Weaning is the Process of Decreasing Ventilator Support and Increasing the Patient Work of Breathing
Weaning Can Range from an Abrupt Transition of the Workload from the Ventilator to the Patient (i.e. Extubation) to a Gradual Transition of the Workload from the Ventilator to the Patient (Pressure Support Trials with a Progressive Decrease in the Amount of Pressure Support)
Subsequently, After the Patient Manifests Successful Weaning During a Spontaneous Breathing Trial, Extubation Can Be Considered
Assessment of Patient Readiness to Wean
Clinicians Frequently Underestimate the Ability of Patients to Wean from the Ventilator
Studies Suggest that Many Patients were Successfully Extubated on the First Day that They were Assessed for Readiness to Extubate (Am J Respir Crit Care Med, 1994) [MEDLINE] (NEJM, 1995) [MEDLINE]
In Patients with Unplanned Extubation, Reintubation Rates were Only 56%, Suggesting that 44% of Patients Were Ready to Extubate at the Time (Am J Respir Crit Care Med, 2000) [MEDLINE]
Clinical Criteria Consistent with Patient Readiness for Ventilator Weaning
General Clinical Criteria
Reversal of Underlying Etiology of the Respiratory Failure
Adequate Resolution of Particularly Cardiogenic Pulmonary Edema, Pneumonia, etc
Optimized Lung/Chest Wall Compliance
Absence of a Pulmonary Process Which Significantly Increases the Work of Breathing (Severe Pneumonia, Large Pleural Effusion, etc)
Absence of a Chest Wall/Abdominal Process Which Significantly Increases the Work of Breathing ((Abdominal Compartment Syndrome, Ascites, etc)
Low Minute Ventilation (VE) Requirement (Generally VE <10 L/min)
Adequate Oxygenation (Generally, pO2 >60 mm Hg on FIO2 ≤40%, pO2/FIO2 Ratio >150-300, PEEP ≤10 cm H2O)
Optimized Treatment of Airway Obstruction
Treated with Bronchodilators, Corticosteroids, etc
Optimized Oxygen Demand
Absence of Physiologic Processes Which Increase Oxygen Consumption (Fever, Anxiety, Agitation, etc)
Optimized Intravascular Volume Status
Extubation (Removal of Positive-Pressure Mechanical Ventilation) Results in an Effective Increase in Right-Sided Venous Return, Which May Exacerbate Congestive Heart Failure)
Optimized Secretion (and Hemoptysis) Management
Ability to Safely Manage Secretions (and Any Hemoptysis) Post-Extubation
Optimized Nutritional and Electrolyte Status
Absence of Severe Malnutrition Which Might Impair Respiratory Neuromuscular Function
Absence of Any Electrolyte Disturbance Which Might Impair Respiratory Neuromuscular Function (Hypokalemia, Hypophosphatemia, etc) or Mental Status (Hyponatremia, etc)
Optimized Neurologic Status
Adequate Mental Status to Allow the Patient to Follow Directions and Cough to Clear Secretions
Absence of Ongoing Sedative/Opiate Infusions
Absence of Recent Paralytic Use
Optimized Acid-Base Status
Absence of Metabolic Acidosis (Which Would Contribute to Excessive Work of Breathing Post-Extubation)
Absence of Metabolic Alkalosis (Which Would Decrease Respiratory Drive Post-Extubation)
Optimized Cardiovascular Status
Absence of Significant Tachycardia/Active Arrhythmias
Absence of Hypotension/Shock Which Requires Significant Amount of Vasopressors
Absence of Unstable Coronary Artery Disease with Myocardial Ischemia
Optimized Hematologic Status
Absence of Severe Anemia (Hb <7 g/dL in Patient without Ischemic Cardiovascular Disease or Hb <10 g/dL in Patient with Ischemic Cardiovascular Disease)
Criteria from Evidence-Based Guidelines for Weaning from the American College of Chest Physicians, American Association for Respiratory Care, and the American College of Critical Care Medicine (Chest, 2001) [MEDLINE]
Required Criteria
Cause of Respiratory Failure Has Improved
pO2/FIO2 Ratio ≥150 or SpO ≥90% on FIO4 ≤40% and PEEP ≤5 cm H2O
pH >7.25
Hemodynamic Stability (No or Low-Dose Vasopressor Requirement) without Myocardial Ischemia
Able to Initiate Respiratory Effort
Optional Criteria
Hemoglobin ≥7 g/dL
Core Temperature ≤38-38.5 Degrees C
Awake or Alert/Easily Arousable Mental Status
Prediction of Patient Undergoing a Spontaneous Awakening Trial/Spontaneous Breathing Trial
Study of Predictors of Patient Undergoing Next-Day Spontaneous Awakening Trial/Spontaneous Breathing Trial from National Quality Improvement Data (Chest, 2022) [MEDLINE]
Population Included Patients from 68 Intensive Care Units
Spontaneous Awakening Trial: n = 4,847
Spontaneous Breathing Trial: n = 4,936
Factors Associated with Higher Odds of a Next-Day Spontaneous Awakening Trial/Spontaneous Breathing Trial
Assessment of the Quality of Weaning Parameters for Predicting Weaning Success/Failure
Likelihood Ratios are Probably the Best Metric (Since They are Independent of the Pretest Probability of Weaning Success)
Positive Likelihood Ratio (Likelihood Ratio for Positive Results) = Sensitivity/1-Specificity
LR = 1-2 -> none/minimal
LR = 2-5 -> small
LR = 5-10 -> moderate
LR = >10 -> large
The Greater the Deviation of the Positive Likelihood Ratio is from 1, the More Powerful a Positive Test is as a Predictor of a Positive Outcome
Negative Likelihood Ratio (Likelihood Ratio for Negative Results) = 1-Sensitivity/Specificity
LR = 0.1-1 -> none/minimal
LR = 0.3-0.5 -> small
LR =0.1-0.3 -> moderate
LR = <0.1 -> large
The Greater the Deviation of the Negative Likelihood Ratio is from 1, the More Powerful a Negative Test is as a Predictor of a Negative Outcome
Positive and Negative Predictive Values are Generally Not Optimal Metrics for Assessing the Quality of a Weaning Predictor, Since They Vary According to the Pretest Probability (i.e. Prevalence) of Weaning Success in the Studied Population
Clinical Efficacy
Study of Prognostic Value of Daily Weaning Parameters (Intensive Care Med, 1999) [MEDLINE]: n = 216
Daily Weaning Parameters Had an 82% Accuracy for Predicting Successful Extubation
Daily Weaning Parameters Had a 73% Accuracy for Predicting In-Hospital Survival
Prognostic Value of Daily Weaning Parameters for Predicting Extubation Decreased Over Time
Passing Weaning Parameters Within 5 Days of Intubation: average time to extubation = 3 days
Passing Weaning Parameters After 10 Days of Intubation: average time to extubation = 8 days
Approximately 30% of Patients Failed Weaning Parameters, But Were Able to Be Successfully Extubated Anyway
Study of Conservative vs Liberal Transfusion Strategies on Mechanical Ventilation Outcomes (Chest, 2001) [MEDLINE]
Liberal Blood Transfusion Strategy (Maintaining Hb 10-12 g/dL) Did Not Decrease the Duration of Mechanical Ventilation in Critically Ill Patients
Retrospective Study of Impact of Transfusion Strategy on Mechanical Ventilation Outcomes (PLoS One, 2013) [MEDLINE]: n = 751 (138 were difficult to wean from mechanical ventilation)
Patients with Hemoglobin Level >10 g/dL were More Likely to Be Successfully Weaned from Mechanical Ventilation, as Compared to Patients with Hemoglobin <8 g/dL (Odds Ratio3.69; 95% CI: 1.22-11.15 for Hemoglobin 8-10 g/dL and Odds Ratio 4.16, 95% CI: 1.30-13.29 for Hemoglobin >10 g/dL)
Multivariate Analysis Demonstrated that the Odds Ratio for Weaning Success Remained Significant for Hemoglobin Levels 8-10 g/dL (Adjusted Odds Ratio 3.3; 95% CI: 1.07-10.15) with Borderline Significance for Hemoglobin Levels >10 g/dL (adjusted Odds Ratio 2.95, 95% CI: 0.88-9.96)
Study of the Effect of Sepsis on Weaning Outcomes in Patients Recovering from Respiratory Failure (Chest, 1997) [MEDLINE]
Patients with Respiratory Failure and Sepsis Breathe with a Higher Respiratory Rate/Tidal Volume Ratio, Have a Lower Maximal Inspiratory Pressure, and Tend to More Likely Encounter First Day Ventilator Weaning Failure, as Compared to Patients with Respiratory Failure without Sepsis
Severity of Illness on ICU Admission Could Explain Some of These Differences
Analysis of Prospective Cohort Study Evaluating the Impact of Fever on Ventilator Weaning in Patients with Acute Respiratory Distress Syndrome (Ann Am Thorac Soc, 2013) [MEDLINE]: n = 450 (from 13 ICU’s at 4 hospitals in Baltimore, Maryland)
Only 12% of Patients were Normothermic During the First 3 Days After Onset of Acute Respiratory Distress Syndrome
Fever was Associated with Delayed Liberation from Mechanical Ventilation
During the First Week Post-Acute Respiratory Distress Syndrome, Each Additional Day of Fever Resulted in a 33% Reduction in the Likelihood of Successful Ventilator Liberation (95% Confidence Interval for Adjusted Hazard Ratio, 0.57-0.78; P<0.001
Hypothermia was Associated with Delayed Liberation from Mechanical Ventilation and Increased Mortality Rate
Hypothermia was Independently Associated with Decreased Ventilator-Free Days (Hypothermia During Each of the First 3 Days: Reduction of 5.58 Days, 95% CI: -9.04 to -2.13; P = 0.002)
Hypothermia was Independently Associated with Increased Mortality (Hypothermia During Each of the First 3 Days: Relative Risk, 1.68; 95% CI: 1.06-2.66; P = 0.03)
Hemodynamic Stability
Clinical Efficacy
Randomized, Controlled Trial of Weaning Predictors (Crit Care Med, 2006) [MEDLINE]: n = 304
Study Assessed pO2/FIO2 Ratio, PEEP, Hemodynamic Stability, Mental Status, Cough, and RSBI with Randomization to RSBI-Dependent or Independent Weaning
Overall Weaning Success: 59% (similar to other trials)
Including RSBI in a Protocol Prolonged the Weaning Time
RSBI Did Not Confer a Survival Benefit or Decrease the Incidence of Extubation Failure or Tracheostomy
Critique: study used a single RSBI threshold (rather than graded RSBI levels, as many clinicians might use)
Mental Status
Clinical Efficacy
Prospective Cohort Study of Weaning Brain-Injured Patients (Am J Respir Crit Care Med, 2000) [MEDLINE]: n = 136
Approximately 73% of Patients were Extubated within 48 hrs of Meeting Readiness Criteria: the other 27% remained intubated for a meedian of 3 days (range: 2-19 days)
Practice Variation Existed After Stratifying for Differences in Glasgow Coma Scale Scores (10 vs 7, p<0.001) at Time of Meeting Readiness Criteria, Particularly for Comatose Patients
Median Hospital Charges were $29,057 Higher for Extubation Delay Patients (p<0.001)
Study of Predictors of Successful Extubation in Neurosurgical Patients (Am J Respir Crit Care Med, 2001) [MEDLINE]
Multivariate Analysis Demonstrated that Glasgow Coma Scale Score (GCS) (p<0.0001) and pO2/FIO2 Ratio (p<0.0001) Were Associated with Extubation Success
Odds of Successful Extubation Increased by 39% with Each GCS Score Increment
GCS Score ≥8 at Extubation was Associated with Success in 75% of Cases, as Compared to 33% for a GCS Score <8 (p<0.0001)
Risk Factors for Extubation Failure Include Low Cough Peak Flow (≤60 L/min), Increased Endotracheal Secretions (Secretions >2.5 ml/hr), and Inability to Complete 4 Simple Tasks (Open Eyes, Follow with Eyes, Grasp Hand, Stick Out Tongue) (Intensive Care Med, 2004) [MEDLINE]
Failure Rate was 100% for Patients with All 3 Risk factors, as Compared to 3% for Those with 0 Risk Factors (RR=23.2; 95% CI: 3.2-167.2)
Presence of Any 2 of the Risk Factors had a Sensitivity of 71% and Specificity of 81% in Predicting Extubation Failure
Patients Who Failed a Trial of Extubation were 3.8x More Likely to Have Any 2 Risk Factors, as Compared to Those Who were Successful
Randomized, Controlled Trial of Weaning Predictors (Crit Care Med, 2006) [MEDLINE]: n = 304
Study Assessed pO2/FIO2 Ratio, PEEP, Hemodynamic Stability, Mental Status, Cough, and RSBI with Randomization to RSBI-Dependent or Independent Weaning
Overall Weaning Success: 59% (similar to other trials)
Including RSBI in a Protocol Prolonged the Weaning Time
RSBI Did Not Confer a Survival Benefit or Decrease the Incidence of Extubation Failure or Tracheostomy
Critique: study used a single RSBI threshold (rather than graded RSBI levels, as many clinicians might use)
French Study of Peak Cough Expiratory Flow as a Predictor of Extubation Success (Intensive Care Med, 2009) [MEDLINE]: n = 130
Inability to Cough on Command or a Peak Cough Expiratory Flow ≤35 l/min Predicted Extubation Failure with a Sensitivity of 79% and a Specificity of 71%
Risk of Extubation Failure was 24% for the Patients Who Did Not Cough on Command or with a Peak Cough Expiratory Flow ≤35 l/min and 3.5% for those with a Peak Cough Expiratory Flow >35 l/min (RR = 6.9 (95% CI: 2-24; P = 0.002)
Mean Peak Cough Flow of Patients Who Failed Extubation (36.3 +/- 15 L/min) was Significantly Lower than the One of Patients Who Succeeded (63.6 +/- 32 L/min) (P<0.001)
Measures of Oxygenation (as Measured by pO2/FIO2 Ratio, etc)
General Comments
While Oxygenation is a Critical Factor to Consider for Weaning/Extubation, it is a Relatively Poor Predictor of Weaning Success
Clinical Efficacy
Single-Center Retrospective Study of Weaning Criteria in Elderly (≥70 y/o) Patients (Crit Care Med, 1989) [MEDLINE]: n = 241
Parameters: spontaneous respiratory rate, tidal volume, minute ventilation, maximal inspiratory pressure (MIP), pH, pCO2, pO2, and pO2/FIO2 ratio
MIP and pH were Lower in the Unsuccessfully Weaned Group, Although the Mean Absolute Differences were Small (-32 vs -38 cm H2O and 7.42 vs. 7.44 cm H2O, respectively)
All Parameters Had Good Positive Predictive Value, But Poor Negative Predictive Value (≤22%) and Only Marginal Diagnostic Accuracy (58-86%)
However, the Pretest Probability of Weaning Success was Unusually High (90%) in this Study
Randomized, Controlled Trial of Weaning Predictors (Crit Care Med, 2006) [MEDLINE]: n = 304
Study Assessed pO2/FIO2 Ratio, PEEP, Hemodynamic Stability, Mental Status, Cough, and RSBI with Randomization to RSBI-Dependent or Independent Weaning
Overall Weaning Success: 59% (similar to other trials)
Including RSBI in a Protocol Prolonged the Weaning Time
RSBI Did Not Confer a Survival Benefit or Decrease the Incidence of Extubation Failure or Tracheostomy
Critique: study used a single RSBI threshold (rather than graded RSBI levels, as many clinicians might use)
Randomized, Controlled Trial of Ventilator Weaning Protocol ofr Mechanically-Ventilated Patients in the ICU (Lancet, 2008) [MEDLINE]: n = 336
Spontaneous Breathing Trials were Safe and Successful Even in Patients with Poorer Oxygenation (pO2/FIO2 Ratio 110-120)
Minute Ventilation (VE)
General Comments
Minute Ventilation Requirement is Inversely Correlated with the Efficiency of Carbon Dioxide Excretion by the Lungs
Minute Ventilation Requirements Can Be Increased by Factors Which Increase Metabolic Demand, Resulting in Increased Carbon Dioxide Production (Fever, etc) and the Presence of Decreased Bicarbonate Buffer (Due to Metabolic Acidosis)
Minute Ventilation Can Also Increase Due to Factors Which Increase Central Respiratory Drive (Agitation, Pain, Central Nervous System Disease, etc)
Clinical Efficacy
Systematic Review of Various Factors Predicting Successful Weaning (Chest, 2001) [MEDLINE]: n = 65 observational studies
Minute Ventilation
Minute Ventilation was a Poor Predictor of Weaning Outcome
After Pooling, Respiratory Rate of >38 Breaths/min Decreased the Probability of Successful Extubation
Maximal Inspiratory Pressure (MIP)
MIP Had a Low Sensitivity and Specificity in Predicting Weaning Success
After Pooling, Maximal Inspiratory Pressure (PImax) <0.3 (More Negative than -30 cm H2O) Had a Pooled Likelihood Ratio of 2.23 (95% CI: 1.15 to 4.34), Indicating that it Appeared to Marginally Increase the Likelihood of Successful Extubation
Rapid Shallow Breathing Index (RSBI)
Unpooled, RSBI Had Positive Likelihood Ratio of 1.66 -> indicates that there was small increase in the probability of weaning success in patients with a positive RSBI
Unpooled, RSBI Had Negative Likelihood Ratio of 0.11 -> indicates that there was a moderate increase in the probability of weaning failure in patients with a negative RSBI
After Pooling, RSBI of >100 Decreased the Probability of Successful Extubation
Based on Receiver Operator Curve for All of the Variables, None of the Variables Demonstrated More than Modest Accuracy in Predicting Weaning Outcome: may be related to the fact that clinicians have already considered the results when they choose patients for trials of weaning
Prospective Study of Weaning Parameters in Predicting Outcome from Ventilator Weaning (NEJM, 1991) [MEDLINE]
Pretest Probability of Weaning Success in Study Population: 60%
Sensitivity was the Highest for Maximal Inspiratory Pressure (Plmax) (1.00), Followed Closely by the Respiratory Rate/Tidal Volume Ratio (Rapid Shallow Breathing Index, RSBI) (0.97)
Specificity was the Highest for the Respiratory Rate/Tidal Volume Ratio (Rapid Shallow Breathing Index, RSBI) (0.64) and Lowest for Maximal Inspiratory Pressure (Plmax) (0.11)
Respiratory Rate/Tidal Volume Ratio (Rapid Shallow Breathing Index, RSBI) was the Best Predictor of Successful Weaning
Positive Likelihood Ratio for RSBI: 2.7 -> means that there was a small increase in the probability of weaning success with positive RSBI (<105)
Negative Likelihood Ratio for RSBI: 0.05 -> means that there was large increase in the probability of weaning failure with negative RSBI (≥105)
Maximal Inspiratory Pressure (Plmax) and the Respiratory Rate/Tidal Volume Ratio (Rapid Shallow Breathing Index, RSBI) were the Best Predictors of Failure
The Area Under the ROC Curve for the Respiratory Rate/Tidal Volume Ratio (Rapid Shallow Breathing Index, RSBI) (0.89) was Larger than that Under the Curves for the CROP Index (0.78, P<0.05), Maximal Inspiratory Pressure (Plmax) (0.61, P less than 0.001), and Minute Ventilation (VE) (0.40, P<0.001
Compliance Had a Poor Predictive Capacity
Study of Integrative Weaning Index (IWI) in Predicting Weaning Outcome (Crit Care, 2009) [MEDLINE]: n = 331
Integrative Weaning Index (IWI) = Static Compliance x Arterial Oxygen Saturation/Respiratory Rate/Tidal Volume
Integrative Weaning Index (IWI) Area Under the ROC Curves was Larger than that Under the Curves for the Respiratory Rate/Tidal Volume Ratio (0.96 vs 0.85, respectively; P = 0.003)
Integrative Weaning Index was the Best Predictive Performance Index for Weaning Outcome in the ICU Setting
Work of Breathing
General Comments
Work of Breathing Can Be Measured Using the Tidal Volume and Intrathoracic Pressure Generated by Respiratory Muscle Contraction (Using an Esophageal Balloon Measurement Device)
It is Unclear if Work of Breathing Measurements are Superior to Other Less Invasive Methods in Predicting Weaning Success
Clinical Efficacy
Study of Work of Breathing in Predicting Success of Weaning (Chest, 1988) [MEDLINE]: n = 17
Bedside Weaning Parameters are Associated with Weaning Success in Patients Requiring Brief Mechanical Ventilation
In Patients Requiring Prolonged Ventilation, Work of Breathing Measurements May Be a Better Predictor of Successful Weaning
Study of Work of Breathing in Predicting Weaning Outcome (Chest, 1995) [MEDLINE]
Measurement of Patient Work of Breathing was Less Accurate than Conventional Weaning Parameters and Clinical Judgement fro Predicting Successful Extubation
Study of Work of Breathing in Patients Failing Weaning from Mechanical Ventilation (Am J Respir Crit Care Med, 1997) [MEDLINE]
The Product of Inspiratory Pressure-Time Product and pCO2, an Index of Inefficient Carbon Dioxide Clearance, was More than Twice as High in the Failure Group than in the Success Group at the End of the Trial (p<0.0005)
Study of Tension-Time Index and Respiratory Rate/Tidal Volume Ratio in Predicting Weaning Success (Am J Respir Crit Care Med, 1998) [MEDLINE]
Tension-Time Index and the Respiratory Rate/Tidal Volume Ratio are the Major Pathophysiologic Determinants Underlying the Transition from Weaning Failure to Weaning Success
Study of Load Balance and Respiratory Rate/Tidal Volume Ratio in Predicting Weaning Success (Intensive Care Med, 2006) [MEDLINE]
Combination of Mean Paw/MIP and Respiratory Rate/Tidal Volume Ratio in a Simplified Discriminant Function is Useful in Predicting Weaning Outcome
Oxygen Cost of Breathing
General Comments
Oxygen Cost of Breathing is the Difference Between Oxygen Consumption While Breathing Spontaneously and Oxygen Consumption While Breathing on Mechanical Ventilation
Requires a Metabolic Cart to Measure (Although Non-Pulmonary Changes in Oxygen Consumption Can Complicate Measurement)
In Normal Subjects, Oxygen Cost of Breathing is <5% of Total Oxygen Consumption
In Patients Being Weaned (Especially Those Failing Weaning), Oxygen Cost of Breathing May Be >50% of Total Oxygen Consumption
Clinical Efficacy
Study of the Oxygen Cost of Breathing (Chest. 1988) [MEDLINE]
Sensitivity and Specificity of Increase in Oxygen Consumption (Delta VO2) and Respiratory Power Output (Wresp were Insufficient for Evaluation of Disease State and Weaning Decisions in Individual Patients
Airway Occlusion Pressure
General Comments
Measurement of Respiratory Drive Can Be Obtained by Occluding the Airway During Inspiration and Measuring the Airway Pressure Generated During the First 0.1 sec (P0.1) of the Occlusion
In Normal Subjects, P0.1 is <2 cm H2O
Patients Failing Weaning Have Higher P0.1 Values (Due to Elevated Inspiratory Drive)
Clinical Efficacy
Study of Airway Occlusion Pressure in Patients Failing Weaning (Am Rev Respir Dis, 1987) [MEDLINE]
Airway Occlusion Pressure >6 cm H2O Has Been Associated with Weaning Failure
Evaluation of Maximal Inspiratory Pressure (Pimax) and Airway Occlusion Pressure (P0.1) in Predicting Weaning Outcome (J Crit Care, 2009) [MEDLINE]
P0.1 (Area Under ROC 0.76) and P0.1/Pimax Ratio (Area Under ROC 0.78) were Moderately Accurate in Predicting Weaning Outcome
Pimax was Less Accurate in Predicting Weaning Outcome (Area Under ROC 0.52)
Maximal Inspiratory Pressure (MIP, PImax, or Pimax)
General Comments
Maximal Inspiratory Pressure is an Assessment of Inspiratory Muscle Strength
Measured Using a Manometer with an Occluded Airway
Measurement Can Be Problematic in a Spontaneously Breathing Patient, Often Underestimating the True MIP Due to Inadequate Patient Effort (Am Rev Respir Dis, 1990) [MEDLINE]
One-Way Valve Devices with Prolonged Occlusion (20-25 sec) May Improve the Measurement
MIP Assesses Only the Respiratory Muscle Strength, But Does Not Assess the Inspiratory Load Placed on the Muscles
Clinical Efficacy
Study of Bedside Weaning Parameters in Predicting Ventilator Weaning (Chest, 1973) [MEDLINE]
MIP Greater than -30 cm H20 (More Negative) was Associated with Weaning Success
MIP Less than -20 cm H2O (Less Negative) was Associated with Weaning Failure
Prospective Study of Weaning Parameters in Predicting Outcome from Ventilator Weaning (NEJM, 1991) [MEDLINE]
Pretest Probability of Weaning Success in Study Population: 60%
Sensitivity was the Highest for Maximal Inspiratory Pressure (Plmax) (1.00), Followed Closely by the Respiratory Rate/Tidal Volume Ratio (Rapid Shallow Breathing Index, RSBI) (0.97)
Specificity was the Highest for the Respiratory Rate/Tidal Volume Ratio (Rapid Shallow Breathing Index, RSBI) (0.64) and Lowest for Maximal Inspiratory Pressure (Plmax) (0.11)
Respiratory Rate/Tidal Volume Ratio (Rapid Shallow Breathing Index, RSBI) was the Best Predictor of Successful Weaning
Positive Likelihood Ratio for RSBI: 2.7 -> means that there was a small increase in the probability of weaning success with positive RSBI (<105)
Negative Likelihood Ratio for RSBI: 0.05 -> means that there was large increase in the probability of weaning failure with negative RSBI (≥105)
Maximal Inspiratory Pressure (Plmax) and the Respiratory Rate/Tidal Volume Ratio (Rapid Shallow Breathing Index, RSBI) were the Best Predictors of Failure
The Area Under the ROC Curve for the Respiratory Rate/Tidal Volume Ratio (Rapid Shallow Breathing Index, RSBI) (0.89) was Larger than that Under the Curves for the CROP Index (0.78, P<0.05), Maximal Inspiratory Pressure (Plmax) (0.61, P less than 0.001), and Minute Ventilation (VE) (0.40, P<0.001
Compliance Had a Poor Predictive Capacity
Systematic Review of Various Factors Predicting Successful Weaning (Chest, 2001) [MEDLINE]: n = 65 observational studies
Minute Ventilation
Minute Ventilation was a Poor Predictor of Weaning Outcome
After Pooling, Respiratory Rate of >38 Breaths/min Decreased the Probability of Successful Extubation
Maximal Inspiratory Pressure (MIP)
MIP Had a Low Sensitivity and Specificity in Predicting Weaning Success
After Pooling, Maximal Inspiratory Pressure (PImax) <0.3 (More Negative than -30 cm H2O) Had a Pooled Likelihood Ratio of 2.23 (95% CI: 1.15 to 4.34), Indicating that it Appeared to Marginally Increase the Likelihood of Successful Extubation
Rapid Shallow Breathing Index (RSBI)
Unpooled, RSBI Had Positive Likelihood Ratio of 1.66 -> indicates that there was small increase in the probability of weaning success in patients with a positive RSBI
Unpooled, RSBI Had Negative Likelihood Ratio of 0.11 -> indicates that there was a moderate increase in the probability of weaning failure in patients with a negative RSBI
After Pooling, RSBI of >100 Decreased the Probability of Successful Extubation
Based on Receiver Operator Curve for All of the Variables, None of the Variables Demonstrated More than Modest Accuracy in Predicting Weaning Outcome: may be related to the fact that clinicians have already considered the results when they choose patients for trials of weaning
Evaluation of Maximal Inspiratory Pressure (Pimax) and Airway Occlusion Pressure (P0.1) in Predicting Weaning Outcome (J Crit Care, 2009) [MEDLINE]
P0.1 (Area Under ROC 0.76) and P0.1/Pimax Ratio (Area Under ROC 0.78) were Moderately Accurate in Predicting Weaning Outcome
Pimax was Less Accurate in Predicting Weaning Outcome (Area Under ROC 0.52)
Observational Prospective Study of Time Inspiratory Effort (TIE), the Integrative Weaning Index (IWI), and Rapid Shallow Breathing Index (RSBI) in Predicting Weaning Outcome (J Intensive Care Med, 2015) [MEDLINE]: n = 103
TIE Index is the Maximal Inspiratory Pressure and the Occlusion Time Required to Reach it
TIE Had the Largest Area Under the Receiver Operating Curve of All the Indices
Gastric Mucosal Acidosis
General Comments
Since Blood Flow May Be Diverted from the Splanchnic Bed to the Respiratory Muscles During Weaning (Especially During Weaning Failure, Resulting in Gastric Mucosal Ischemia), Measurement of Gastric Mucosal Acidosis May Be Useful
Measurement Requires a Nasogastric Tube
Clinical Efficacy
Study of Gastric Mucosal Acidosis in Weaning Failure (Ann Intern Med, 1993) [MEDLINE]: n = 29
Gastrointestinal Acidosis May Be an Early Sign of Weaning Failure
Uruguayan Prospective Clinical Study of Gastric Mucosal Acidosis in Weaning Patients (Crit Care Med, 2001) [MEDLINE]
Weaning Failure was Associated with Gastric Intramucosal Acidosis
Diaphragmatic Ultrasound
General Comments
Using B-Mode or M-Mode Ultrasound, Diaphragmatic Function Can Be Assessed to Determine the Probability of Weaning Success
Clinical Efficacy
Study of Diaphragmatic Ultrasound in Predicting Weaning Success (Crit Care Med, 2011) [MEDLINE]
Less than 10 mm of Diaphragmatic Descent, or Paradoxical Diaphragmatic Ascent During Inspiration was Associated with Longer Ventilator Weaning Time
Study of Diaphragmatic Ultrasound in Predicting Weaning Success (Thorax, 2014) [MEDLINE]: n = 63
Diaphragmatic Thickening Fraction of >30% was Associated with a Sensitivity 88%, Specificity of 71%, Positive-Predictive Value of 91%, and Negative-Predictive Value of 63% for Predicting Extubation Success
Systematic Review and Meta-Analysis of Diaphragmatic Ultrasound in Predicting Weaning Success (Chest, 2017) [MEDLINE]: n = 1,071 (19 studies)
Both Diaphragmatic Thickening Fraction (Pooled Odds Ratio = 21) and Diaphragmatic Excursion (Pooled Odds Ratio = 10) Predicted Weaning Outcome
Study of Diaphragmatic Ultrasound and Rapid Shallow Breathing Index (RSBI) in Predicting Weaning Success (J Intensive Care, 2018) [MEDLINE]
The Combination of Diaphragmatic Ultrasound and Rapid Shallow Breathing Index (RSBI Increased Accuracy of Predicting Weaning Outcome
Rapid Shallow Breathing Index (RSBI)
Clinical Use
Rapid Shallow Breathing Index (RSBI) is the Most Commonly Used Weaning Parameter/Predictor
Rationale
Patients with High Work of Breathing (and Highest Risk to Fail Weaning and Extubation) Tend to Breathe at High Respiratory Rates with Low Tidal Volumes
Based on Studies of the Clinical Performance of RSBI, a Negative RSBI (RSBI >105) is Better at Identifying Patients Who Will Fail Weaning than a Positive RSBI (RSBI <105) is at Identifying Patients Who Can Be Successfully Weaned
For This Reason, RSBI is Best Utilized to Assess a Patient Who Has Already Been Deemed Stable Enough by Clinical Criteria to Undergo a Spontaneous Breathing Trial, But in Whom There is a Concern as to Whether the Patient Will Succeed with Weaning
RSBI Can Then Identify a Patient Who May Be at High Risk of Weaning Failure to Avoid the Risks of a Failed Spontaneous Breathing Trial in Such a Patient
Technique
RSBI Has Been Traditionally Performed Using One Minute Independent Breathing Trial on CPAP 0 with Pressure Support 0
Original Study Used a Handheld Spirometer to Measure the RSBI (NEJM, 1991) [MEDLINE]
At the End of One Minute, Calculate the Average Respiratory Rate/Average Tidal Volume
Measuring the RSBI While on Ventilator Support: this will result in lower values than those measured on no ventilator support
Use of Pressure Support Ventilation and/or PEEP as Low as 5 cm H2O Influenced the RSBI, While FIO2 Did Not Impact the RSBI (Intensive Care Med, 2008) [MEDLINE]
RSBI is Impacted by the Level of Ventilatory Support, But is Relatively Unaffected by the Technique Used to Determine the Breathing Pattern and the Time of Day at Which it is Measured (Respir Care, 2009) [MEDLINE]
Measuring the RSBI on Ventilators with Flow Triggering: this will result in lower values than those measured on venetilators without flow triggering
Values Measured Through the Ventilator with CPAP-5 cm H2O were Much Lower than the Values Measured with a Handheld Spirometer and Even RSBI Values Measured with CPAP-0 cm H2O were Significantly Lower (Due to Base Flow Delivered by Some Ventilators) (J Crit Care, 2012) [MEDLINE]
RSBI Values were Lower (Approximately 17% Lower) on Ventilators with Flow Triggering (Due to the Base Flow) (J Intensive Care Med, 2015) [MEDLINE]
Measuring RSBI in a Patient with Dynamic Hyperinflation (Due to COPD, Asthma, etc)
Unmeasured Inspiratory Efforts on the Ventilator (Due to the Ventilator Not Sensing These and Properly Triggering) Can Falsely Decrease the RSBI (Am J Respir Crit Care Med, 2000) [MEDLINE]
Factors Which Can Increase the RSBI
Small Diameter Endotracheal Tube (Am J Respir Crit Care Med, 1996) [MEDLINE]
Prospective Study of Weaning Parameters in Predicting Outcome from Ventilator Weaning (NEJM, 1991) [MEDLINE]
Pretest Probability of Weaning Success in Study Population: 60%
Sensitivity was the Highest for Maximal Inspiratory Pressure (Plmax) (1.00), Followed Closely by the Respiratory Rate/Tidal Volume Ratio (Rapid Shallow Breathing Index, RSBI) (0.97)
Specificity was the Highest for the Respiratory Rate/Tidal Volume Ratio (Rapid Shallow Breathing Index, RSBI) (0.64) and Lowest for Maximal Inspiratory Pressure (Plmax) (0.11)
Respiratory Rate/Tidal Volume Ratio (Rapid Shallow Breathing Index, RSBI) was the Best Predictor of Successful Weaning
Positive Likelihood Ratio for RSBI: 2.7 -> means that there was a small increase in the probability of weaning success with positive RSBI (<105)
Negative Likelihood Ratio for RSBI: 0.05 -> means that there was large increase in the probability of weaning failure with negative RSBI (≥105)
Maximal Inspiratory Pressure (Plmax) and the Respiratory Rate/Tidal Volume Ratio (Rapid Shallow Breathing Index, RSBI) were the Best Predictors of Failure
The Area Under the ROC Curve for the Respiratory Rate/Tidal Volume Ratio (Rapid Shallow Breathing Index, RSBI) (0.89) was Larger than that Under the Curves for the CROP Index (0.78, P<0.05), Maximal Inspiratory Pressure (Plmax) (0.61, P less than 0.001), and Minute Ventilation (VE) (0.40, P<0.001
Compliance Had a Poor Predictive Capacity
Systematic Review of Various Factors Predicting Successful Weaning (Chest, 2001) [MEDLINE]: n = 65 observational studies
Minute Ventilation
Minute Ventilation was a Poor Predictor of Weaning Outcome
After Pooling, Respiratory Rate of >38 Breaths/min Decreased the Probability of Successful Extubation
Maximal Inspiratory Pressure (MIP)
MIP Had a Low Sensitivity and Specificity in Predicting Weaning Success
After Pooling, Maximal Inspiratory Pressure (PImax) <0.3 (More Negative than -30 cm H2O) Had a Pooled Likelihood Ratio of 2.23 (95% CI: 1.15 to 4.34), Indicating that it Appeared to Marginally Increase the Likelihood of Successful Extubation
Rapid Shallow Breathing Index (RSBI)
Unpooled, RSBI Had Positive Likelihood Ratio of 1.66 -> indicates that there was small increase in the probability of weaning success in patients with a positive RSBI
Unpooled, RSBI Had Negative Likelihood Ratio of 0.11 -> indicates that there was a moderate increase in the probability of weaning failure in patients with a negative RSBI
After Pooling, RSBI of >100 Decreased the Probability of Successful Extubation
Based on Receiver Operator Curve for All of the Variables, None of the Variables Demonstrated More than Modest Accuracy in Predicting Weaning Outcome: may be related to the fact that clinicians have already considered the results when they choose patients for trials of weaning
Bayesian Analysis of RSBI in Predicting Weaning Outcome (Intensive Care Med, 2006) [MEDLINE]
Much of the Heterogeneity in Performance of RSBI Can Be Explained by Variation in Pretest Probability of Successful Weaning Outcome (Which May Be Secondary to Spectrum and Test-Referral Bias)
Average Sensitivity of 0.87 indicates that RSBI) is a Reliable Screening Test for Successful Weaning
Randomized, Controlled Trial of Weaning Predictors (Crit Care Med, 2006) [MEDLINE]: n = 304
Study Assessed pO2/FIO2 Ratio, PEEP, Hemodynamic Stability, Mental Status, Cough, and RSBI with Randomization to RSBI-Dependent or Independent Weaning
Overall Weaning Success: 59% (similar to other trials)
Including RSBI in a Protocol Prolonged the Weaning Time
RSBI Did Not Confer a Survival Benefit or Decrease the Incidence of Extubation Failure or Tracheostomy
Critique: study used a single RSBI threshold (rather than graded RSBI levels, as many clinicians might use)
Observational Prospective Study of Time Inspiratory Effort (TIE), the Integrative Weaning Index (IWI), and Rapid Shallow Breathing Index (RSBI) in Predicting Weaning Outcome (J Intensive Care Med, 2015) [MEDLINE]: n = 103
TIE Index is the Maximal Inspiratory Pressure and the Occlusion Time Required to Reach it
TIE Had the Largest Area Under the Receiver Operating Curve of All the Indices
Study of Diaphragmatic Ultrasound and Rapid Shallow Breathing Index (RSBI) in Predicting Weaning Success (J Intensive Care, 2018) [MEDLINE]
The Combination of Diaphragmatic Ultrasound and Rapid Shallow Breathing Index (RSBI Increased Accuracy of Predicting Weaning Outcome
Inspiratory Effort Quotient (IEQ)
General Comments
IEQ = [(0.75VT/Cdyn) x (TI/TTOT)]/MIP
VT = Tidal volume
Cdyn = dynamic compliance
TI = inspiratory time
TTOT = respiratory duty cycle
MIP = maximal inspiratory pressure
Clinical Efficacy
Study of Weaning Predictors (Am Rev Respir Dis, 1986) [MEDLINE]
IEQ May Predict Weaning Outcome
CROP Index (Compliance, Rate, Oxygenation, Pressure)
General Comments
CROP Index = [Cdyn * MIP * (PaO2/PAO2)]/R
Cdyn = dynamic compliance
MIP = maximal inspiratory pressure
pO2/PAO2 = ratio of arterial pO2 to alveolar pO2
R = respiratory rate
Clinical Efficacy
Prospective Study of Weaning Parameters in Predicting Outcome from Ventilator Weaning (NEJM, 1991) [MEDLINE]
Pretest Probability of Weaning Success in Study Population: 60%
Sensitivity was the Highest for Maximal Inspiratory Pressure (Plmax) (1.00), Followed Closely by the Respiratory Rate/Tidal Volume Ratio (Rapid Shallow Breathing Index, RSBI) (0.97)
Specificity was the Highest for the Respiratory Rate/Tidal Volume Ratio (Rapid Shallow Breathing Index, RSBI) (0.64) and Lowest for Maximal Inspiratory Pressure (Plmax) (0.11)
Respiratory Rate/Tidal Volume Ratio (Rapid Shallow Breathing Index, RSBI) was the Best Predictor of Successful Weaning
Maximal Inspiratory Pressure (Plmax) and the Respiratory Rate/Tidal Volume Ratio (Rapid Shallow Breathing Index, RSBI) were the Best Predictors of Failure
The Area Under the ROC Curve for the Respiratory Rate/Tidal Volume Ratio (Rapid Shallow Breathing Index, RSBI) (0.89) was Larger than that Under the Curves for the CROP Index (0.78, P<0.05), Maximal Inspiratory Pressure (Plmax) (0.61, P less than 0.001), and Minute Ventilation (VE) (0.40, P<0.001
Compliance Had a Poor Predictive Capacity
CORE Index (Compliance, Oxygenation, Respiration, Effort)
General Comments
CORE Index = [Cdyn * (MIP/P0.1) * (PaO2/PAO2)]/R
Cdyn = dynamic compliance
P0.1 = airway occlusion pressure 0.1 sec after the start of inspiratory flow
MIP = maximal inspiratory pressure
pO2/PAO2 = ratio of arterial pO2 to alveolar pO2
R = respiratory rate
Clinical Efficacy
Study of CORE Index (vs CROP Index, Airway Occlusion Pressure, and RSBI) in Predicting Ventilator Weaning (Respir Care, 2011) [MEDLINE]: n = 47
CORE Index was the Most Accurate Predictor of Weaning Success/Failure
CORE Index Positive Likelihood Ratio was 20 and Negative Likelihood Ratio was 0
Weaning Index (WI)
General Comments
WI = PTI x (VE40/VTsb)
PTI = modified pressure time index (time integral of respiratory muscle pressure, which quantifies ventilatory endurance)
VE40 = minute ventilation needed to bring pCO2 to 40 mmHg (estimate of the efficiency of gas exchange, which quantifies ventilatory endurance)
VTsb = tidal volume during spontaneous breathing
Clinical Efficacy
Study of Weaning Index (WI) (Am Rev Respir Dis, 1991) [MEDLINE]; n = 38
Using a threshold of 4 min-1, WI was Highly Accurate in Predicting Weaning Outcome
Integrative Weaning Index (IWI)
General Comments
IWI = [(Cst,rs) x SaO2]/[f/VT]
Cst,rs = static compliance (Cst,rs)
SaO2 = arterial oxygen saturation
f = respiratory rate
VT = tidal volume
Difficult to Measure in Spontaneously Breathing Patient
Clinical Efficacy
Study of Integrative Weaning Index (IWI) in Predicting Weaning Outcome (Crit Care, 2009) [MEDLINE]: n = 331
Integrative Weaning Index (IWI) = Static Compliance x Arterial Oxygen Saturation/Respiratory Rate/Tidal Volume
Integrative Weaning Index (IWI) Area Under the ROC Curves was Larger than that Under the Curves for the Respiratory Rate/Tidal Volume Ratio (0.96 vs 0.85, respectively; P = 0.003)
Integrative Weaning Index was the Best Predictive Performance Index for Weaning Outcome in the ICU Setting
Observational Prospective Study of Time Inspiratory Effort (TIE), the Integrative Weaning Index (IWI), and Rapid Shallow Breathing Index (RSBI) in Predicting Weaning Outcome (J Intensive Care Med, 2015) [MEDLINE]: n = 103
TIE Index is the Maximal Inspiratory Pressure and the Occlusion Time Required to Reach it
TIE Had the Largest Area Under the Receiver Operating Curve of All the Indices
Bedrest During Critical Illness Adversely Impacts Musculoskeletal, Cardiovascular, Respiratory, and Immune System Function, Slowing Recovery
Immobility-Related Complications (Muscular Atrophy, Decubitus Ulcers, Venous Thromboembolism, etc) are Common in ICU Patients
Profound Weakness is Common (and May Be Persistent for Months-Years) in ICU Survivors
Weakness is Associated with Decreased Post-ICU Survival (Am J Respir Crit Care Med, 2014) [MEDLINE]
Clinical Efficacy
Pooled Meta-Analysis of Early Mobilization Data in Mechanically Ventilated Patients (Am J Respir Crit Care Med, 2017) [MEDLINE]
Early Mobilization Decreased the Duration of Mechanical Ventilation (Mean Difference, 2.7 Fewer Days; 95% CIL 1.19–4.21)
Early Mobilization Patients were More Likely to Be Able to Walk at Discharge (64% vs. 41.4%; RR, 1.56; 95% CI: 1.15–2.10)
There was No Impact on Mortality Rate, ICU Length of Stay, Ability to Walk at ICU Discharge, 6-Minute Walk Distance or Ventilator-Free Days
Trials Did Not Provide Adequate Details to Assess Adverse Events
Recommendations (American Thoracic Society/American College of Chest Physicians Clinical Practice Guideline for Liberation from Mechanical Ventilation in Critically Ill Adults) (Am J Respir Crit Care Med, 2017) [MEDLINE]
For Acutely Hospitalized Adults Who Have Been Mechanically Ventilated for >24 hrs, Protocolized Early Mobilization is Recommended (Conditional Recommendation, Low Certainty of Evidence)
Protocol May Be Implemented by Nurse, Physical Therapist, or Other Clinician
Safety of Weaning
Clinical Efficacy
Study of Large-Scale Respiratory Therapist-Driven Weaning Protocol (Am J Respir Crit Care Med, 1999) [MEDLINE]: n = 1,067
Weaning Trials were Associated with Low Complication Rates (<0.1%)
Study of the Impact of Weaning Failure on Diaphragmatic Function (Am J Respir Crit Care Med, 2003) [MEDLINE]
Weaning Failure was Not Associated with Low-Frequency Diaphragmatic Fatigue (Which Can Impair Future Weaning Attempts), Although Many Patients Demonstrated Diaphragmatic Weakness
Observational Study of Weaning Outcomes (Eur Respir J, 2010) [MEDLINE]
No Difference in Mortality Between Patients Who Passed Their First Spontaneous Breathing Trial, as Compared to Patients Who Failed Their First Breathing Trial
General Measures to Address for Weaning
Ensure Upright Posture
Upright Posture is Generally Preferred to Advantage the Diaphragm Mechanically (Especially in Patients with Diaphragmatic Paresis/Paralysis)
Optimize Bronchodilation
Clinical Efficacy
Small Study of the Effects of Albuterol on the Work of Breathing During Weaning from Mechanical Ventilation (Am Rev Respir Dis, 1991) [MEDLINE]
Decreased Work of Breathing was More Likely to Occur in Patients with the Largest Bronchodilating Effect of Albuterol at Baseline
Ensure Upper and Lower Airway Secretion Clearance
Clinical Efficacy
However, Suctioning of Lower Airways Should Be Performed in Advance of a Spontaneous Breathing Trial, Since Recent Suctioning Can Increase the RSBI (to >100) for Up to 5 min (Respir Care, 2009) [MEDLINE]
Inspiratory Muscle Training
Unproven Therapy
Clinical Efficacy
Systematic Review of Inspiratory Muscle Training in Mechanically-Ventilated Patients (J Physiother, 2015) [MEDLINE]
Inspiratory Muscle Training for Selected Patients in the ICU Facilitates Ventilator Weaning, with Potential Reductions in Length of Stay and the Duration of Noninvasive Positive-Pressure Ventilation (NIPPV) After Extubation
Weaning Protocols
Rationale
Weaning Protocols were Developed to Expedite the Performance of Daily Spontaneous Breathing Trials (and Avoiding Prolonged Unnecessary Mechanical Ventilation)
Clinical Efficacy
Effect of Daily Sedation Vacation and Spontaneous Breathing Trials (NEJM, 1996) [MEDLINE]
Daily Spontaneous Breathing Trials Decreased the Duration of Mechanical Ventilation, Decreased the Cost of Intensive Care, and Decrease Complication Rates
Randomized, Controlled Trial of Protocol-Drive vs Physician-Directed Weaning (Crit Care Med, 1997) [MEDLINE]
Protocol-Guided Weaning (Performed by Nurses and Respiratory Therapists) is Safe and Led to Extubation More Rapidly than Physician-Directed Weaning
Study of Large-Scale Respiratory Therapist-Driven Weaning Protocol (Am J Respir Crit Care Med, 1999) [MEDLINE]: n = 1,067
Weaning Trials were Associated with Low Complication Rates (<0.1%)
Randomized, Controlled Trial of Weaning Predictors (Crit Care Med, 2006) [MEDLINE]: n = 304
Study Assessed pO2/FIO2 Ratio, PEEP, Hemodynamic Stability, Mental Status, Cough, and RSBI with Randomization to RSBI-Dependent or Independent Weaning
Overall Weaning Success: 59% (similar to other trials)
Including RSBI in a Protocol Prolonged the Weaning Time
RSBI Did Not Confer a Survival Benefit or Decrease the Incidence of Extubation Failure or Tracheostomy
Critique: study used a single RSBI threshold (rather than graded RSBI levels, as many clinicians might use)
Randomized, Controlled Awakening and Breathing Controlled (ABC) Trial (Lancet, 2008) [MEDLINE]: n = 336
Patients were Screened Daily for Adequate Oxygenation (SpO2 >88% on FiO2 <50% and PEEP ≤8 cm H2O), Hemodynamic Stability, and Any Spontaneous Inspiratory Effort During a 5 min Period, Absence of Agitation, Absence of Myocardial Ischemia, and Absence of Increased Intracranial Pressure
Weaning Predictors were Not Measured
Those Passing Screening were Initiated on a Spontaneous Breathing Trial (without Ventilator Assistance)
Over 50% of Patients Initiated on a Spontaneous Breathing Trial Tolerated the Trial
Paired Daily Sedation Vacation and Spontaneous Breathing Trial Decreased the Duration of Mechanical Ventilation, Decreased ICU/Hospital Length of Stay, and Decreased the Mortality Rate
Patients in the Intervention Group Spent More Days Breathing without Ventilatory Assistance During the 28-day Study, as Compared to the Control Group (14.7 days vs 11.6 days; mean difference 3.1 Days, 95% CI 0.7 to 5.6; p=0.02)
Patients in the Intervention Group Had Less ICU Days, as Compared to the Control Group (9.1 Days vs 12.9 Days; p=0.01)
Patients in the Intervention Group Left the Hospital Earlier, as Compared to the Control Group (Median Time in the Hospital 14.9 Days vs 19.2 Days; p=0.04)
More Patients in the Intervention Group Self-Extubated, as Compared to the Control Group (16 Patients vs 6 Patients; 6.0% Difference, 95% CI: 0.6% to 11.8%; p=0.03)
Number of Patients Who Required Reintubation After Self-Extubation was Similar Between the Intervention and Control Groups (5 Patients vs 3 Patients; 1.2% difference, 95% CI: -5.2% to 2.5%; p=0.47
Reintubation Rate was Similar Between the Intervention and Control Groups (13.8% vs 12.5%; 1.3% difference, 95% CI: -8.6% to 6.1%; p=0.73)
At Any Point During the Year after Enrollment, Patients in the Intervention Group were Less Likely to Die than were the Patients in the Control Group (HR 0.68, 95% CI: 0.50 to 0.92; p=0.01)
For Every 7 Patients Treated with the Intervention, 1 Life was Saved (Number Needed to Treat was 7.4 (95% CI: 4.2 to 35.5)
Spontaneous Breathing Trials were Safe and Successful Even in Patients with Poorer Oxygenation (pO2/FIO2 Ratio 110-120)
Prospective Observational Cohort Study of Mechanical Ventilation Practices from 1998 to 2004 (349 ICU’s in 23 Countries) (Am J Respir Crit Care Med, 2008) [MEDLINE]
From 1998 to 2004, More Patients were Extubated After Their First Attempt of Spontaneous Breathing (77 vs 62%, P<0.001), Perhaps Suggesting that Clinicians were More Commonly Performing Daily Spontaneous Breathing Trials (Possibly with Weaning Protocols)
WEAN Study of Automated Weaning (Am J Respir Crit Care Med, 2013) [MEDLINE]: n = 92
As Compared with a Standardized Weaning Protocol, Automated Weaning was Associated with Promising Outcomes
Automated Closed Loop Systems May Result in Decreased Weaning Duration, Decreased Ventilation, and Decreased ICU Length of Stay
Reductions are More Likely to Occur in Mixed or Medical ICU Populations
Cochrane Database Systematic Review of Automated Weaning in Postoperative Adults (Cochrane Database Syst Rev, 2014) [MEDLINE]
Inadequate Evidence
Study of Standardized Weaning Protocols from Mechanical Ventilation in Critically Ill Adults (Cochrane Database Syst Rev, 2014) [MEDLINE]: n = 17 trials
Standardized Weaning Protocols Decrease the Duration of Mechanical Ventilation, Weaning Duration, and ICU Length of Stay
Weaning Protocols Decreased the Duration of Mechanical Ventilation by 26%, as Compared to Usual Care (n = 14 trials, 95% CI: 13% to 37%, P=0.0002)
Reductions were most likely to occur in medical, surgical and mixed ICUs, but not in neurosurgical ICUs
Weaning Protocols Decreased the Duration of Weaning by 70% (n = 8 trials, 95% CI: 27% to 88%, P=0.009)
Weaning Protocols Decreased ICU Length of Stay by 11% (n = 9 trials, 95% CI: 3% to 19%, P=0.01
Cochrane Database Systematic Review of Factors Which Impact the Use of Weaning Protocols in Adults and Children (Cochrane Database Syst Rev, 2016) [MEDLINE]: n = 267 (11 studies)
Factors Related to Weaning Protocol Development and Implementation
Need for Continual Staff Training and Development
Clinical Experience as this Promotes Perceived Competence and Confidence to Wean
Vulnerability of Weaning to Disparate Interprofessional Working
Understanding of Protocols as Militating Against a Necessary Proactivity in Clinical Practice
Perceived Nursing Scope of Practice and Professional Risk
ICU Structure and Processes of Care
Ability of Protocols to Act as a Prompt for Shared Care and Consistency in Weaning Practice
Maximizing the Use of Protocols through Visibility and Ease of Implementation
Ability of Protocols to Act as a Framework for Communication with Parents
Pooled Meta-Analysis of Weaning Protocol Data in Mechanically Ventilated Patients (Am J Respir Crit Care Med, 2017) [MEDLINE]
Ventilator Weaning Protocols Decreased the Duration of Mechanical Ventilation by Approximately 25 hrs (95% CI, 12.5–35.5 Hours)
Ventilator Weaning Protocols Decreased ICU Length of Stay by 0.96 Days (95% CI: 0.24–1.7 Days)
Ventilator Weaning Protocols Did Not Impact the Mortality Rate (22.3 vs 22.2%; Odds Ratio 1.02; 95% CI: 0.82–1.26)
Ventilator Weaning Protocols Did Not Impact the Reintubation Rate (10.6 vs 11.9%; Odds Ratio 0.74; 95% CI: 0.44–1.23)
Weaning Protocols Did Not Impact Adverse Event Rates
In Subgroup Analyses, Personnel-Driven and Computer-Driven Protocols Had Similar Effects, as Compared to Management without a Ventilator Weaning Protocols
International Study of Weaning Practice (Ann Am Thorac Soc, 2018) [MEDLINE]
Most Providers Screened Patients Once Daily to Identify Spontaneous Breathing Trial Candidates (Regional Range, 70.0-95.6%)
Most Providers Used Pressure Support Alone (Range, 31.0-71.7%) or with Spontaneous Breathing Trials (Range, 35.7-68.1%)
To Conduct Spontaneous Breathing Trials, Most Providers Used Pressure Support with Positive End-Expiratory Pressure (Range, 56.5-72.3%) and T-Piece (Range 8.9-59.5%)
Less than 50% of ICU’s Outside of North America Have Written Directives to Conduct Spontaneous Breathing Trials
Recommendations (American Thoracic Society/American College of Chest Physicians Clinical Practice Guideline for Liberation from Mechanical Ventilation in Critically Ill Adults) (Am J Respir Crit Care Med, 2017) [MEDLINE]
Ventilator Weaning Protocols are Recommended for Acutely Ill Hospitalized Adults Who Have Been Mechanically Ventilated for >24 hrs (Conditional Recommendation, Low Certainty of Evidence)
Endotracheal Intubation Can Result in Laryngeal Edema, Especially in Patients Who Have Been Intubated for >36 hrs (Anesthesiology, 1992) [MEDLINE]
Incidence of Postextubation Stridor Has Been Reported to Be Between 6-37% (J Evid Based Med, 2011) [MEDLINE]
Identification of Laryngeal Edema Prior to Extubation is Useful to Decrease the Risk of Reintubation
Since Direct Visualization of the Vocal Cords is Difficult with the Endotracheal Tube in Place, Endotracheal Tube Cuff Leak Testing is Used as a Surrogate Indicator for the Presence of Laryngeal Edema
Technique
General Concept
Endotracheal Tube Cuff Leak (with the Cuff Deflated) Indicates the Presence of Airflow Around the Endotracheal Tube, Suggesting Adequate Space Between the Airway and the Endotracheal Tube
Lack of Leak (i.e. Lack of Space) May Be Suggestive of Laryngeal Edema, Laryngeal Injury, Secretions Laryngeal Stenosis, or a Large Endotracheal Tube within a Small Airway
Types of Leak Tests
Qualitative Endotracheal Tube Cuff Leak Test
Deflation of Endotracheal Tube Cuff with Subsequent Listening for an Air Leak (Either with or without a Stethoscope Over the Trachea)
Quantitative Endotracheal Tube Cuff Leak Test
Deflation of Endotracheal Tube Cuff with Subsequent Measurement of the Amount of Air Leak Via the Ventilator (Difference Between the Inspired and Expired Tidal Volumes During Volume-Cycled Ventilation)
Generally Accepted Threshold for Adequate Air Leak: >110 mL (or >24% of the Delivered Tidal Volume) (Crit Care Med, 2006) [
False-Positive Endotracheal Tube Cuff Leak Test: can occur in cases with late post-extubation upper airway edema
False-Negative Endotracheal Tube Cuff Leak Test: can occur with large ETT with crusted secretions
Clinical Efficacy
Systematic Review and Meta-Analysis of Cuff Leak Testing for the Diagnosis of Airway Obstruction in Adults (Intensive Care Med, 2009) [MEDLINE]
Overall Incidence of Upper Airway Obstruction: 6.9%
A Positive Cuff Leak Test (Absence of Leak) Should Alert the Clinician of a High Risk of Upper Airway Obstruction
Pooled Sensitivity was 0.56 (95% CI: 0.48-0.63), the Specificity was 0.92 (95% CI: 0.90-0.93)
Positive Likelihood Ratio was 5.90 (95% CI: 4.00-8.69) and the Negative Likelihood Ratio was 0.48 (95% CI: 0.33-0.72)
Diagnostic Odds Ratio was 18.78 (95% CI: 7.36-47.92
Area Under the Curve of the Summary Receiver Operator Characteristic (SROC) was 0.92 (95% CI: 0.89-0.94)
Systematic Review of Cuff Leak Testing for Predicting Postextubation Airway Complications (J Evid Based Med, 2011) [MEDLINE]
Cuff Leak Testing Accurately Predicts Which Adult Patients are at High Risk of Postextubation Airway Complications
Median Diagnostic Odds Ratios for Predicting Postextubation Laryngeal Edema and Reintubation were 18.16 (Range: 3.54-356.00) and 10.80 (Range: 2.74-1665.00), Respectively
Accuracy of the Cuff Leak Test Varied with the Methods, Duration of Intubation, and Study Population
Study of Endotracheal Tube Cuff Leak Testing for the Prediction of Postextubation Stridor (J Intensive Care Med, 2019) [MEDLINE]: n = 34
Postextubation Stridor Occurred in <10% of Unselected Critically Ill Patients
Postextubation Stridor Patients More Frequently Required Reintubation (17.6% vs 7.9%, P = .041), Prolonged Duration of Mechanical Ventilation (6 vs 5 Days, P = .029), and Longer ICU Length of Stay (12 vs 7.5 Days, P = .018)
However, ICU Mortality was Similar in Both Groups (2.9% vs 7.0%, P = .61)
Four Endotracheal Tube Cuff Leak Tests Had Poor Diagnostic Accuracy (Sensitivities Ranged from 27-46%, Specificities from 70-88%, Positive Predictive Values from 14-19%, and Negative Predictive Values from 92-93%)
Simulated Study of Cuff Leak Testing (Am J Respir Crit Care Med, 2017) [MEDLINE]
Cuff Leak Test–Guided Management Decreased Both the Reintubation Rate (2.4 vs 4.2%; RR, 0.58; 95% CI: 0.40–0.83) and Postextubation Stridor Rate (4.0 vs 6.7%; RR, 0.60; 95% CI: 0.47–0.77)
Cuff Leak Test–Guided Management Resulted in More Unnecessarily Delayed Extubations (9.2% Absolute Increase)
Cuff Leak Test–Guided Management Had No Effect on the Duration of Mechanical Ventilation
Recommendations (American Thoracic Society/American College of Chest Physicians Clinical Practice Guideline for Liberation from Mechanical Ventilation in Critically Ill Adults) (Am J Respir Crit Care Med, 2017) [MEDLINE]
Cuff Leak Test in Should Be Performed in Mechanically Ventilated Adults Who Meet Extubation Criteria and are Deemed to Be High Risk for Postextubation Stridor (Conditional Recommendation, Very Low Certainty of Evidence)
Criteria for High Risk
Female Sex
Traumatic Intubation
Intubation for >6 Days
Large Endotracheal Tube
Reintubated after an Unplanned Extubation
For Adults Who Have Failed a Cuff Leak Test But are Otherwise Ready for Extubation, Administering Systemic Steroids for >4 hrs Before Extubation is Recommended (Conditional Recommendation, Moderate Certainty of Evidence)
Weaning Modalities
Modalities
Extubation
Although Not Really Considered a Modality of Ventilator “Weaning” Per Se, Extubation (Liberation from the Ventilator) Transfers All of the Work of Breathing from the Ventilator to the Patient
Advantages
Simple and Useful for a Patient with Minimal Cardiopulmonary Disease (Especially in the Postoperative Setting When the Effects of General Anesthesia Have Resolved)
Disadvantages
Abruptly Transfers the Work of Breathing (and Requirement to Maintain a Patent Airway and Secretion Clearance) to the Patient
If the Patient is Unable to Tolerate this Increase in Work of Breathing, Extubation Failure Can Occur Precipitously
Pressure Support (PS) Weaning
Generally, Pressure Support Ventilation is Considered the Preferred Method of Ventilator Weaning (Chest, 2017) [MEDLINE]
Advantages
Allows Either Intermittent or Continuous Trials with the Pressure Support Level Adjusted According to the Patient’s Need
Gradual Increase in Work of Breathing May Be Useful in Patients with Unstable Coronary Artery Disease or Other Underlying Cardiopulmonary Limitations
Presence of Ventilator Alarms to Alert Provider to High Respiratory Rate and/or Low Tidal Volume
Easily Used in Respiratory Therapist-Driven Weaning Protocols
Disadvantages
An Inappropriately Low Level of Set Pressure Support Can Result in Respiratory Muscle Fatigue (Manifested by Low Spontaneous Tidal Volumes and Tachypnea), Recurrent Weaning Failure, and Patient Distress
This is Especially True in the Case of a Small Diameter Endotracheal Tube (≤7 mm), Which Generally Requires a Pressure Support of 7-10 cm H20 to Overcome the Resistance of the Endotracheal Tube Alone
Automatic Tube Compensation (ATC)
Available on Draeger Ventilators, ATC Compensates for the Endotracheal Tube Resistance
CPAP Weaning
Less Commonly Used in Modern Weaning Protocols
Advantages
Simple Method to Determine Readiness for Extubation
Presence of Ventilator Alarms to Alert Provider to High Respiratory Rate and/or Low Tidal Volume
T-Piece Weaning
Advantage
Simple Method (with Longstanding Clinical Experience) to Determine Readiness for Extubation
Disadvantages
Intermittent T-Piece Trials Provide No Ventilatory Support to the Patient (Patient Assumes Full Work of Breathing Plus the Resistance of the Endotracheal Tube During the Trial)
Inability to Maintain the Work of Breathing Required During the Trial Can Result in Abrupt (or Recurrent) Weaning Failure
T-Piece Trials are Not Indicated for Patients with Small Endotracheal Tubes (≤7 mm), Due to the Increased Endotracheal Tube Resistance
Lack of Ventilator Alarms to Alert Provider to High Respiratory Rate and/or Low Tidal Volume
Synchronized Intermittent Mandatory Ventilation (SIMV) with Pressure Support Weaning
Less Commonly Used in Modern Weaning Protocols
Advantages
Presence of Ventilator Alarms to Alert Provider to High Respiratory Rate and/or Low Tidal Volume
Disadvantages
Adjustment of Both the SIMV Backup Rate and Pressure Support Level Can Be Complicated and Vary Between Providers
Patient Work of Breathing with Various Ventilator Weaning Modes
Clinical Efficacy-Ventilator Weaning Modality
Study of T-Piece vs CPAP (5 cm H2O) for Weaning (Chest, 1991) [MEDLINE]
No Difference in Reintubation Rate
Comparative Trial of T-Piece, Intermittent Mandatory Ventilation (IMV) and Pressure Support (PS) Ventilator Weaning (Am J Respir Crit Care Med, 1994) [MEDLINE]: n = 109 patients who failed an initial spontaneous breathing trial
After Failing an Initial Spontaneous Breathing Trial, Patients were Randomized to Groups
After Excluding Patients Whose Weaning was Terminated for Complications Unrelated to the Weaning Process, Pressure Support Weaning Failure was Lowest (8%), as Compared to T-Piece and SIMV Weaning (p<0.025)
Spanish Randomized Trial of T-Piece (Once Daily or Two-Three Times Daily), Synchronized Intermittent Mandatory Ventilation (SIMV) and Pressure Support (PS) Ventilator Weaning (NEJM, 1995) [MEDLINE]: n = 130 patients who failed an initial spontaneous breathing trial
After Failing an Initial Spontaneous Breathing Trial, Patients were Randomized to Groups
Once Daily Spontaneous Breathing Trials with T-Piece
Multiple (2-3) Times Daily Spontaneous Breathing Trials with T-Piece
Once Daily Trial of Spontaneous Breathing with T-Piece Led to Extubation 3x More Quickly than Intermittent Mandatory Ventilation Weaning and Twice as Quickly as Pressure Support Weaning
Multiple (2-3) Daily Spontaneous Breathing Trials with T-Piece and Daily Spontaneous Breathing Trials with T-Piece were Equally Effective
Trial of T-Piece vs Pressure Support Ventilation Weaning (Am J Respir Crit Care Med, 1997) [MEDLINE]
No Difference Between Spontaneous Breathing Trials with Pressure Support Ventilation or T-Piece
Study of the Contribution of the Endotracheal Tube to Breathing Workload (Am J Respir Crit Care Med, 1998) [MEDLINE]
Work of Breathing was the Same Through a T-Piece and Following Extubation
Study of Automatic Tube Compensation, Pressure Support Ventilation, and T-Piece for Weaning (Acta Anaesthesiol Scand, 2002) [MEDLINE]
No Difference Between the Weaning Modes
Randomized Crossover Trial of Work of Breathing with Weaning Modes (Crit Care Med, 2000) [MEDLINE]
No Differences in the Work of Breathing During Spontaneous Breathing Trials Using a T-Piece, Low Level Pressure Support, or CPAP
In Fact, the Work of Breathing was Higher After Removal of the Endotracheal Tube than with Any of the Spontaneous Breathing Trial Methods: suggests that the endotracheal tube contribution to work of breathing is relatively small, in comparison to work of breathing with airway (which is possibly edematous) after extubation
Randomized, Prospective Trial of T-Piece vs Pressure Support Weaning (Croat Med J, 2004) [MEDLINE]
In Patients with Weaning Difficulties, Pressure Support Ventilation with 8 cm H2O was a More Successful Weaning Method than T-Piece
Study of Automatic Tube Compensation vs CPAP for Weaning (Crit Care Med, 2006) [MEDLINE]
No Difference in the Rate of Reintubation
Study of Crossover to Pressure Support Weaning in Patients Failing T-Piece Weaning (Intensive Care Med, 2006) [MEDLINE]
In Patients Failing a 30 min T-Piece Trial, Conversion to Pressure Support Ventilation (at 7 cm H2O) For an Additional 30 min Resulted in Weaning Success in 68% of Patients
Data Suggest that Endotracheal Tube Resistance May Contribute to Weaning Failure
Randomized, Controlled Trial of Automatic Tube Compensation vs Pressure Support Ventilation for Weaning (Crit Care, 2009) [MEDLINE]
No Difference in the Rate of Reintubation
Cochrane Database Systematic Review of Pressure support vs T-Piece for Ventilator Weaning in Adults (Cochrane Database Syst Rev, 2014) [MEDLINE]
Low Quality Data from Existing Studies
However, Pressure Support Ventilation was More Effective than T-Piece for Successful Spontaneous Breathing Trials Among Patients with Simple Weaning
Based on the Findings of Single Trials, Three Studies Presented a Shorter Weaning Duration in the Group undergoing Pressure Support Spontaneous Breathing Trials, However a Fourth Study Found a Shorter Weaning Duration with a T-Piece
Chinese Comparative Study of Pressure Support Ventilation vs T-Piece to Determine the Threshold RSBI During Spontaneous Breathing Trials (Am J Med Sci, 2014) [MEDLINE]: n = 208
The Threshold values of RSBI (75 for Pressure Support Ventilation and 100 for T-Piece) were the Most Accurate for Predicting Successful Weaning
Methods Had Comparable Weaning Success Rates (Pressure Support Ventilation: 83.9%, T-Piece: 78.3%)
Systematic Review and Meta-Analysis of Weaning Modalities with Pressure Augmentation (Pressure Support with 5-8 cm H2O or Automatic Tube Compensation) or without Pressure Augmentation (T-Piece or CPAP) (Chest, 2017) [MEDLINE]: n = 4 trials
Conducting the Spontaneous Breathing Trial with Pressure Augmentation (Pressure Support) was More Likely to Be Successful (84.6% vs 76.7%; RR, 1.11; 95% CI: 1.02-1.18), Produced a Higher Rate of Extubation Success (75.4% vs 68.9%; RR, 1.09; 95% CI: 1.02-1.18), and was Associated with a Trend Toward Lower ICU Mortality Rate (8.6% vs 11.6%; RR, 0.74; 95% CI: 0.45-1.24)
French Multicenter, Open-Label Trial Comparing Pressure-Support Ventilation (CPAP 0 cm H2O and PS 8 cm H2O) or T-Piece for Spontaneous Breathing Trials in Patients at High-Risk for Extubation Failure (>65 y/o or with Chronic Cardiopulmonary Disease) (NEJM, 2022) [MEDLINE]: n = 969
At Day 28, There were No Differences in Ventilator-Free Days Between the PS Group (Median 27; Interquartile Range: 24-27) and the T-Piece Group 27 (Interquartile Range: 23-27) (Difference: 0 days; 95% CI: -0.5 to 1; P = 0.31)
Extubation was Performed within 24 hrs in 77.7% of Patients in the PS Group and in 72.2% of Patients in the T-Piece Group (Difference: 5.5 Percentage Points; 95% CI: 0.01 to 10.9)
Extubation was Performed within 7 Days in 97.7% of Patients in the PS Group and 94.4% of Patients in the T-Piece Group (Difference: 3.3 Percentage Points; 95% CI: 0.8 to 5.9)
Reintubation was Performed in 14.9% of Patients in the PS Group and 13.6% of Patients in the T-Piece Group (Difference 1.3 Percentage Points; 95% CI: -3.1 to 5.8)
Cardiac or Respiratory Arrest was a Reason for Reintubation in 9 Patients (3 in the PS Group and 6 in the T-piece Group)
Recommendations (American College of Chest Physicians/American Thoracic Society Clinical Practice Guideline for Liberation from Mechanical Ventilation in Critically Ill Adults) (Chest, 2017) [MEDLINE]
Weaning Modality
For Acutely Hospitalized Patients Ventilated >24 hrs, Initial Spontaneous Breathing Trial Should Be Conducted with Inspiratory Pressure Augmentation (Pressure Support Ventilation of 5-8 cm H2O), Rather than with T-piece or CPAP (Conditional Recommendation, Moderate-Quality Evidence)
Duration of Weaning Trials
Background
Weaning Trials are Typically 30-120 min in Length
Trials of 30 min are Generally Adequate to Determine Patient Tolerance, Although Longer Trials Can Be Used in Some Cases to Assess Patient Endurance
Weaning Trials Should Be Terminated at the First Signs of Failure: prolonged weaning trials should be avoided to avoid fatigue, which may impair performance during future weaning trials
Clinical Efficacy
Multicenter Study of Weaning Trial Length (Am J Respir Crit Care Med, 1999) [MEDLINE]
T-Piece Weaning Trials of 30 or 120 min were Comparable in Terms of Rate of Weaning Failure and Reintubation
Prospective, Multicenter, Randomized Trial of Spontaneous Breathing vs Pressure Support in COPD Patients Requiring Ventilation >15 Days and Failing T-Piece Trials (Am J Respir Crit Care Med, 2001) [MEDLINE]
No Significant Difference were Found in Weaning Success Rate (73% vs 77% in the Pressure Support and Spontaneous Breathing Group, Respectively), Mortality Rate (11.5% vs 7.6%), Duration of Ventilatory Assistance (181 +/- 161 vs 130 +/- 106 h), Duration of Long-Term Weaning Units (33 +/- 12 vs 35 +/- 19 d), or Total Hospital Stay
Median Time to Spontaneous Breathing Trial Failure was 120 min
Multicenter, Cohort Study of Central Venous Saturation in Difficult to Wean Patients (Crit Care Med, 2010) [MEDLINE]
Central Venous Saturation was an Early and Independent Predictor of Extubation Failure in Difficult to Wean Patients
Rest After Weaning Trial
Rationale
Rest Between Weaning Trials is Critical to Facilitate Patient Recovery and Avoid Fatigue
Patients are Standardly Returned to Their Prior Ventilator Settings (Which Presumably Supplies a High Level of Ventilatory Support)
Rest After a Successful Weaning Trial, Prior to Extubation is Also Recommended: see the following section
Clinical Efficacy
Spanish Randomized Multicenter Trial of Reconnection to the Ventilator for 1 Hour of Rest After a Successful Spontaneous Breathing Trial, Prior to Extubation (Intensive Care Med, 2017) [MEDLINE]: n = 470
One Hours Rest (on the Ventilator) After a Successful Spontaneous Breathing Trial Decreased the 48-hr Reintubation Rate (5%), as Compared to the Control Group (14%)
Multivariable Regression Model Demonstrated that the Variables Independently Associated with Reintubation Rate were Rest [Odds Ratio 0.34 (95%CI: 0.17-0.68)], APACHE II [Odds Ratio 1.04 (95% CI: 1.002-1.077)], and Days of Mechanical Ventilation Before Spontaneous Breathing Trial [Odds Ratio 1.04 (95% CI: 1.001-1.073)]
Age, Reason for Admission, and Type and Duration of Spontaneous Breathing Trial were Not Associated with Reintubation Rate
Weaning Success
Prediction of Weaning Success
Clinical Efficacy
Diaphragmatic Atrophy Can Be Identified by Diaphragmatic Ultrasound (Thorax, 2014)[MEDLINE]
Diaphragmatic Thickening Can Predict Weaning Success
Diaphragmatic Atrophy (Due to Abnormally Low Inspiratory Effort) Which Develops During Mechanical Ventilation (As Assessed by Diaphragmatic Ultrasound) Decreased the Probability of Liberation from Mechanical Ventilation (Adjusted Hazard Ratio, 0.69; 95% CI: 0.54-0.87; Per 10% Decrease), Prolonged ICU Length of Stay (Adjusted Duration Ratio, 1.71; 95% CI: 1.29-2.27), and Increased the Risk of Complications (Adjusted Odds Ratio, 3.00; 95% CI: 1.34-6.72) (Am J Respir Crit Care Med, 2018) [MEDLINE]
Increased Diaphragmatic Thickness (Due to Excessive Inspiratory Effort) Also Predicted Prolonged Mechanical Ventilation (Adjusted Duration Ratio, 1.38; 95% CI: 1.00-1.90)
Patients with Thickening Fraction 15-30% (Similar to Breathing at Rest) During the First 3 Days Had the Shortest Duration of Mechanical Ventilation
Classification of Outcome of Patients with Failure to Wean
Prospective, Multicenter 6-Month Cohort Study of the Outcome of Weaning (Eur Respir J, 2010) [MEDLINE]: n = 510
Definition
Simple Wean: weaning after passing the first spontaneous breathing trial
Difficult Weaning: failure of first spontaneous breathing trial, then requiring ≤3 spontaneous breathing trials or 7 days to pass a spontaneous breathing trial
Prolonged Weaning: failure of at least 3 spontaneous breathing trials or require >7 days to pass a spontaneous breathing trial
Incidence by Category
Simple Weaning: 59%
Difficult Weaning: 26%
Prolonged Weaning: 14%
Outcome
Hospital Mortality was Increased in Patients with Prolonged Weaning (32%), But Not Difficult Weaning (13%) (p=0.0205)
In Multivariate Logistic Reression Model, Prolonged Weaning (But Not Difficult Weaning) was Associated with an Increased Risk of Death
Ventilator-Free Days and ICU-Free Days were Decreased in Both the Difficult and Prolonged Weaning Groups
Study of Outcome of Weaning (Am J Respir Crit Care Med, 2011) [MEDLINE]; n = 4,968
Incidence by Category
Simple Weaning: 55%
Difficult Weaning: 39%
Prolonged Weaning: 6%
Variables Associated with Prolonged Weaning
SAPS II Score (Odds Ratio Per Unit of Simplified Acute Physiology Score II, 1.01; 95% confidence interval [CI], 1.001–1.02)
Duration of Mechanical Ventilation Prior to First Weaning (Odds Ratio Per Day, 1.10; 95% CI, 1.06–1.13)
Chronic Pulmonary Disease Other than COPD (Odds Ratio 13.23; 95% CI, 3.44–51.05
Pneumonia as the Reason to Start Mechanical Ventilation (Odds Ratio 1.82; 95% CI, 1.07–3.08)
Level of PEEP Before Weaning (Odds Ratio Per Unit,1.09; 95% CI, 1.04–1.14)
Prolonged Weaning Group Had a Nonsignificant Trend Toward a Higher Rate of Reintubation, Tracheostomy
Prolonged Weaning Group Had a Significant Longer Length of Stay and Higher ICU Mortality Rate (Odds Ratio for Death, 1.97;95% CI, 1.17–3.31)
Baseline Brain Natriuretic Peptide (BNP) Measured Before First Weaning Trials Has Been Found to Be Higher in Patients with Subsequent Weaning Failure and Levels Correlate with Weaning Duration (Intensive Care Med, 2006) [MEDLINE]
Myocardial Injury After Non-Cardiac Surgery (MINS) Has Been Identified as a Risk Factor for Weaning Failure in Patients Who Have Undergone Abdominal Surgery (Independent of Age, Lower Preoperative Left Ventricular Ejection Fraction, and Postoperative Hypoalbuminemia (PLoS One, 2014) [MEDLINE]
Weaning-Induced Pulmonary Edema (WiPO) Has Been Identified as a Risk Factor for Weaning Failure (Crit Care, 2016) [MEDLINE]: risk of WIPO was increased by presence of COPD, prior structural cardiomyopathy. and obesity (to a lesser extent)
Weaning Strategies Which Include the Use of PEEP During a Pressure Support Trial Can Mask the Presence of Weaning-Associated Cardiac Dysfunction, Since PEEP is a Treatment for Heart Failure (Intensive Care Med, 2010) [MEDLINE]
Spontaneous Breathing Trial-Induced Increases in Extravascular Lung Water (Indexed for Ideal Body Weight), Plasma Protein Concentrations, Hemoglobin Concentration, and BNP are Reliable Alternatives to the Swan-Ganz Catheter for Diagnosing Weaning-Induced Pulmonary Edema (Crit Care Med, 2014) [MEDLINE]
Thoracic Ultrasound Demonstrating B-Lines ≥6 on Four Anterior Points Allows the Diagnosis Weaning-Induced Pulmonary Edema (Intensive Care Med, 2019) [MEDLINE]
Passive Leg Raise Prior to Weaning Trial May Predict Weaning Failure Due to Cardiac Dysfunction (Intensive Care Med, 2015) [MEDLINE]
Stress Echocardiography May Be Useful to Detect Silent Diastolic Dysfunction, Systolic Dysfunction, or Mitral Regurgitation Which May Impact Weaning (J Crit Care, 2017) [MEDLINE]
Depression Has Been Demonstrated in 42% of Patients During Weaning from Prolonged Mechanical Ventilation and Patients with Depression were More Likely to Experience Weaning Failure and Death (Intensive Care Med, 2010) [MEDLINE]
Delirium (Assessed by CAM-ICU at the Time of the First Weaning Trial) Has Been Found to Be Associated with Weaning Failure (Respirology, 2016) [MEDLINE]
Note that in a Patient with Chronic Hypoventilation (Chronic Hypoxemic, Hypercapnic Respiratory Failure) Who Has Been Inadvertently Overventilated During Their Course Prior to Weaning, Compensatory Renal Bicarbonate Excretion Decreases the Serum Bicarbonate Below the Patient’s Baseline (i.e. a “Relative Metabolic Acidosis), Resulting in Hypercapnia (at Their Baseline pCO2) with Undesirable Acidemia During Weaning Trials
Small Diameter Endotracheal Tube/Tracheostomy (Respir Care, 2012) [MEDLINE]
This Can Be Overcome by Switching from T-Piece trial to Pressure Support, Which Allows the Pressure Support to Overcome the Resistance of the Smaller Diameter Artificial Airway (Intensive Care Med, 2006) [MEDLINE]
Inability to Progress to Increasing Patient Workload During Successive Spontaneous Breathing Trials
Management
Clinical Efficacy-Changing the Weaning Modality in Patients with Failure to Wean
Comparative Trial of T-Piece, Intermittent Mandatory Ventilation (IMV) and Pressure Support (PS) Ventilator Weaning (Am J Respir Crit Care Med, 1994) [MEDLINE]: n = 109 patients who failed an initial spontaneous breathing trial
After Failing an Initial Spontaneous Breathing Trial, Patients were Randomized to Groups
After Excluding Patients Whose Weaning was Terminated for Complications Unrelated to the Weaning Process, Pressure Support Weaning Failure was Lowest (8%), as Compared to T-Piece and SIMV Weaning (p<0.025)
Critique
Trial Allowed Patient to Undergo Up to 3 T-Piece Trials (2 hrs Each) in a 24 hr Period Which May Have Resulted in Respiratory Muscle Fatigue, Which May Have Slowed the Weaning Process
Respiratory Muscle Fatigue Can Take Up to 24 hrs to Resolve ( J Appl Physiol, 1985) [MEDLINE]
Spanish Randomized Trial of T-Piece (Once Daily or Two-Three Times Daily), Synchronized Intermittent Mandatory Ventilation (SIMV) and Pressure Support (PS) Ventilator Weaning (NEJM, 1995) [MEDLINE]: n = 130 patients who failed an initial spontaneous breathing trial
After Failing an Initial Spontaneous Breathing Trial, Patients were Randomized to Groups
Once Daily Spontaneous Breathing Trials with T-Piece
Multiple (2-3) Times Daily Spontaneous Breathing Trials with T-Piece
Once Daily Trial of Spontaneous Breathing with T-Piece Led to Extubation 3x More Quickly than Intermittent Mandatory Ventilation Weaning and Twice as Quickly as Pressure Support Weaning
Multiple (2-3) Daily Spontaneous Breathing Trials with T-Piece and Daily Spontaneous Breathing Trials with T-Piece were Equally Effective
Trial Allowed Patient to Be Extubated After a Successful 2 hr Spontaneous Breathing Trial: fatigue was less likely to occur in this trial
Conclusions
While T-Piece and Pressure Spontaneous Breathing Trials are Probably Comparable, IMV is Notably Inferior
During IMV, the Respiratory Neuromuscular System Poorly Adapts to Changing Respiratory Workloads Between the Supported (Mandatory) and Unsupported (Spontaneous) Breaths
Muscle Contraction During Lower Levels of IMV is Similar During Both Supported (Mandatory) and Unsupported (Spontaneous) Breaths (Anesthesiology, 1994) [MEDLINE]
This Drawback of IMV Can Be Mitigated to Some Extent by Using Adding Pressure Support to IMV for the “Spontaneous” Breaths (Chest, 1994) [MEDLINE]
Clinical Efficacy-Management of Pleural Effusions in Patients with Failure to Wean
Study of Effect of Pleural Effusion Drainage in Mechanically-Ventilated Patients (Ann Am Thorac Soc, 2014) [MEDLINE]
Drainage of Large (≥500 mL) Pleural Effusions Improved Oxygenation and End-Expiratory Lung Volume
Oxygenation Improvement Correlated with Increased Lung Volume and a Decrease in Transpulmonary Pressure (Less So Though in Patients with ARDS)
Clinical Efficacy-Heart Failure Management in Patients with Failure to Wean
Randomized, Controlled Multicenter Trial of BNP-Guided Fluid Management During Ventilator Weaning (Am J Respir Crit Care Med. 2012) [MEDLINE]
BNP-Guided Fluid Management Decreased the Duration of Weaning without Increasing Adverse Events, Especially in Patients with Left Ventricular Systolic Dysfunction
Clinical Efficacy-Nitroglycerin Treatment of Patients with Failure to Wean
Small Non-Randomized Trial of Nitroglycerin for Difficult to Wean COPD Patients (Crit Care, 2010) [MEDLINE]: n = 12
In Difficult to Wean COPD Patients, Mean Arterial Pressure Increased, Rate-Pressure Product Increased, Mean Pulmonary Artery Pressure Increased, Pulmonary Capillary Wedge Pressure Increased, and Mixed Venous Oxygen Saturation Decreased During Failing Weaning Trials
During Weaning with Nitroglycerin Infusion in Difficult to Wean COPD Patients, These Parameters Did Not Change
Nitroglycerin Infusion Allowed a Successful Weaning Trial in 92% of Cases and a Extubation in 88% of Cases
Clinical Efficacy-Supportive in Patients with Failure to Wean
Study of Relaxation Biofeedback During Weaning (Am Rev Respir Dis, 1990) [MEDLINE]
Relaxation Biofeedback Has Been Demonstrated to Decrease Weaning Time
General Recommendations
While T-Piece and Pressure Spontaneous Breathing Trials are Probably Comparable in Patients Who Fail to Wean, Most Clinicians Use Pressure Support Trials with Graded Levels of Support (Per Patient Tolerance)
Once Daily Spontaneous Breathing Trials are Probably Recommended to Avoid Fatigue
Ongoing Assessment of Factors Potentially Contributing to Failure to Wean Should Continue on a Daily Basis
If the Patient Then Tolerates Spontaneous Breathing Trial, Patient Should Be Returned to Normal Ventilator Mode for One Hour of Rest Prior to Extubation (Intensive Care Med, 2017) [MEDLINE]
Once Extubated, Prophylactic Noninvasive Ventilation (NIPPV) Can Be Considered in High-Risk Patients
Tracheostomy (see Tracheostomy): may be required for refractory failure to wean
In Tracheostomized Patients Requiring Prolonged Ventilation in a Long-Term Acute Care Facility, Unassisted Breathing Via Tracheostomy Resulted in Shorter Weaning Times, as Compared to Pressure Support (JAMA, 2013) [MEDLINE]
Weaning Mode Had No Effect on 6 and 12-Month Mortality Rates
Importantly, in This Study, Approximately 37% of Patients Could Have Been Weaned in the ICU and May Not Have Required Transfer to the LTAC for Weaning
Once Tracheostomy Has Been Placed, Patients Typically are Considered for Transfer to a Long-Term Acute Care (LTAC) Facility for Prolonged Ventilator Weaning
Long-Term Care Facilities Specialize in Specialized Rehabilitation and Ventilator Weaning
Long-Term Acute Care Facility Admissions Have Increased from 13,732 in 1997 to 40,353 in 2006, with Annual Costs Increasing from from $484 Million to $1.325 Billion (JAMA, 2010) [MEDLINE]
In the “Ventilation Outcomes Study”, Post-Critical Illness Ventilator-Dependent Patients Admitted to LTAC Facilities Had a Mean APACHE III Score of 35, >90% of Patients Had ≥3 Indwelling Lines/Tubes, and 42% of Patients Had ≥Stage 2 Decubitus Ulcers (Chest, 2007) [MEDLINE]
Preparation for Extubation
Required Pre-Extubation Criteria
Resolution (or Significant Improvement) in Condition Which Initially Resulted in Intubation (ARDS, Pneumonia, Cardiogenic Pulmonary Edema, Inability to Protect Airway, etc)
Performance of Successful Weaning Trial: required in most cases
Exception-Patient Intubated for Short Period of Time During Recovery from General Anesthesia
Exception-Patient Being Terminally Extubated During End of Life Care
Adequate Mental Status (Typically with Glasgow Coma Scale ≥8) with Intact Ability to Protect Airway
Adequate Ability to Cough
Assessed by Clinical Examination, White Card Test, Spirometry, etc
Low Amount of Secretions (Generally Requiring Suctioning Less than Every 2-3 hrs)
Thick Secretions are Usually Only a Significant Factor in the Presence of a Weak Cough
Pre-Extubation Checklist
Discontinue Tube Feeding (2-4 hrs Before Extubation)
Some Patients with Ileus/High Residual Volumes May Require that Tube Feedings Be Held for Longer Periods Prior to Extubation
Prepare Suction Set-Up and Bag-Valve-Mask (BVM) Ventilation System
Setup is Critical in Case Reintubation is Required
Standard Flow Nasal Cannula Oxygen (2-6 LPM) is Typically Applied, as Required
Some Patients Who are Deemed to Be at Low Risk for Reintubation But with Significant Hypoxemia, May Benefit from High-Flow Nasal Cannula (as Described Below)
Randomized, Controlled, Open-Label Trial of High-Flow Nasal Cannula in Extubated Patients with pO2/FIO2 <300 (J Crit Care, 2010) [MEDLINE]: n = 105
After Extubation, High-Flow Nasal Cannla was Associated with Improved Oxygenation for the Same FGIO2, as Compared to Venturi Mask
Trial of High-Flow Nasal Cannula in Extubated Patients Who Required High-Flow Oxygen (Am J Respir Crit Care Med, 2014) [MEDLINE]
After Extubation, High-Flow Nasal Cannula were as Effective as High-Flow Face Mask Oxygen
Tolerance of High-Flow Nasal Cannula was Better than High-Flow Face Mask
French Multicenter Randomized OPERA Study of Early Postextubation High-Flow Nasal Cannula After Major Abdominal Surgery (Intensive Care Med, 2016) [MEDLINE]: n = 220
In Patients Undergoing Major Abdominal Surgery, Early Postextubation Preventive High-Flow Nasal Cannula Oxygen Did Not Result in Improved Pulmonary Outcomes, as Compared with Standard Oxygen Therapy
Spanish Randomized Trial of High-Flow Nasal Cannula Oxygen in Patients at Low Risk for Reintubation (JAMA, 2016) [MEDLINE]: n = 527
In Extubated Patients at Low Risk for Reintubation, the High-Flow Nasal Cannula Oxygen Decreased the Risk of Reintubation within 72 hrs, as Compared to Conventional Oxygen Therapy
Postextubation NIPPV Can Be Applied Using a Variety of Strategies
Early Extubation (Before a Patient Has Passed a Spontaneous Breathing Trial), Followed by Immediate Application of Postextubation NIPPV (i.e. NIPPV as an Extension of Invasive Mechanical Ventilation)
Extubation After After a Patient Had Passed a Spontaneous Breathing Trial, Followed by Immediate/Prompt Application of Postextubation NIPPV (i.e. Prophylactic to Decrease the Risk of Reintubation)
Extubation, Followed by the Application of Postextubation NIPPV Only When the Patient Appears to Manifest Worsening Respiratory Status (i.e. Rescue Therapy to Mitigate the Risk of Reintubation)
After Thoracoabdominal Surgery, Prophylactic Post-Extubation NIPPV Decreased Pulmonary Morbidity and Length of Stay (Chest, 2005) [MEDLINE]
In At-Risk Patients (with Risk Factors Such as Hypercapnia, Congestive Heart Failure, Ineffective Cough and Excessive Tracheobronchial Secretions, More Than One Failure of a Weaning Trial, More Than One Comorbid Condition, and Upper Airway Obstruction), Prophylactic NIPPV for First 48 hrs After Extubation Decreased Reintubation Rate and Mortality Rate (Am J Respir Crit Care Med, 2006) [MEDLINE]
Randomized Trial of Prophylactic NIPPV vs Usual Care in Extubated Patients Who were at Risk for Reintubation (Am J Respir Crit Care Med, 2006) [MEDLINE]
Overall, NIPPV Decreased the Reintubation Rate and ICU Mortality Rate
In the Subgroup of Chronically Hypercapnic Patients (Identified by the Presence of Hypercapnia with pCO2 ≥45 mm Hg During Spontaneous Breathing Trial), NIPPV Decreased the Reintubation Rate, ICU Mortality Rate, and 90-Day Mortality Rate
In 12 Studies with Predominantly COPD Patients, Postextubation NIPPV Decreased the Mortality Rate and Ventilator-Associated Pneumonia Rate
Meta-Analysis of NIPPV in Postextubation Respiratory Failure (Indian J Crit Care, 2013) [MEDLINE]
Prophylactic NIPPV Improved Reintubation and Hospital Mortality Rates
Therapeutic NIPPV Only Improved ICU Length of Stay, But Did Not Impact the Reintubation or Mortality Rate
Systematic Review and Meta-Analysis of Trials Using NIPPV for Prevention or Treatment of Acute Respiratory Failure or as a Tool to Facilitate Early Extubation (Crit Care Med, 2015) [MEDLINE]: n = 78 trials
NIPPV Decreased the Mortality Rate in Patients Treated for Acute Respiratory Failure (Due to COPD Exacerbation, Pulmonary Edema, Postoperative Acute Respiratory Failure, and Mixed Etiologies)
NIPPV Decreased the Mortality Rate When Used to Prevent Acute Respiratory Failure
NIPPV Did Not Decrease the Mortality Rate When Used to Facilitate Early Extubation
Cochrane Systematic Review of NIPPV as a Weaning Strategy in Adults with Acute Respiratory Failure (Population with Predominantly COPD) (CMAJ, 2014) [MEDLINE]: n= 16 trials (n = 994 patients)
Most of Patients in Trials Had COPD
NIPPV Decreased the Mortality Rate and Pneumonia Rate without Increasing the Risk of Weaning Failure or Reintubation
In Subgroup Analysis, Mortality Benefits were Significantly Greater in Patients with COPD
Systematic Review and Meta-Analysis of Trials Using NIPPV for Prevention or Treatment of Acute Respiratory Failure or as a Tool to Facilitate Early Extubation (Crit Care Med, 2015) [MEDLINE]: n = 78 trials
Overall (in All Populations), NIPPV Decreased the Mortality Rate (at Longest F/U) with Relative Risk 0.73 (95% CI: 0.66–0.81) (p<0.001): number needed to treat = 19
Facilitation of Early Extubation
NIPPV Did Not Decrease the Mortality Rate (at Longest F/U) with Relative Risk 0.81 (95% CI: 0.51–1.30) (p=0.39)
Pooled Analysis of Use of Postextubation NIPPV in High-Risk Patients (Chest, 2017) [MEDLINE]: n = 5 trials
High-Risk Factors: COPD, CHF, hypercapnia, older age, and a higher severity of illness
NIPPV was Favored Postextubation Over Standard Care in High-Risk Patients (RR, 1.14; 95% CI: 1.05-1.23)
NIPPV was Significantly Better than Conventional Therapy for ICU Length of Stay (Mean Difference –2.48 Days; 95% CI, –4.03 to –0.93) and Short-Term Mortality (RR 0.37; 95% CI: 0.19-0.70)
Trial of Early Extubation to Immediate NIPPV in Patients with Hypoxemic Respiratory Failure (Intensive Care Med, 2018) [MEDLINE]: n = 130
In Highly Selected Hypoxemic Patients, Early Extubation Followed by Immediate NIPPV Decreased the Duration of Invasive Mechanical Ventilation without Affecting ICU Length of Stay
Incidence of VAP, Rate of Patients Requiring Sedative Infusion, and Hospital Length of Stay were All Decreased in the Early Extubation Group, as Compared to Control
No Difference was Observed in ICU or Hospital Mortality Rate, Number of Treatment Failures, Severe Events, and Tracheostomy Rate
UK Randomized Breathe Trial of Early Extubation to NIPPV in General Population of Patients with Respiratory Failure (JAMA, 2018) [MEDLINE]: n = 364
The Median Time to Liberation was 4.3 Days in the NIPPV Group vs 4.5 Days in the Invasive Ventilation Group (Adjusted Hazard Ratio, 1.1; 95% CI: 0.89-1.40)
The NIPPV Group Received Less Invasive Ventilation (Median, 1 Day vs 4 Days; Incidence Rate Ratio, 0.6; 95% CI: 0.47-0.87) and Fewer Total Ventilator Days (Median, 3 Days vs 4 Days; Incidence Rate Ratio, 0.8; 95% CI: 0.62-1.0)
There was No Significant Difference in Reintubation Rates, Tracheostomy Rates, or Mortality Rates
Adverse Events Occurred in 24.7% of Patients in the NIPPV Group vs 25.8% of Patients in the Invasive Ventilation Group
In Patients Requiring Mechanical Ventilation in Whom a Spontaneous Breathing Trial Had Failed, Early Extubation to NIPPV Did Not Shorten time to Liberation from Any Ventilation
Systematic Review of Postextubation NIPPV in Patients with Respiratory Failure (Intensive Care Med, 2018) [MEDLINE]
Postextubation NIPPV Decreased Hospital Mortality, Decreased VAP Incidence, and Decreased ICU Length of Stay
Effect was Most Beneficial in Patients with COPD
Small Randomized Trial of Early Extubation with Immediate Postextubation NIPPV in Highly-Selected Patients with Hypoxemic Respiratory Failure (Intensive Care Med, 2019) [MEDLINE]: n = 130
In Highly-Selected Hypoxemic Patients, Early Extubation with Immediate Postextubation NIPPV Decreased Ventilator Days, But Did Not Impact ICU Length of Stay
No Significant Difference in ICU Mortality, Hospital Mortality, Number of Treatment Failures, Severe Event Rate, or Tracheostomy Rate
Recommendations (American College of Chest Physicians/American Thoracic Society Clinical Practice Guideline for Liberation from Mechanical Ventilation in Critically Ill Adults) (Chest, 2017) [MEDLINE]
Management of Patients at High Risk for Post-Extubation Respiratory Failure
For Patients at High Risk for Extubation Failure (Hypercapnia, COPD, Congestive Heart Failure, or Other Serious Comorbidities) Who Have Been Receiving Mechanical Ventilation for >24 hrs, and Who Have Passed a Spontaneous Breathing Trial, Extubation to Preventative Noninvasive Positive-Pressure Ventilation (NIPPV) is Recommended (Strong Recommendation, Moderate Quality of Evidence)
Apply NIPPV Immediately After Extubation to Maximize the Outcome Benefit
Extubation Failure
Epidemiology
Statistics
Extubation Failure Occurs in Approximately 10-15% of Extubated Patients
Study of Extubation Failure in Patients Following a Spontaneous Breathing Trial (Chest, 2006) [MEDLINE]: n = 900
Extubation Failure Occured in Approximately 13.4% of Patients
Cohort Study Using Data from the Project IMPACT Database of 185 ICU’s in the United States (Crit Care Med, 2017) [MEDLINE]: n = 98,367
Reintubation Rate for ICU Patients Extubated from Mechanical Ventilation was 10%
Median Time to Reintubation was 15 hrs (Interquartile Range: 2-45 hrs)
Of the Patients Who Required Reintubation in the ICU, 90% Did So Within the First 96 hrs After Initial Extubation
Extubation Failure Increases the Mortality Rate
Extubation Failure is Associated with 43% Mortality Rate, vs 12% in Those Who Were Successfully Extubated [MEDLINE]
Predictors of Extubation Failure
Predictors of Extubation Failure
Weak Cough (Cough Peak Expiratory Flow ≤60 L/min)
Requirement for Frequent Suctioning (Sputum Volume >2.5 mL/hr)
Glasgow Coma Score <8
Positive Fluid Balance in the 24 hrs Preceding Extubation
Pneumonia as the Initial Etiology of Respiratory Failure
Age ≥65 y/o with Severe Chronic Cardiac and Pulmonary Disease
Decreased/Absent Endotracheal Tube Cuff Leak
Supporting Data
Study of Predictors of Successful Extubation in Neurosurgical Patients (Am J Respir Crit Care Med, 2001) [MEDLINE]
Multivariate Analysis Demonstrated that Glasgow Coma Scale Score (GCS) (p<0.0001) and pO2/FIO2 Ratio (p<0.0001) Were Associated with Extubation Success
Odds of Successful Extubation Increased by 39% with Each GCS Score Increment
GCS Score ≥8 at Extubation was Associated with Success in 75% of Cases, as Compared to 33% for a GCS Score <8 (p<0.0001)
Study of Predictors of Extubation Failure(Chest, 2001) [MEDLINE]
Inability to Moisten an Index Card Held 1-2 cm from the End of the Endotracheal Tube with 3-4 Coughs is 3x More Likely to Fail Extubation
Study of Cough Peak Flow as a Predictor of Extubation Failure (Chest, 2003) [MEDLINE]: n = 95
Patients with Cough Peak Expiratory Flow ≤60 L/min were 5x More Likely to Have Extubation Failure and Were 19x More Likely to Die During that Hospital Stay
Risk Factors for Extubation Failure Include Low Cough Peak Flow (≤60 L/min), Increased Endotracheal Secretions (Secretions >2.5 ml/hr), and Inability to Complete 4 Simple Tasks (Open Eyes, Follow with Eyes, Grasp Hand, Stick Out Tongue) (Intensive Care Med, 2004) [MEDLINE]
Failure Rate was 100% for Patients with All 3 Risk factors, as Compared to 3% for Those with 0 Risk Factors (RR=23.2; 95% CI: 3.2-167.2)
Presence of Any 2 of the Risk Factors had a Sensitivity of 71% and Specificity of 81% in Predicting Extubation Failure
Patients Who Failed a Trial of Extubation were 3.8x More Likely to Have Any 2 Risk Factors, as Compared to Those Who were Successful
Multicountry Study of Predictors of Extubation Failure (Chest, 2006) [MEDLINE]: n = 900 Patients
Pneumonia as the Reason for Initial Intubation: odds ratio 1.77 (95% CI: 1.10-2.84)
Positive Fluid Balance: odds ratio 1.70 (95% CI: 1.15-2.53)
Elevated Rapid Shallow Breathing Index (RSBI): odds ratio 1.009 per unit (95% CI: 1.003-1.015)
Analysis Allowed Partitioning of Risk Using Multiple Variables
French Study of Peak Cough Expiratory Flow as a Predictor of Extubation Success (Intensive Care Med, 2009) [MEDLINE]: n = 130
Inability to Cough on Command or a Peak Cough Expiratory Flow ≤35 l/min Predicted Extubation Failure with a Sensitivity of 79% and a Specificity of 71%
Risk of Extubation Failure was 24% for the Patients Who Did Not Cough on Command or with a Peak Cough Expiratory Flow ≤35 l/min and 3.5% for those with a Peak Cough Expiratory Flow >35 l/min (RR = 6.9 (95% CI: 2-24; P = 0.002)
Mean Peak Cough Flow of Patients Who Failed Extubation (36.3 +/- 15 L/min) was Significantly Lower than the One of Patients Who Succeeded (63.6 +/- 32 L/min) (P<0.001)
Study of Extubation Failure (Crit Care Med, 2011) [MEDLINE]
Extubation Failure Rate was 15%
Patients >65 y/o with Underlying Chronic Cardiac or Pulmonary Disease were at High Risk for Extubation Failure and Subsequent Pneumonia and Death
Prospective Observational Study of Risk Factors for Extubation Failure (Crit Care Med, 2015) [MEDLINE]: n = 225
Ineffective Cough, Prior Duration of Mechanical Ventilation >7 Days, and Severe Left Ventricular Systolic Dysfunction were Stronger Predictors of Extubation Failure tahn Delirium or ICU-Acquired Weakness
Only 33% of Patients Who Required Reintubation were Considered High Risk for Extubation Failure by the Providers Caring for the Patient
Common Etiologies of Extubation Failure
Hypoxemia (i.e. Hypoxemic Respiratory Failure) (see Hypoxemia)
Mechanisms
Incomplete Resolution of Lung Process Which Led to Intubation (ARDS, Cardiogenic Pulmonary Edema, Pneumonia, etc)
New-Onset Cardiogenic Pulmonary Edema Associated with Removal of Positive-Pressure Ventilation (and Increased Venous Return to the Right Side of Heart)
Management
Supplemental Oxygen Therapy
High-Flow Nasal Cannula (HFNC) (see Oxygen): commonly used in this setting
High Work of Breathing Related to Low Lung Compliance (Due to Recovering ARDS, Cardiogenic Pulmonary Edema, Pneumonia, etc) and/or Increased Airway Resistance (Due to Bronchospasm, etc)
New-Onset Cardiogenic Pulmonary Edema Associated with Removal of Positive-Pressure Ventilation (and Increased Venous Return to the Right Side of Heart)
Excessive Endotracheal Tube Mobility (Due to Improper Fixation)
Female Gender
Glasgow Coma Score <8
History of Asthma
Inadequate Sedation
Large Endotracheal Tube (>7 mm in Females, >8 mm in Males)
Low Ratio of Patient Height/Endotracheal Tube Diameter
Prolonged Intubation
Ratio of Endotracheal Tube/Laryngeal Diameter >45% on Computed Tomography
Traumatic Intubation
Prognosis
Postextubation Stridor is Associated with Increased Duration of Mechanical Ventilation and Increased ICU Length of Stay (J Intensive Care Med, 2019) [MEDLINE]
Physiology
Endotracheal Intubation Can Result in Injury to Oropharynx/Larynx/Trachea
Laryngeal Edema and Mucosal Ulceration Occurs in Almost All Patients Who Have Been Intubated for ≥4 Days (Crit Care, 2009) [MEDLINE]
Laryngeal Injuries are Usually Reversible (Typically within 1 mo of Extubation) (Crit Care, 2009) [MEDLINE]
Common Mechanisms
Laryngeal Injury with Vocal Cord Edema: most common etiology
Upper Airway Secretions: common etiology
Cricoarytenoid Dislocation: uncommon etiology
Tracheal Stenosis/Obstruction: rare etiology
Diagnosis
Endotracheal Tube Cuff Leak Test (See Above): generally recommended only for patients who are deemed to be at high risk for postextubation stridor
Laryngeal Ultrasound: has been reported to be useful for assessing laryngeal patency (J Crit Care, 2013) [MEDLINE]
Simultaneous Assessment of Cough and Endotracheal Tube Cuff Leak: lack of audible cough and cuff leak indicates a 10x increased risk of postextubation stridor(J Crit Care, 2004) [MEDLINE]
While Laryngeal Injury is Common, Postextubation Stridor Has Been Reported to Occur in <10% of Unselected Critically Ill Patients (J Intensive Care Med, 2019) [MEDLINE]
Prevention
General Comments
Corticosteroids are Generally Recommended Only for Patients Who Have Failed an Endotracheal Tube Cuff Leak Test or Patients Who Have Failed Extubation Due to Laryngeal Edema
Methylprednisolone (Solumedrol) (see Methylprednisolone): 20 mg q4hrs x 4 doses
Intravenous Methylprednisolone was Effective in Decreasing the Risk of Postextubation Stridor in Patients with Endotracheal Tube Cuff Leak Volume <24% of Tidal Volume (Crit Care Med, 2006) [MEDLINE]
Systematic Review of Corticosteroids in the Prevention and Treatment of Postextubation Stridor in Unselected Neonates, Children and Adults Demonstrated No Benefit in Preventing Extubation Stridor (Cochrane Database Syst Rev, 2009) [MEDLINE]
Meta-Analysis in Mechanically-Ventilated Patients Who Have Failed an Endotracheal Tube Cuff Leak Test Demonstrated that Glucocorticoids Decreased the Incidence of Postextubation Stridor (11% vs 32%; RR 0.35; 95% CI: 0.20–0.63) and the Reintubation Rate (6% vs 17%; RR 0.32; 95% CI: 0.14–0.76) (Am J Respir Crit Care Med, 2017) [MEDLINE]
Prophylactic Multiple Dose Dexamethasone is Effective in Decreasing the Incidence of Postextubation Stridor in Adult Patients at High Risk for Postextubation Laryngeal Edema (Crit Care, 2007) [MEDLINE]
Systematic Review of Corticosteroids in the Prevention and Treatment of Postextubation Stridor in Unselected Neonates, Children and Adults Demonstrated No Benefit in Preventing Extubation Stridor (Cochrane Database Syst Rev, 2009) [MEDLINE]
Meta-Analysis in Mechanically-Ventilated Patients Who Have Failed an Endotracheal Tube Cuff Leak Test Demonstrated that Glucocorticoids Decreased the Incidence of Postextubation Stridor (11% vs 32%; RR 0.35; 95% CI: 0.20–0.63) and the Reintubation Rate (6% vs 17%; RR 0.32; 95% CI: 0.14–0.76)(Am J Respir Crit Care Med, 2017) [MEDLINE]
Management
Nebulized Racemic Epinephrine (Racepinephrine) (see Epinephrine)
Recommendations (American Thoracic Society/American College of Chest Physicians Clinical Practice Guideline for Liberation from Mechanical Ventilation in Critically Ill Adults) (Am J Respir Crit Care Med, 2017) [MEDLINE]
Cuff Leak Test in Should Be Performed in Mechanically Ventilated Adults Who Meet Extubation Criteria and are Deemed to Be High Risk for Postextubation Stridor (Conditional Recommendation, Very Low Certainty of Evidence)
Criteria for High Risk
Female Sex
Traumatic Intubation
Intubation for >6 Days
Large Endotracheal Tube
Reintubated after an Unplanned Extubation
For Adults Who Have Failed a Cuff Leak Test But are Otherwise Ready for Extubation, Administering Systemic Steroids for at Least 4 hrs Before Extubation is Recommended (Conditional Recommendation, Moderate Certainty of Evidence)
References
Assessment of Patient Readiness to Wean
General
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Trials comparing alternative weaning modes and discontinuation assessments. Chest 2001; 120(suppl):425S-437S
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Fever is associated with delayed ventilator liberation in acute lung injury. Ann Am Thorac Soc. 2013;10(6):608 [MEDLINE]
Hemodynamic Stability
A randomized, controlled trial of the role of weaning predictors in clinical decision making. Crit Care Med. 2006;34(10):2530 [MEDLINE]
Mental Status
Implications of extubation delay in brain-injured patients meeting standard weaning criteria. Am J Respir Crit Care Med. 2000;161(5):1530 [MEDLINE]
Predictors of successful extubation in neurosurgical patients. Am J Respir Crit Care Med. 2001;163(3 Pt 1):658 [MEDLINE]
Neurologic status, cough, secretions and extubation outcomes. Intensive Care Med. 2004;30(7):1334 [MEDLINE]
Interest of an objective evaluation of cough during weaning from mechanical ventilation. Intensive Care Med. 2009;35(6):1090 [MEDLINE]
Measures of Oxygenation (as Measured by pO2/FIO2 Ratio, etc)
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Minute Ventilation
Predicting success in weaning from mechanical ventilation. Chest. 2001;120(6 Suppl):400S [MEDLINE]
Compliance (Lung and Chest Wall)
A prospective study of indexes predicting the outcome of trials of weaning from mechanical ventilation. N Engl J Med. 1991;324(21):1445 [MEDLINE]
A new integrative weaning index of discontinuation from mechanical ventilation. Crit Care. 2009;13(5):R152 [MEDLINE]
Work of Breathing
Comparison of standard weaning parameters and the mechanical work of breathing in mechanically ventilated patients. Chest. 1988;94(2):232 [MEDLINE]
Work of breathing as a weaning parameter in mechanically ventilated patients. Chest. 1995;108(4):1018 [MEDLINE]
Pathophysiologic basis of acute respiratory distress in patients who fail a trial of weaning from mechanical ventilation. Am J Respir Crit Care Med. 1997;155(3):906 [MEDLINE]
The tension-time index and the frequency/tidal volume ratio are the major pathophysiologic determinants of weaning failure and success. Am J Respir Crit Care Med. 1998;158(2):378 [MEDLINE]
The combination of the load/force balance and the frequency/tidal volume can predict weaning outcome. Intensive Care Med. 2006;32(5):684 [MEDLINE]
Oxygen Cost of Breathing
The oxygen cost of breathing in patients with cardiorespiratory disease. Am Rev Respir Dis. 1982;126(1):9 [MEDLINE]
Metabolic and respiratory changes during weaning from mechanical ventilation. Chest. 1987;92(6):979 [MEDLINE]
Oxygen uptake during weaning from mechanical ventilation. Chest. 1988;94(6):1148 [MEDLINE]
Airway Occlusion Pressure
Airway occlusion pressure. An important indicator for successful weaning in patients with chronic obstructive pulmonary disease. Am Rev Respir Dis. 1987;135(1):107 [MEDLINE]
Prediction of successful ventilator weaning using airway occlusion pressure and hypercapnic challenge. Chest. 1987;91(4):496 [MEDLINE]
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A prospective, blinded evaluation of indexes proposed to predict weaning from mechanical ventilation. Intensive Care Med. 2004;30(5):830 [MEDLINE]
Evaluation of maximal inspiratory pressure, tracheal airway occlusion pressure, and its ratio in the weaning outcome. J Crit Care. 2009;24(3):441 [MEDLINE]
Maximal Inspiratory Pressure (MIP, PImax, or Pimax)
Bedside criteria for discontinuation of mechanical ventilation. Chest. 1973;63(6):1002 [MEDLINE]
Maximal inspiratory pressure is not a reliable test of inspiratory muscle strength in mechanically ventilated patients. Am Rev Respir Dis. 1990;142(3):529 [MEDLINE]
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Evaluation of a new index of mechanical ventilation weaning: the timed inspiratory effort. J Intensive Care Med. 2015;30(1):37 [MEDLINE]
Gastric Mucosal Acidosis
Gastric intramural pH as a predictor of success or failure in weaning patients from mechanical ventilation. Ann Intern Med. 1993;119(8):794 [MEDLINE]
Gastric intramucosal pH and intraluminal PCO2 during weaning from mechanical ventilation. Crit Care Med. 2001;29(1):70 [MEDLINE]
Diaphragmatic Ultrasound
Diaphragm dysfunction assessed by ultrasonography: influence on weaning from mechanical ventilation. Crit Care Med. 2011;39(12):2627 [MEDLINE]
Diaphragm ultrasound as a predictor of successful extubation from mechanical ventilation. Thorax. 2014 May;69(5):423-7 [MEDLINE]
Diaphragm and Lung Ultrasound to Predict Weaning Outcome: Systematic Review and Meta-Analysis. Chest. 2017;152(6):1140 [MEDLINE]
Use of diaphragm thickening fraction combined with rapid shallow breathing index for predicting success of weaning from mechanical ventilator in medical patients. J Intensive Care. 2018;6:6 [MEDLINE]
Rapid Shallow Breathing Index (RSBI)
A prospective study of indexes predicting the outcome of trials of weaning from mechanical ventilation. N Engl J Med. 1991;324(21):1445 [MEDLINE]
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Inspiratory Effort Quotient (IEQ)
Is weaning an art or a science? Am Rev Respir Dis. 1986;134(6):1107 [MEDLINE]
CROP Index (Compliance, Rate, Oxygenation, Pressure)
A prospective study of indexes predicting the outcome of trials of weaning from mechanical ventilation. N Engl J Med. 1991;324(21):1445 [MEDLINE]
CORE Index (Compliance, Oxygenation, Respiration, Effort)
Preliminary evaluation of a new index to predict the outcome of a spontaneous breathing trial. Respir Care. 2011 Oct;56(10):1500-5 [MEDLINE]
Weaning Index (WI)
Evaluation of a new weaning index based on ventilatory endurance and the efficiency of gas exchange. Am Rev Respir Dis. 1991;144(3 Pt 1):531 [MEDLINE]
Integrative Weaning Index (IWI)
A new integrative weaning index of discontinuation from mechanical ventilation. Crit Care. 2009;13(5):R152 [MEDLINE]
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Rapid disuse atrophy of diaphragm fibers in mechanically ventilated humans. N Engl J Med 2008; 358(13):1327-1335 [MEDLINE]
Estimation of inspiratory muscle pressure in critically ill patients. Intensive Care Med 2010; 36(4):648-655 [MEDLINE]
Ventilator-induced diaphragmatic dysfunction. Curr Opin Crit Care 2010; 16(1):19-25 [MEDLINE]
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Safety of Weaning
Large scale implementation of a respiratory therapist-driven protocol for ventilator weaning. Am J Respir Crit Care Med. 1999;159(2):439 [MEDLINE]
Is weaning failure caused by low-frequency fatigue of the diaphragm? Am J Respir Crit Care Med. 2003;167(2):120 [MEDLINE]
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General Measures During Weaning
Effects of albuterol inhalation on the work of breathing during weaning from mechanical ventilation. Am Rev Respir Dis. 1991;144(1):95 [MEDLINE]
Inspiratory Muscle Training
Inspiratory muscle training facilitates weaning from mechanical ventilation among patients in the intensive care unit: a systematic review. J Physiother. 2015;61(3):125 [MEDLINE]
Weaning Protocols
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A randomized, controlled trial of protocol-directed versus physician-directed weaning from mechanical ventilation. Crit Care Med. 1997 Apr;25(4):567-74 [MEDLINE]
Large scale implementation of a respiratory therapist-driven protocol for ventilator weaning. Am J Respir Crit Care Med. 1999;159(2):439 [MEDLINE]
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Automating the weaning process with advanced closed-loop systems. Intensive Care Med. 2008 Oct;34(10):1757-65 [MEDLINE]
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Endotracheal Tube Cuff Leak Testing
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;77:245–251 [MEDLINE]
Association between reduced cuff leak volume and postextubation stridor. Chest. 1996;110(4):1035 [MEDLINE]
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Cuff Leak Test for the Diagnosis of Post-Extubation Stridor. J Intensive Care Med. 2019 May;34(5):391-396. doi: 10.1177/0885066617700095 [MEDLINE]
Weaning Modalities
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Positive end-expiratory pressure vs T-piece. Extubation after mechanical ventilation. Chest. 1991;100(6):1655 [MEDLINE]
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A comparison of four methods of weaning patients from mechanical ventilation. N Engl J Med 1995; 332:345-350 [MEDLINE]
Tidal volume maintenance during weaning with pressure support. Am J Respir Crit Care Med. 1995;152(3):1034 [MEDLINE]
Extubation outcome after spontaneous breathing trials with T-tube or pressure support ventilation. The Spanish Lung Failure Collaborative Group. Am J Respir Crit Care Med. 1997;156(2 Pt 1):459-465 [MEDLINE]
Contribution of the endotracheal tube and the upper airway to breathing workload. Am J Respir Crit Care Med. 1998;157(1):23 [MEDLINE]
Prediction of post-extubation work of breathing. Crit Care Med. 2000;28(5):1341 [MEDLINE]
Extubation after breathing trials with automatic tube compensation, T-tube, or pressure support ventilation. Acta Anaesthesiol Scand. 2002;46(8):973 [MEDLINE]
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Weaning from mechanical ventilation with pressure support in patients failing a T-tube trial of spontaneous breathing. Intensive Care Med. 2006;32(1):165 [MEDLINE]
Extubation outcome following a spontaneous breathing trial with automatic tube compensation versus continuous positive airway pressure. Crit Care Med. 2006;34(3):682 [MEDLINE]
Prediction of extubation outcome: a randomised, controlled trial with automatic tube compensation vs. pressure support ventilation. Crit Care. 2009;13(1):R21 [MEDLINE]
Pressure support versus T-tube for weaning from mechanical ventilation in adults. Cochrane Database Syst Rev. 2014 May 27;(5):CD006056. doi: 10.1002/14651858.CD006056.pub2 [MEDLINE]
Comparison of pressure support ventilation and T-piece in determining rapid shallow breathing index in spontaneous breathing trials. Am J Med Sci. 2014 Oct;348(4):300-5 [MEDLINE]
Spontaneous-Breathing Trials with Pressure-Support Ventilation or a T-Piece. N Engl J Med. 2022 Nov 17;387(20):1843-1854. doi: 10.1056/NEJMoa2209041 [MEDLINE]
Duration of Weaning Trials
Effect of spontaneous breathing trial duration on outcome of attempts to discontinue mechanical ventilation. Spanish Lung Failure Collaborative Group. Am J Respir Crit Care Med. 1999;159(2):512 [MEDLINE]
Comparison of two methods for weaning patients with chronic obstructive pulmonary disease requiring mechanical ventilation for more than 15 days. Am J Respir Crit Care Med. 2001;164(2):225 [MEDLINE]
Central venous saturation is a predictor of reintubation in difficult-to-wean patients. Crit Care Med. 2010 Feb;38(2):491-6 [MEDLINE]
Rest After Weaning Trial
Reconnection to mechanical ventilation for 1 h after a successful spontaneous breathing trial reduces reintubation in critically ill patients: a multicenter randomized controlled trial. Intensive Care Med. 2017;43(11):1660 [MEDLINE]
Weaning Success
Diaphragm ultrasound as a predictor of successful extubation from mechanical ventilation. Thorax. 2014 May;69(5):423-7 [MEDLINE]
Mechanical Ventilation-induced Diaphragm Atrophy Strongly Impacts Clinical Outcomes. Am J Respir Crit Care Med. 2018;197(2):204 [MEDLINE]
Failure to Wean
The reduction of weaning time from mechanical ventilation using tidal volume and relaxation biofeedback. Am Rev Respir Dis. 1990;141(5 Pt 1):1214 [MEDLINE]
Pattern of recovery from diaphragmatic fatigue over 24 hours. J Appl Physiol (1985). 1995;79(2):539 [MEDLINE]
Influence of pressure and flow-triggered synchronous intermittent mandatory ventilation on inspiratory muscle work. Crit Care Med. 1994;22(12):1933 [MEDLINE]
Synchronized intermittent mandatory ventilation with and without pressure support ventilation in weaning patients with COPD from mechanical ventilation. Chest. 1994;105(4):1204 [MEDLINE]
Comparison of three methods of gradual withdrawal from ventilatory support during weaning from mechanical ventilation. Am J Respir Crit Care Med 1994; 150:896-903 [MEDLINE]
A comparison of four methods of weaning patients from mechanical ventilation. N Engl J Med 1995; 332:345-350 [MEDLINE]
Disorders of the respiratory muscles. Am J Respir Crit Care Med. 2003;168(1):10 [MEDLINE]
Caloric intake in medical ICU patients: consistency of care with guidelines and relationship to clinical outcomes. Chest. 2003;124(1):297 [MEDLINE]
B-type natriuretic peptide and weaning from mechanical ventilation. Intensive Care Med. 2006 Oct;32(10):1529-36 [MEDLINE]
Weaning from mechanical ventilation with pressure support in patients failing a T-tube trial of spontaneous breathing. Intensive Care Med. 2006;32(1):165 [MEDLINE]
Use of N-terminal pro-brain natriuretic peptide to detect acute cardiac dysfunction during weaning failure in difficult-to-wean patients with chronic obstructive pulmonary disease. Crit Care Med. 2007 Jan;35(1):96-105 [MEDLINE]
Ventilator-dependent survivors of catastrophic illness transferred to 23 long-term care hospitals for weaning from prolonged mechanical ventilation. Chest. 2007;131(1):76 [MEDLINE]
Changes in B-type natriuretic peptide improve weaning outcome predicted by spontaneous breathing trial. Crit Care Med. 2008 May;36(5):1421-6 [MEDLINE]
Echocardiographic diagnosis of pulmonary artery occlusion pressure elevation during weaning from mechanical ventilation. Crit Care Med. 2009 May;37(5):1696-701 [MEDLINE]
Nitroglycerin can facilitate weaning of difficult-to-wean chronic obstructive pulmonary disease patients: a prospective interventional non-randomized study. Crit Care. 2010;14(6):R204 [MEDLINE]
Long-term acute care hospital utilization after critical illness. JAMA. 2010;303(22):2253 [MEDLINE]
Depressive disorders during weaning from prolonged mechanical ventilation. Intensive Care Med. 2010;36(5):828 [MEDLINE]
Physiological comparison of three spontaneous breathing trials in difficult-to-wean patients. Intensive Care Med. 2010 Jul;36(7):1171-9 [MEDLINE]
Incidence and outcome of weaning from mechanical ventilation according to new categories. Eur Respir J. 2010;35(1):88 [MEDLINE]
Characteristics and outcomes of ventilated patients according to time to liberation from mechanical ventilation. Am J Respir Crit Care Med. 2011 Aug;184(4):430-7 [MEDLINE]
Natriuretic peptide-driven fluid management during ventilator weaning: a randomized controlled trial. Am J Respir Crit Care Med. 2012 Dec;186(12):1256-63 [MEDLINE]
Different tracheotomy tube diameters influence diaphragmatic effort and indices of weanability in difficult to wean patients. Respir Care. 2012;57(12):2012 [MEDLINE]
Effect of pressure support vs unassisted breathing through a tracheostomy collar on weaning duration in patients requiring prolonged mechanical ventilation: a randomized trial. JAMA. 2013;309(7):671 [MEDLINE]
Effects of pleural effusion drainage on oxygenation, respiratory mechanics, and hemodynamics in mechanically ventilated patients. Ann Am Thorac Soc. 2014 Sep;11(7):1018-24 [MEDLINE]
Extravascular lung water, B-type natriuretic peptide, and blood volume contraction enable diagnosis of weaning-induced pulmonary edema. Crit Care Med. 2014 Aug;42(8):1882-9 [MEDLINE]
Myocardial injury after surgery is a risk factor for weaning failure from mechanical ventilation in critical patients undergoing major abdominal surgery. PLoS One. 2014;9(11):e113410 [MEDLINE]
Passive leg raising performed before a spontaneous breathing trial predicts weaning-induced cardiac dysfunction. Intensive Care Med. 2015 Mar;41(3):487-94 [MEDLINE]
Cardiac dysfunction induced by weaning from mechanical ventilation: incidence, risk factors, and effects of fluid removal. Crit Care. 2016;20(1):369 [MEDLINE]
Impact of delirium on weaning from mechanical ventilation in medical patients. Respirology. 2016;21(2):313 [MEDLINE]
Noninvasive monitoring of cardiac output during weaning from mechanical ventilation: a pilot study Amer J Crit Care. 2016;25:257
Left ventricular diastolic dysfunction–an independent risk factor for weaning failure from mechanical ventilation. Anaesth Intensive Care. 2016;44(4):466 [MEDLINE]
Stress echocardiography in patients who experienced mechanical ventilation weaning failure. J Crit Care. 2017;39:66 [MEDLINE]
Lung ultrasound allows the diagnosis of weaning-induced pulmonary oedema. Intensive Care Med. 2019;45(5):601 [MEDLINE]
Timing of Extubation (Daytime vs Nightime)
Daytime Versus Nighttime Extubations: A Comparison of Reintubation, Length of Stay, and Mortality. J Intensive Care Med. 2016 Feb;31(2):118-26 [MEDLINE]
Association Between Overnight Extubations and Outcomes in the Intensive Care Unit. JAMA Intern Med. 2016;176(11):1651 [MEDLINE]
Is routine extubation overnight safe in cardiac surgery patients? J Thorac Cardiovasc Surg. 2019;157(4):1533 [MEDLINE]
High-flow nasal oxygen vs high-flow face mask: a randomized crossover trial in extubated patients. J Crit Care. 2010 Sep;25(3):463-8 [MEDLINE]
Nasal high-flow versus Venturi mask oxygen therapy after extubation. Effects on oxygenation, comfort, and clinical outcome. Am J Respir Crit Care Med. 2014;190(3):282 [MEDLINE]
Effect of early postextubation high-flow nasal cannula vs conventional oxygen therapy on hypoxaemia in patients after major abdominal surgery: a French multicentre randomised controlled trial (OPERA). Intensive Care Med. 2016;42(12):1888 [MEDLINE]
Effect of Postextubation High-Flow Nasal Cannula vs Conventional Oxygen Therapy on Reintubation in Low-Risk Patients: A Randomized Clinical Trial. JAMA. 2016;315(13):1354 [MEDLINE]
Noninvasive positive pressure ventilation as a weaning strategy for intubated adults with respiratory failure. Cochrane Database Syst Rev. 2003;(4):CD004127[MEDLINE]
Use of non-invasive ventilation to wean critically ill adults off invasive ventilation: meta-analysis and systematic review. BMJ. 2009 May 21;338:b1574. doi: 10.1136/bmj.b1574 [MEDLINE]
Noninvasive positive pressure ventilation as a weaning strategy for intubated adults with respiratory failure. Cochrane Database Syst Rev. 2010 Aug 4;(8):CD004127. doi: 10.1002/14651858.CD004127.pub2 [MEDLINE]
Noninvasive ventilation as a weaning strategy for mechanical ventilation in adults with respiratory failure: a Cochrane systematic review. CMAJ. 2014 Feb 18;186(3):E112-22. doi: 10.1503/cmaj.130974 [MEDLINE]
Noninvasive ventilation and survival in acute care settings: a comprehensive systematic review and metaanalysis of randomized controlled trials. Crit Care Med. 2015 Apr;43(4):880-8. doi: 10.1097/CCM.0000000000000819 [MEDLINE]
An Official American Thoracic Society/American College of Chest Physicians Clinical Practice Guideline: Liberation from Mechanical Ventilation in Critically Ill Adults. Chest. 2017 Jan;151(1):166-180. doi: 10.1016/j.chest.2016.10.036 [MEDLINE]
Non-invasive ventilation as a strategy for weaning from invasive mechanical ventilation: a systematic review and Bayesian meta-analysis. Intensive Care Med. 2018;44(12):2192 [MEDLINE]
Early extubation followed by immediate noninvasive ventilation vs. standard extubation in hypoxemic patients: a randomized clinical trial. Intensive Care Med. 2018 Dec 10. doi: 10.1007/s00134-018-5478-0 [MEDLINE]
Effect of Protocolized Weaning With Early Extubation to Noninvasive Ventilation vs Invasive Weaning on Time to Liberation From Mechanical Ventilation Among Patients With Respiratory Failure: The Breathe Randomized Clinical Trial. JAMA. 2018;320(18):1881 [MEDLINE]
Early extubation followed by immediate noninvasive ventilation vs. standard extubation in hypoxemic patients: a randomized clinical trial. Intensive Care Med. 2019;45(1):62 [MEDLINE]
Extubation Failure
General
Predictors of successful extubation in neurosurgical patients. Am J Respir Crit Care Med. 2001;163(3 Pt 1):658 [MEDLINE]
Predictors of extubation outcome in patients who have successfully completed a spontaneous breathing trial. Chest. 2001;120(4):1262 [MEDLINE]
Cough peak flows and extubation outcomes. Chest. 2003;124(1):262 [MEDLINE]
Putting it all together to predict extubation outcome. Intensive Care Med. 2004;30(7):1255 [MEDLINE]
Neurologic status, cough, secretions and extubation outcomes. Intensive Care Med. 2004;30(7):1334 [MEDLINE]
Nasal-continuous positive airway pressure reduces pulmonary morbidity and length of hospital stay following thoracoabdominal aortic surgery. Chest. 2005 Aug;128(2):821-8 [MEDLINE]
Early noninvasive ventilation averts extubation failure in patients at risk: a randomized trial. Am J Respir Crit Care Med. 2006 Jan 15;173(2):164-70. Epub 2005 Oct 13 [MEDLINE]
Risk factors for extubation failure in patients following a successful spontaneous breathing trial. Chest. 2006;130(6):1664-1671 [MEDLINE]
Continuous positive airway pressure for treatment of respiratory complications after abdominal surgery: a systematic review and meta-analysis. Ann Surg. 2008 Apr;247(4):617-26. doi: 10.1097/SLA.0b013e3181675829 [MEDLINE]
Interest of an objective evaluation of cough during weaning from mechanical ventilation. Intensive Care Med. 2009;35(6):1090 [MEDLINE]
Non-invasive ventilation after extubation in hypercapnic patients with chronic respiratory disorders: randomised controlled trial. Lancet. 2009 Sep 26;374(9695):1082-8. doi: 10.1016/S0140-6736(09)61038-2. Epub 2009 Aug 12 [MEDLINE]
Noninvasive ventilation to prevent respiratory failure after extubation in high-risk patients. Crit Care Med. 2005 Nov;33(11):2465-70 [MEDLINE]
Outcomes of extubation failure in medical intensive care unit patients. Crit Care Med. 2011;39(12):2612 [MEDLINE]
Risk factors for and prediction by caregivers of extubation failure in ICU patients: a prospective study. Crit Care Med. 2015;43(3):613 [MEDLINE]
Cumulative Probability and Time to Reintubation in U.S. ICUs. Crit Care Med. 2017;45(5):835 [MEDLINE]
Postextubation Stridor
Laryngeal injuries secondary to nasogastric tubes. Ann Otol Rhinol Laryngol. 1981;90(5 Pt 1):469 [MEDLINE]
Risk factors associated with prolonged intubation and laryngeal injury. Otolaryngol Head Neck Surg. 1994;111(4):453 [MEDLINE]
Association between reduced cuff leak volume and postextubation stridor. Chest. 1996;110(4):1035 [MEDLINE]
The cuff leak test to predict failure of tracheal extubation for laryngeal edema. Intensive Care Med. 2002;28(9):1267 [MEDLINE]
Post-extubation stridor in intensive care unit patients. Risk factors evaluation and importance of the cuff-leak test. Intensive Care Med. 2003;29(1):69 [MEDLINE]
How to identify patients with no risk for postextubation stridor? J Crit Care. 2004;19(1):23 [MEDLINE]
The endotracheal tube cuff-leak test as a predictor for postextubation stridor. Respir Care. 2005;50(12):1632 [MEDLINE]
Intravenous injection of methylprednisolone reduces the incidence of postextubation stridor in intensive care unit patients. Crit Care Med. 2006;34(5):1345 [MEDLINE]
Laryngeal ultrasound: a useful method in predicting post-extubation stridor. A pilot study. Eur Respir J. 2006;27(2):384 [MEDLINE]
Dexamethasone to prevent postextubation airway obstruction in adults: a prospective, randomized, double-blind, placebo-controlled study. Crit Care. 2007;11(4):R72 [MEDLINE]
12-h pretreatment with methylprednisolone versus placebo for prevention of postextubation laryngeal oedema: a randomised double-blind trial. Lancet. 2007;369(9567):108 [MEDLINE]
Risk factors evaluation and the cuff leak test as predictors for postextubation stridor. J Med Assoc Thai. 2008;91(5):648 [MEDLINE]
Corticosteroids for the prevention and treatment of post-extubation stridor in neonates, children and adults. Cochrane Database Syst Rev. 2009 [MEDLINE]
Clinical review: post-extubation laryngeal edema and extubation failure in critically ill adult patients. Crit Care. 2009;13(6):233 [MEDLINE]
Predicting laryngeal edema in intubated patients by portable intensive care unit ultrasound. J Crit Care. 2013 Oct;28(5):675-80 [MEDLINE]
Cuff Leak Test for the Diagnosis of Post-Extubation Stridor. J Intensive Care Med. 2019 May;34(5):391-396. doi: 10.1177/0885066617700095 [MEDLINE]
