# Ventilator Weaning and Liberation

## Definitions and Concepts

### Terminology

The process of transitioning a patient from mechanical ventilatory support to independent breathing encompasses several distinct but related concepts that must be understood precisely. Weaning refers to the gradual reduction of ventilator support in preparation for the patient to resume independent breathing. Liberation denotes the successful discontinuation of mechanical ventilation as a clinical intervention. Extubation, the physical removal of the endotracheal tube, is a separate process from liberation and should not be conflated with it, as patients can be liberated from the ventilator while remaining intubated, and conversely, can be extubated while still requiring some form of respiratory support such as non-invasive ventilation. The International Consensus Conference on Weaning classifies patients into three categories based on the difficulty of their weaning trajectory. Simple weaning applies to the approximately 66 percent of patients who pass their first spontaneous breathing trial and are successfully extubated on the initial attempt. Difficult weaning encompasses patients who fail their initial spontaneous breathing trial but require no more than three trials or up to seven days from the first trial to achieve successful liberation. Prolonged weaning, affecting approximately 15 percent of mechanically ventilated patients, is defined by the need for more than three spontaneous breathing trials or more than seven days from the first trial, and represents a population with substantially higher morbidity and mortality.

### Burden of Prolonged Mechanical Ventilation

The consequences of prolonged mechanical ventilation extend far beyond the immediate physiological effects of positive pressure breathing. Each additional day of mechanical ventilation is estimated to increase mortality by approximately 1 to 2 percent, representing a cumulative and compounding risk that underscores the urgency of liberation efforts. The ventilator-associated complications that accumulate with prolonged mechanical ventilation include ventilator-associated pneumonia, barotrauma, progressive diaphragm dysfunction from ventilator-induced diaphragm atrophy, and ICU-acquired delirium, each of which independently contributes to adverse outcomes. Prolonged mechanical ventilation, formally defined as ventilation exceeding 21 days, is associated with hospital mortality rates of 40 to 50 percent and extraordinary resource utilization including prolonged ICU stays, complex discharge planning, and the need for long-term acute care facilities. A frequently underappreciated statistic is that approximately 40 percent of the total duration of mechanical ventilation is spent in the weaning process, highlighting that optimization of weaning protocols represents one of the highest-yield quality improvement targets in critical care.

## Readiness Assessment

### Prerequisites for Weaning

Before initiating a spontaneous breathing trial, a systematic assessment of weaning readiness must confirm that several prerequisite conditions are met. The underlying cause of respiratory failure should be resolving or substantially improved, as attempting liberation before addressing the precipitating condition predictably leads to failure. Adequate oxygenation must be confirmed, typically defined as a PaO2/FiO2 ratio of 150 or greater, or equivalently, an SpO2 of 92 percent or higher on an FiO2 of 0.4 or less and PEEP of 8 cmH2O or less. Hemodynamic stability, defined as requiring no or low-dose vasopressor support with norepinephrine at or below 0.1 mcg/kg/min and the absence of active myocardial ischemia, ensures that the cardiovascular system can tolerate the hemodynamic shifts that accompany the transition from positive pressure to spontaneous breathing. Adequate neurological function, manifested by the ability to follow commands or the presence of spontaneous respiratory drive with a Glasgow Coma Scale score of 8 or higher for airway protection, is essential. Electrolyte balance, particularly normal potassium, magnesium, phosphate, and calcium levels, must be ensured, as derangements in any of these electrolytes can profoundly impair respiratory muscle function. Temperature should be below 38.5 degrees Celsius, as fever increases metabolic demand and ventilatory requirements. Hemoglobin should be at or above 7 g/dL to ensure adequate oxygen delivery. Finally, an adequate cough reflex, assessed subjectively during suctioning, provides important information about the patient's ability to protect their airway and clear secretions independently after extubation.

### Rapid Shallow Breathing Index (RSBI)

The rapid shallow breathing index, calculated as the respiratory frequency divided by the tidal volume in liters, measured during one to two minutes of unassisted breathing, remains one of the most widely used bedside screening tools for weaning readiness. The landmark study by Yang and Tobin in 1991 established that an RSBI below 105 has a positive predictive value of approximately 80 percent for successful extubation, while an RSBI of 105 or greater carries a negative predictive value of approximately 95 percent for weaning failure. However, the limitations of the RSBI must be appreciated in clinical practice. Its performance is notably diminished in elderly patients, those with COPD, and patients who have undergone prolonged mechanical ventilation, all populations in which the index tends to overestimate the likelihood of failure. The RSBI is best utilized as a screening tool to identify candidates who should proceed to a spontaneous breathing trial, rather than as a standalone criterion for making extubation decisions. Clinical judgment integrating multiple factors must always complement the RSBI in the decision-making process.

## Spontaneous Breathing Trials (SBT)

### Methods

| SBT Method | Support Level | Physiological Basis | Advantages | Disadvantages |
|---|---|---|---|---|
| T-Piece | None (supplemental O₂ only) | Complete independence from ventilator | Most rigorous test | May be excessively demanding; no apnea monitoring |
| Pressure Support (5–8 cmH₂O) | Low PS + PEEP 0–5 | Compensates for ETT resistance | Better predicts post-extubation work; preferred method (BREATHE trial) | May overestimate readiness if PS too high |
| CPAP (5 cmH₂O) | PEEP only | Pneumatic splinting without inspiratory assist | Maintains FRC; ventilator alarms active | Does not compensate for ETT resistance |
| Automatic Tube Compensation | Calculated ETT compensation | Real-time ETT resistance offset | Simulates post-extubation physiology | Not available on all ventilators |

Several methods exist for conducting spontaneous breathing trials, each with distinct physiological characteristics. The T-piece trial involves complete disconnection from the ventilator, allowing the patient to breathe spontaneously through the endotracheal tube with supplemental oxygen delivered directly but without any ventilatory assistance. The pressure support trial provides a low level of pressure support, typically 5 to 8 cmH2O, combined with 0 to 5 cmH2O of PEEP, which serves to compensate for the additional resistance imposed by the endotracheal tube and ventilator circuit. The CPAP trial applies 5 cmH2O of continuous positive airway pressure alone, providing some degree of pneumatic splinting without active inspiratory assistance. Automatic tube compensation is a ventilator mode that calculates and compensates for the resistance attributable to the endotracheal tube in real time, theoretically simulating the work of breathing that the patient will experience after extubation.

### SBT Duration

The traditional approach to spontaneous breathing trial duration involved trials lasting 30 to 120 minutes, but contemporary evidence has shifted practice toward shorter trials. The SOS trial, published in 2023, demonstrated that a 30-minute spontaneous breathing trial was non-inferior to a 120-minute trial for predicting successful extubation, providing level one evidence for shortened trial duration. Current practice therefore favors the 30-minute trial, which is less likely to cause respiratory muscle fatigue, allows for faster liberation, and maintains equivalent predictive accuracy. If a patient tolerates 30 minutes of spontaneous breathing without signs of distress, the trial is considered successful, and the clinician should proceed to the extubation readiness assessment.

### SBT Failure Criteria

The criteria for declaring a spontaneous breathing trial unsuccessful are based on a combination of physiological parameters and clinical signs. Tachypnea with a respiratory rate exceeding 35 per minute sustained for more than 5 minutes indicates an unsustainable ventilatory workload. Oxygen desaturation below 90 percent on pulse oximetry signals inadequate gas exchange. Tachycardia with a heart rate above 140 or a change of more than 20 percent from baseline suggests excessive cardiopulmonary stress. Hemodynamic instability, defined as a systolic blood pressure above 180 or below 90 mmHg, indicates cardiovascular intolerance of the increased work of breathing. Clinical signs including diaphoresis, agitation, and visible distress reflect systemic sympathetic activation in response to respiratory decompensation. A paradoxical breathing pattern, characterized by inward motion of the abdomen during inspiration (abdominal paradox), indicates diaphragmatic fatigue and impending ventilatory failure. An RSBI exceeding 105 during the trial provides objective confirmation of rapid shallow breathing.

### T-Piece vs. Pressure Support SBT

The BREATHE trial by Subira and colleagues in 2019 directly compared a pressure support SBT at 8 cmH2O against a T-piece SBT and found that the pressure support group achieved a significantly higher rate of successful extubation at 82.3 percent versus 74 percent, with shorter ICU length of stay. These findings suggest that the T-piece trial may be excessively demanding and that pressure support at modest levels more accurately simulates the post-extubation work of breathing. The current consensus preference is for conducting spontaneous breathing trials using pressure support of 5 to 8 cmH2O, which provides a more physiologically relevant assessment of the patient's readiness for independent breathing while compensating for the artifactual increase in work of breathing imposed by the endotracheal tube.

<image>Weaning readiness and SBT protocol flowchart. Starting point: "Daily screening for weaning readiness" with checklist of prerequisites (FiO2 <=0.4, PEEP <=8, hemodynamically stable, neurologically adequate, underlying cause improving). If ready: calculate RSBI (branch: <105 proceed to SBT, >=105 defer and reassess next day). SBT box showing PS 5-8 cmH2O + PEEP 0-5 cmH2O for 30 minutes with pass/fail criteria listed. If SBT passed: proceed to extubation readiness assessment (cuff leak test, cough assessment, secretion volume, upper airway patency). If SBT failed: return to full support, identify and address barriers, retry in 24 hours. Post-extubation pathway: low-risk → HFNC, high-risk → NIV. Include reintubation criteria at bottom.</image>

## Extubation Assessment

### Cuff Leak Test

The cuff leak test assesses for the presence of upper airway edema that might cause post-extubation stridor or airway obstruction. The test is performed by deflating the endotracheal tube cuff and measuring the difference between the inspiratory and expiratory tidal volumes on the ventilator. A quantitative cuff leak volume of less than 110 mL, or less than 12 percent of the delivered tidal volume, suggests the presence of significant upper airway edema that may complicate extubation. A positive cuff leak, manifested by audible air movement around the deflated tube during ventilator-delivered breaths, is a reassuring finding. When the cuff leak is absent, dexamethasone pretreatment before extubation should be considered, with the evidence-based regimen being 4 mg intravenously every 6 hours for 4 doses beginning 12 to 24 hours before the planned extubation. It is essential to recognize that an absent cuff leak is not an absolute contraindication to extubation, as the false positive rate of this test is high, and delaying extubation based solely on a failed cuff leak test may expose the patient to unnecessary additional days of mechanical ventilation.

### Cough Strength Assessment

The assessment of cough strength provides critical information about the patient's ability to clear secretions independently after extubation, which is a major determinant of extubation success. A strong cough elicited during suctioning is a favorable predictor. Objective measurement of peak cough expiratory flow greater than 60 liters per minute through the endotracheal tube is associated with successful extubation. The white card test, in which a white card is held 1 to 2 cm from the end of the endotracheal tube during a cough effort and inspected for visible secretion deposition, provides a simple bedside assessment of cough effectiveness. The combination of weak cough and copious secretions is particularly concerning, as it identifies patients at high risk for reintubation, and should prompt consideration of either delaying extubation or initiating a discussion about tracheostomy.

### Secretion Management

The volume and character of airway secretions significantly influence extubation outcomes. A suctioning frequency requirement of less than every 2 hours is considered favorable for extubation. Copious secretions, defined as volumes exceeding 2.5 mL per hour, represent an independent risk factor for extubation failure. Importantly, the patient's capacity to clear secretions through effective cough matters more than the absolute volume of secretion production, as some patients with moderate secretion volumes can manage them effectively with a strong cough while others with lesser volumes cannot.

### Airway Edema Prevention

The use of corticosteroids to prevent post-extubation airway edema has been validated in select populations. The study by Francois and colleagues in 2007 demonstrated that dexamethasone administered as 20 mg starting 12 hours before extubation followed by 5 mg every 6 hours for three additional doses reduced the incidence of post-extubation stridor from 22 percent to 3 percent. This intervention is most effective in patients with prolonged intubation exceeding 36 to 48 hours, women, and those with a history of traumatic intubation. Routine administration to all patients undergoing extubation is not recommended; rather, corticosteroid pretreatment should be targeted to patients who have demonstrated a failed cuff leak test.

## Post-Extubation Management

### Preventive Strategies (High-Risk Patients)

The identification of patients at high risk for post-extubation failure enables the application of preventive respiratory support strategies that have been shown to reduce reintubation rates. High-risk criteria include age greater than 65 years, chronic obstructive pulmonary disease, congestive heart failure, multiple comorbidities, prior failed spontaneous breathing trials, prolonged mechanical ventilation exceeding 7 days, and an APACHE II score above 12. The study by Nava and colleagues in 2005 demonstrated that the application of non-invasive ventilation immediately upon extubation in high-risk patients reduced the reintubation rate from 24 percent to 8 percent. Ferrer and colleagues in 2006 similarly showed that preventive non-invasive ventilation in high-risk patients reduced ICU mortality. For low-risk patients, the HIGH trial of 2019 established that high-flow nasal cannula was non-inferior to non-invasive ventilation for preventing reintubation, offering a more comfortable and better-tolerated alternative.

### Treatment of Post-Extubation Failure

A critical distinction that has profound clinical implications exists between preventive non-invasive ventilation, applied immediately upon extubation in high-risk patients, and therapeutic non-invasive ventilation, applied after post-extubation respiratory failure has already developed. The landmark study by Esteban and colleagues in 2004 demonstrated that the application of non-invasive ventilation for established post-extubation respiratory failure actually increased mortality by delaying the inevitable reintubation. This finding has been one of the most important practice-changing observations in weaning medicine: preventive application is beneficial in high-risk patients, while therapeutic application after failure has developed is harmful because it creates a false sense of security and delays necessary reintubation. When post-extubation respiratory failure develops, the appropriate action is to reintubate promptly, ideally within 6 to 12 hours of failure recognition.

### Reintubation

Reintubation occurs in 10 to 20 percent of extubated patients and is independently associated with substantially increased mortality, with odds ratios of 5 to 10 times higher than successfully extubated patients, as well as prolonged ICU stay. The common causes of reintubation include upper airway obstruction from laryngeal edema, inadequate cough with inability to manage secretions, respiratory muscle fatigue from an unsustainable work of breathing, and cardiac failure precipitated by the hemodynamic shifts of spontaneous breathing. The timing of reintubation has prognostic significance: early reintubation within 12 hours of extubation is associated with significantly better outcomes than late reintubation, reinforcing the importance of close monitoring in the post-extubation period and a low threshold for proceeding with reintubation when deterioration is recognized.

## Causes of Weaning Failure

| Category | Common Causes | Diagnostic Clues | Interventions |
|---|---|---|---|
| Respiratory muscle weakness | VIDD, ICU-acquired weakness, phrenic nerve injury | Diaphragm TFdi <20%, MIP >−25 cmH₂O, RSBI >105 | Inspiratory muscle training, minimize sedation, early mobilization |
| Increased work of breathing | Bronchospasm, secretions, airway edema, reduced compliance | Elevated peak-plateau gradient, wheezing, copious secretions | Bronchodilators, suctioning, steroids, optimize compliance |
| Ventilatory demand-capacity mismatch | High dead space, metabolic acidosis, fever | Elevated VD/VT, low bicarbonate, tachypnea | Treat underlying cause; correct acidosis, fever |
| Auto-PEEP / dynamic hyperinflation | COPD, asthma | Incomplete exhalation on flow tracing, measured auto-PEEP | Reduce RR, increase expiratory time, bronchodilators |
| Cardiac (weaning-induced cardiac failure) | LV dysfunction, diastolic failure, volume overload | Rising BNP during SBT, elevated E/e', PAOP >18 | Pre-SBT diuresis, nitroglycerin, afterload reduction |
| Neurological | Residual sedation, encephalopathy, central sleep apnea | Decreased respiratory drive, P0.1 <1, apneic episodes | Clear sedatives, treat metabolic causes, acetazolamide |
| Psychological | Ventilator dependence, anxiety, panic | Agitation during SBT without physiological cause | Graduated exposure, anxiolytics, psychological support |

### Respiratory Causes

Respiratory causes of weaning failure encompass a broad range of pathophysiology. Respiratory muscle weakness, including diaphragm dysfunction from ventilator-induced diaphragm atrophy and critical illness polyneuropathy or myopathy, represents one of the most common and underappreciated causes. Increased work of breathing from bronchospasm, retained secretions, upper airway edema, or reduced respiratory system compliance places demands on the respiratory muscles that exceed their capacity. A ventilatory demand that exceeds the patient's ventilatory capacity, driven by high physiological dead space or a metabolic acidosis that requires compensatory hyperventilation, creates a supply-demand mismatch that makes liberation impossible. In patients with obstructive lung disease, auto-PEEP from dynamic hyperinflation imposes a threshold inspiratory load that substantially increases the work of triggering each breath, contributing to ventilatory failure during weaning attempts.

### Cardiovascular Causes

Weaning-induced cardiac failure is a frequently underdiagnosed cause of weaning failure, estimated to account for 25 to 30 percent of all weaning failures. The physiological mechanism is fundamentally hemodynamic: the transition from positive pressure ventilation to spontaneous breathing converts intrathoracic pressure from positive to negative, which simultaneously increases both preload and afterload on the left ventricle. The increase in preload occurs because negative intrathoracic pressure augments venous return to the right heart, which translates to increased left ventricular filling volume. The increase in afterload results from the negative intrathoracic pressure increasing the transmural pressure gradient across the left ventricle, effectively increasing the pressure against which the ventricle must eject. In patients with underlying cardiac dysfunction, these hemodynamic changes can precipitate acute pulmonary edema during the spontaneous breathing trial. The diagnosis should be suspected in patients with recurrent weaning failures and can be confirmed by demonstrating a rising pulmonary artery occlusion pressure above 18 mmHg or an elevated E/e' ratio on echocardiography during the spontaneous breathing trial, or by a rise in brain natriuretic peptide of more than 20 percent during the trial. Treatment involves aggressive diuresis and afterload reduction, and spontaneous breathing trials can be scheduled with pre-treatment consisting of nitroglycerin or furosemide administered before the trial.

### Neurological Causes

Neurological causes of weaning failure include inadequate respiratory drive from residual sedation, metabolic encephalopathy, or brainstem dysfunction, all of which result in insufficient neural output to the respiratory muscles to sustain independent ventilation. Central sleep apnea may manifest during weaning attempts, producing repetitive apneic episodes that prevent successful liberation. Delirium and agitation can prevent the patient from cooperating with spontaneous breathing trials, resulting in apparent failure that is behavioral rather than physiological.

### Psychological Causes

Psychological barriers to weaning are particularly prevalent in patients who have undergone prolonged mechanical ventilation and include ventilator dependence, anxiety about breathing independently, and frank panic attacks during spontaneous breathing trials. The approach to these patients requires patience and graduated exposure, with progressively increasing periods of spontaneous breathing accompanied by psychological support, reassurance, and often anxiolytic medication to facilitate the weaning process.

<image>Comprehensive illustration of causes of weaning failure organized by organ system. Central image of a ventilated patient with four branching pathways: (1) Respiratory - showing diaphragm atrophy with muscle fiber thinning (ultrasound image reference showing diaphragm thickness <2 mm), auto-PEEP with flow-time tracing showing incomplete exhalation, and secretion burden; (2) Cardiovascular - showing heart with failing LV, diagram of intrathoracic pressure changes during transition from positive pressure to spontaneous breathing with arrows showing increased preload and afterload, and rising BNP/PAOP graph; (3) Neurological - showing brain with sedative drug molecules, reduced respiratory drive waveform; (4) Metabolic - showing electrolyte imbalances (low phosphate, low magnesium), thyroid dysfunction, malnutrition with muscle wasting. Each pathway includes diagnostic tests and interventions.</image>

## Diaphragm Dysfunction

### Ventilator-Induced Diaphragm Dysfunction (VIDD)

Ventilator-induced diaphragm dysfunction is a rapidly developing and clinically consequential complication of controlled mechanical ventilation. Animal models have demonstrated a 50 percent reduction in diaphragm contractile force after just 18 hours of controlled mechanical ventilation, and human data confirm that diaphragm muscle fiber atrophy begins within hours of mechanical ventilation initiation. The mechanisms driving this remarkably rapid atrophy include proteolysis via the ubiquitin-proteasome pathway, oxidative stress, mitochondrial dysfunction, and dysregulated autophagy. The risk factors for ventilator-induced diaphragm dysfunction include complete diaphragm rest without any spontaneous breathing efforts, the duration of mechanical ventilation, concurrent corticosteroid administration, and the use of neuromuscular blocking agents, all of which contribute to an environment that accelerates diaphragm wasting.

### Assessment

The assessment of diaphragm function has advanced considerably with the development of bedside ultrasound techniques. Diaphragm thickness is measured at the zone of apposition, with normal values ranging from 1.5 to 5 mm. The thickening fraction, calculated as the difference between inspiratory and expiratory thickness divided by expiratory thickness multiplied by 100, provides a quantitative measure of diaphragmatic contractile activity. A thickening fraction greater than 30 percent indicates adequate diaphragm effort, while a thickening fraction below 20 percent suggests diaphragm dysfunction, and values below 15 percent predict extubation failure. Diaphragm excursion, measured as the amplitude of diaphragmatic movement during tidal breathing, should normally exceed 10 mm. Bilateral phrenic nerve stimulation remains the gold standard for assessing diaphragm contractility but is not routinely available in most clinical settings. Maximal inspiratory pressure, also known as negative inspiratory force, provides a global measure of inspiratory muscle strength, with values less negative than negative 20 to negative 25 cmH2O suggesting an inability to maintain spontaneous ventilation. The airway occlusion pressure at 100 milliseconds, or P0.1, reflects the patient's respiratory drive, with normal values between 1 and 4 cmH2O.

### Prevention and Management

The prevention of ventilator-induced diaphragm dysfunction begins with maintaining spontaneous respiratory effort throughout the course of mechanical ventilation, avoiding complete ventilator takeover whenever clinically feasible. The concept of diaphragm-protective ventilation has emerged as a framework for optimizing the level of ventilatory support to maintain a thickening fraction of 15 to 30 percent, avoiding both the excessive support that leads to disuse atrophy and the insufficient support that leads to load-induced diaphragm injury. Early mobilization, including upright positioning and progressive mobility protocols, supports diaphragm recovery. Inspiratory muscle training using threshold inspiratory muscle training devices during the weaning phase provides targeted exercise to the inspiratory muscles. Phrenic nerve stimulation represents an emerging technology under active investigation for the prevention and treatment of diaphragm dysfunction in mechanically ventilated patients.

## Tracheostomy

### Timing

The optimal timing of tracheostomy in patients anticipated to require prolonged mechanical ventilation has been a subject of extensive investigation. The TracMan trial of 2013 compared early tracheostomy, performed within 4 days of ICU admission, against late tracheostomy, performed after 10 days if the patient still required ventilation, and found no mortality difference between the two strategies. A particularly important finding from TracMan was that one-third of patients randomized to the late tracheostomy group were successfully extubated before day 10 and never required a tracheostomy at all, highlighting the risk of performing the procedure prematurely. The SETPOINT2 trial, which examined early tracheostomy in stroke patients with predicted prolonged ventilation, similarly demonstrated no benefit. The current approach favors individualization of tracheostomy timing, with consideration at 10 to 14 days if prolonged mechanical ventilation exceeding 14 to 21 days is anticipated. Earlier tracheostomy may offer practical benefits including reduced sedation requirements, improved patient comfort, and facilitation of early mobilization, even in the absence of a demonstrated mortality advantage.

### Technique

Two primary techniques for tracheostomy are available: percutaneous dilatational tracheostomy and surgical tracheostomy. Percutaneous dilatational tracheostomy is performed as a bedside procedure in the ICU with bronchoscopic guidance, avoiding the need for operating room transport. Surgical tracheostomy is preferred in patients with difficult cervical anatomy, cervical spine issues, or significant coagulopathy. Both techniques have comparable complication rates when performed by experienced operators. The procedure should be performed when the patient is stable, with an FiO2 of 0.6 or less and PEEP of 10 cmH2O or less.

### Benefits

Tracheostomy confers several physiological and practical advantages over continued translaryngeal intubation. The shorter, wider tracheostomy tube reduces dead space by approximately 50 percent compared to a standard endotracheal tube, improving the efficiency of ventilation. Patient comfort is markedly improved, enabling reduced sedation requirements and the ability to eat and communicate using a speaking valve. Weaning is facilitated by easier suctioning access and reduced airway resistance. Early mobilization is safer and more feasible with a tracheostomy than with an endotracheal tube, enabling more aggressive rehabilitation efforts that contribute to functional recovery.

## Key Clinical Pearls

- Daily spontaneous awakening trials (SAT) paired with spontaneous breathing trials (SBT) — the ABC bundle — reduce ventilator days and mortality (Girard et al., Wake Up and Breathe protocol)
- A 30-minute PS SBT (5-8 cmH2O) is the preferred weaning method — non-inferior to 120-minute trials and less fatiguing
- RSBI <105 is a useful screening tool but should not be the sole determinant of extubation readiness
- Weaning-induced cardiac failure is underdiagnosed — measure BNP or echo during SBT if recurrent failures
- Preventive NIV post-extubation reduces reintubation in HIGH-RISK patients; therapeutic NIV for established failure is HARMFUL
- Diaphragm ultrasound (thickening fraction) is an emerging bedside tool for predicting extubation success — TFdi <20% predicts failure
- Absent cuff leak should prompt steroid pre-treatment, not necessarily delayed extubation
- TracMan demonstrated that many patients predicted to require prolonged MV are successfully extubated — avoid premature tracheostomy

## References

1. Girard TD, Kress JP, Fuchs BD, et al. Efficacy and safety of a paired sedation and ventilator weaning protocol for mechanically ventilated patients in intensive care (Awakening and Breathing Controlled trial). Lancet. 2008;371(9607):126-134.
2. Subirà C, Hernandez G, Vazquez A, et al. Effect of pressure support vs T-piece ventilation strategies during spontaneous breathing trials on successful extubation among patients receiving mechanical ventilation. JAMA. 2019;321(22):2175-2182.
3. Esteban A, Frutos-Vivar F, Ferguson ND, et al. Noninvasive positive-pressure ventilation for respiratory failure after extubation. N Engl J Med. 2004;350(24):2452-2460.
4. Young D, Harrison DA, Cuthbertson BH, et al. Effect of early vs late tracheostomy placement on survival in patients receiving mechanical ventilation: the TracMan randomized trial. JAMA. 2013;309(20):2121-2129.
5. Goligher EC, Dres M, Fan E, et al. Mechanical ventilation-induced diaphragm atrophy strongly impacts clinical outcomes. Am J Respir Crit Care Med. 2018;197(2):204-213.