Ultrasonography as a way of evaluating the diaphragm muscle in patients with chronic obstructive pulmonary disease.

Abstract

Abstract Background: Diaphragmatic mobility (DM) may be reduced in chronic obstructive pulmonary disease (COPD) patients, but little is known about whether this mobility correlates with functional parameters, exercise capacity, and indicators of disease severity. Objective: To evaluate the DM of COPD patients and relate the findings with the distance achieved in the six-minute walk test (6MWT), forced expiratory volume in one second (FEV1) % of predicted, residual volume (RV) % of predicted, and dyspnea. Methods: An observational cohort study was conducted to analyze DM through ultrasound during breathing, at rest and during deep inspiration and expiration. Results: It was included 49 COPD stable patients. There was a correlation between the DM measured between expiration and maximum inspiration with FEV1% of predicted (r = 0.36; p = 0.012), RV % of predicted (r = -0.42; p = 0.01), RV/Total Lung Capacity (TLC) (r = -0.61; p < 0.001), and distance reached in the 6MWT (r = 0.46; p = 0.001). In addition, patients with MRCm <2 had a greater DM than those with a score >2 (mean difference 13.20 + 4.6 mm; p = 0.0059), and patients with a BODE index <4 presented greater mobility (61.95 mm) than patients with a BODE index >4 (47.89 mm) (mean difference 14.05 + 5.3 mm; 95% CI 25.09 to 3.01 mm). Conclusion: The results obtained suggest that DM is related to bronchial obstruction (FEV1), lung hyperinflation (RV and RV/TLC), exercise capacity, and the measurement of dyspnea, suggesting that it is an option for evaluating COPD patients.