Spontaneous Breathing Trial in Infants on Mechanical Ventilation
Spontaneous breathing trials should be considered daily for infants on mechanical ventilation once they demonstrate hemodynamic stability, adequate mental status, resolution of the primary indication for ventilation, and adequate oxygenation/ventilation parameters. 1
Prerequisites for SBT Readiness
Before attempting an SBT in infants, a two-step screening process is essential:
Daily Screening Assessment
- Resolution of primary indication for mechanical ventilation 1
- Hemodynamic stability without vasopressor support 2
- Adequate mental status (infant is arousable) 1, 2
- Low ventilatory requirements and PEEP 2
- Low FiO2 requirements (typically FiO2 ≤0.30-0.40 for preterm infants) 2, 3
Objective Respiratory Parameters
The screening tool should evaluate: 1
- Frequency-to-tidal volume ratio
- Oxygenation (PaO2/FiO2 ratio)
- Maximal inspiratory pressure
- Maximal expiratory pressure
- Airway occlusion pressure
- Vital capacity
SBT Methods and Duration
Trial Techniques
For infants, SBTs can be performed using either: 4
- Pressure support ventilation (10 cmH2O) - equally effective as T-piece in pediatric patients 4
- T-piece breathing 1, 4
- Flow-by with PEEP of 5 cmH2O 1
Recent evidence suggests using inspiratory pressure augmentation (5-8 cmH2O) rather than T-piece or CPAP alone for the initial SBT in mechanically ventilated patients. 2
Duration of Trial
- Minimum 30 minutes, though approximately half of patients may fail after this timeframe 1
- Optimal duration: 60-120 minutes for more reliable assessment 1
- Modified 10-minute SBT has shown 95% sensitivity and 90% positive predictive value for successful extubation in preterm neonates ≤30 weeks gestation 5
Special Considerations for Preterm Infants
Extubation Readiness in Premature Neonates
For preterm infants ≤30 weeks gestation: 5
- Use an extubation bundle that includes modified SBT
- Higher gestational age and weight at extubation correlate with success
- Modified 10-minute SBT demonstrates excellent predictive value (95.3% sensitivity in infants >27-≤30 weeks) 5
Post-Extubation Support
- PEEP is beneficial during initial stabilization of apneic preterm infants requiring positive-pressure ventilation 6
- Avoid excessive chest wall movement during ventilation 6
- Caution with high PEEP levels (8-12 cmH2O) as they may reduce pulmonary blood flow and increase pneumothorax risk 6
Common Pitfalls and Caveats
Contraindications to SBT
Do not attempt SBT in infants with: 1
- Significant hemodynamic instability
- Altered mental status
- New serious conditions
Monitoring During Trial
- Continuous monitoring of heart rate, blood pressure, and oxygen saturation is essential 1
- Observe for respiratory distress, increased work of breathing, or desaturation
- Any respiratory effort inconsistent with readiness should prompt trial termination 1
Ventilation Mode Benefits
Patient-triggered ventilation reduces work of breathing compared to conventional IMV by providing synchronized assistance, allowing infants to adapt their breathing pattern while maintaining minute ventilation. 7 This may facilitate easier transition to spontaneous breathing trials.
Success Prediction
Infants who tolerate an SBT for 2 hours have approximately 85% success rate with complete discontinuation of mechanical ventilation. 2 However, reintubation rates of 12-15% within 48 hours are expected even after successful trials. 4