Diaphragm ultrasound as a predictor of successful extubation from mechanical ventilation

Abstract

Difficulty in weaning from mechanical ventilation (MV) is one of the most frequently encountered problems in modern ICUs. An estimated 20% of mechanically ventilated patients face failed extubation (requiring reintubation within 48 h of extubation) (Epstein SK 2002). A trial of failed extubation induces several detrimental consequences, including cardiorespiratory stress, prolonged ICU stay, and increased mortality (Funk GC et al., 2010). Another predictive tool, the rapid-shallow breathing index (RSBI) has gained popularity as a more accurate index in predicting success of extubation, but this ability is limited in patients weaned through pressure support (PS) (Jiang JR et al., 2004). The diaphragm plays a central role in the process of spontaneous ventilation, and it seems that, in patients receiving MV, a properly functioning diaphragm should predict successful weaning. Although the maximal inspiratory pressure is an indirect method of assessing the diaphragm, the more traditional methods of studying diaphragmatic dysfunction include fluoroscopy, phrenic nerve conduction study, and transdiaphragmatic pressure measurement (Ferrari G et al., 2014).