Effect of high-flow nasal oxygen on postoperative oxygenation in obese patients: A randomized controlled trial.

Background And Aim: Postoperative hypoxemia is common after general anesthesia in obese patients. We investigated if early application of high-flow nasal oxygen (HFNO) improved postoperative oxygenation in obese patients compared with standard oxygen therapy following general anesthesia for laparoscopic bariatric surgery.

Methods: This was an open labeled randomized controlled trial conducted at a university hospital in Sweden between October 23, 2018 and February 11, 2020. The study was performed as a substudy within a previously published trial. After ethics committee approval and written informed consent, 40 obese patients (body mass index [BMI] ≥ 35 kg m) scheduled for laparoscopic bariatric surgery were randomized to receive oxygen using a standard low-flow nasal cannula (NC group) or HFNO at 40 L min (HF group) immediately upon arrival to the post-anesthesia care unit. Flow rate (NC group) or FiO (HF group) was titrated to reach an initial SpO of 95%-98% after which settings were left unchanged. The primary outcome was PaO at 60 min following postoperative baseline values. Secondary outcomes included PaCO, SpO, hemodynamic variables, and patient self-assessed discomfort.

Results: Thirty-four patients were available for analysis. PaO was similar between groups at postoperative baseline. After 60 min, PaO had increased to 12.6 ± 2.8 kPa in the NC group ( = 15) and 14.0 ± 2.7 kPa in the HF group ( = 19); (mean difference 1.4 kPa, 95% confidence interval -0.6 to 3.3;  = 0.16). There were no differences in PaCO, hemodynamic variables, or self-assessed discomfort between groups after 60 min.

Conclusion: In obese patients, HFNO did not improve postoperative short-term oxygenation compared with standard low-flow oxygen following general anesthesia for laparoscopic bariatric surgery.