From the Guidelines
For patients ventilated for more than 24 hours, the initial spontaneous breathing trial (SBT) should be conducted with inspiratory pressure augmentation (5-8 cm H2O) rather than without (T-piece or CPAP). This approach is recommended based on the American College of Chest Physicians/American Thoracic Society clinical practice guideline 1. The guideline suggests that inspiratory pressure augmentation during SBTs can help improve the likelihood of successful liberation from mechanical ventilation.
Key Considerations for SBTs
- The patient should be hemodynamically stable with adequate oxygenation before initiating an SBT.
- Minimal secretions and the ability to initiate respiratory effort are also essential prerequisites.
- The trial involves reducing or eliminating ventilator support for 30-120 minutes while closely monitoring the patient for signs of respiratory distress.
- Common SBT methods include T-piece trials, pressure support ventilation (reducing to 5-8 cmH2O), or continuous positive airway pressure (CPAP) at 5 cmH2O.
Monitoring During SBTs
- Increased respiratory rate (>35 breaths/min)
- Decreased oxygen saturation (<90%)
- Increased heart rate (>140 beats/min or >20% change)
- Blood pressure instability
- Anxiety
- Diaphoresis
- Paradoxical breathing
Post-Extubation Care
- For patients at high risk for extubation failure who have been receiving mechanical ventilation for more than 24 hours and have passed an SBT, extubation to preventative noninvasive ventilation (NIV) is recommended 1.
- This approach can help reduce the risk of extubation failure and improve patient outcomes.
From the Research
Spontaneous Breathing Trial Overview
- A spontaneous breathing trial (SBT) is a crucial step in liberating adult critically ill patients from mechanical ventilation 2.
- The trial assesses a patient's ability to breathe on their own without the support of a ventilator.
Conducting a Spontaneous Breathing Trial
- SBTs can be conducted with or without pressure support ventilation (PSV) 2.
- A standardized approach to assessment and completion of an SBT before noon each day is suggested 2.
- The fraction of inspired oxygen (FIO2) should not be increased during an SBT 2.
- A more challenging SBT performed with a T-piece may not further reduce the risk of reintubation, whereas a less challenging SBT performed with PSV may hasten extubation 3.
Predicting Weaning Readiness
- Applied mechanical power (MP) during artificial ventilation may serve as a readiness test before proceeding with an SBT 4.
- MP normalized to lung-thorax compliance may help identify prolonged mechanically ventilated patients ready for spontaneous breathing 4.
- A power index of the respiratory system (PIrs) can also be used to predict SBT failure 4.
Duration of Spontaneous Breathing Trial
- The optimal duration of an SBT in prolonged mechanical ventilation (PMV) patients remains uncertain 5.
- A 12-hour T-piece SBT and a 24-hour T-piece SBT have similar extubation and weaning outcomes in PMV patients 5.
- A prolonged SBT does not necessarily reduce the risk of reintubation 3.