Obstructive sleep apnea and pulmonary function in morbid obesity before and after bariatric surgery: a randomized controlled clinical trial

Introduction The aim of the present study was to assess daytime sleepiness, sleep architecture and pulmonary function in patients with morbid obesity before and after bariatric surgery. Materials and methods Patients were divided into a bariatric surgery group and control group. The clinical evaluation was performed at the Sleep Laboratory of the Universidade Nove de Julho (Sao Paulo, Brazil) and consisted of the collection of clinical data, weight, height, body mass index (BMI), measurements of neck and abdomen circumferences, spirometry, respiratory pressure measurements, full standard polysomnography (PSG) and the administration of the Berlin Questionnaire and Epworth Sleepiness Scale. Results Fifty-two patients participated in the study and underwent PSG, 16 of whom also underwent bariatric surgery. Following surgery, mean BMI decreased from 48.15  ±  8.58 to 36.91  ±  6.67 kg/m 2 . Significant differences were found between the preoperative and postoperative periods regarding neck and waist circumference ( p p p  = 0.002 and p  = 0.004) and maximum expiratory pressure ( p  = 0.001 and p  = 0.002) for women and men, respectively, as well as sleep stage N3 ( p 0.001), REM sleep ( p  = 0.049) and the apnea–hypopnea index ( p  = 0.008) Conclusion Bariatric surgery effectively reduces neck and waist circumference, increases maximum respiratory pressures, enhances sleep architecture and reduces respiratory sleep disorders, specifically obstructive sleep apnea, in patients with morbid obesity. Acknowledgements The Sleep Laboratory receives funding from the Universidade Nove de Julho (Brazil) and research projects approved by the Brazilian fostering agencies Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq) and Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP). LVFO received a grant from CNPq (Research Productivity modality - PQID, process number 307618/2010–2).