Background: Chronic obstructive pulmonary disease (COPD) has several systemic manifestations that impacts its severity, exercise capacity, and progression. Pulmonary rehabilitation (PR) program helps to decrease symptoms and improve exercise capacity.
Objective: To assess the effect of pulmonary rehabilitation on exercise capacity, skeletal and   diaphragmatic muscles in stable COPD patients.
Methodology: A prospective interventional study was conducted on 60 patients with stable COPD. All of them were assessed by the following at baseline and 12 weeks after PR program; spirometric-indices, arterial blood gases, ultrasonographic assessment of diaphragm thickness fraction (DTF%) and tidal breathing diaphragm excursion (TDE), assessment of diaphragm and quadriceps muscle shear wave elastography (SWE), measurement of right ventricular systolic pressure (RVSP) gradient by echocardiography, and evaluation of functional health status by; COPD assessment (CAT) test, modified medical research council (mMRC) scale and six minutes' walk test (6MWT).
Results: In COPD patients, the spirometry-indices were significantly improved after PR compared to baseline value (p<0.001). The oxygen saturation (SaO₂%), and arterial partial of oxygen (PaO₂) were significantly improved as both were increased, while the arterial partial of carbon dioxide (PaCO₂) and pH were significantly decreased after PR compared to the baseline value (p< 0.05). The DTF %, and TDE were significantly increased after PR compared to baseline (p<0.05). The diaphragm SWE, quadriceps SWE, and RVSP were significantly improved after PR compared to the baseline values, all decreased (p<0.05). The exercise tolerance parameters, CAT score and mMRC scale were significantly decreased (p<0.001), while the 6MWT distance, and pre and post 6MWT SpO₂ were significantly increased (p<0.001) after PR compared to the baseline values.
Conclusion: PR confers benefits to COPD patients that manifest in diverse ways as improvement of ventilatory function, arterial blood gases, exercise capacity, and diaphragm functions, with decrease of diaphragm and quadriceps muscle stiffness and pulmonary artery pressure.