Diaphragm dysfunction assessed by ultrasonography: Influence on weaning from mechanical ventilation*

Abstract

Objective: To determine the prevalence of diaphragmatic dysfunction diagnosed by M-mode ultrasonography (vertical excursion p < .01) and total ventilation time (576 [range, 374–850] hrs vs. 203 [range, 109–408] hrs, p < .01) than patients without diaphragmatic dysfunction. Patients with diaphragmatic dysfunction also had higher rates of primary (20 of 24 vs. 34 of 58, p < .01) and secondary (ten of 20 vs. ten of 46, p = .01) weaning failures than patients without diaphragmatic dysfunction. The area under the receiver operating characteristics curve of ultrasonographic criteria in predicting weaning failure was similar to that of rapid shallow breathing index. Conclusions: Using M-mode ultrasonography, diaphragmatic dysfunction was found in a substantial number of medical intensive care unit patients without histories of diaphragmatic disease. Patients with such diaphragmatic dysfunction showed frequent early and delayed weaning failures. Ultrasonography of the diaphragm may be useful in identifying patients at high risk of difficulty weaning.