OCCLUSION PRESSURE AND ITS RATIO TO MAXIMUM INSPIRATORY PRESSURE ARE USEFUL PREDICTORS FOR SUCCESSFUL EXTUBATION FOLLOWING T-PIECE WEANING TRIAL

Study objective: In most weaning studies, failure group patients are r eventilated prior to extubation, thus compromising the evaluation of t he applied weaning indices' predictive values. This study determines t he usefulness of both standard and recent indices in predicting succes sful extubation following prolonged mechanical ventilation. Design and methods: Following a successful 20-min T-piece trial ten traditional weaning criteria, as well as airway occlusion pressure (PO.1), maximal inspiratory pressure (MIP),PO.1/MIP ratio, and shallow breathing (F/V T were determined in unselected patients undergoing prolonged mechanic al ventilation. Having satisfied 8 of 10 classic weaning criteria, 67 patients were extubated after an additional 40 min of successful spont aneous T-piece breathing, and included in the study. After extubation, the tracheal tube resistive pressure (RP) values were measured. Resul ts: Twelve (18%) patients failed extubation. The failure group's avera ge age was significantly greater (69.43 vs 48.43 years). The PO.1, PO. 1/MIP, and F/VT values of the success (3.62+/-1.35 cm H2O, 0.05+/-0.04 , and 50+/-23 b . min(-1). L(-1) and failure (7.38+/-2.67 cm H2O, 0.14 +/-0.04, and 69+/-25 b . min(-1). L(-1) groups were significantly diff erent (p<0.005). The diagostic accuracies of these indices were, respe ctively, 88%, 98%, and 73%. The spirometric, gas exchange, and trachea l tube RP values of the two groups showed no significant differences. Conclusion: PO.1 and PO.1/MIP ratio provide the best means of predicti ng extubation success, and they are not influenced by tracheal tube re sistance.