High-flow nasal cannula oxygenation reduces postoperative hypoxemia in morbidly obese patients: a randomized controlled trial.

Postoperative pulmonary complications (PPCs) are common in high-risk surgical patients. Postoperative ventilatory management may improve their outcomes. Supplemental oxygen through a high-flow nasal cannula (HFNC) has become an alternative to classical oxygenation techniques, although the results published for postoperative patients are contradictory. We examined the efficacy of HFNC in postoperative morbidly obese patients who were ventilated intraoperatively with an open-lung approach (OLA).We performed an open, two-arm, randomized controlled trial in 64 patients undergoing bariatric surgery (N=32 in each arm) from May to November 2017 at the Hospital Clínico of Valencia. Patients were randomly assigned to receive HFNC oxygen therapy at the time of extubation or to receive conventional oxygen therapy, both applied during the first three postoperative hours. Intraoperatively, a recruitment maneuver and individualized positive end-expiratory pressure was applied in all patients. The primary outcome was postoperative hypoxemia.All patients were included in the final analysis. There were no significant differences between the baseline characteristics in either group. Postoperative hypoxemia was less frequent in the HFNC group compared to those who received standard care (28.6% vs. 80.0%, relative risk [RR]: 0.35; 95%CI: 0.150-0.849, p=0.009). Prevalence of atelectasis was lower in the HFNC group (31 vs. 77%, RR: 0.39; 95%CI: 0.166-0.925, p=0.013). No severe PPCs were reported in any patient.Early application of HFNC in the operating room before extubation and during the immediate postoperative period decreases postoperative hypoxemia in obese patients after bariatric surgery who were intraoperatively ventilated using an OLA approach.