Assessment of diaphragmatic mobility by chest ultrasound in patients with chronic obstructive pulmonary disease on different modes of mechanical ventilation

Abstract

Background Chronic obstructive pulmonary disease (COPD) is a disease characterized by airway obstruction and air trapping that is not fully reversible. The diaphragm is the principal respiratory muscle, and its dysfunction can prolong the duration of mechanical ventilation. Ultrasonography is a fast, easy, and accurate method of bedside evaluation for diaphragmatic function. In the ICU population, it can quantify normal and abnormal movements in a variety of clinical conditions. Patients and methods A prospective observational study was carried on 32 patients with COPD admitted to the respiratory ICU. Diaphragmatic excursion had been assessed by chest ultrasonography in every mode of mechanical ventilation and was correlated with weaning off mechanical ventilation and other physiological parameters. Results Of 32 patients with COPD included in the study, 24 patients were successfully weaned versus eight patients failed to be weaned off mechanical ventilation. Diaphragmatic excursions in every mode of mechanical ventilation (noninvasive, volume control, bilevel positive airway pressure, and pressure support) were higher in weaned patients with best cutoff values of 1.4, 1.3, 1.5, and 1.6 cm, respectively. Moreover, the diaphragmatic excursions were directly correlated with tidal volumes and inversely correlated with days of mechanical ventilation and rapid shallow breathing index. Conclusion Diaphragmatic displacement assessed by ultrasound is a good predictor for weaning off mechanical ventilation in patients with COPD, as it is sensitive, specific, and accurate. Diaphragmatic excursions are directly related to tidal volumes and inversely related with rapid shallow breathing index and days of mechanical ventilation.