Fig. 3

Correlation between the difference in PaCO2 and respiratory effort parameters. ΔPOCC, airway pressure swing during occlusion; PMI, pressure muscle index; ΔPaCO2, the value of PaCO2 in the High PaCO2 phase minus the base PaCO2 value; ΔΔPOCC, the value of ΔPOCC in the High PaCO2 phase minus the base ΔPOCC value; ΔPMI, the value of PMI in the High PaCO2 phase minus the base PMI value