The Utility of Diaphragm Ultrasound in Reducing Time to Extubation

PURPOSE: Prediction of optimal timing for extubation of mechanically ventilated patients is challenging. Ultrasound measures of diaphragm thickness or diaphragm dome excursion have been used to aid in predicting extubation success or failure. The aim of this study was to determine if incorporating results of diaphragm ultrasound into usual ICU care would shorten the time to extubation. METHODS: We performed a prospective, randomized, controlled study at three Brown University teaching hospitals. Included subjects underwent block randomization to either usual care (Control) or usual care enhanced with ultrasound measurements of the diaphragm (Intervention). The primary outcome was the time to extubation after ultrasound, and the secondary outcome was the total days on the ventilator. Only intensivists in the Intervention group would have the ultrasound information on the likelihood of successful extubation available to incorporate with traditional clinical and physiologic measures to determine the timing of extubation. RESULTS: A total of 32 subjects were studied; 15 were randomized into the Control group and 17 into the Intervention group. The time from ultrasound to extubation was significantly reduced in the Intervention group compared to the Control group in patients with a ∆tdi% ≥ 30% (4.8 ± 8.4 vs 35.0 ± 41.0 h, p = 0.04). The time from ultrasound to extubation was shorter in subjects with a normally functioning diaphragm (∆tdi% ≥ 30%) compared to those with diaphragm dysfunction (∆tdi% < 30%) (23.2 ± 35.2 vs 57.3 ± 52.0 h p = 0.046). When combining the Intervention and Control groups, a value of ∆tdi% ≥ 30% for extubation success at 24 h provided a sensitivity, specificity, PPV and NPV of 90.9%, 86.7%, 90.9%, and 86.7%, respectively. CONCLUSIONS: Diaphragm ultrasound evaluation of ∆tdi% aids in reducing time to extubation.