Weaning from Mechanical Ventilation
Use a standardized two-step protocol with daily readiness screening followed by spontaneous breathing trials (SBTs) conducted with modest pressure support (5-8 cm H₂O) rather than T-piece or gradual weaning methods, as this approach reduces mechanical ventilation duration by approximately 50% and achieves extubation three times faster than gradual methods. 1, 2
Step 1: Daily Readiness Screening
Before attempting any SBT, verify the patient meets ALL of these criteria 3, 1, 2:
- Oxygenation: PaO₂/FiO₂ ratio ≥ 200 and FiO₂ < 0.50 3, 1
- PEEP: ≤ 5 cm H₂O 3, 1, 2
- Hemodynamics: Stable without vasopressor support 3, 2
- Mental status: Arousable with adequate mentation 2
- Airway protection: Intact airway reflexes and cough on suctioning 1, 2
- Secretions: Minimal secretions or effective clearance mechanism 3
- Clinical stability: Resolution of the primary condition that necessitated intubation 3
- No sedation: Absence of continuous sedative infusions 1
Step 2: Conduct the Spontaneous Breathing Trial
Use pressure support ventilation (5-8 cm H₂O) for the initial SBT, NOT T-piece alone. This method achieves 84.6% success rate versus 76.7% with T-piece, and extubation success of 75.4% versus 68.9% 3, 2. The American Thoracic Society specifically recommends this approach over T-piece 1, 2.
SBT Duration and Monitoring
- Standard duration: 30-120 minutes, with most failures occurring within the first 30 minutes 3, 1
- High-risk patients (cerebral palsy, neuromuscular disorders): Consider longer trials of 60-120 minutes 3
Immediate SBT Termination Criteria
Stop the trial immediately if ANY of these develop 2:
- Respiratory distress (increased work of breathing, accessory muscle use)
- Hemodynamic instability (significant blood pressure changes, arrhythmias)
- Oxygen desaturation or deteriorating gas exchange
- Altered mental status or agitation
- Diaphoresis or subjective discomfort
Critical pitfall: Do NOT repeat SBTs on the same day after failure—this causes respiratory muscle fatigue and worsens outcomes 3, 2.
Step 3: Pre-Extubation Assessment
Even after passing an SBT, approximately 10% of patients will still fail extubation 3, 1. Before removing the endotracheal tube, assess 3, 2:
- Cough effectiveness: Critical in patients with neuromuscular weakness
- Bulbar function: Ability to protect the airway
- Sputum load: Ability to clear secretions independently
- Upper airway patency: Risk of post-extubation stridor
Step 4: Post-Extubation Management
High-Risk Patients Require Prophylactic Support
For patients at high risk of extubation failure, initiate prophylactic noninvasive ventilation (NIV) immediately after extubation 3, 2. This approach shows:
- Decreased mortality (RR 0.54) 3, 1
- Reduced weaning failure (RR 0.61) 3, 1
- Lower incidence of ventilator-associated pneumonia (RR 0.22) 1
High-risk patients include those with 3:
- Hypercapnic respiratory failure (especially COPD)
- Neuromuscular disorders
- Multiple previous extubation failures
- Weak cough or excessive secretions
Alternative Support Options
- High-flow nasal cannula oxygen therapy can reduce reintubation rates 3
- Intensive respiratory physiotherapy with bronchial drainage and mechanically assisted coughing for patients with secretion management issues 3
Monitoring Period
- Extubation is considered successful only if the patient does not require reintubation or NIV within 48 hours 3
- Monitor closely during this 48-hour window for signs of respiratory distress 3
- Keep equipment readily available for non-invasive support or reintubation 3
Avoid These Inferior Weaning Methods
Do NOT use synchronized intermittent mandatory ventilation (SIMV) or gradual pressure support reduction as primary weaning strategies. The American Thoracic Society and European Respiratory Society state that SIMV is inferior to both pressure support SBTs and T-piece weaning 1. Daily SBTs are approximately three times faster than gradual weaning approaches 2.
Special Considerations for Prolonged Weaning
If the patient fails three or more SBTs or requires more than 7 days of weaning attempts (prolonged weaning, occurring in ~15% of patients) 1:
- Consider tracheostomy within the first 7 days if multiple extubation attempts fail 3
- Tracheostomy facilitates ventilatory weaning in patients with neuromuscular disorders 3
- Implement a respiratory bundle approach including active physiotherapy with mechanical insufflation/exsufflation devices 3
Protocol-Driven Weaning
Implement standardized weaning protocols driven by respiratory therapists or ICU nurses rather than physician-directed weaning alone. The Society of Critical Care Medicine strongly recommends protocol-based weaning with SBTs, as this improves outcomes and reduces mechanical ventilation duration 1, 4, 5.