Evaluation of diaphragm ultrasound in predicting extubation outcome in mechanically ventilated patients with COPD

To explore the value of the right hemi-diaphragmatic excursion (DE) and its variation in predicting extubation outcome in mechanically ventilated patients with COPD.

All included patients with COPD received mechanical ventilation (MV) and were ready to wean from MV. After patients passed the 30 min spontaneous breathing trail (SBT), extubation was considered to be feasible, and the right DE measured by ultrasound at 0 min, 5 min, and 30 min of SBT were named as DE₀, DE₅, and DE₃₀, respectively.

Twenty-five patients succeeded extubation; 12 patients failed. The area under receiver operator characteristic curve (AUC_ROC) of DE₃₀ and ΔDE_30-5 (the variation between 30 and 5 min) were 0.762 and 0.835; a cutoff value of DE₃₀ > 1.72 cm and ΔDE_30-5 > 0.16 cm were associated with a successful extubation with a sensitivity of 76% and 84%, a specificity of 75% and 83.3%, respectively. The predictive probability equation of the DE₃₀ plus ∆DE_30-5 was P = 1/[1 + e^{-(-5.625+17.689×∆DE}_30-5^+1.802×DE₃₀⁾], a cutoff value of P > 0.626 was associated with a successful extubation with the AUC_ROC of 0.867, a sensitivity of 92%, and a specificity of 83.3%.

The combination of DE₃₀ and ∆DE_30-5 could improve the predictive value and could be used as the predictor of extubation outcome in mechanically ventilated patients with COPD.