Gastrointestinal Instability

• Recent Esophageal/Gastric Surgery (see Esophagectomy and Gastrectomy)
• Significant Gastrointestinal Hemorrhage (see Gastrointestinal Hemorrhage)
• Vomiting/Aspiration Risk (see Nausea and Vomiting)

Neuropsychiatric Instability

• Agitated Delirium/Inability to Cooperate (see Delirium)
• Psychosis (see Psychosis)
• Severe Encephalopathy (GCS <10) (see Obtundation/Coma)
  • However, Selected Patients with Hypercapnic Encephalopathy Can Be Cautiously Treated with NIPPV (Chest, 2005) [MEDLINE] (Chest, 2005) [MEDLINE]
  • In Such Patients, Mental Status Generally Improves within 1-2 hrs (as pCO2 Decreases)

Otolaryngologic/Facial Instability

• Facial Surgery, Trauma, or Anatomic Deformity
• Inability to Achieve NIPPV Mask/Helmet Fit/Seal
• Recent Upper Airway Surgery
• Upper Airway Obstruction/Inability to Protect Airway (see Obstructive Lung Disease)

Pulmonary Instability

• Excessive Secretions
• Hemoptysis (see Hemoptysis)
• Respiratory Arrest
• Untreated Pneumothorax (see Pneumothorax)

Physiologic Effects of Noninvasive Positive Pressure Ventilation (NIPPV)

• Increased Functional Residual Capacity (FRC)
  • Resulting in Increased Lung Compliance and Decreased the Elastic Work of Breathing, Culminating in More Efficient Ventilation
• Decreased Preload (Venous Return to the Right Side of the Heart) (NEJM, 1991) [MEDLINE]
• Decreased Left Ventricular Afterload (NEJM, 1991) [MEDLINE]

Timing of Initiation of Noninvasive Positive Pressure Ventilation (NIPPV)

Pre-Hospital Initiation of Noninvasive Positive-Pressure Ventilation

• Systematic Review and Meta-Analysis of Pre-Hospital Initiation of NIPPV in Adults with Severe Respiratory Distress (Ann Emerg Med, 2014) [MEDLINE]: n = 632 (7 trials)
  • Pre-Hospital Initiation of NIPPV for Respiratory Distress Decreased In-Hospital Mortality Rate (Relative Risk 0.58) and Need for Invasive Mechanical Ventilation (Relative Risk 0.37)
  • There was No Difference in ICU Length of Stay or Hospital Length of Stay
• Systematic Review, Network Meta-Analysis, and Individual Patient Data Meta-Analysis of Pre-Hospital NIPPV in Acute Respiratory Failure (Acad Emerg Med, 2014) [MEDLINE]: n = 8 trials
  • Pre-Hospital CPAP Decreased the Mortality Rate and Intubation Rate
  • Pre-Hospital BiPAP Effect on Mortality Rate and Intubation was Uncertain

Hospital Initiation of Noninvasive Positive-Pressure Ventilation

• Initiate NIPPV as Soon as Possible
  • Early Application of NIPPV Improved the Arterial Blood Gas and Decreased the Need for Intubation in Acute COPD Exacerbation (Chin Med J, 2005) [MEDLINE]

Site of Initiation of Noninvasive Positive Pressure Ventilation (NIPPV)

General Comments

• Clinical Monitoring of NIPPV is Best Accomplished in the ICU Setting (or Emergency Department)
  • Some Facilities Allow for Short Duration Use of NIPPV in Other Less Monitored Settings

Clinical Efficacy

• Italian Study of the Use of NIPPV on Hospital Wards (Crit Care Med, 2016) [MEDLINE]
  • Use of NIPPV on Hospital Wards Has Been Reported to Have Similar Mortality Rates as Those in the ICU
  • Good Prognostic Factors
    • Postoperative Respiratory Failure
  • Poor Prognostic Factors
    • Pneumonia with Hematologic Malignancy
    • Solid Malignancy
    • Do Not Resuscitate Status
• Italian Observational Study of Noninvasive Positive-Pressure Ventilation in Pneumonia Outside of the ICU (Eur J Intern Med, 2018) [MEDLINE]
  • Outside of the ICU Setting, CPAP was Predominantly Used for Hypoxemic (Non-Hypercapnic) Respiratory Failure, While NIPPV was Predominantly Used for Hypoxemic, Hypercapnic Respiratory Failure
  • Do Not Intubate (DNI) Order and Charlson Comorbidity Index (CCI) ≥3 were Independent Risk Factors for In-Hospital Mortality

Mask Interface

Types of Masks

• Oronasal Mask (Encompassing Both the Nose and Mouth)
  • Most Commonly Used Initial Mask
  • Advantages
    • Higher Level of Ventilation than a Nasal Mask (Due to Less Oral Air Leak)
  • Disadvantages
    • Carbon Dioxide Rebreathing
    • More Difficult to Monitor for Vomiting/Aspiration (as Compared to a Nasal Mask)
• Nasal Mask
  • Advantages
    • Produces Less Claustrophobia and a Higher Level of Comfort (as Compared to an Oronasal Mask): this may be beneficial for longer-term use
    • Allows Expectoration
    • Allows Speech
    • Allows Oral Intake
    • Easier Monitoring for Vomiting/Aspiration (as Compared to a Oronasal Mask)
  • Disadvantages
    • Air Leak: chin strap may be used to decrease the oral leak
    • Due to Significant Airflow Resistance of Nasal Passages, the Selected Inspiratory Pressure Needs to Account for This When a Nasal Mask is Used
• Nasal Pillows
  • Advantages
    • Produces Less Claustrophobia and a Higher Level of Comfort (as Compared to an Oronasal Mask): this may be beneficial for longer-term use
    • Allows Expectoration
    • Allows Speech
    • Allows Oral Intake
    • Easier Monitoring for Vomiting/Aspiration (as Compared to a Oronasal Mask)
  • Disadvantages
    • Air Leak: chin strap may be used to decrease the oral leak
    • Due to Significant Airflow Resistance of Nasal Passages, the Selected Inspiratory Pressure Needs to Account for This When a Nasal Mask is Used
• Full Face Mask (Encompassing the Nose, Mouth, and Eyes)
  • Full Face Mask May Be Useful in Some Cases if the Oronasal Mask Fails (Crit Care Med, 2013) [MEDLINE]
• Helmet
  • Helmet May Be Used in Some Cases if the Oronasal Mask Fails
  • Advantages
    • Allows Speech
    • Allows Drinking Through a Straw
    • Allows Reading
  • Disadvantages
    • Carbon Dioxide Rebreathing (Which is Typically Compensated for by Increased Flow Rates) (Intensive Care Med, 2003) [MEDLINE] (Intensive Care Med, 2008) [MEDLINE]
    • High Noise Level (Which May Cause Hearing Damage) (Intensive Care Med, 2004) [MEDLINE]
    • Patient-Ventilator Dyssynchrony (Due to Delayed Triggering and Cycling) (Intensive Care Med, 2007) [MEDLINE]
    • Less Relief of Inspiratory Effort

Clinical Efficacy

• Prospective Case Series of Nasal NIPPV for Hypercapnic Respiratory Failure Due to COPD (Crit Care Med, 1994) [MEDLINE]
  • Patients who Failed Nasal NIPPV Had a Higher Severity of Illness and They were Unable to Minimize Oral Leak (Due to of Lack of Teeth, Secretions, or Respiratory Pattern) and Coordinate with the Ventilator
• Randomized Trial of NIPPV Masks in Chronic Hypercapnic Respiratory Failure (Crit Care Med, 2000) [MEDLINE]
  • Overall, the Nasal Mask was Better Tolerated than the Nasal Plugs or Full-Face Mask
  • pCO2 was Lower with the Full-Face Mask or Nasal Plugs than with the Nasal Mask
  • Minute Ventilation was Higher (Due to increased Tidal Volume) with the Full-Face Mask than with the Nasal Mask
  • No Differences were Observed in Tolerance to Ventilation, ABG, or Breathing Pattern Using Assist Control or Pressure-Assisted Modes
• Prospective Pilot Study of Helmet NIPPV (Crit Care Med, 2002) [MEDLINE]
  • Helmet Interface Had Better Tolerance and Fewer Complications (Skin Necrosis, Gastric Distension, Eye Irritation) than Face Mask NIPPV
• Multicenter Randomized Trial of Helmet NIPPV (Intensive Care Med, 2002) [MEDLINE]
  • Helmet Interface Decreased Skin Breakdown and Increased Patient Comfort, as Compared to Face Mask NIPPV
• Study of Helmet NIPPV in COPD Exacerbation (Anesthesiology, 2004) [MEDLINE]
  • Helmet was Less Efficient at Decreasing pCO2, as Compared to Face Mask NIPPV in COPD Exacerbation
• Randomized Trial of NIPPV Masks in Acute Hypercapnic Respiratory Failure (Crit Care Med, 2009) [MEDLINE]
  • Mask Failure (Need for Mask Change Due to Oral Air Leak) Occurred More Commonly in the Nasal Mask Group, as Compared to the Face Mask Group
  • Face Mask Group Had Higher Lower Respiratory Comfort and Higher Complications, as Compared to the Nasal Mask Group
• Trial of Rescue Therapy Switching to a Total Face Mask in “Do Not Intubate” Patients with Acute Respiratory Failure (Crit Care Med, 2013) [MEDLINE]
  • In Patients with Acute Hypercapnic Respiratory Failure, for Whom Escalation to Intubation Would Be Deemed Inappropriate, Switching to a Total Face Mask Can Be Used as Last Resort Therapy When Face Mask-Delivered NIPPV Has Failed to Reverse the Acute Respiratory Failure (Especially in the Setting of Prolonged NIPPV with Risk of Facial Pressure Sores)
• Trial Comparing Helmet vs Face Mask NIPPV in ARDS (JAMA, 2016) [MEDLINE]: single-center randomized, controlled trial
  • Helmet NIPPV Decreased the Intubation Rate and 90-Day Mortality in ARDS, as Compared to Face Mask NIPPV
  • Helmet NIPPV Increased Ventilator-Free Days, as Compared to Face Mask NIPPV

Ventilator Mode and Settings

Ventilator Modes

• General Comments
  • Use of a Standard ICU Ventilator or Bilevel-Type Ventilator is Strongly Recommended Over a Portable Ventilator for Several Reasons
    • Ability to Monitor Closely (with Alarms) to Rapidly Detect a Mask Leak or Patient Disconnection
    • Ability to Deliver a Precise and High Oxygen Concentration
    • Ability to Deliver Time-Limited Pressure Support Modes of Ventilation
    • Separate Inspiratory and Expiratory Tubing to Minimize Carbon Dioxide Rebreathing
• Assist Control (AC)
  • Advantage
    • Guarantees a Minimum Minute Ventilation
• Bilevel Positive Airway Pressure (BPAP)
  • Commonly Used
  • Related Terminology
    • “BiPAP”: specific type of BPAP delivered by a portable ventilator manufactured by the Respironics Corporation
    • “BIPAP”: specific type of BPAP delivered by a ventilator made by the Drager Medical Company
  • Bilevel-Type NIPPV Ventilator with an Oxygen Blender and Waveform Display
    • Examples
      • Philips Respironics V60 Ventilator
  • Conventional Ventilator
• Continuous Positive Airway Pressure (CPAP)
  • Commonly Used to Treat Cardiogenic Pulmonary Edema
• Pressure Support Ventilation (PSV)
  • Advantages
    • Maximizes Patient Comfort
    • Maximizes Patient-Ventilator Synchrony
• Proportional Assist Ventilation (PAV)

Clinical Efficacy-Chronic Obstructive Pulmonary Disease (COPD) Exacerbation

• Assist Control (AC) NIPPV Has Been Demonstrated to Decrease the Work of Breathing More than Pressure Support Ventilation (PSV) NIPPV, But PSV is Better Tolerated (Intensive Care Med, 1993) [MEDLINE] (Chest, 1997) [MEDLINE]
• Bilevel Positive Airway Pressure (BPAP) Has Been Demonstrated to Result in Improved Gas Exchange and Work of Breathing, as Compared tp Pressure Support Ventilation (PSV) (Am J Respir Crit Care Med, 1994) [MEDLINE] (Chest, 2000) [MEDLINE]

Clinical Efficacy-Cardiogenic Pulmonary Edema

• Meta-Analysis of NIPPV Modalities in Cardiogenic Pulmonary Edema (Lancet, 2006) [MEDLINE]: n = 23 trials
  • Bilevel Positive Airway Pressure (BPAP) and Continuous Positive Airway Pressure (CPAP) Had Similar Mortality Rates
• Prospective Randomized Trial of NIPPV Modalities in Cardiogenic Pulmonary Edema (Intensive Care Med, 2011) [MEDLINE]
  • Continuous Positive Airway Pressure (CPAP) and Pressure Support Ventilation (PSV) Had Similar Mortality Rates and Intubation Rates
  • Pressure Support Ventilation (PSV) Resulted in More Rapid Resolution of Respiratory Distress

Clinical Efficacy-Mixed Etiologies of Acute Respiratory Failure

• Pressure Support Ventilation (PSV) NIPPV and Proportional Assist Ventilation (PAV) NIPPV Have Been Demonstrated to Be Comparable (Am J Respir Crit Care Med, 2001) [MEDLINE] (Crit Care Med, 2002) [MEDLINE] (Intensive Care Med, 2003) [MEDLINE]

Clinical Efficacy-Tidal Volume

• Study of Tidal Volume on NIPPV in De Novo Acute Hypoxemic Respiratory Failure (Crit Care Med, 2016) [MEDLINE]: n = 62 (82% of cases were due to pneumonia)
  • Rationale: a low-moderate expired tidal volume can be difficult to achieve during NIPPV for de novo acute hypoxemic respiratory failure (i.e. respiratory failure not due to chronic lung disease or heart failure)
  • A Low Exhaled Tidal Volume is Almost Impossible to Achieve in Patients Receiving NIPPV for De Novo Acute Hypoxemic Respiratory Failure
  • High Exhaled Tidal Volume is Independently Associated with NIPPV Failure
    • In Patients with Moderate-Severe Hypoxemia, Exhaled Tidal Volume >9.5 mL/kg Predicted Body Weight Accurately Predicted NIPPV Failure

General Recommendations

• The Best Clinical Outcomes are Achieved in NIPPV with the Use of Assist Control (AC), Pressure Support Ventilation (PSV), or Bilevel Positive Airway Pressure (BPAP) Modes

Settings for Bilevel Positive Airway Pressure (BPAP)

• Initial Settings
  • Start with Low Pressures (Typically 8/4 cm H2O or 10/4 cm H2O) to Allow the Patient to Acclimate and Then Subsequently Gradually Ramp the Pressure Up to Optimize Lung Volumes
• Inspiratory Flow Rate
  • Adjust the “Rise Time” (Inspiratory Flow Rate) to Patient Comfort
  • COPD Patients Typically Prefer Shorter Inspiratory Times (Higher Inspiratory Flow Rates), Which Allow for Longer Expiratory Times
• Backup Respiratory Rate
  • Can Be Used
• Oxygen Delivery
  • Bilevel Devices without an Oxygen Blender: maximum FIO2 that can be achieved is 45-50%
  • Bilevel Device with an Oxygen Blender: necessary when higher FIO2 is required
• Humidification
  • Humidifier is Routinely Used to Decrease Work of Breathing and Enhance Patient Tolerance
    • Humidification is Recommended Since NIPPV Delivers Air with Low Relative Humidity, Especially with a High Inspiratory Pressure (Respir Care, 2007) [MEDLINE]

Monitoring of Noninvasive Positive Pressure Ventilation (NIPPV)

General Comments

• Clinical Monitoring is Crucial (Especially Early in the Application of NIPPV)

Monitor for Air Leaks

• Proper Mask Fit and Monitoring for Air Leaks from the Mask are Critical

Monitor Patient Tolerance

• Routine Monitoring of Patient Tolerance and Providing Encouragement/Assurance to the Patient are Critical to Ensure Patient Compliance

Gas Exchange Monitoring

• Serial Arterial Blood Gas (ABG) (see Arterial Blood Gas): routinely used
• Continuous Pulse Oximetry (see Pulse Oximetry): routinely used
• Continuous Capnography (see Capnography): may be used

Sedation

General Comments

• Sedation May Be Used Judiciously to Facilitate Patient Cooperation with NIPPV
  • Sedation with Non-Respiratory Depressants May Be Useful
    • Dexmedetomidine (Precedex) (see Dexmedetomidine)

Clinical Efficacy

• Randomized Trial of Dexmedetomidine vs Midazolam in Acute Respiratory Failure (Due to Acute COPD Exacerbation) Treated with NIPPV (Curr Ther Res Clin Exp, 2010) [MEDLINE]
  • Dexmedetomidine and Midazolam are Both Effective Sedatives for Patients Requiring NIPPV
  • Dexmedetomidine Required Fewer Adjustments in Dosing to Maintain Adequate Sedation, as Compared with Midazolam
• Study of Dexmedetomidine vs Midazolam in Acute Respiratory Failure (Due to Cardiogenic Pulmonary Edema) Treated with NIPPV (Intern Med, 2012) [MEDLINE]
  • In Acute Cardiogenic Pulmonary Edema, Dexmedetomidine Resulted in Improved Level of Sedation, Shortened the Duration of Mechanical Ventilation, Shortened the Length of ICU Stay, and Decreased the Risk of Nosocomial Pneumonia, as Compared to Midazolam
• Small Randomized Pilot Study of Dexmedetomidine During Noninvasive Ventilation for Patients with Acute Respiratory Failure (Chest, 2014) [MEDLINE]
  • Initiating Dexmedetomidine Soon After NIPPV for Acute Respiratory Failure Neither Improves Tolerance Nor Maintains Sedation at a Desired Goal
• Spanish Study of Use of Sedatives and Analgesics During NIPPV (Intensive Care Med, 2015) [MEDLINE]
  • Slightly <20% of Patients Received Analgesics or Sedatives During NIPPV and These Individually Did Not Impact Outcome
  • Simultaneous Use of Analgesics and Sedatives During NIPPV was Associated with an Increased NIPPV Failure Rate
• Study of Sedation for Treatment of Agitation During Noninvasive Positive-Pressure Ventilation (BMC Pulm Med, 2015) [MEDLINE]
  • Using RASS Score, Sedation During NIPPV in Proficient Hospitals May Be Favorably Used to Avoid NIPPV Failure in Agitated Patients, Even in Those Patients with Diseases with Poor Evidence for the Usefulness of NIPPV

Predictors of Successful Noninvasive Positive-Pressure Ventilation (NIPPV)

Clinical Efficacy

• Study of Factors Associated with NIPPV Success
  • Illness-Related Factors
    • Presence of COPD or Cardiogenic Pulmonary Edema
    • Lack of Pneumonia or ARDS
    • APACHE II Score <29 (X)
    • Minimal Secretions
    • Adequate Neurologic Status (Glasgow Coma at least 15) (X)
  • Patient-Related Factors
    • Dentate + Compatible Facial Structure with Minimal Air Leakage Around Mask
    • Patient Ability to Tolerate
  • Clinical Assessment-Related Factors
    • RR < 30 (X)
    • pH > 7.30 (X)
    • pO2/FIO2 Ratio >146 After First Hour (In Hypoxemic Respiratory Failure)
    • Good Synchronization with NIPPV
    • Good Response to NIPPV Within First 1-2 Hrs
      • Decreased RR
      • Improved pO2 + Decreased pCO2
      • Improved pH
  • (X) Presence of All Four in COPD Patients at Baseline: 94% Success Rate
  • (X) Presence of All Four After 2 Hrs: 97% Success Rate
• Prospective Study of Factors Predicting Success of NIPPV in Patients with Respiratory Failure Associated with Chronic Obstructive Pulmonary Disease (Chest, 2000) [MEDLINE]
  • Good Level of Consciousness at the Beginning of NIPPV and Improvement in pH, pCO2, and Level of Consciousness Values After 1 hr of NIPPV were Associated with Successful Responses to NIPPV in COPD Patients with Acute Hypercapnic Respiratory Failure
• Predictors of Success in Noninvasive Positive-Pressure Ventilation (International Consensus Conferences in Intensive Care Medicine: Noninvasive Positive-Pressure Ventilation in Acute Respiratory Failure, 2001) (Am J Respir Crit Care Med, 2001) [MEDLINE]
  • Ability to Cooperate
  • Better Neurologic Function
  • Improvement in Gas Exchange, Heart Rate, and Respiratory Rate within 2 hrs After Starting NIPPV
  • Less Air Leak (with Intact Dentition, etc)
  • Lower Acuity of Illness (Lower APACHE Score)
  • Moderate Acidemia (pH 7.10-7.35)
  • Moderate Hypercapnia (pCO2 45-92 mm Hg)
  • Younger Age
• Study of Risk Factors for NIPPV Failure in COPD (Eur Respir J, 2005) [MEDLINE]
  • Risk Factors for NIPPV Failure (at Admission)
    • APACHE II ≥29: odds ratio 3.30
    • GCS ≤11: odds ratio 4.40
    • GCS 12-14: odds ratio 2.29
    • pH <7.25: odds ratio 1.97
    • pH 7.25-7.29: odds ratio 1.08
    • RR ≥35: odds ratio 2.66
    • RR 30-34: odds ratio 1.83
  • Risk Factors for NIPPV Failure (at 2 hrs)
    • APACHE II ≥29: odds ratio 4.79
    • GCS ≤11: odds ratio 5.16
    • GCS 12-14: odds ratio 1.93
    • pH <7.25: odds ratio 21.02
    • pH 7.25-7.29: odds ratio 2.92
    • RR ≥35: odds ratio 4.95
    • RR 30-34: odds ratio 2.67
• Study of Factors Predicting Failure of Noninvasive Positive-Pressure Ventilation (Med Intensiva, 2016) [MEDLINE]: n = 410
  • Overall Failure Rate was 50% (with Overall Mortality Rate of 33%)
    • Failure Rate in Patients with Hypoxemic Respiratory Failure: 74%
    • Failure Rate in Postextubation Respiratory Failure: 54%
    • Failure Rate in Hypercapnic Respiratory Failure without COPD: 31%
    • Failure Rate in Respiratory Failure Due to COPD Exacerbation: 27%
    • Failure Rate in Respiratory Failure Due to Cardiogenic Pulmonary Edema: 21%
  • Factors Associated with Failure
    • Etiology of Respiratory Failure
    • Serum Bilirubin at the Start
    • APACHE II Score
    • Radiological Findings
    • Need for Sedation to Tolerate NIPPV
    • Change in Level of Consciousness
    • pO2/FIO2 Ratio
    • Respiratory Rate
    • Heart Rate
• Post-Hoc Analysis of Randomized Trial Studying the Predictors of Successful Noninvasive Positive-Pressure Ventilation Treatment for Acute Respiratory Failure (Crit Care Med, 2018) [MEDLINE]
  • Respiratory Rate ≥30 Breaths/min (One Hour After Treatment Initiation) was a Predictor of Intubation When Using Standard Oxygen Therapy (Odds Ratio, 2.76; 95% CI, 1.13-6.75; p = 0.03), But Not When Using High-Flow Nasal Cannula or Noninvasive Positive-Pressure Ventilation
  • pO2/FIO2 Ratio <200 mm Hg and a Tidal Volume >9 mL/kg Predicted Body Weight (One Hour After Treatment Initiation) were the Two Strongest Predictors of Intubation When Using Noninvasive Positive-Pressure Ventilation (Adjusted Odds Ratio, 4.26; 95% CI, 1.62-11.16; p = 0.003 and Adjusted Odds Ratio, 3.14; 95% CI, 1.22-8.06; p = 0.02, Respectively)
  • Tidal Volume >9 mL/kg Predicted Body Weight Predicted 90-Day Mortality

Impact of Noninvasive Positive-Pressure Ventilation (NIPPV) on Infection Rates

Clinical Efficacy

• Study of NIPPV Impact on Complication Rates in the Treatment of Acute Hypoxemic Respiratory Failure (NEJM, 1998) [MEDLINE]
  • NIPPV Decreased the Pneumonia and Sinusitis Complication Rates, as Compared to Invasive Mechanical Ventilation
  • NIPPV Decreased the Duration of Ventilation and the ICU Length of Stay, as Compared to Invasive Mechanical Ventilation
• French Case Control Study of NIPPV on Nosocomial Infection Rates in the Treatment of Respiratory Failure Due to COPD Exacerbation or Cardiogenic Pulmonary Edema (JAMA, 2000) [MEDLINE]
  • Use of NIPPV Instead of Invasive Mechanical Ventilation was Associated with a Decreased Risk of Nosocomial Infections, Decreased Antibiotic Use, Decreased Length of ICU Stay, and Decreased Mortality Rate

Cardiovascular Adverse Effects/Complications

Hypotension

• Mechanisms
  • Positive-Pressure Ventilation Increases Intrathoracic and Right Atrial Pressure, Resulting in Decreased Venous Return to the Right Side of the Heart and, Consequently, Decreased Right Ventricular Cardiac Output
    • Effect of Positive-Pressure Ventilation is Accentuated by the Presence of Hypovolemia (Anesthesiology, 1975) [MEDLINE]
  • Positive-Pressure Ventilation Causes Alveolar Inflation with Compression of the Pulmonary Vascular Bed, Resulting in Increased Pulmonary Vascular Resistance (PVR), and Consequently, Decreased 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, Resulting in Increased Pulmonary Vascular Resistance (PVR, and Consequently, Shift of the Intraventricular Septum Toward the Left (with Impaired Diastolic Left Ventricular Filling), Culminating in Decreased Left Ventricular Cardiac Output
  • Interaction Between Airway Pressures and Thoracic Structures
    • Hemodynamic Effects of Positive-Pressure 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)

Increased Risk of Myocardial Infarction (see Coronary Artery Disease)

• Epidemiology
  • Meta-Analysis of CPAP and BPAP NIPPV in Cardiogenic Pulmonary Edema (Crit Care, 2006) [MEDLINE]
    • Based on Limited Data, There was an Insignificant Trend Toward an Increase in New Acute Myocardial Infarction in Patients Treated with BiPAP (RR 2.10, 95% CI 0.91-4.84; P = 0.08; I2 = 25.3%)
  • Meta-Analysis of NIPPV in Cardiogenic Pulmonary Edema (Lancet, 2006) [MEDLINE]
    • Weak Evidence of an Increased Incidence of New Acute Myocardial Infarction with BPAP vs CPAP was Observed (1.49, 0.92-2.42, p=0.11)

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 (Such as the Pulmonary Capillary Wedge Pressure) are Assessed at End-Expiration (When Positive End-Expiratory Pressure/PEEP is the Predominant Determinant of Airway Pressure)
• Clinical
  • Positive End-Expiratory Pressure (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
  • Positive End-Expiratory Pressure (PEEP) May Also Artifactually Elevate the Central Venous Pressure (CVP)

Dermatologic Adverse Effects/Complications

Mask Discomfort/Skin Breakdown at Site of Mask or Strap Contact

• Epidemiology
  • Common with Prolonged Use of NIPPV

Gastrointestinal Adverse Effects/Complications

Gastric Insufflation/Distention

• Epidemiology
  • Frequent
• Clinical
  • Not Typically Severe
    • Use of Nasogastric Tube is Usually Not Required and, if Used, May Worsen the Mask Seal

Neurologic Adverse Effects/Complications

Claustrophobia (see Claustrophobia)

• Epidemiology
  • Common

Ophthalmologic Adverse Effects/Complications

Eye Irritation

• Epidemiology
  • May Occur with Use of a Full Face Mask

Otolaryngologic Adverse Effects/Complications

Mask Fit/Seal Problems

• Modest Mask Leaks are Common
• Air Leak from Mask May Require Mask Adjustment

Parotitis (see Parotitis)

• Epidemiology
  • Has Been Reported (J Intensive Care Med, 2016) [MEDLINE]

Sinus Pain/Ear Pain

• Physiology
  • Due to Excessive Air Pressure

Pulmonary Adverse Effects/Complications

Aspiration (see Aspiration Pneumonia)

• Epidemiology
  • May Occur

Barotrauma and Ventilator-Induced Lung Injury

• Epidemiology
  • 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]
• Physiology
  • Mechanical Ventilation Itself Increases the Risk of Barotrauma by Causing Alveolar Overdistention, Resulting in Alveolar Rupture
    • 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) (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)
  • Ventilator-Induced Lung Injury Has Been Observed in Moderate-Severe ARDS Patients Treated with NIPPV (Ann Transl Med, 2017) [MEDLINE]
  • Low Tidal Volumes May Be Difficult to Achieve in Acute Hypoxemic Respiratory Failure Treated with NIPPV (Crit Care Med, 2016) [MEDLINE]
    • In Patients with Moderate-Severe Hypoxemia, Tidal Volume >9.5 mL/kg Predicted Body Weight Accurately Predicted NIPPV Failure: high tidal volume was independently associated with NIPPV failure
• Clinical
  • Clinical Worsening of Lung Injury
  • Pneumothorax (see Pneumothorax)

Dyssynchrony

• Epidemiology
  • Dyssynchrony is Common in NIPPV (Intensive Care Med, 2009) [MEDLINE]
• Physiology
  • Leak is Believed to Play a Major Role in the Development of Dyssynchrony (Intensive Care Med, 2009)[MEDLINE]
• Treatment
  • Pressure Support Ventilation (PSV) is Believed to Decrease Dyssynchrony (and Bilevel Positive Airway Pressure/BPAP Likely is Similar)
  • Proportional Assist Ventilation (PAV) May Be an Alternative in a Patient Who Experiences Dyssynchrony on BPAP or PSV
  • While Proportional Assist Ventilation (PAV) is More Comfortable and Better Tolerated than Pressure Support Ventilation (PSV), There Have Been No Demonstrated Differences in Mortality or Intubation Rates (Am J Respir Crit Care Med, 2001) [MEDLINE] (Crit Care Med, 2002) [MEDLINE] (Intensive Care Med, 2003) [MEDLINE]
  • If an Air Leak is Present, a Time-Cycled Expiratory Trigger is Superior to a Flow-Cycled Expiratory Trigger (in Terms of Synchrony) (Intensive Care Med, 1999) [MEDLINE]: only specific ventilators are capable of delivering time-limited pressure support ventilation (PSV)

Impaired Cough and Secretion Clearance

• Expectoration May Be Facilitated by Using a Nasal Interface (Instead of a Full Face Mask, Oronasal Mask, etc)
• Early Bronchoscopy May Be Used in Some Cases to Clear Airway Secretions (Crit Care, 2010) [MEDLINE]
• In Patients with COPD Exacerbation or Bronchiectasis, High-frequency Chest Wall Oscillation or Intrapulmonary Percussive Ventilation (IPV) May Be Used to Mobilize Secretions (Crit Care, 2005) [MEDLINE] (Crit Care Med, 2006) [MEDLINE]
• In Patient with Neuromuscular Disease, But Intact Bulbar Function, NIPPV with Mechanical Cough Assistance (In-Exsufflator) or Manual Cough Assistance (Breath-Stacking Technique) May Be Useful to Enhance Secretion Clearance

Respiratory Failure Requiring Intubation

• Clinical Efficacy
  • Systematic Review of Noninvasive Positive Pressure Ventilation in COPD Exacerbation (Cochrane Database Syst Rev, 2004) [MEDLINE]
    • Noninvasive Positive Pressure Ventilation Has Clinical Benefit (Decreased Mortality Rate, Decreased Need for Intubation, Decreased Complications Associated with Treatment, and Decreased Length of Hospital Stay), in Addition to Usual Care, in the Management of COPD Exacerbation
    • Intubation Rate with Noninvasive Positive Pressure Ventilation Had a Relative Risk of 0.41 (95% CI 0.33, 0.53), as Compared to Standard Care
  • Meta-Analysis Noninvasive Positive Pressure Ventilation in Acute Cardiogenic Pulmonary Edema (Ann Intern Med, 2010) [MEDLINE]
    • Continuous Positive Airway Pressure Decreased the Mortality Rate with a Relative Risk of 0.64 (95% CI, 0.44 to 0.92)
    • Continuous Positive Airway Pressure Decreased the Intubation Rate with a Relative Risk of 0.44 (95% CI, 0.32 to 0.60]
  • Single-Center Retrospective Study of Failure of Noninvasive Positive-Pressure Ventilation in Acute Respiratory Failure (Ann Intensive Care, 2015) [MEDLINE]
    • In a Propensity-Adjusted Multivariate Regression Analysis (Corrected for Presence of Pneumonia or ARDS and Adjusted for Factors Known to Increase Intubation Complications), NIPPV Failure Resulted in Increased Odds of a Composite Complication of Intubation (2.20; CI 1.14-4.25)
    • When a Composite Complication Occurred, the Unadjusted Odds of Death in the ICU were 1.79 (95% CI 1.03-3.12)

Sleep Disruption

• 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]
  • 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)