Role of chest ultrasound in diaphragmatic assessment among stable chronic obstructive pulmonary disease patients before and after pulmonary rehabilitation

Abstract

Background The cornerstone of nonpharmacological treatment of chronic obstructive pulmonary disease (COPD) is pulmonary rehabilitation, not only for enhancement of exercise performance but also for improvement of quality of life. However, the responses to rehabilitation varied among individuals. Aim To evaluate the role of chest ultrasound in the assessment of the diaphragm among patients with stable COPD before and after pulmonary rehabilitation. Patients and methods Spirometric pulmonary functions, sonographic assessment of diaphragmatic thickness and excursion, and 6-min walking test were done before and after rehabilitation. Based on a decrease in Saint George’s Respiratory Questionnaire (SGRQ), the patients were classified into failed and successful groups. Results The prevalence of successful rehabilitation was 71.1%, which was significantly higher in mild and moderate COPD cases. Pulmonary rehabilitation reported a significant improvement of dyspnea scale by 35%, SGRQ by 10%, 6 min walk distance by 9%, and pulmonary functions by up to 2%. There was a significant improvement in diaphragmatic excursion and thickness after rehabilitation by 5 and 13%, respectively. Percentage change of both diaphragmatic excursion (DE) and diaphragmatic thickness (DT) showed significant capability in predicting successful rehabilitation; the area under the curve was 87 and 92%, respectively. The cutoff points of percentage change in DE and DT were 24 and 10%, respectively, with sensitivity, specificity, positive predicative value, and negative predicative value of 95, 85, 58, and 99%, respectively, for DE and 94, 81, 52, and 98%, respectively, for DT. Conclusions The effect of pulmonary rehabilitation was significant regarding pulmonary functions, exercise, and diaphragmatic performance. The use of ultrasound in detecting changes of DT and DE after rehabilitation was excellent, which correlated significantly either positively with pulmonary function and 6 min walk distance changes or negatively with changes in SGRQ.