Assessment of Respiratory Mechanics and Inspiratory Effort During Spontaneous Breathing Trials to Predict Extubation Failure in High-Risk Patients

Rationale. Conventional parameters to determine spontaneous breathing trials (SBTs) success may fail to detect impending respiratory distress. Objectives. To assess whether SBT-induced changes in respiratory system compliance, inspiratory effort and respiratory drive (P0.1), all assessed noninvasively through airway occlusions, are associated with extubation outcomes. Methods: Multicenter study on patients at high-risk of extubation failure who successfully passed a 30-minute SBT based on conventional parameters. The SBT was reproduced using a specific ventilator immediately before extubation to continuously monitor respiratory system compliance, inspiratory effort and P0.1. Extubation failure was defined as reintubation within 72 hours. Main Results: Forty-six of 238 extubated patients (19%) required reintubation. No differences in tidal volume or respiratory rate were observed between successfully extubated and reintubated patients, at any time. In success group, inspiratory effort and normalized compliance (i.e. scaled to predicted body weight) remained unchanged throughout the SBT. In failure group, normalized compliance declined (1.0 0.8-1.2 to 0.7 0.6-0.9 mL/cmH2O/kg, p2 cmH2O >1; >3 were the most accurate predictors of extubation failure (AUC 0.90 0.84-0.93, sensitivity 80%, specificity 83%; AUC 0.94 0.90–0.97, sensitivity 89%, specificity 93%, respectively). Conclusion: In high-risk patients, SBT-induced declines in respiratory system compliance and increases in inspiratory effort are associated with extubation failure.