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Table 2 Threshold values of variables used to predict weaning outcome—mean values derived from the training sets

From: Mechanical power normalized to lung-thorax compliance predicts prolonged ventilation weaning failure: a prospective study

Variables Failure of prolonged weaning
Post-SBT Pre-weaning completion
PaCO2 on MV (mmHg)  > 35.3  > 34.6
VR  > 1.23  > 1.23
LTCdyn (mL/cmH2O)  ≤ 31.2  ≤ 33.6
MP (J/min)  > 20.8  > 20.3
PBW-MP (J/min/kg)  > 0.3164  > 0.3158
LTCdyn-MP (cmH2O2/min)  > 6496  > 6341
PIrs1.0 (cmH2O2/min)  > 5020  > 4915
PIrs2.0 (cmH2O2/min)  > 3895  > 3704
  1.  > / ≤ indicate whether values above/below the threshold value predicted failure of prolonged weaning. The associated criterion is the threshold value that minimized the difference between sensitivity and specificity of the test, graphically corresponding to the intersection of the line connecting the left-upper corner and the right-lower corner of the unit square and the ROC curve
  2. SBT spontaneous breathing trial, MV mechanical ventilation, VR ventilatory ratio, LTCdyn dynamic lung-thorax compliance, MP mechanical power, PBW-MP mechanical power normalized to predicted body weight, LTCdyn-MP mechanical power normalized to dynamic lung-thorax compliance, PIrs power index of the respiratory system