Objective: To evaluate the predictive value of central venous saturation to detect extubation failure in difficult-to-wean patients.
Design: Cohort, multicentric, clinical study.
Setting: Three medical-surgical intensive care units.
Patients: All difficult-to-wean patients (defined as failure to tolerate the first 2-hr T-tube trial), mechanically ventilated for >48 hrs, were extubated after undergoing a two-step weaning protocol (measurements of predictors followed by a T-tube trial). Extubation failure was defined as the need of reintubation within 48 hrs.
Interventions: The weaning protocol evaluated hemodynamic and ventilation parameters, and arterial and venous gases during mechanical ventilation (immediately before T-tube trial), and at the 30th min of spontaneous breathing trial.
Measurements and main results: Seventy-three patients were enrolled in the study over a 6-mo period. Reintubation rate was 42.5%. Analysis by logistic regression revealed that central venous saturation was the only variable able to discriminate outcome of extubation. Reduction of central venous saturation by >4.5% was an independent predictor of reintubation, with odds ratio of 49.4 (95% confidence interval 12.1-201.5), a sensitivity of 88%, and a specificity of 95%. Reduction of central venous saturation during spontaneous breathing trial was associated with extubation failure and could reflect the increase of respiratory muscles oxygen consumption.
Conclusions: Central venous saturation was an early and independent predictor of extubation failure and may be a valuable accurate parameter to be included in weaning protocols of difficult-to-wean patients.