Evaluation of maximal inspiratory pressure, tracheal airway occlusion pressure, and its ratio in the weaning outcome

Purpose: The objective of this study is to evaluate the predictive performance of maximal inspiratory pressure (PImax), airway occlusion pressure (P 0.1), and its ratio (P 0.1/PImax) in the weaning outcome. Materials and Methods: Seventy patients on mechanical ventilation for more than 24 hours, who fulfilled weaning criteria, were prospectively evaluated. PImax less than -25 cm H2O, P 0.1 less than 4.2 cm H2O, and P 0.1/Pimax less than 0.14 were evaluated in all patients before spontaneous breathing trials. The receiver operating characteristic (ROQ curve was calculated to evaluate the predictive performance of each index. Results: PImax presented the area under the ROC curves smaller than those for P 0.1 and P 0.1/PImax (0.52 x 0.76 and 0.52 x 0.78; P = .004 and P = .0006, respectively), being the criteria of worst performance. P 0.1/PImax presented excellent predictive performance in weaned patients, with sensitivity of 98.08, but with the area under the ROC curves only slightly larger than those for P 0.1 (0.78 x 0.76, respectively; P = .69). Conclusion: in our study, P 0.1 and P 0.1/PImax ratio were moderately accurate, whereas PImax was less accurate in predicting the weaning outcome. (C) 2009 Elsevier Inc. All rights reserved.