The influence of biphasic positive airway pressure vs. sham biphasic positive airway pressure on pulmonary function in morbidly obese patients after bariatric surgery

Background
The effect of biphasic positive airway pressure (BPAP) at individualized pressures on the postoperative pulmonary recovery of morbidly obese patients (MOP) undergoing open bariatric surgery (OBS) and possible placebo device-related effects (sham BPAP) were investigated.

Methods
Forty-eight MOP scheduled for OBS were initially enrolled. Subjects were randomly assigned to: A) the BPAP group in which BPAP, at individualized inspiratory positive airway pressure/expiratory positive airway pressure (IPAP/EPAP), was applied for 3 days postoperatively and B) the sham BPAP group in which sham BPAP was applied for the same time. Pulmonary function was assessed by spirometry 24 h prior to surgery and at 24, 48 and 72 h postoperatively and respiratory complications were recorded.

Results
Thirty-five subjects, 21 in the BPAP group and 14 in the sham BPAP group, completed the study. Baseline characteristics and pulmonary function were similar between groups preoperatively. Subjects in the BPAP group showed in general better spirometric performance and SpO2 values postoperatively and expedited pulmonary recovery. Atelectasis combined with respiratory distress syndrome (RDS) symptoms was observed in 21% of subjects in the sham BPAP group and one of these subjects developed lower respiratory tract infection. No respiratory complications were recorded in the BPAP group. Use of higher BPAP pressures was not associated with anastomosis leakage or disruption in any patient.

Conclusion
Use of BPAP, at individualized pressures, expedites postoperative pulmonary recovery and eliminates respiratory complications in MOP who have undergone OBS.