Weaning Mode of Ventilation
Use spontaneous breathing trials (SBTs) with modest inspiratory pressure support (5-8 cm H₂O) as the preferred weaning mode, conducted daily in patients who meet readiness criteria, rather than gradual reduction methods like SIMV or progressive PSV weaning. 1, 2
Recommended Weaning Approach
Daily Spontaneous Breathing Trials Are Superior
Perform daily SBTs rather than gradual weaning methods (SIMV or progressive PSV reduction) as this approach reduces mechanical ventilation duration by approximately 50% and leads to extubation about three times more quickly than gradual methods. 1, 3
The Surviving Sepsis Campaign strongly recommends using SBTs in mechanically ventilated patients with sepsis who are ready for weaning (strong recommendation, high quality evidence). 1
A weaning protocol incorporating daily SBTs should be implemented (strong recommendation, moderate quality evidence). 1, 2
Optimal SBT Technique: Pressure Support vs T-Piece
Conduct the initial SBT with modest inspiratory pressure augmentation (5-8 cm H₂O pressure support) rather than T-piece alone. 1, 2, 4
The evidence strongly favors pressure-supported SBTs:
SBT success rate: 84.6% with pressure support vs 76.7% with T-piece (RR 1.11,95% CI 1.02-1.18). 1, 4
Extubation success rate: 75.4% with pressure support vs 68.9% with T-piece (RR 1.09,95% CI 1.02-1.18). 1, 4, 5
A 2019 randomized trial of 1,153 patients demonstrated that 30 minutes of pressure support (8 cm H₂O) resulted in 82.3% successful extubation vs 74.0% with 2-hour T-piece (difference 8.2%, P=0.001), with significantly lower 90-day mortality (13.2% vs 17.3%, P=0.04). 5
SBT Duration
Standard-risk patients: 30 minutes is sufficient for most patients, as most SBT failures occur within the first 30 minutes. 2, 4
High-risk patients: 60-120 minutes for those with previous extubation failure, prolonged ventilation >14 days, chronic lung disease, myocardial dysfunction, or neurologic impairment. 4
Patient Readiness Screening (Two-Step Process)
Before conducting an SBT, patients must meet these criteria 1, 2:
- FiO₂ < 0.50 (or ≤0.50)
- PEEP ≤ 5 cm H₂O
- Hemodynamically stable (no vasopressor agents)
- Arousable/adequate mental status
- Intact airway reflexes
- No new potentially serious conditions
Inferior Weaning Methods to Avoid
SIMV is inferior to both PSV and T-piece weaning and should not be used. 2, 4
- Gradual reduction approaches (progressive decreases in SIMV rate or PSV levels) prolong weaning duration compared to daily SBT protocols. 3
SBT Failure Criteria
Terminate the SBT immediately if any of these develop 4:
- Respiratory distress (increased respiratory rate, accessory muscle use, paradoxical breathing)
- Hemodynamic instability (tachycardia, hypertension, hypotension)
- Oxygen desaturation or deteriorating gas exchange
- Altered mental status or agitation
- Diaphoresis or subjective discomfort
Post-SBT Management
If SBT Successful
Before extubation, assess 4:
- Upper airway patency (no stridor)
- Bulbar function (swallowing ability)
- Cough effectiveness
- Sputum load
Do not repeat SBTs on the same day after failure - this leads to respiratory muscle fatigue and worsening outcomes. 4
High-Risk Patients
Consider prophylactic noninvasive ventilation (NIV) immediately after extubation for patients at high risk of extubation failure. 2, 4
For hypercapnic respiratory failure (especially COPD), NIV facilitates weaning with decreased mortality (RR 0.54,95% CI 0.41-0.70) and reduced weaning failure (RR 0.61,95% CI 0.48-0.79). 2
Common Pitfalls
Approximately 10% of patients who pass an SBT will still fail extubation - success on SBT does not guarantee extubation success, so assess upper airway patency, cough, and secretion management. 2, 4
Pressure-supported SBTs may underestimate post-extubation work of breathing, but the overall outcomes favor this approach over T-piece. 4
Failed extubation requiring reintubation increases mortality by 10-20% and increases ventilator-associated pneumonia risk, but acceptable extubation failure rates should be 5-10%. 4