Effect of continuous positive airway pressure on umbilical artery pH during scheduled cesarean delivery in individuals with class III obesity: A randomized controlled trial

Abstract Objective To evaluate the effect of continuous positive airway pressure (CPAP) on umbilical artery pH when utilized intraoperatively during scheduled cesarean delivery in individuals with class III obesity, defined as a body mass index (BMI) ≥ 40 kg/m 2 . Study design This was a randomized controlled study of individuals with class III obesity and singleton pregnancy who underwent scheduled cesarean delivery. Subjects were randomized to receive the institutional standard of care consisting of oxygen 2 liters per minute (L/min) via nasal cannula or CPAP containing oxygen supplementation of 2 L/min during cesarean delivery. The primary outcome was umbilical artery pH. Secondary outcomes included umbilical venous blood gas values, maternal venous blood gas values, neonatal and maternal outcomes, intraoperative parameters, and maternal satisfaction. Results Of 65 subjects, 33 were randomized to CPAP and 32 to oxygen 2 L/min via nasal cannula. A total of 12 participants in the CPAP group were unable to tolerate the device for the planned duration and subsequently received 2 L/min of oxygen via nasal cannula. Modified intention to treat analysis showed no difference in the mean umbilical arterial pH between the CPAP and routine management groups (7.18 vs. 7.19; p = 0.61). Similarly, there was no difference in the proportion of arterial pH < 7.1 between the CPAP and routine management groups (12.1% vs. 12.1%; p = 1.00). There was no difference in other secondary outcomes. Conclusion Compared to routine oxygen supplementation, CPAP was not associated with improved umbilical artery pH in individuals with class III obesity undergoing scheduled cesarean delivery. Trial Registration ClinicalTrials.gov Identifier: NCT04993651