The role of diaphragmatic rapid shallow breathing index and maximum inspiratory pressure in predicting outcome of weaning from mechanical ventilation

Abstract

Introduction The rapid shallow breathing index (RSBI) is considered an accurate weaning predictor. The diaphragmatic excursion (DE) and maximum inspiratory pressure (MIP) can be used as weaning parameters. Substitution of the tidal volume by the DE in the RSBI, that is, calculating the diaphragmatic RSBI (DRSBI, RR/DE), might yield a more precise weaning predictor. Objective The aim of this research was to evaluate the predictive value of the DRSBI, MIP, and the ratio between them (MIP/DRSBI) in the weaning of mechanically ventilated patients. Patients and methods In our study, 64 mechanically ventilated patients were enrolled. At the time of their first spontaneous breathing trial, ultrasonographic assessment of the DE was done, MIP was measured, and RSBI, DRSBI, and MIP/DRSBI were calculated. A total of 36 (56.25%) patients had successful weaning, whereas 28 (43.75%) failed the weaning trial. The new composite parameter (MIP/DRSBI) with a cutoff value greater than or equal to 17 cmH2O/min/mm/breath was the best tool to predict successful weaning with area under the receiver operating characteristics curve of 0.982, with sensitivity and specificity of 100 and 96%, respectively. Conclusion Combining the MIP and DRSBI in one composite parameter (MIP/DRSBI) improved the sensitivity, specificity, and accuracy of both parameters when compared with either parameter alone.