Improvement of dyspnea after bariatric surgery is associated with increased Expiratory Reserve Volume: A prospective follow-up study of 45 patients

Objectives To assess the effects of bariatric surgery in patients with obesity on dyspnea and to analyze the relationships between improvement of dyspnea after bariatric surgery and changes in pulmonary function, especially Expiratory Reserve Volume (ERV) which is the lung volume abnormality most frequently associated with obesity. Methods Forty-five patients (5 males/40 females, mean Body Mass Index = 46.2 ± 6.8 kg/m2) were evaluated before and 6 to 12 months after bariatric surgery. Dyspnea was assessed by the modified Medical Research Council (mMRC) scale. Pulmonary function tests, arterial blood gases and six-minute walk test were performed. Laboratory parameters including C-Reactive Protein (CRP) were analyzed. Results Ninety percent of patients were dyspneic before surgery (mMRC scale ≥ 1) versus 59% after surgery (p