- Reliability and adequacy (sensitivity, specificity, positive and negative predictive values) between the IC devices, is tested using ROC curves with kappa coefficient (reliability coefficient). For coefficient of variation, ANOVA is used when applicable. Results are adjusted using Greenhouse-Geisser correction in case of non-sphericity. Post-hoc tests using Bonferroni correction compared the results between two IC devices. The prediction of EE differences between devices are analyzed by multivariate regression. As 91 are expected to complete the entire protocol, 9 factors are introduced in the model (Peduzzi P, J Clin Epidemiol 1996, 49, 1373-9), i.e. ventilator type, ventilator mode, minute ventilation, FiO2, BMI, SOFA, heart rate, body temperature, medical/surgical category.