New Predictors for the Weaning from Mechanical Ventilation

New indicators, Oxygen Cost of Breathing (ΔVO2), Work of Breathing (WOBp), intrapreural Pressure Time Product (PTP) and P0.1 were clinically examined to determine which of these indicators is the most specific and sensitive for predicting the outcome of weaning from mechanical ventilation. Twenty-three weanings were attempted and divided into a successful weaning group (Group-S) and a failed weaning group (Group-F). There were significant differences in Minute Volume, ΔVO2, ΔVCO2, WOBp, P0.1, PTP, Lung Compliance and Intrinsic PEEP between the groups. ΔVO2 and P0.1 in particular, were statsitically significantly different in the two groups (ΔVO2: 14.4±11.7 in Group-F VS. -7.7±9.6% in Group-S P<0.005, P0.1: 4.9±1.6 in Group-F VS. 2.5±1.3cmH2O in Group-S P<0.01) and 5% in ΔVO2 and 3.5cmH2O in P0.1 are the Cutt-Off values for prediction of the success or failure of weaning trials. WOBp greater than 9 Joule min-1 and PTP above 200cmH2O sec min-1 suggested difficulty in weaning from the ventilator. ΔVO2 and P0.1 are considered to be the most sensitive indicators, because in the group-F these indicators exhibited significant increases in the early stage of weaning from the ventilator.