Noninvasive ventilation in the immediate postoperative of gastrojejunal derivation with Roux-en-Y gastric bypass

Background: Morbidly obese patients develop more atelectasis during general anesthesia than non-obese ones, and these atelectasis persist for 24 hours after the end of the surgical procedure. Objectives: This study evaluated the effect of noninvasive ventilation with two pressure levels (BiPAP) in the pulmonary function, incidence of immediate postoperative pulmonary complications and the development of anastomotic dehiscence in morbid obese patients submitted to gastrojejunal derivation in Roux-en-Y (RYGB). Methods: It was an analytical and clinical study involving patients who were submitted to RYGB, had a body mass index (BMI) of at least 35 kg/cm(2), and were randomly chosen to receive BiPAP (experimental group) or standard oxygen therapy (control group), in the first four hours of the post-operation period. Patients with chronic or acute pulmonary disease were not included, and neither were the ones who needed invasive mechanical ventilation by the end of the surgery. Vital capacity, maximal inspiratory and expiratory pressure, and arterial blood gases were measured in the preoperative and in the first postoperative. Chest X-ray was performed in the third postoperative. Results: Eighteen patients were chosen for the study: ten received BiPAP and eight received standard oxygen therapy. The study group had better partial oxygen pressure and lower maximal expiratory pressure levels in the postoperative state than the control group. Anastomotic dehiscence was not observed in any group. There was no significant difference between the control group and the study group relating to the loss of vital capacity, maximal inspiratory pressure in the postoperative period or the incidence of atelectasis. Conclusion: The BiPAP in the postoperative period of gastroplasty was useful to improve oxygenation and did not increase the incidence of anastomotic dehiscence. Article registered in the Australian New Zealand Clinical Trials Registry under the number ACTRN12609000979257.