Fig. 2

The ROC curve for E/Ea (average) after SBT predicting respiratory failure within 48 h. The AUC of E/Ea was 0.789 (P < 0.001). A cut-off value ≥ 12.5 of E/Ea (average) after SBT showed the highest diagnostic accuracy with a sensitivity and specificity of 72.4 and 77.4%, respectively. AUC area under curve, E/Ea the ratio of mitral Doppler inflow velocity (E) to annular tissue Doppler wave velocity (Ea), ROC receiver operating characteristic curve, SBT spontaneous breathing trial