Oxygen concentration during surgery: not helpful for postoperative nausea and vomiting

NEW ORLEANS – There is no benefit to giving patients supplemental oxygen during surgery to reduce postoperative nausea and vomiting (PONV), according to a post hoc analysis of a randomized trial.

Multiple crossover cluster trial with 8 separate operating rooms randomized to 80% and 30% inspired oxygen fractions every 2 weeks for 3 years. David Sessler, MD, of the Cleveland Clinic, reported that PONV did not improve in the first 24 hours after noncardiac surgery during 80% of intraoperative oxygen.

At 80% and in a presentation he gave at the American Society of Anesthesiologists (ASA) annual meeting, inhaling 30% oxygen, “absolutely made no difference. This [trial] did not Underpowered. This is the most negative result you can get.” An ASA session presenter noted that the manuscript has been accepted for publication by Anesthesiology.

PONV is one of the most common complications of surgery, occurring in approximately 30% of the general population. Guidelines recommend that all patients receive PONV prophylaxis in the perioperative period. Clinicians were instructed to use less opioids in the perioperative period, opt for regional anesthesia and propofol infusion, avoid the use of volatile anesthetics, and maintain adequate hydration for patients undergoing same-day surgery.

In theory, intraoperative oxygen supplementation should help, as hypoxia is thought to promote PONV: surgery creates physiological stress, and cells with high metabolic demands are tolerant of hypoxia Sex is poor.

However, Sessler’s group found not only in PONV but other results such as:

• Initial Antiemetic Administration Time
• Antiemetic Dose
• PONV severity reported by patients in the post-anesthesia care unit

when the study was included in a Results were consistent when a meta-analysis of 10 trials with a total of 6,773 patients was included. Overall, supplemental oxygen had no beneficial effect on PONV (RR 0.97, 95% CI 0.86-1.08) or antiemetic dose (RR 0.92, 95% CI 0.79-1.09), Sessler noted.

His group conducted a post hoc sub-analysis of an earlier randomized trial that found supplemental oxygen did not help prevent infection after colorectal surgery. Other studies have shown that 80% oxygen does not reduce atelectasis, lung complications or long-term mortality.

“So we concluded that any oxygen level between 30% and 80% would do. Use whatever you want,” Sessler said.

Study patients were adults who had undergone colorectal surgery for at least 2 hours with general endotracheal anesthesia and who had spent at least one night in the hospital. Of the 5,749 persons registered in 2013-2016, 5,167 persons with sufficient PONV data were included in this analysis.

The mean age of the cohort was 52 years, and approximately half were male. Surgery lasted an average of 4 hours, and most patients had an Apfel risk score of 2 or 3.

Only about 3% of participants received preoperative antiemetics, while almost all received intraoperatively. Nearly all patients received postoperative opioid therapy.

Sessler cautions that the study was not randomized, which leaves room for bias. Furthermore, some PONV variables, such as the number of episodes, were missing from the dataset.



Nicole Lou is a reporter for MedPage Today covering cardiology news and other medical developments. Follow