A comparison between the Boussignac^sup (TM)^ continuous positive airway pressure mask and the venturi mask in terms of improvement in the PaO2/F^sub i^O2 ratio in morbidly obese patients undergoing bariatric surgery: a randomized controlled trial

This study compared the Boussignac^sup (TM)^ continuous positive airway pressure (CPAP) mask with the venturi face mask in terms of the postoperative PaO2/F^sub i^O2 (PF) ratio in morbidly obese patients after bariatric surgery. Following hospital Research Ethics Board approval and written informed consent, morbidly obese (body mass index > 35 kg·m^sup -2^) patients undergoing bariatric surgery were recruited. The patients were anesthetized and laparoscopic Roux-en-Y gastric bypass was performed. Patients were assigned randomly to receive either the Boussignac (Boussignac Group) or the venturi face mask (Venturi Group) immediately after tracheal extubation. Patients were transported to the postanesthesia care unit, and the respective devices were applied for one hour. The PF ratio was recorded after tracheal intubation and at one hour and two hours post extubation. The percent forced expiratory volume (%FEV^sub 1^) and the percent forced vital capacity (%FVC) were recorded preoperatively and at one hour and two hours post extubation. Independent Student's t tests were used for continuous variables, and the Chi square test was used for categorical variables. P < 0.05 was considered statistically significant. Eighty-one patients (Group Boussignac, n = 43; Group Venturi, n = 38) completed the study. Mean ages and body mass indices were similar in the two groups. At one hour post extubation, the PF ratio in the Boussignac Group was 361 (170) compared with 279 (91) in the Venturi Group (P = 0.007), and at two hours post extubation, the PF ratio in the Boussignac Group was 371 (162) compared with 323 (127) in the Venturi Group (P = 0.1). The postoperative %FEV^sub 1^ and %FVC were comparable in both groups at all time points. Compared with the venturi mask, the Boussignac CPAP mask improves the postoperative PF ratio in morbidly obese patients after bariatric surgery. The postoperative %FEV^sub 1^ and %FVC are comparable for both groups.[PUBLICATION ABSTRACT]