What test checks if a patient is ready for extubation (removal of endotracheal tube)?

Extubation Readiness Testing

A spontaneous breathing trial (SBT) is the primary test to check if a patient is ready for extubation, and should be performed as part of a protocolized extubation readiness testing (ERT) bundle that includes assessment of airway patency, cough effectiveness, secretion management, and neurologic control. 1

Core Components of Extubation Readiness Assessment

1. Protocolized Screening

• Daily screening should be performed for all patients mechanically ventilated >24 hours to identify eligibility for extubation readiness testing 1, 2
• Screening assesses resolution of the primary indication for mechanical ventilation, adequate oxygenation (FiO₂ ≤0.5, PEEP ≤6 cm H₂O, SpO₂ >92%), hemodynamic stability, and adequate respiratory drive 1, 3

2. Spontaneous Breathing Trial (SBT) - The Gold Standard Test

The SBT objectively assesses the patient's ability to independently maintain adequate minute ventilation and gas exchange without excessive respiratory effort 1, 4

SBT Technique Selection:

• For standard-risk patients: Use pressure support ventilation of 5-8 cm H₂O with CPAP for 30 minutes 1, 4, 2

  • This approach achieves higher success rates (84.6% vs 76.7% with T-piece) and better extubation outcomes (75.4% vs 68.9%) 4, 2, 5

• For high-risk patients: Use CPAP alone (without pressure support) for 60-120 minutes to better assess true extubation readiness 1, 4

  • High-risk features include: prolonged ventilation >14 days, chronic lung disease, myocardial dysfunction, neurologic impairment, upper airway anomalies, or previously failed extubation 4, 3

SBT Failure Criteria (Monitor During Trial):

• Respiratory rate >30/min or <10/min 4, 3
• Oxygen desaturation (SpO₂ <92%) 4, 3
• Respiratory distress (accessory muscle use, paradoxical breathing, diaphoresis) 4, 3
• Hemodynamic instability (tachycardia, hypertension, hypotension) 4, 3
• Altered mental status or agitation 4, 3

3. Additional Critical Assessments Beyond SBT

Cuff Leak Test (Airway Patency Assessment):

• Perform before extubation to predict laryngeal edema risk, especially in patients with risk factors: female gender, traumatic/difficult intubation, large tube size, prolonged intubation 3
• Deflate the endotracheal tube cuff and measure the difference between inspired and expired tidal volumes 3
• If leak volume is low or absent, administer corticosteroids at least 6 hours before extubation 1, 3
• In pediatric patients with cuffed ETT, air leak pressure >25 cm H₂O indicates high risk for postextubation upper airway obstruction 3

Respiratory Muscle Strength Assessment:

• Measure PiMax (maximal inspiratory pressure) as an element of the ERT bundle for critically ill children at risk for muscle weakness or extubation failure 1
• Airway occlusion pressure (P0.1) ≤4 cm H₂O indicates likely extubation success, while >6 cm H₂O predicts weaning failure 3

Cough Effectiveness and Secretion Management:

• Assess cough strength and sputum load before extubation 4, 3
• Evaluate bulbar function to ensure adequate airway protection 4, 3

Algorithmic Approach to Extubation Decision

1. Daily screening: Check if patient meets basic criteria (adequate oxygenation, hemodynamic stability, resolution of primary indication) 1, 2

2. Perform SBT:

   • Standard-risk: 30 minutes with PS 5-8 cm H₂O 4, 2
   • High-risk: 60-120 minutes with CPAP alone 1, 4

3. If SBT successful, assess:

   • Cuff leak test (especially if risk factors present) 3
   • Cough effectiveness 4, 3
   • Secretion burden 4, 3
   • Neurologic status/airway protection 1, 3

4. If all assessments favorable: Proceed with extubation 1, 2

5. Post-extubation support:

   • For high-risk patients (reintubation risk >20%), apply prophylactic NIV immediately after extubation 2
   • For children <1 year at high risk, use CPAP over high-flow nasal cannula 2

Critical Pitfalls to Avoid

• Do not perform repeat SBTs on the same day after failure - this can lead to respiratory muscle fatigue and worsening respiratory mechanics 4
• Do not rely solely on successful SBT - approximately 10% of patients who pass an SBT will still fail extubation due to issues with airway patency, secretions, or cough 4, 3
• Do not skip cuff leak testing in high-risk patients - absence of a leak around an appropriately sized tube generally precludes safe extubation 3
• Avoid using T-piece alone for initial SBT in standard-risk patients - pressure support trials are more likely to result in successful extubation without increasing reintubation rates 4, 5, 6

Pediatric-Specific Considerations

• Use protocolized ERT bundles including SBT assessment 1, 2
• Administer dexamethasone at least 6 hours before extubation in children at high risk of postextubation upper airway obstruction 1, 2, 3
• For children at higher risk of extubation failure, use CPAP without pressure support during SBTs 1