
In in Systematic Review and Meta-Analysis, Use of Neuromuscular Blockade is Associated with a Decreased Risk of Barotrauma (Crit Care, 2013) [MEDLINE]
Use Appropriate Amounts of PEEP
PEEP is Standardly Titrated Per the FIO2/PEEP Table as was Used in the 2000 Study on Low Tidal Volume Ventilation (N Engl J Med, 2000) [MEDLINE]
Use Low Respiratory Rate: even using permissive hypercapnia in some cases
Management-General
Since the Occurrence of Any Barotrauma in the Setting of Mechanical Ventilation for ARDS Suggests Either a Patient with More Severe ARDS (at Higher Mortality Risk) or a Suboptimal Ventilation Strategy (or Both), the First Priority Should Be Measures to Optimize the Ventilation Management
Use Lung Protective/Low Tidal Volume Ventilation (Ideally to 6 mL/kg PBW) and Adjust the Respiratory Rate to the Minimum Required to Maintain an Adequate pH (i.e. Permissive Hypercapnia)
Use Sedation and Pharmacologic Paralysis as Necessary to Maintain Ventilator Parameters
Avoid Patient-Ventilator Dyssynchrony and Overbreathing
Use Sedation and Pharmacologic Paralysis as Necessary to Maintain Synchrony
Decrease Both the Auto-PEEP and Extrinsic PEEP (As Allowed by Oxygenation)
Target a Low I/E Ratio (Around 0.33) to Maintain a Low Mean Airway Pressure
Shorten Inspiratory Time with Higher Inspiratory Flow Rate (Around 70-100 L/min)
Lengthen Expiratory Time
Avoid Inverse Ratio Ventilation
Use a Low Compressible Volume (Non-Disposable) Ventilator Circuit
Chest Tube is Generally Required for Mechanical Ventilation-Associated Pneumothorax, Since >30% of These Progress to Tension Pneumothorax
Management-Chest Tube with Air Leak (i.e. Bronchopleural/Alveolopleural Fistula) (see Bronchopleural Fistula, [[Bronchopleural Fistula]]): ventilator changes should aim to decrease the plateau pressure (to Pplat ≤30 cm H2O)
Optimization of Ventilation Management: as above
Continue Chest Tube Drainage (see Chest Tube, [[Chest Tube]]): while this may seem obvious, prematurely removing a chest tube in a patient with an air leak from a bronchopleural fistula can result in the rapid development of tension pneumothorax (which can be potentially fatal)
Use the Least Amount of Chest Tube Suction Which Maintains Lung Inflation and Decreases the Amount of Air Leak
Optimize Body Position and Patient’s Sedation/Pharmacologic Paralysis to Minimize the Air Leak
Management-Pneumomediastinum (see Pneumomediastinum, [[Pneumomediastinum]])
Optimization of Ventilation Management: as above
Rare Cases of Tension Pneumomediastinum May Require Mediastinotomy For Decompression
Management-Pneumopericardium (see Pneumopericardium, [[Pneumopericardium]])
Optimization of Ventilation Management: as above
Rare Cases with Tamponade May Require Pericardiocentesis with Drain Placement for Decompression
Management-Pneumoperitoneum (see Pneumoperitoneum, [[Pneumoperitoneum]])
Optimization of Ventilation Management: as above
Barotrauma-Associated Pneumoperitoneum is Usually Self-Limited and Doesn’t Require Specific Intervention (Other than Ventilator Adjustments, Such as a Decrease in Plateau Pressure, etc)
Rare Cases of Pneumoperitoneum-Associated Abdominal Compartment Syndrome May Require Lapartotomy/Laparoscopy for Surgical Decompression (to Both Relieve the Compartment Syndrome and to Exclude a Perforated Viscus)
Management-Pulmonary Interstitial Emphysema
Optimization of Ventilation Management: as above
Treat Underlying Etiology
Management-Subcutaneous Emphysema (see Subcutaneous Emphysema, [[Subcutaneous Emphysema]])
Optimization of Ventilation Management: as above
Manage Underlying Pneumothorax (If Present) (see Pneumothorax, [[Pneumothorax]]): as above
Management-Venous Air Embolism (see Air Embolism, [[Air Embolism]])
Optimization of Ventilation Management: as above
Standard Management
Prognosis
In Mixed Populations, Mechanical Ventilation-Associated Barotrauma is Associated with an Increased Mortality Rate (Chest, 1986) [MEDLINE]
ARDS-Associated Barotrauma is Associated with an Increased Mortality Rate: likely related to the fact that the barotrauma is a marker for patients with worse ARDS (Crit Care Med, 1995) [MEDLINE] (JAMA, 1994) [MEDLINE]
In Patients with Underlying Reactive Airways Disease, Postoperative Bronchospasm Occurs Commonly with Endotracheal Intubation (Masui, 1995) [MEDLINE]: bronchospasm occurs in 8.9% of patients with reactive airways disease undergoing endotracheal intubation with general anesthesia
In Patients with Underlying Reactive Airways Disease, the Incidence of Postoperative Bronchospasm was Higher with Thoracic/Abdominal Surgery (39.5%), as Compared to Other Surgeries (10.4%) (Masui, 1995) [MEDLINE]
Mechanisms
Aspiration of Acidic Gastric Contents During Intubation, Resulting in Airway Irritation
May Occur When Endotracheal Intubation is Performed in Presence of Gastric Contents
Physiology
Vomiting with Aspiration of Oropharyngeal/Gastric Contents (see Nausea and Vomiting, [[Nausea and Vomiting]])
Endotracheal Tube Cuff/Ventilator Circuit Leak
Epidemiology of Endotracheal Tube Cuff Leak
In One Study of Patients with Lost Volume on the Ventilator and Suspected Endotracheal Tube Cuff Rupture, 61% of the Leaks Were Actually Due to Endotracheal Tube Dislodgment and Only 39% Were Due to a Ruptured Cuff (Crit Care Med, 1993) [MEDLINE]
Mechanisms
Defective Endotracheal Tube Cuff System
Laceration of Endotracheal Tube Cuff (Typically on the Teeth During Intubation)
Puncture of Pilot Balloon
Puncture of Pilot Balloon Tubing
Intact Endotracheal Tube Cuff System
Discrepancy Between Endotracheal Tube Size and Tracheal Diameter (Especially in a Patient with Tracheomalacia, etc)
Endotracheal Tube Cuff Underinflation
High Peak Airway Pressure (PIP): may result in leak around the endotracheal tube cuff
Inadvertent Tracheal Placement of Nasogastric/Orogastric Tube (see Nasogastric-Orogastric Tube, [[Nasogastric-Orogastric Tube]])
Proximal Migration of the Endotracheal Tube
Diagnosis
Check Endotracheal Tube and Ventilator Circuit for Disconnections or Leaks
Monitor Endotracheal Tube Cuff Pressure with Manometer
Bronchoscopy (see Bronchoscopy, [[Bronchoscopy]]): useful to rapidly determine the location of the endotracheal tube tip, in cases where endotracheal tube proximal malpositioning is suspected
With a Suspected Cuff Leak, if the Endotracheal Tube Tip is in the Appropriate Position, This Makes the Diagnosis of Endotracheal Tube Cuff Rupture More Likely as the Etiology
Clinical: extent and leak and patient tolerance of the leak are variable (Anesth Analg, 2013) [MEDLINE]
Audible Leak from Air Passing Through Around the Cuff of the Endotracheal Tube: with endotracheal tube cuff leak
Decreased Peak Airway Pressure (PIP) on Ventilator (see xxxx, [[xxxx]])
Inability to Maintain Endotracheal Tube Cuff Pressure
“Lost Volume” on the Ventilator (Inspired Tidal Volume > Expired Tidal Volume)
Treatment
Pilot Ballon Tubing Can Be Repaired in Select Cases Using a Commercially-Available Kit
Endotracheal Tube Malpositioning/Proximal Migration of Endotracheal Tube (i.e. Inadvertent Extubation)
Epidemiology
In One Study of Patients with Lost Volume on the Ventilator and Suspected Endotracheal Tube Cuff Rupture, 61% of the Leaks Were Actually Due to Endotracheal Tube Dislodgment and Only 39% Were Due to a Ruptured Cuff (Crit Care Med, 1993) [MEDLINE]
Mechanisms
Improper Securement of Endotracheal Tube Following Intubation with Proximal Migration of the Tip Out of the Trachea
Diagnostic
Bronchoscopy (see Bronchoscopy, [[Bronchoscopy]]): useful to rapidly determine the location of the endotracheal tube tip and replace the endotracheal tube into the trachea (should that be required)
Thoracic Ultrasound (see Thoracic Ultrasound, [[Thoracic Ultrasound]]): useful
Clinical
Decreased Peak Airway Pressure (PIP) on Ventilator (see xxxx, [[xxxx]])
“Lost Volume” on the Ventilator (Inspired Tidal Volume > Expired Tidal Volume)
Requirement for Increasing Volume to Maintain Endotracheal Tube Cuff Pressure: caution should be exercised in cases such as these, as unrecognized excessive inflation of the cuff may occur in the posterior oropharynx in a patient with a proximally-migrated endotracheal tube
Bronchoscopy (see Bronchoscopy, [[Bronchoscopy]]): useful to rapidly identify and treat large airway mucous plugging and identify endotracheal tube tip location
Chest X-Ray (CXR)/Chest CT (see Chest X-Ray, [[Chest X-Ray]] and Chest Computed Tomography, [[Chest Computed Tomography]]): useful to exclude pneumothorax and diagnose atelectasis
Thoracic Ultrasound (see Thoracic Ultrasound, [[Thoracic Ultrasound]]): useful to exclude pneumothorax
Clinical
Unilaterally Absent Breath Sounds: on the non-ventilated side
Increased Peak Airway Pressure (PIP) on Ventilator (see xxxx, [[xxxx]])
Pneumothorax (see Pneumothorax, [[Pneumothorax]]): use of large tidal volume delivered unilaterally may particularly predispose to the development of pneumothorax on the ventilated side
Kinked Endotracheal Tube
Mechanism
Kinking at Endotracheal Tube Securement Device (Hollister, etc): common
Kinking in Posterior Oropharynx: less common
Kinking at Teeth (i.e. Patient Biting the Endotracheal Tube): most common site of kinking
Diagnosis
Bronchoscopy (see Bronchoscopy, [[Bronchoscopy]]): useful to rapidly evaluate endotracheal tube patency
Clinical
Increased Peak Airway Pressure (PIP) on Ventilator (see xxxx, [[xxxx]])
Increased Peak-Plateau Pressure Difference (≥5 cm H2O): reflecting an increase in the airway resistance
Prevention
Use of a Bite Block to Prevent Kinking of the Endotracheal Tube at the Teeth is Routinely Recommended
Post-Intubation Hypotension is the Most Common Complication of Intubation
Up to 40% of Patients Intubated in the ICU Setting Experience Significant Procedure-Related Hypoxemia or Hypotension (Crit Care, 2015) [MEDLINE]
Risk Factors for Post-Intubation Hypotension (Crit Care, 2015) [MEDLINE]
Age >60 y/o
Acute Respiratory Failure as the Indication for Intubation
First Intubation in the ICU
Noninvasive Ventilation Required for Preoxygenation
Inspired FIO2 >70% After Intubation
Mechanisms
Positive-Pressure Ventilation Increases Intrathoracic and Right Atrial Pressure -> Decreases Venous Return to the Right Side of the Heart -> Decreases Right Ventricular Cardiac Output
This Effect is Accentuated by the Concomitant Presence of Auto-PEEP, Extrinsic PEEP, and/or Hypovolemia (Anesthesiology, 1975) [MEDLINE]
The Use of Pharmacologic Agents with Vasodilator Properties (Opiates, Benzodiazepines, Propofol, etc) Can Further Exacerbate this Effect
This Effect May Be Most Pronounced Immediately After Intubation and Initiation of Mechanical Ventilation in a Patient Who is Hypovolemic and Has Just Received Vasodilating Sedatives (Such as Midazolam, Propofol, etc) or Analgesics (Fentanyl, etc)
Positive-Pressure Ventilation Causes Alveolar Inflation with Compression of the Pulmonary Vascular Bed -> Increases Pulmonary Vascular Resistance (PVR) -> Decreases Right Ventricular Output (Crit Care Med, 2010) [MEDLINE]
Passive Leg Raise Maneuver Has Been Demonstrated to Increase Central Blood Volume and Mitigate this Effect (Crit Care Med, 2010) [MEDLINE]
Positive-Pressure Ventilation Causes Alveolar Inflation with Compression of the Pulmonary Vascular Bed -> Increases Pulmonary Vascular Resistance (PVR) -> Shifts the Intraventricular Septum Toward the Left (with Impaired Diastolic Left Ventricular Filling) -> Decreases Left Ventricular Cardiac Output
Interaction Between Airway Pressures and Thoracic Structures
Hemodynamic Effects of Positive-Pressure Mechanical Ventilation are Due to Transmission of the Airway Pressure to the Adjacent Thoracic Structures
Transmission is Greatest When There is Low Chest Wall Compliance (Due to Fibrothorax, etc) or High Chest Wall Compliance (Due to COPD, etc)
Transmission is Least When There is High Chest Wall Compliance (Due to Sternotomy, etc) or Low Lung Compliance (Due to ARDS, Pulmonary Edema, etc)
Prophylactic Intravenous Fluid/Vasopressors Prior to andor During Endotracheal Intubation: especially indicated in patients with marginal pre-intubation blood pressure and/or known hypovolemia
Once Life-Threatening Etiologies are Promptly Excluded, Oxygenation Can Be Carefully Monitored for Improvement Over Time
Sympathetic Nervous System Response
Mechanisms
Glottic Stimulation from Laryngoscopy Blade/Endotracheal Tube (Typically in the Setting of Inadequate Sedation): since the glottis is highly innervated
Paralysis with Inadequate Sedation: may occur following rapid sequence intubation with a short-acting sedative (such as etomidate, etc) and a long-acting paralytic (such as rocuronium, etc)
Note that Sinus Tachycardia May Alternatively Represent a Normal Physiologic Response to Hypovolemia Induced by Positive-Pressure Ventilation (and Decreased Venous Return to the Right Side of the Heart): it is critical to rule out hypovolemia as the etiology in this case
Prevention of Sympathetic Nervous Response Due to Glottic Stimulation
Bronchoscopy is Recommended to Rapidly Determine the Site of Post-Intubation Hemoptysis (Larynx vs Tracheal Mucosal vs Endobronchial Mucosal vs Diffuse Alveolar Hemorrhage): this is especially useful in patients with pre-existing diffuse alveolar hemorrhage who only manifest hemoptysis after intubation
Clinical
Post-Intubation Hemoptysis (see Hemoptysis, [[Hemoptysis]])
Hemoptysis May Be Significant in Patients with Coagulopathy
Vagal Response
Epidemiology
Laryngoscopy-Related Vagal Response is More Common in Young Patients
Mechanical Ventilation is Associated with an Increased Risk of Acute Kidney Injury
BEST Kidney Trial (JAMA, 2005) [MEDLINE]: n = 29,269 critically ill patients
Positive-Pressure Mechanical Ventilation was an Independent Risk Factor for Acute Kidney Injury (Odds Ratio 2.11, 95% CI: 1.58-2.82)
Mechanism
May Be Related to Increased Release of Inflammatory Mediators (Such as IL-6), Impaired Renal Perfusion Associated with Decreased Cardiac Output, Increased Sympathetic Tone, and/or Humoral Pathway Activation (Crit Care Med, 2005) [MEDLINE]
Arytenoid Cartilage Dislocation (see xxxx, [[xxxx]])
Aspiration of Oropharyngeal Secretions is Common with Endotracheal Tubes and Tracheostomy Tubes
Polyurethane Endotracheal Tube Cuffs Decrease the Amount of Leakage Around the Cuff, as Compared to Polyvinyl Chloride Cuff Endotracheal Tubes (Crit Care Med, 2008) [MEDLINE]
Mechanisms
Delayed Triggering of the Swallowing Response (Crit Care Med, 1990) [MEDLINE]
Pharyngeal Pooling of Secretions Above the Airway Cuff (Crit Care Med, 1990) [MEDLINE]
Risk of Aspiration is Correlated with the Amount of Oropharyngeal Secretions
Auto-Positive End-Expiratory Airway Pressure (Auto-PEEP or Intrinsic PEEP) (see PEEP+Auto-PEEP) (Am Rev Respir Dis, 1982) [MEDLINE]
Erosive Esophagitis Has Been Reported to Occur in 48% of Mechanically-Ventilated Patients (Chest, 2001) [MEDLINE]
Gastrointestinal Stress Ulceration (see Peptic Ulcer Disease, [[Peptic Ulcer Disease]])
Epidemiology
Stress-Related Mucosal Damage is the Most Common Etiology of Gastrointestinal Hemorrhage in Mechanically-Ventilated Patients
Endoscopically-Identified But Asymptomatic Stress Ulceration Has Been Reported to Occur in 74-100% of Mechanically-Ventilated Patients (Chest, 2001) [MEDLINE]
Clinically Evident Gastrointestinal Hemorrhage Due to Stress Ulceration Has Been Reported to Occur in 5-25% of Mechanically-Ventilated Patients (Chest, 2001) [MEDLINE]
Clinically Significant Gastrointestinal Hemorrhage Due to Stress Ulceration Has Been Reported to Occur in 3-4% of Mechanically-Ventilated Patients (Chest, 2001) [MEDLINE]
Mechanisms
Positive-Pressure Mechanical Ventilation is Associated with Decreased Splanchnic Perfusion, Possibly Related to Decreased Cardiac Output (Intensive Care Med, 2000) [MEDLINE] (Intensive Care Med, 2000) [MEDLINE]: decreased splanchnic perfusion results in increased levels of aminotransferases and lactate dehydrogenase (LDH)
Clinical
Mucosal Lesions Tend to Be Multiple and Occur Predominantly in the Fundus of the Stomach (Typically Sparing the Antrum)
Distal (Antral and Duodenal) Mucosal Erosions and/or Ulcers May Also Occur
Distal (Antral and Duodenal) Mucosal Erosions Tend to Appear Later
Distal (Antral and Duodenal) Mucosal Erosions Tend to Be Deeper
Distal (Antral and Duodenal) Mucosal Erosions May Be Associated with a Higher Incidence of Gastrointestinal Hemorrhage
Ileus (and Gastrointestinal Hypomotility) (see Ileus, [[Ileus]])
Epidemiology
Decreased Bowel Sounds Have Been Reported on Occur in 50% of Mechanically-Ventilated Patients (Chest, 2001) [MEDLINE]
High Gastric Residuals Have Been Reported to Occur in 39% of Mechanically-Ventilated Patients (Chest, 2001) [MEDLINE]
Ileus Has Been Reported to Occur in 4-10% of Mechanically-Ventilated Patients (Chest, 2001) [MEDLINE]
Mechanisms
Gastrointestinal Dysmotility Has Been Demonstrated in Mechanically-Ventilated Patients (Crit Care Med, 1994) [MEDLINE]
Clinical
Hypomotility with Tube Feeding Intolerance/Ileus
Management
Avoid Medications Which Impair Gastrointestinal Motility
Randomized Trial of Early Mobilization in Mechanically-Ventilated Patients (Lancet, 2009) [MEDLINE]
Early Mobilization within 72 hrs of Intubation was Safe, Well-Tolerated, and Associated with Improved Functional Outcomes at Hospital Discharge, Shorter Duration of Delirium, and More Ventilator-Free Days, as Compared to Standard Care
Recommendations (Related to Early Mobilization) (Society of Critical Care Medicine Clinical Practice Guidelines for the Prevention and Management of Pain, Agitation/Sedation, Delirium, Immobility, and Sleep Disruption in Adult Patients in the ICU) (Crit Care Med, 2018) [MEDLINE]
Assuming Stability of the Following Parameters, Rehabilitation or Mobilization is Recommended in Critically Ill Adults (Conditional Recommendation, Low Quality Evidence)
Cardiovascular Stability Criteria
Heart Rate 60-130 bpm
Systolic Blood Pressure 90-180 mm Hg (or Mean Arterial Pressure 60-100 mm Hg)
Absence of New/Symptomatic Arrhythmia
Absence of Chest Pain Due to Myocardial Ischemia
Respiratory Stability Criteria
Respiratory Rate 5-40 breaths/min
SpO2 ≥88%
FiO2 <60% and Positive End-Expiratory Pressure <10 cm H2O
Endotracheal Tube/Tracheostomy is Adequately Secured
Neurologic Stability Criteria
Able to Open Eyes to Voice
Absence of Unstable Spinal Injury/Lesion
Other Stability Criteria
Absence of Unstable Fracture and Active/Uncontrolled Gastrointestinal Hemorrhage
Mobilization May Be Performed with Femoral Vascular Access Devices (Except Femoral Sheaths in Which Hip Mobilization is Generally Avoided), Continuous Renal Replacement Therapy, and Infusion of Vasoactive Medications
Serious Safety Events or Harms are Uncommon During Physical Rehabilitation/Early Mobilization (Ungraded Statement)
Indicators for Stopping Physical Rehabilitation/Early Mobilization Include the Development of New Cardiovascular, Respiratory, or Neurologic Instability (Ungraded Statement)
Cardiovascular Instability
Deviation from Above Stability Criteria
Pulmonary Instability
Deviation from Above Stability Criteria
Ventilator Dyssynchrony
Neurologic Instability
Change in Level of Consciousness (Not Following Directions, Lightheadedness, Combative Behavior, or Agitation)
Other Instability
Fall
Hemorrhage
Medical Device Removal or Malfunction
Patient Distress
Impaired Mucociliary Motility
Physiology
Positive-Pressure Mechanical Ventilation Impairs Airway Mucociliary Clearance, Increasing the Risk of Secretion Retention and Pneumonia (Chest, 1994) [MEDLINE]
Randomized Trial of Routine vs On-Demand Nebulized N-Acetylcysteine with Salbutamol in Mechanically-Ventilated Patients (≥24hrs) in the ICU (JAMA, 2018) [MEDLINE]: n = 922
Routine Nebulized N-Acetylcysteine with Salbutamol Did Not Decrease the Number of Ventilator-Free Days, as Compared to On-Demand Nebulized N-Acetylcysteine with Salbutamol
There was No Difference in Length of Stay, Mortality, or the Proportion of Patients Developing Pulmonary Complications Between the Groups
Routine Nebulized N-Acetylcysteine Increased the Risk of Tachyarrhythmias and Agitation
Laryngeal Injury
Epidemiology
Endotracheal Tube-Associated Laryngeal Injury is the Most Common Complication Associated with Endotracheal Tube Placement
Laryngeal Edema/Inflammation is Observed Post-Extubation in >50% of Intubations (Chest, 1989) [MEDLINE] and (Intensive Care Med, 2010) [MEDLINE]
However, Not All Cases are Significantly Symptomatic
Clinically Significant Laryngeal Edema Occurs in 5-13% of Extubated Patients, But Only 1% Require Reintubation (Anesthesiology, 1992) [MEDLINE]
Fiberoptic Study of Endotracheal Intubation-Associated Laryngeal Injuries (Intensive Care Med, 2010) [MEDLINE]: prospective study of n = 136 patients extubated after >24 hrs of mechanical ventilation (median duration of intubation = 3 days)
Approximately 73% of Patients Demonstrated a Laryngeal Injury
The Most Common Lesions were Edema (67% of Cases) and Abnormal Vocal Mobility (67% of Cases)
Sex
Laryngeal Injuries are More Common in Females than Males (Anesthesiology, 1992) [MEDLINE]
Obesity
Obesity Does Not Appear to Increase the Risk of Laryngeal Injury, Although it Increases the Risk for Difficult Intubation (Intern Emerg Med, 2013) [MEDLINE]
Risk Factors Associated with Endotracheal Tube-Associated Laryngeal Injury (Otolaryngol Head Neck Surg, 1994) [MEDLINE] and (Intensive Care Med, 2010) [MEDLINE]
Positive-Pressure Mechanical Ventilation Increases Intracranial Pressure (Likely Mediated by Impairment of Cerebral Venous Outflow)
Neuronal Damage
Mechanism
Positive-Pressure Mechanical Ventilation Has Been Demonstrated to Cause Hippocampal Apoptosis in Animal Studies (Am J Respir Crit Care Med, 2013) [MEDLINE]
Hippocampal Changes May Be Related to the Development of Delirium
Pharyngitis is Common and Occurs in Anywhere from 14-57% of Patients Intubated for Operative General Anesthesia (J Clin Anesth, 2010) [MEDLINE] (J Int Med Res, 2017) [MEDLINE]
Risk Factors for Postoperative Endotracheal Intubation-Associated Pharyngitis
Cough During Emergence from General Anesthesia (J Int Med Res, 2017) [MEDLINE]
Preoperative Use of Zinc Lozenges ( Anesth Analg. 2018;126(1):78 [MEDLINE]
Note: Topical Lidocaine Applied to Upper Airway Structures or the Endotracheal Tube May Actually Increase the Risk of Postoperative Pharyngitis Due to the Endotracheal Tube (Can Anaesth Soc J, 1980) [MEDLINE] (Acta Anaesthesiol Scand, 1992) [MEDLINE]
Use of Conical-Shaped Endotracheal Tube Cuff (As Compared to Cylindrical-Shaped Cuff) (Anesth Analg, 2017) [MEDLINE]
Use the Lowest Effective Endotracheal Tube Cuff Pressure: generally <20 mm Hg
Use of Nitrous Oxide During Surgery Results in the Nitrous Oxide Diffusing into the Endotracheal Tube Cuff (and Undesirably Increasing the Endotracheal Tube Cuff Pressure)
Head Down Positioning During Surgery Increases the Endotracheal Tube Cuff Pressure
Use the Appropriate Endotracheal Tube Size (for Patient Sex and Size)
Female: 7-7.5 mm (internal diameter), which may require adjustment for patient size
Male: 7.5-8 mm (internal diameter), which may require adjustment for patient size
Treatment
Usually Self-Limited: lasting <48 hrs (Acta Anaesthesiol Scand, 2010) [MEDLINE]
In Cases with Persistent or Severe Hoarseness/Dysphagia, Otolaryngologic Evaluation May Be Warranted to Evaluate for Specific Intubation-Associated Injury
Positive Pressure-Induced Artifacts Introduced into the Measurement of Hemodynamic Pressures
Mechanism
Airway Pressure Transmission to Thoracic Structures, Resulting in Artifactual Elevation of Hemodynamic Pressure Measurements: this occurs because (by convention) most hemodynamic pressures are assessed at end-expiration (when PEEP is the predominant determinant of airway pressure)
Clinical
PEEP Artifactually Elevates the Pulmonary Capillary Wedge Pressure (PCWP)
Correction of PEEP Consists of Subtracting Approximately One Half of the PEEP Level from the PCWP if the Lung Compliance is Normal (or One Quarter of the PEEP Level if the Lung Compliance is Decreased) (J Appl Physiol Respir Environ Exerc Physiol, 1982) [MEDLINE]
Correction of the PCWP for the Amount of PEEP Can More Accurately Done Using the Index of Transmission (Crit Care Med, 2000) [MEDLINE]
Index of Transmission = (End Inspiratory PCWP – End Expiratory PCWP) / (Plateau Pressure – Total PEEP)
Transmural PCWP = End-Expiratory PCWP – (Index of Transmission x Total PEEP)
This Estimation Can Be Unreliable if the Respiratory Variation of the PCWP is Greater than that of the Pulmonary Arterial Pressure Tracing
PEEP May Also Artifactually Elevate the Central Venous Pressure (CVP)
Sleep Disruption
Epidemiology
Sleep Disruption is Common in Mechanically-Ventilated Patients (Chest, 2000) [MEDLINE]
Mechanisms (Am J Respir Crit Care Med, 2003) [MEDLINE]
Patient-Related Factors (Anxiety, Fear, Hospital Attire, Disorientation, Lack of Privacy, Loneliness, Lack of Familiarity with Staff, Lack of Understanding of Medical Terms, etc)
Environment-Related Factors (Noise, Light, Comfort of Bed, Disrupted Circadian Rhythms, Visitors, Room Ventilation, Bad Odor, Hand Washing by Providers, etc)
Disease-Related Factors (Pain, Dyspnea, Coughing, Thirst, Nausea, Need to Use Bedpan/Urinal, etc)
Specific Ventilator Modes Might Contribute Differentially to Sleep Disruption (Am J Respir Crit Care Med, 2002) [MEDLINE] (Crit Care Med, 2008) [MEDLINE]
Diagnosis
Identification of Sleep in Critically Ill Patients is Difficult with Standard Criteria (Sleep Med, 2012) [MEDLINE]
General Management
Sound Reduction Strategies May Be Useful to Improve Sleep in ICU Patients (Crit Care, 2013) [MEDLINE]
Pressure Support Ventilation Should Be Avoided in Patients with Central Sleep Apnea (Especially Those with Congestive Heart Failure and Chronic Respiratory Failure) (Intensive Care Med, 2016) [MEDLINE]
Recommendations (Society of Critical Care Medicine Clinical Practice Guidelines for the Prevention and Management of Pain, Agitation/Sedation, Delirium, Immobility, and Sleep Disruption in Adult Patients in the ICU) (Crit Care Med, 2018) [MEDLINE]
Features of Sleep in the Critically Ill Patient (Ungraded Statement)
Total Sleep Time (TST) and Sleep Efficiency are Often Normal
Sleep Fragmentation, the Proportion of Time Spent in Light Sleep (Stages N1 + N2), and Time Spent Sleeping During the Day (vs Night) are Higher
The proportion of Time Spent in Deep Sleep (Stage N3 Sleep and REM) is Lower
Subjective Sleep Quality is Decreased
Influence of Delirium on Sleep (Ungraded Statement)
The Presence of Delirium May Not Affect Total Sleep Time, Sleep Efficiency, or Sleep Fragmentation
The Influence of Delirium on the Proportion of Time Spent in Light (N1 + N2) vs Deeper (N3) Sleep is Unknown
The Presence of Delirium Decreases REM Sleep
Delirium is Associated with Greater Circadian Sleep-Cycle Disruption and Increased Daytime Sleep
Although an Association Between Sleep Quality and Delirium Occurrence Exists in Critically Ill Adults, a Causal Relationship Has Not Been Established
Influence of Mechanical Ventilation on Sleep (Ungraded Statement)
Use of Mechanical Ventilation in Critically Ill Adults May Worsen Sleep Fragmentation, Sleep Architecture, and Circadian Rhythm (Daytime Sleep), as Compared to Normal Sleep, But These Effects are Often Variable and Have Not Yet Been Fully Investigated
Use of Mechanical Ventilation (vs Periods without Mechanical Ventilation) in Patients with Respiratory Failure May Improve Sleep Efficiency and Decrease Sleep Fragmentation, But the Data are Limited
Unclear Association Between Sleep Quality and Duration of Mechanical Ventilation, Length of ICU Stay, and ICU Mortality in Critically Ill Adults
Assist-Control Ventilation is Recommended at Night (vs Pressure Support Ventilation) for Improving Sleep in Critically Ill Adults (Conditional Recommendation, Low Quality of Evidence)
In Patient Requiring Noninvasive Positive-Pressure Ventilation (NIPPV), Either an NIPPV-Dedicated Ventilator or a Standard ICU Ventilator May Be Used for Critically Ill Adults to Improve Sleep (Conditional Recommendation, Very Low Quality of Evidence)
Unusual Sleep Patterns (Ungraded Statement)
The Prevalence of Unusual or Dissociated Sleep Patterns is Highly Variable and Depends on Patient Characteristics
Risk Factors (Ungraded Statement)
Patients Who Report Poor Quality Sleep and/or Use of a Pharmacologic Sleep Aid at Home are More Likely to Report Poor Quality Sleep in the ICU
Pain, Environmental Stimuli, Healthcare-Related Interruptions, Psychologic Factors, Respiratory Factors, and Medications Each Affect Sleep Quality in the ICU: see above
Monitoring of Sleep in the ICU
Clinical Physiologic Sleep Monitoring is Not Routinely Recommended in Critically Ill Adults (Conditional Recommendation, Very Low Quality of Evidence)
Other Adjunctive Therapies to Improve Sleep in the ICU
Aromatherapy, Acupressure, and Music at Night are Not Recommended to Improve Sleep in Critically Ill Adults (Conditional Recommendation, Low Quality of Evidence for Aromatherapy and Acupressure, Very Low Quality of Evidence for Music)
Noise/Light Reduction Strategies are Recommended to Improve Sleep in Critically Ill Adults (Conditional Recommendation, Low Quality of Evidence)
No Recommendation Regarding the Use of Melatonin to Improve Sleep in Critically Ill Adults (No Recommendation, Very Low Quality of Evidence)
Propofol is Not Recommended to Improve Sleep in Critically Ill Adults (Conditional Recommendation, Low Quality of Evidence)
No Recommendation Regarding the Use of Dexmedetomidine at Night to Improve Sleep in Critically Ill Adults (No Recommendation, Low Quality of Evidence)
Use of a Sleep-Promoting, Multicomponent Protocol is Recommended in Critically Ill Adults (Conditional Recommendation, Very Low Quality of Evidence)
Outcomes
The Effects of Sleep Quality and Circadian Rhythm Alterations on Outcomes in Critically Ill Patients After ICU Discharge are Unknown
Swallowing/Speech Impairment
Epidemiology
Swallowing/Speech Impairment is Common Following Extubation: occurs in approximately 50% of patients (range: 3-62%) (Chest, 2010) [MEDLINE]
However, Clinically-Significant Aspiration is Far Less Common
Mechanisms
Laryngeal Injury: likely mechanism for speech impairment
Formal Swallowing Evaluation (Fiberoptic Endoscopic Evaluation of Swallowing/FEES, barium swallowing study, etc) is Generally Recommended for Patients Who Have Been Intubated for ≥7 Days (or Who Have Other Risk Factors for Dysphagia)
Due to Excessive Force Used to Open the Mouth During Intubation
Trachebronchial Wall Injury
Clinical
Bronchial Mucosal Injury: may result in hemoptysis from the site of mucosal injury
Bronchial Wall Mucosal Injury May Occur with Inadvertent Mainstem Intubation with a Single Lumen Tube or with Standard Use of a Double-Lumen Tube (Where the Tube Tip is Placed in Either the Right or Left Mainstem Bronchus)
Tracheal Mucosal Injury: may result in hemoptysis from the site of mucosal injury
Diaphragmatic Proteolysis May Develop within the First Day of Mechanical Ventilation (N Engl J Med, 2008) [MEDLINE] (Am J Respir Crit Care Med, 2011) [MEDLINE]
Diaphragmatic Proteolysis Appears to Be Mediated Via Oxidative Stress-Induced Mitochondrial Dysfunction (Am J Respir Crit Care Med, 2012) [MEDLINE]
Clinical
Diaphragmatic Atrophy During Mechanical Ventilation is Associated with Prolonged Mechanical Ventilation, Difficulty Weaning from the Ventilator (Adjusted Hazard Ratio, 0.69; 95% CI: 0.54-0.87; Per 10% Decrease in Diaphragmatic Thickness), Prolonged ICU Length of Stay (Adjusted Duration Ratio, 1.71; 95% CI: 1.29-2.27), and a Higher Risk of Complications (Adjusted Odds Ratio, 3.00; 95% CI: 1.34-6.72) (Am J Respir Crit Care Med, 2018) [MEDLINE]
Vocal Cord Granuloma(s) May Occur in 30-40% of Patients Intubated for >3-4 Days (Intensive Care Med, 2010) [MEDLINE]
Duration of Intubation and Severity of Initial Laryngeal Injury Do Not Predict the Formation of Vocal Cord Granulomas (Am Rev Respir Dis, 1992) [MEDLINE]
Elevation of the Head of the Bed (Which is Standardly Used in the Mechanically-Ventilated Patient to Decrease the Risk of Aspiration) is Associated with Increased Risk of Sacral Decubitus Ulcers (Crit Care Med, 2008) [MEDLINE]
Prolonged Immobilization Associated with Mechanical Ventilation is Associated with an Increased Risk of Deep Venous Thrombosis
Additionally, Deep Venous Thrombosis is Common in Mechanically-Ventilated Patients, Despite the Use of Pharmacologic Prophylaxis (J Thromb Thrombolysis, 2017) [MEDLINE]
Induction of Inflammatory Response
Mechanism
Positive-Pressure Mechanical Ventilation Induces an Inflammatory Cytokine Response (in the Bloodstream and Bronchoalveolar Lavage Fluid), Which May Be Attenuated by a the Use of Low Tidal Volume/High PEEP Strategy to Minimize Overdistention and Recruitment/Derecruitment of the Lung (JAMA, 1999) [MEDLINE]
Insulin Resistance
Epidemiology
Prolonged Bedrest Associated with Mechanical Ventilation Has Been Associated with the Development of Insulin Resistance (Arterioscler Thromb Vasc Biol, 2007) [MEDLINE]
Joint Contractures
Epidemiology
Prolonged Bed Rest is Associated with the Development of Joint Contractures (CMAJ, 2008) [MEDLINE]
Tracheal Bacterial Translocation into the Bloodstream
Mechanism
Positive-Pressure Mechanical Ventilation Has Been Demonstrated to Induce Translocation of Tracheal Bacteria into the Bloodstream in Animal Studies (Especially with High Tidal Volumes and Low PEEP) (Crit Care Med, 1997) [MEDLINE]
Late Adverse Effects/Complications of Endotracheal Intubation (Manifest Within Weeks-Months After Endotracheal Intubation
Prior Irradiation for Oropharyngeal/Laryngeal Tumor
Prior Non-Airway Surgery
Prolonged Intubation >7 Days: rarely occurs in those intubated for <3 days
Physiology
Laryngeal (Glottic) Stenosis: due to pressure from the endotracheal tube itself with local ischemia, inflammation, tissue necrosis, and scarring
Usual Location: posterior glottis and interarytenoid regions (where the endotracheal tube exerts the most pressure)
Tracheal Stenosis: due to high endotracheal tube cuff pressure (at 20 cm H20, cuff pressure will exceed the mean capillary pressure in the mucosa), with obstruction of capillary blood flow and associated ischemia, inflammation, erosion of the mucosa, tissue necrosis, distorted tracheal architecture, and scarring
Usual Location/Appearance: web-like stenosis at the cuff site
In Contrast, Tracheal Stenosis Associated with Tracheostomy Typically Occurs Around the Tracheal Stoma (see Tracheostomy, [[Tracheostomy]])
Pulmonary Function Tests (PFT’s) (see Pulmonary Function Tests, [[Pulmonary Function Tests]]): fixed upper airway obstruction
Spiral CT with Virtual Bronchoscopy (see Chest Computed Tomography, [[Chest Computed Tomography]]): may be diagnostic (Eur Arch Otorhinolaryngol, 2009) [MEDLINE]
Clinical
Failure to Wean from Mechanical Ventilation: in patients on mechanical ventilation
Subacute/Progressive Dyspnea (see Dyspnea, [[Dyspnea]])
Usually Becomes Symptomatic Approximately 5 wks-Months After Extubation
Treatment
Rigid Bronchoscopy with Dilation/Laser Resection/Stenting (see Bronchoscopy, [[Bronchoscopy]]): may be required for tracheal stenosis
Mitomycin C (see Mitomycin, [[Mitomycin]]): has been used to prevent tracheal restenosis after local procedures
Surgical Resection: may be required in refractory cases of tracheal stenosis
Cases Have Been Reported with Prolonged Endotracheal Intubation: although it has more commonly been reported with tracheostomy (see Tracheostomy, [[Tracheostomy]])
Mechanism
Erosion Through Tracheal Wall into Innominate Artery
Safe intrahospital transport of critically ill ventilator-dependent patients. Chest 1989; 96:631-635 [MEDLINE]
Airway considerations in the management of patients requiring long-term endotracheal intubation. Anesth Analg. 1992;74(2):276 [MEDLINE]
Unplanned extubations in the adult intensive care unit. Am J Respir Crit Care Med 1998; 157:1131-1137 [MEDLINE]
Death and other complications of emergency airway management in critically ill adults. Anesthesiology 1995; 82:367-376 [MEDLINE]
Bedside procedures: solutions to the pitfalls of intrahospital transport. Crit Care Clin 2000; 16:1-6 [MEDLINE]
Difficult airway management in the emergency department. J Emerg Med. 2002 Jan;22(1):31-48 [MEDLINE]
Clinical practice guidelines for sustained neuromuscular blockade in the adult critically ill patient. Crit Care Med. 2002 Jan;30(1):142-56 [MEDLINE]
Towards evidence based emergency medicine: best BETs from the Manchester Royal Infirmary. Colourimetric CO(2) detector compared with capnography for confirming ET tube placement. Emerg Med J 2003: 20: 265-266 [MEDLINE]
The effectiveness of out-of-hospital use of continuous end-tidal carbon dioxide monitoring on the rate of unrecognized misplaced intubation within a regional emergency medical services system. Ann Emerg Med 2005; 45:497-503 [MEDLINE]
Clinical review: management of difficult airways. Crit Care 2006;10:243. doi: 10.1186/cc5112 [MEDLINE]
2010 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care. Part 8: adult advanced cardiovascular life support. Circulation 2010; 122(18 Suppl 3):S729-S767 [MEDLINE]
Airway management in critically ill patients. Lung 2011; 189:181-192 [MEDLINE]
Emergency airway management: the difficult airway. Emerg Med Clin North Am 2012; 30:401-420 [MEDLINE]
Practice guidelines for management of the difficult airway: an updated report by the American Society of Anesthesiologists Task Force on Management of the Difficult Airway. Anesthesiology. 2013;118:251–270 [MEDLINE]
The effect of body mass index on intubation success rates and complications during emergency airway management. Intern Emerg Med. 2013 Feb;8(1):75-82. Epub 2012 Nov 25 [MEDLINE]
Heated humidified high-flow nasal oxygen in adults: mechanisms of action and clinical implications. Chest. 2015;148(1):253–261 [MEDLINE]
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Indications
Part 7: Adult Advanced Cardiovascular Life Support: 2015 American Heart Association Guidelines Update for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care. Circulation. 2015 Nov 3;132(18 Suppl 2):S444-64. doi: 10.1161/CIR.0000000000000261 [MEDLINE]
Effect of Bag-Mask Ventilation vs Endotracheal Intubation During Cardiopulmonary Resuscitation on Neurological Outcome After Out-of-Hospital Cardiorespiratory Arrest: A Randomized Clinical Trial. JAMA 2018; 319:779 [MEDLINE]
Effect of a Strategy of a Supraglottic Airway Device vs Tracheal Intubation During Out-of-Hospital Cardiac Arrest on Functional Outcome: The AIRWAYS-2 Randomized Clinical Trial. JAMA 2018; 320:779 [MEDLINE]
Effect of a Strategy of Initial Laryngeal Tube Insertion vs Endotracheal Intubation on 72-Hour Survival in Adults With Out-of-Hospital Cardiac Arrest: A Randomized Clinical Trial. JAMA 2018; 320:769 [MEDLINE]
Assessment for Upper Airway Obstruction
A life-saving maneuver to prevent food-choking. JAMA. 1975;234(4):398 [MEDLINE]
Heimlich versus a slap on the back. N Engl J Med. 1979;300(17):990 [MEDLINE]
The choking controversy: critique of evidence on the Heimlich maneuver. Crit Care Med. 1979;7(10):475 [MEDLINE]
Chest compression–an alternative to the Heimlich manoeuver? Resuscitation. 1992;24(1):91 [MEDLINE]
Traumatic rupture of the stomach secondary to Heimlich maneuver. Am J Emerg Med. 1993;11(6):611 [MEDLINE]
Assessment of upper airway anatomy in awake, sedated and anaesthetised patients using magnetic resonance imaging. Anaesth Intensive Care. 1994;22(2):165 [MEDLINE]
Magnetic resonance imaging of the upper airway. Effects of propofol anesthesia and nasal continuous positive airway pressure in humans. Anesthesiology. 1996;84(2):273 [MEDLINE]
Gastric rupture secondary to successful Heimlich manoeuvre. Postgrad Med J. 1998;74(876):609 [MEDLINE]
Airway pressure with chest compressions versus Heimlich manoeuvre in recently dead adults with complete airway obstruction. Resuscitation. 2000;44(2):105 [MEDLINE]
Rupture of the lesser gastric curvature after a Heimlich maneuver. Surg Endosc. 2003;17(9):1495 [MEDLINE]
Part 4: CPR overview: 2010 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care. Circulation. 2010;122(18 Suppl 3):S676 [MEDLINE]
Part 5: Adult Basic Life Support and Cardiopulmonary Resuscitation Quality: 2015 American Heart Association Guidelines Update for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care. Circulation. 2015;132(18 Suppl 2):S414 [MEDLINE]
Airway Maneuvers
Resuscitation–opening the airway. A comparative study of techniques for opening an airway obstructed by the tongue. JACEP. 1976;5(8):588 [MEDLINE]
The effect of airway maneuvers on the unstable C1-C2 segment. A cadaver study. Spine (Phila Pa 1976). 1997;22(11):1215 [MEDLINE]
Cervical spine motion during airway management: a cinefluoroscopic study of the posteriorly destabilized third cervical vertebrae in human cadavers. Anesth Analg. 2000;91(5):1274 [MEDLINE]
Effectiveness of the jaw-thrust maneuver in opening the airway: a flexible fiberoptic endoscopic study. ORL J Otorhinolaryngol Relat Spec. 2005;67(1):39 [MEDLINE]
Airway Adjuncts
The nasopharyngeal airway. Assessment of position by fibreoptic laryngoscopy. Anaesthesia. 1993;48(7):575 [MEDLINE]
The nasopharyngeal airway: dispelling myths and establishing the facts. Emerg Med J. 2005;22(6):394 [MEDLINE]
Preintubation Assessment
Early identification of patients at risk for difficult intubation in the intensive care unit: development and validation of the MACOCHA score in a multicenter cohort study. Am J Respir Crit Care Med. 2013 Apr 15;187(8):832-9. doi: 10.1164/rccm.201210-1851OC [MEDLINE]
The MACOCHA score is feasible to predict intubation failure of nonanesthesiologist intensive care unit trainees. J Crit Care. 2015 Oct;30(5):876-80. doi: 10.1016/j.jcrc.2015.04.118 [MEDLINE]
Prospective validation of the modified LEMON criteria to predict difficult intubation in the ED. Am J Emerg Med. 2015 Oct;33(10):1492-6. doi: 10.1016/j.ajem.2015.06.038 [MEDLINE]
The diagnostic validity of clinical airway assessments for predicting difficult laryngoscopy using a grey zone approach. J Int Med Res. 2016 Aug;44(4):893-904. doi: 10.1177/0300060516642647 [MEDLINE]
Bag-Valve-Mask Ventilation
Simultaneous aortic, jugular bulb, and right atrial pressures during cardiopulmonary resuscitation in humans. Insights into mechanisms. Circulation. 1989;80(2):361 [MEDLINE]
Comparison of self-inflating bags with anesthesia bags for bag-mask ventilation in the pediatric emergency department. Pediatr Emerg Care. 1997;13(5):312 [MEDLINE]
Prediction of difficult mask ventilation. Anesthesiology 2000;92:1229–1236 [MEDLINE]
Hyperventilation-induced hypotension during cardiopulmonary resuscitation. Circulation. 2004;109(16):1960 [MEDLINE]
Death by hyperventilation: a common and life-threatening problem during cardiopulmonary resuscitation. Crit Care Med. 2004;32(9 Suppl):S345 [MEDLINE]
Incidence and predictors of difficult or impossible mask ventilation. Anesthesiology 2006;105:885–891 [MEDLINE]
The effect of leaving dentures in place on bag-mask ventilation at induction of general anesthesia. Anesth Analg. 2007;105(2):370 [MEDLINE]
A two-handed jaw-thrust technique is superior to the one-handed “EC-clamp” technique for mask ventilation in the apneic unconscious person. Anesthesiology. 2010;113(4):873 [MEDLINE]
Face mask ventilation in edentulous patients: a comparison of mandibular groove and lower lip placement. Anesthesiology. 2010;112(5):1190 [MEDLINE]
Efficacy of facemask ventilation techniques in novice providers. Clin Anesth. 2013 May;25(3):193-7 [MEDLINE]
Optimizing Mask Ventilation: Literature Review and Development of a Conceptual Framework. Respir Care. 2015 Dec;60(12):1834-40. doi: 10.4187/respcare.04183 [MEDLINE]
Body Position
Analysis of the forces and position required for direct laryngoscopic exposure of the anterior vocal folds. Ann Otol Rhinol Laryngol. 1999;108(8):715 [MEDLINE]
Head and neck elevation beyond the sniffing position improves laryngeal view in cases of difficult direct laryngoscopy. J Clin Anesth. 2002;14(5):335 [MEDLINE]
Head-elevated laryngoscopy position: improving laryngeal exposure during laryngoscopy by increasing head elevation. Ann Emerg Med. 2003;41(3):322 [MEDLINE]
Laryngoscopy and morbid obesity: a comparison of the “sniff” and “ramped” positions. Obes Surg. 2004;14(9):1171 [MEDLINE]
Head-Elevated Patient Positioning Decreases Complications of Emergent Tracheal Intubation in the Ward and Intensive Care Unit. Anesth Analg. 2016 Apr;122(4):1101-7 [MEDLINE]
Cricoid Pressure (Sellick Maneuver)
Best evidence topic report. Cricoid pressure in emergency rapid sequence induction. Emerg Med J. 2005;22(11):815 [MEDLINE]
Laryngeal view during laryngoscopy: a randomized trial comparing cricoid pressure, backward-upward-rightward pressure, and bimanual laryngoscopy. Ann Emerg Med. 2006;47(6):548 [MEDLINE]
Cricoid pressure in emergency department rapid sequence tracheal intubations: a risk-benefit analysis. Ann Emerg Med. 2007;50(6):653 [MEDLINE]
The effect of cricoid pressure on intubation facilitated by the gum elastic bougie. Anaesthesia. 2007;62(5):456 [MEDLINE]
Cricoid pressure and laryngeal manipulation in 402 pre-hospital emergency anaesthetics: essential safety measure or a hindrance to rapid safe intubation? Resuscitation. 2010 Jul;81(7):810-6. doi: 10.1016/j.resuscitation.2010.02.023 [MEDLINE]
The effectiveness of cricoid pressure for occluding the esophageal entrance in anesthetized and paralyzed patients: an experimental and observational glidescope study. Anesth Analg. 2014;118(3):580 [MEDLINE]
Videographic analysis of glottic view with increasing cricoid pressure force. Ann Emerg Med. 2013 Apr;61(4):407-13 [MEDLINE]
Effectiveness and risks of cricoid pressure during rapid sequence induction for endotracheal intubation. Cochrane Database Syst Rev. 2015 [MEDLINE]
Effect of Cricoid Pressure Compared With a Sham Procedure in the Rapid Sequence Induction of Anesthesia: The IRIS Randomized Clinical Trial. JAMA Surg. 2018 Oct 17. doi: 10.1001/jamasurg.2018.3577 [MEDLINE]
Backward-Upward-Rightward (BURP) Maneuver
Laryngeal view during laryngoscopy: a randomized trial comparing cricoid pressure, backward-upward-rightward pressure, and bimanual laryngoscopy. Ann Emerg Med. 2006;47(6):548 [MEDLINE]
Cricoid pressure and laryngeal manipulation in 402 pre-hospital emergency anaesthetics: essential safety measure or a hindrance to rapid safe intubation? Resuscitation. 2010 Jul;81(7):810-6. doi: 10.1016/j.resuscitation.2010.02.023 [MEDLINE]
A novel bimanual lip extraction and backward, upward, rightward pressure combination for improved laryngoscopy. Am J Emerg Med. 2017 Jan;35(1):177. doi: 10.1016/j.ajem.2016.10.014 [MEDLINE]
Mandibular Advancement
Mandibular advancement improves the laryngeal view during direct laryngoscopy performed by inexperienced physicians. Anesthesiology. 2004 Mar;100(3):598-601 [MEDLINE]
Gum Elastic Bougie
Effect of Use of a Bougie vs Endotracheal Tube and Stylet on First-Attempt Intubation Success Among Patients With Difficult Airways Undergoing Emergency Intubation: A Randomized Clinical Trial. JAMA. 2018 Jun 5;319(21):2179-2189. doi: 10.1001/jama.2018.6496 [MEDLINE]
Rapid Sequence Intubation (RSI)
A comparison of blind nasotracheal and succinylcholine-assisted intubation in the poisoned patient. Ann Emerg Med. 1987;16(6):650 [MEDLINE]
Decreased circulation time in the upper limb reduces the lag time of the finger pulse oximeter response. Can J Anaesth. 1992 Jan;39(1):87-9 [MEDLINE]
Rapid-sequence intubation in head trauma. Ann Emerg Med. 1993;22(6):1008 [MEDLINE]
Critical hemoglobin desaturation will occur before return to an unparalyzed state following 1 mg/kg intravenous succinylcholine. Anesthesiology. 1997;87(4):979 [MEDLINE]
Airway management in the emergency department: a one-year study of 610 tracheal intubations. Ann Emerg Med. 1998;31(3):325 [MEDLINE]
Complications of emergency intubation with and without paralysis. Am J Emerg Med. 1999;17(2):141 [MEDLINE]
The failed intubation attempt in the emergency department: analysis of prevalence, rescue techniques, and personnel. J Emerg Med. 2002;23(2):131 [MEDLINE]
A preliminary study of the optimal anesthesia positioning for the morbidly obese patient. Obes Surg. 2003;13(1):4 [MEDLINE]
Airway management by US and Canadian emergency medicine residents: a multicenter analysis of more than 6,000 endotracheal intubation attempts. Ann Emerg Med. 2005;46(4):328 [MEDLINE]
A prospective, randomised controlled trial comparing the efficacy of pre-oxygenation in the 20 degrees head-up vs supine position. Anaesthesia. 2005;60(11):1064 [MEDLINE]
Nasopharyngeal oxygen insufflation following pre-oxygenation using the four deep breath technique. Anaesthesia. 2006;61(5):427 [MEDLINE]
Optimizing preoxygenation in adults. Can J Anaesth. 2009 Jun;56(6):449-66 [MEDLINE]
Apneic oxygenation during prolonged laryngoscopy in obese patients: a randomized, controlled trial of nasal oxygen administration. J Clin Anesth. 2010;22(3):164 [MEDLINE]
Rapid sequence induction and intubation: current controversy. Anesth Analg. 2010 May;110(5):1318-25 [MEDLINE]
Preoxygenation with 20ºhead-up tilt provides longer duration of non-hypoxic apnea than conventional preoxygenation in non-obese healthy adults. J Anesth. 2011 Apr;25(2):189-94 [MEDLINE]
Preoxygenation and prevention of desaturation during emergency airway management. Ann Emerg Med. 2012 Mar;59(3):165-75.e1 [MEDLINE]
Neuromuscular blocking agent administration for emergent tracheal intubation is associated with decreased prevalence of procedure-related complications. Crit Care Med. 2012 Jun;40(6):1808-1 [MEDLINE]
Association between repeated intubation attempts and adverse events in emergency departments: an analysis of a multicenter prospective observational study. Ann Emerg Med. 2012 Dec;60(6):749-754.e2 [MEDLINE]
Preoxygenation and prevention of desaturation during emergency airway management. Ann Emerg Med. 2012 Mar;59(3):165-75.e1 [MEDLINE]
The importance of first pass success when performing orotracheal intubation in the emergency department. Acad Emerg Med. 2013;20(1):71 [MEDLINE]
Neuromuscular blockade improves first-attempt success for intubation in the intensive care unit. A propensity matched analysis. Ann Am Thorac Soc. 2015;12(5):734 [MEDLINE]
Techniques, success, and adverse events of emergency department adult intubations. Ann Emerg Med. 2015 Apr;65(4):363-370.e1 [MEDLINE]
PREOXYFLOW Trial. High-flow nasal cannula oxygen during endotracheal intubation in hypoxemic patients: a randomized controlled clinical trial. Intensive Care Med. 2015;41(9):1538 [MEDLINE]
Transnasal humidified rapid-insufflation ventilatory exchange (THRIVE): a physiological method of increasing apnoea time in patients with difficult airways. Anaesthesia 2015;70:323-9 [MEDLINE]
Use of high-flow nasal cannula oxygen therapy to prevent desaturation during tracheal intubation of intensive care patients with mild-to-moderate hypoxemia. Crit Care Med. 2015;43:574–583 [MEDLINE]
The Physiologically Difficult Airway. West J Emerg Med. 2015;16(7):1109 [MEDLINE]
Apneic oxygenation was associated with decreased desaturation rates during rapid sequence intubation by an Australian helicopter emergency medicine service. Ann Emerg Med. 2015 Apr;65(4):371-6 [MEDLINE]
Randomized Trial of Apneic Oxygenation during Endotracheal Intubation of the Critically Ill. Am J Respir Crit Care Med. 2016;193(3):273 [MEDLINE]
First Pass Success Without Hypoxemia Is Increased With the Use of Apneic Oxygenation During Rapid Sequence Intubation in the Emergency Department. Acad Emerg Med. 2016;23(6):703 [MEDLINE]
High-Flow Nasal Cannula Versus Bag-Valve-Mask for Preoxygenation Before Intubation in Subjects With Hypoxemic Respiratory Failure. Respir Care. 2016;61(9):1160 [MEDLINE]
The effectiveness of rapid sequence intubation (RSI) versus non-RSI in emergency department: an analysis of multicenter prospective observational study. Int J Emerg Med. 2017;10(1):1 [MEDLINE]
Management of Patients with Predicted Difficult Airways in an Academic Emergency Department. J Emerg Med. 2017;53(2):163 [MEDLINE]
Pre-oxygenation: Implications in emergency airway management. Am J Emerg Med. 2017;35(8):1177 [MEDLINE]
Respiratory support techniques to avoid desaturation in critically ill patients requiring endotracheal intubation: A systematic review and meta-analysis J Crit Care. 2017 Oct;41:98-106. doi: 10.1016/j.jcrc.2017.05.003 [MEDLINE]
Emergency Department use of Apneic Oxygenation Versus Usual Care During Rapid Sequence Intubation: A Randomized Controlled Trial (The ENDAO Trial). Acad Emerg Med. 2017;24(11):1387 [MEDLINE]
Apneic oxygenation reduces the incidence of hypoxemia during emergency intubation: A systematic review and meta-analysis. Am J Emerg Med. 2017;35(8):1184 [MEDLINE]
Intubation using apnoeic oxygenation to prevent desaturation: A systematic review and meta-analysis. J Crit Care. 2017;41:42 [MEDLINE]
Effectiveness of Apneic Oxygenation During Intubation: A Systematic Review and Meta-Analysis. Ann Emerg Med. 2017;70(4):483 [MEDLINE]
PreVent Trial. Bag-Mask Ventilation during Tracheal Intubation of Critically Ill Adults. N Engl J Med. 2019;380(9):811 [MEDLINE]
Delayed Sequence Intubation (DSI)
Delayed sequence intubation: a prospective observational study. Ann Emerg Med. 2015;65(4):349 [MEDLINE]
Awake Laryngoscopy
Endotracheal intubation in the ICU. Crit Care. 2015;19:258 [MEDLINE]
Awake Laryngoscopy in the Emergency Department. J Emerg Med. 2017;52(3):324 [MEDLINE]
Video Laryngoscopy
Videolaryngoscopy with glidescope reduces cervical spine movement in patients with unsecured cervical spine. J Emerg Med. 2013 Apr;44(4):750-6 [MEDLINE]
Video laryngoscopy versus direct laryngoscopy for orotracheal intubation in the intensive care unit: a systematic review and meta-analysis. Intensive Care Med. 2014 May;40(5):629-39. doi: 10.1007/s00134-014-3236-5 [MEDLINE]
Comparison of video laryngoscopy versus direct laryngoscopy during urgent endotracheal intubation: a randomized controlled trial. Crit Care Med. 2015;43(3):636 [MEDLINE]
Confirmation of Endotracheal Tube Placement
Accidental intubation of the oesophagus. Anaesth Intensive Care. 1980;8(2):183 [MEDLINE]
End-tidal CO2 as a guide to successful cardiopulmonary resuscitation: a preliminary report. Crit Care Med. 1985;13(11):910 [MEDLINE]
Esophageal intubation: a review of detection techniques. Anesth Analg. 1986;65(8):886 [MEDLINE]
Unrecognized endobronchial intubation of emergency patients. Ann Emerg Med. 1989;18(8):853 [MEDLINE]
A comparative study of methods of detection of esophageal intubation. Anesth Analg. 1989;69(5):627 [MEDLINE]
Multicenter study of a portable, hand-size, colorimetric end-tidal carbon dioxide detection device. Ann Emerg Med. 1992 May;21(5):518-23 [MEDLINE]
Women are at greater risk than men for malpositioning of the endotracheal tube after emergent intubation. Crit Care Med. 1994;22(7):1127 [MEDLINE]
Proper depth placement of oral endotracheal tubes in adults prior to radiographic confirmation. Acad Emerg Med. 1995;2(1):20 [MEDLINE]
Use of tube condensation as an indicator of endotracheal tube placement. Ann Emerg Med. 1998;31(5):575 [MEDLINE]
Comparison of three different methods to confirm tracheal tube placement in emergency intubation. Intensive Care Med. 2002;28(6):701 [MEDLINE]
Towards evidence based emergency medicine: best BETs from the Manchester Royal Infirmary. Colourimetric CO(2) detector compared with capnography for confirming ET tube placement. Emerg Med J. 2003 May;20(3):265-6 [MEDLINE]
The assessment of three methods to verify tracheal tube placement in the emergency setting. Resuscitation 2003; 56:153-157 [MEDLINE]
An assessment of a tracheal tube introducer as an endotracheal tube placement confirmation device. Am J Emerg Med. 2005;23(6):754 [MEDLINE]
Caution when using colorimetry to confirm endotracheal intubation. Anesth Analg 2007;104:738 [MEDLINE]
Endobronchial intubation detected by insertion depth of endotracheal tube, bilateral auscultation, or observation of chest movements: randomised trial. BMJ. 2010;341:c5943 [MEDLINE]
Ultrasonography in the management of the airway. Acta Anaesthesiol Scand. 2011 Nov;55(10):1155-73. Epub 2011 Sep 7 [MEDLINE]
Tracheal rapid ultrasound exam (T.R.U.E.) for confirming endotracheal tube placement during emergency intubation. Resuscitation. 2011 Oct;82(10):1279-84. Epub 2011 Jun 1 [MEDLINE]
Transtracheal ultrasound for verification of endotracheal tube placement: a systematic review and meta-analysis. Can J Anaesth. 2015 Apr;62(4):413-23. Epub 2014 Dec 24 [MEDLINE]
Ultrasonography for confirmation of endotracheal tube placement: a systematic review and meta-analysis. Resuscitation. 2015;90:97 [MEDLINE]
Auscultation versus Point-of-care Ultrasound to Determine Endotracheal versus Bronchial Intubation: A Diagnostic Accuracy Study. Anesthesiology. 2016 May;124(5):1012-20 [MEDLINE]
Endotracheal Tube Movement with Change in Head Position
Alteration of endotracheal tube position. Flexion and extension of the neck. Crit Care Med. 1976 Jan-Feb;4(1):8-12 [MEDLINE]
Laryngeal Mask Airway (LMA)
Effect of the laryngeal mask airway on lower oesophageal sphincter pressure in patients during general anaesthesia. Br J Anaesth. 1992 Oct;69(4):346-8 [MEDLINE]
Clinical significance of pulmonary aspiration during the perioperative period. Anesthesiology. 1993;78(1):56 [MEDLINE]
The incidence of aspiration associated with the laryngeal mask airway: a meta-analysis of published literature. J Clin Anesth. 1995;7(4):297 [MEDLINE]
Gastric regurgitation during general anaesthesia in different positions with the laryngeal mask airway. Anaesthesia. 1995 Dec;50(12):1053-5 [MEDLINE]
Survey of laryngeal mask airway usage in 11,910 patients: safety and efficacy for conventional and nonconventional usage. Anesth Analg. 1996 Jan;82(1):129-33 [MEDLINE]
Gastroesophageal reflux during spontaneous respiration with the laryngeal mask airway. Can J Anaesth. 1999 Mar;46(3):268-70 [MEDLINE]
ProSeal laryngeal mask protects against aspiration of fluid in the pharynx. Br J Anaesth. 2002 Apr;88(4):584-7 [MEDLINE]
Aspiration and the laryngeal mask airway: three cases and a review of the literature. Br J Anaesth. 2004 Oct;93(4):579-82 [MEDLINE]
The Proseal LMA is a useful rescue device during failed rapid sequence intubation: two additional cases. Can J Anaesth. 2005 Jun;52(6):630-3 [MEDLINE]
Use of manometry for laryngeal mask airway reduces postoperative pharyngolaryngeal adverse events: a prospective, randomized trial. Anesthesiology. 2010 Mar;112(3):652-7 [MEDLINE]
Major complications of airway management in the UK: results of the Fourth National Audit Project of the Royal College of Anaesthetists and the Difficult Airway Society. Part 1: anaesthesia. Br J Anaesth. 2011 May;106(5):617-31 [MEDLINE]
Major complications of airway management in the UK: results of the Fourth National Audit Project of the Royal College of Anaesthetists and the Difficult Airway Society. Part 2: intensive care and emergency departments. Br J Anaesth. 2011;106(5):632 [MEDLINE]
Can we make airway management (even) safer?–lessons from national audit. Anaesthesia. 2011;66 Suppl 2:27 [MEDLINE]
New supraglottic airway with built-in pressure indicator decreases postoperative pharyngolaryngeal symptoms: a randomized controlled trial. Can J Anaesth. 2013 Dec;60(12):1197-203 [MEDLINE]
Feasibility of a laryngeal tube for airway management during cardiac arrest by first responders. Resuscitation. 2013;84(4):446 [MEDLINE]
Supraglottic airway devices versus tracheal intubation for airway management during general anaesthesia in obese patients. Cochrane Database Syst Rev. 2013 [MEDLINE]
Airway management by physician-staffed Helicopter Emergency Medical Services – a prospective, multicentre, observational study of 2,327 patients. Scand J Trauma Resusc Emerg Med. 2015;23:57 [MEDLINE]
Safety and feasibility of the laryngeal tube when used by EMTs during out-of-hospital cardiac arrest. Am J Emerg Med. 2015;33(8):1050 [MEDLINE]
Effect of a Strategy of Initial Laryngeal Tube Insertion vs Endotracheal Intubation on 72-Hour Survival in Adults With Out-of-Hospital Cardiac Arrest: A Randomized Clinical Trial. JAMA. 2018;320(8):769 [MEDLINE]
Effect of a Strategy of a Supraglottic Airway Device vs Tracheal Intubation During Out-of-Hospital Cardiac Arrest on Functional Outcome: The AIRWAYS-2 Randomized Clinical Trial. JAMA. 2018;320(8):779 [MEDLINE]
Cricothyrotomy in the emergency department. Ann Emerg Med. 1982;11(7):361 [MEDLINE]
Cricothyrotomy in the emergency department revisited. J Emerg Med. 1989;7(2):115 [MEDLINE]
Prehospital cricothyrotomy: an investigation of indications, technique, complications, and patient outcome. Ann Emerg Med. 1990;19(3):279 [MEDLINE]
Declining rate of cricothyrotomy in trauma patients with an emergency medicine residency: implications for skills training. Acad Emerg Med. 1998;5(3):247 [MEDLINE]
Comparison of 2 cricothyrotomy techniques: standard method versus rapid 4-step technique. Ann Emerg Med. 1998;32(4):442 [MEDLINE]
Outcomes of emergency surgical airway procedures in a hospital-wide setting. Laryngoscope. 1999;109(11):1766 [MEDLINE]
Comparison of wire-guided cricothyrotomy versus standard surgical cricothyrotomy technique. J Emerg Med. 1999;17(6):957 [MEDLINE]
Cricothyroidotomy: when, why, and why not? Am J Otolaryngol. 2000;21(3):195 [MEDLINE]
Cricothyrotomy: a 5-year experience at one institution. J Emerg Med. 2003;24(2):151 [MEDLINE]
[Emergency cricothyrotomy–puncture or anatomical preparation? Peculiarities of two methods for emergency airway access demonstrated in a cadaver model]. Anaesthesist. 2003;52(4):304 [MEDLINE]
Needle vs surgical cricothyroidotomy: a short cut to effective ventilation. Anaesthesia. 2006;61(10):962[MEDLINE]
A comparison of two emergency cricothyroidotomy kits in human cadavers. Anesth Analg. 2008;106(1):182 [MEDLINE]
Accuracy of surface landmark identification for cannula cricothyroidotomy. Anaesthesia. 2010;65(9):889 [MEDLINE]
Accuracy of identification of the cricothyroid membrane in female subjects using palpation: an observational study. Anesth Analg. 2012 May;114(5):987-92 [MEDLINE]
Accuracy of conventional digital palpation and ultrasound of the cricothyroid membrane in obese women in labour. Anaesthesia. 2015 Nov;70(11):1230-4 [MEDLINE]
Comparing success rates of anesthesia providers versus trauma surgeons in their use of palpation to identify the cricothyroid membrane in female subjects: a prospective observational study. Can J Anaesth. 2016 Jul;63(7):807-817 [MEDLINE]
Adverse Effects/Complications
Ulcerative tracheo-oesophageal fistula during treatment by tracheostomy and intermittent positive pressure ventilation. Thorax. 1972;27(3):338 [MEDLINE]
Tracheal injury following prolonged intubation. Aust N Z J Surg. 1976 Feb;46(1):18-25 [MEDLINE]
Intubation lesions of the larynx. Br J Anaesth. 1978;50(6):587 [MEDLINE]
Postoperative sore throat: influence of tracheal tube lubrication versus cuff design. Can Anaesth Soc J. 1980;27(2):156 [MEDLINE]
Laryngeal injuries secondary to nasogastric tubes. Ann Otol Rhinol Laryngol. 1981;90(5 Pt 1):469 [MEDLINE]
The influence of endotracheal tube cuff design and cuff lubrication on postoperative sore throat. Anesthesiology. 1983;58(4):376 [MEDLINE]
Laryngotracheal injury due to endotracheal intubation: incidence, evolution, and predisposing factors. A prospective long-term study. Crit Care Med. 1983;11(5):362 [MEDLINE]
True vocal cord paralysis following intubation. Laryngoscope. 1985;95(11):1352 [MEDLINE]
Correlation of endotracheal tube size with sore throat and hoarseness following general anesthesia. Anesthesiology. 1987 Sep;67(3):419-21 [MEDLINE]
Laryngeal complications of prolonged intubation. Chest. 1989;96(4):877 [MEDLINE]
Anesthesia-induced dental injury. Int Anesthesiol Clin. 1989;27(2):120 [MEDLINE]
Unsuspected cervical fractures: a common problem in ankylosing spondylitis. Anesthesiology. 1989;70(5):869 [MEDLINE]
Tracheoesophageal fistula formation in intubated patients. Risk factors and treatment with high-frequency jet ventilation. Chest. 1990;98(1):161 [MEDLINE]
Swallowing disorders in patients with prolonged orotracheal intubation or tracheostomy tubes. Crit Care Med. 1990;18(12):1328 [MEDLINE]
Adverse respiratory events infrequently leading to malpractice suits. A closed claims analysis. Anesthesiology. 1991;75(6):932 [MEDLINE]
Surgical considerations in tracheal stenosis. Laryngoscope. 1992 Mar;102(3):237-43 [MEDLINE]
Resolution of laryngeal injury following translaryngeal intubation. Am Rev Respir Dis. 1992;145(2 Pt 1):361 [MEDLINE]
Evaluation of risk factors for laryngeal edema after tracheal extubation in adults and its prevention by dexamethasone. A placebo-controlled, double-blind, multicenter study. Anesthesiology. 1992;77(2):245 [MEDLINE]
Massive airway leaks: an analysis of the role of endotracheal tubes. Crit Care Med. 1993;21(4):518 [MEDLINE]
Mediastinitis and sepsis syndrome following intubation. Anaesthesia. 1994;49(10):883 [MEDLINE]
Risk factors associated with prolonged intubation and laryngeal injury. Otolaryngol Head Neck Surg. 1994;111(4):453 [MEDLINE]
[A survey of perioperative bronchospasm in 105 patients with reactive airway disease]. Masui. 1995;44(3):396 [MEDLINE]
Management of acquired tracheoesophageal fistula. Chest Surg Clin N Am. 1996 Nov;6(4):819-36 [MEDLINE]
Gastroesophageal reflux in patients with subglottic stenosis. Arch Otolaryngol Head Neck Surg. 1998 May;124(5):551-5 [MEDLINE]
Airway injury during anesthesia: a closed claims analysis. Anesthesiology. 1999;91(6):170 [MEDLINE]
Postextubation fiberoptic endoscopic evaluation of swallowing after prolonged endotracheal intubation: a randomized, prospective trial. Crit Care Med. 2001;29(9):1710 [MEDLINE]
Association of airway abnormalities and risk factors in 37 subglottic stenosis patients. Otolaryngol Head Neck Surg. 2006 Sep;135(3):434-7 [MEDLINE]
Review of tracheo-esophageal fistula associated with endotracheal intubation. J Surg Educ. 2007 Jul-Aug;64(4):237-40 [MEDLINE]
Risk factors for adult laryngotracheal stenosis: a review of 74 cases. Ann Otol Rhinol Laryngol. 2007 Mar;116(3):206-10 [MEDLINE]
Short-term effects of endotracheal intubation on voice. J Voice. 2007 Nov;21(6):762-8 [MEDLINE]
Age and comorbidity as risk factors for vocal cord paralysis associated with tracheal intubation. Br J Anaesth. 2007 Apr;98(4):524-30 [MEDLINE]
Effect of positive expiratory pressure and type of tracheal cuff on the incidence of aspiration in mechanically ventilated patients in an intensive care unit. Crit Care Med. 2008;36(2):409 [MEDLINE]
CDC/NHSN surveillance definition of health care-associated infection and criteria for specific types of infections in the acute care setting. Am J Infect Control. 2008;36(5):309 [MEDLINE]
Spiral CT virtual bronchoscopy with multiplanar reformatting in the evaluation of post-intubation tracheal stenosis: comparison between endoscopic, radiological and surgical findings. Eur Arch Otorhinolaryngol. 2009;266(6):863 [MEDLINE]
Epidemiology of anesthesia-related mortality in the United States, 1999-2005. Anesthesiology. 2009 Apr;110(4):759-65 [MEDLINE]
Incidence and impact of dysphagia in patients receiving prolonged endotracheal intubation after cardiac surgery. Can J Surg. 2009;52(2):119 [MEDLINE]
An intervention to decrease complications related to endotracheal intubation in the intensive care unit: a prospective, multiple-center study. Intensive Care Med. 2010;36(2):248 [MEDLINE]
The incidence of dysphagia following endotracheal intubation: a systematic review. Chest. 2010;137(3):665 [MEDLINE]
Postoperative patient complaints: a prospective interview study of 12,276 patients. J Clin Anesth. 2010;22(1):13 [MEDLINE]
Cost analysis of intubation-related tracheal injury using a national database. Otolaryngol Head Neck Surg. 2010 Jul;143(1):31-6. doi: 10.1016/j.otohns.2009.11.004 [MEDLINE]
Endotracheal tube size and sore throat following surgery: a randomized-controlled study. Acta Anaesthesiol Scand. 2010 Feb;54(2):147-53 [MEDLINE]
Post-intubation laryngeal injuries and extubation failure: a fiberoptic endoscopic study. Intensive Care Med. 2010 Jun;36(6):991-8. Epub 2010 Mar 18 [MEDLINE]
Postextubation obstructive pseudomembranes: a case series and review of a rare complication after endotracheal intubation. Lung. 2011 Feb;189(1):81-6. Epub 2010 Nov 17 [MEDLINE]
Laryngeal injury from prolonged intubation: a prospective analysis of contributing factors. Laryngoscope. 2011;121(3):596 [MEDLINE]
Major complications of airway management in the UK: results of the Fourth National Audit Project of the Royal College of Anaesthetists and the Difficult Airway Society. Part 1: anaesthesia. Br J Anaesth. 2011 May;106(5):617-31. doi: 10.1093/bja/aer058 [MEDLINE]
Major complications of airway management in the UK: results of the Fourth National Audit Project of the Royal College of Anaesthetists and the Difficult Airway Society. Part 2: intensive care and emergency departments. Br J Anaesth. 2011 May;106(5):632-42. doi: 10.1093/bja/aer059 [MEDLINE]
Association between repeated intubation attempts and adverse events in emergency departments: an analysis of a multicenter prospective observational study. Ann Emerg Med. 2012 Dec;60(6):749-754.e2 [MEDLINE]
Incidence of and risk factors for severe cardiovascular collapse after endotracheal intubation in the ICU: a multicenter observational study. Crit Care. 2015 Jun 18;19:257. doi: 10.1186/s13054-015-0975-9 [MEDLINE]
Surgical Management of Benign Acquired Tracheoesophageal Fistulas: A Ten-Year Experience. Ann Thorac Surg. 2016;102(4):1081 [MEDLINE]
Incidence and risk factors of postoperative sore throat after endotracheal intubation in Korean patients. J Int Med Res. 2017;45(2):744 [MEDLINE]
Effect of Endotracheal Tube Cuff Shape on Postoperative Sore Throat After Endotracheal Intubation. Anesth Analg. 2017;125(4):1240 [MEDLINE]
The Effect of Zinc Lozenge on Postoperative Sore Throat: A Prospective Randomized, Double-Blinded, Placebo-Controlled Study. Anesth Analg. 2018;126(1):78 [MEDLINE]
Cardiac Arrest and Mortality Related to Intubation Procedure in Critically Ill Adult Patients: A Multicenter Cohort Study. Crit Care Med. 2018 Apr;46(4):532-539. doi: 10.1097/CCM.0000000000002925 [MEDLINE]
