Effects of Preoperative Respiratory Physical Therapy on Postoperative Respiratory Function After Bariatric Surgery

Background. Morbidly obese patients show an increased risk of hypoxemia and a higher incidence of postoperative pulmonary complications during the postoperative period resulting in prolonged hospital length of stay when compared with normal weight subjects. Preoperative respiratory physiotherapy including inspiratory muscle training (IMT) has been shown to reduce the incidence of post operative respiratory complications in some different settings. Objective. To determine wether a program of preoperative respiratory physical therapy could reduce the incidence and severity of postoperative hypoxemia in morbidly obese patients undergoing laparoscopic bariatric surgery. Setting. Hospital Clínico Universitario, Valencia, Spain. Design and Patients. A double-blind, randomized clinical trial. 50 patients (BMI≥40%) consecutively scheduled for laparoscopic bariatric surgery were included of whom 44 completed the study. Sample size was calculated using the repeated measures of the PaO2/FiO2 ratio along the postoperative period as the primary endpoint and considering an effect size of 0.25. Interventions. Patients were randomly assigned to receive either preoperative respiratory physical therapy (n=23) or usual care (n=21) during a month just before the date of surgery. Both groups received the same postoperative physical therapy. Measures. Data on oxygenation (primary outcome, PaO2/Fio2 ratio) were obtained at 1hour and at 12 hours after surgery. Data on spirometry and maximum static respiratory pressures (secondary outcomes) were obtained before and after the training period, and in the postoperative period.