Bilevel positive airway pressure in two moments after bariatric surgery.

OBJECTIVE: To investigate the use of Bilevel Positive Airway Pressure (BiPAP) in morbidly obese individuals in two moments following bariatric surgery (Roux-en-Y gastric bypass): post-anesthetic recovery (PAR) and first postoperative day (1PO). DESIGN: Randomized and blinded clinical trial. METHODS: We studied 40 morbidly obese individuals aged between 25 and 55 years who underwent pulmonary function test and chest X-ray preoperatively, and on the day of discharge (2nd day after surgery). They were randomly allocated into two groups: PAR-G (BiPAP in PAR for one hour), and 1PO-G (BIPAP for one hour on the 1PO). RESULTS: In the PAR-G and 1PO-G, respectively there were significant reductions in slow vital capacity (SVC) (p=0.0007 vs. p<0.0001), inspiratory reserve volume (IRV) (p=0.0016 vs. p=0.0026), and forced vital capacity (FVC) (p=0.0013 vs. p<0.0001) and expiratory reserve volume (ERV) was maintained only for the PAR-G (p=0.4446 vs. p=0.0191). Comparing the groups, the SVC (p=0.0027) and FVC (p=0.0028) showed a significant difference between the treatments, while the PAR-G showed smaller declines in these capacities. The prevalence of atelectasis was 10% for the PAR-G and 30% for the 1PO-G (p=0.0027). CONCLUSION: Thus, the use of BiPAP in PAR can promote restoration of ERV and contribute to the reduction of atelectasis.