Effects of high intraoperative inspired oxygen on postoperative nausea and vomiting in gynecologic laparoscopic surgery ★★★

Study ObjectiveTo assess the efficacy of intraoperative inspired oxygen fractions (FIO2) of 0.8 and 0.5 when compared with standard FIO2 of 0.3 in the prevention of postoperative nausea and vomiting (PONV).DesignProspective, randomized, double-blinded, controlled study.SettingGeneral hospital, postanesthesia care unit (PACU), and gynecology floor room.Patients120 ASA physical status I and II women, aged 21 to 76 years, undergoing elective gynecologic laparoscopic surgery.InterventionsPatients were randomized to receive a gas mixture of 30% oxygen in air (FIO2 = 0.3, Group G30), 50% oxygen in air (FIO2 = 0.5, Group G50), or 80% oxygen in air (FIO2 = 0.8, Group G80); there were 36 patients in each group. A standardized sevoflurane general anesthesia, postoperative pain management, and antiemetic regimen were used.MeasurementsFrequency of nausea, vomiting, and both was assessed for early (0 to two hrs) and late PONV (two to 24 hrs), along with use of rescue antiemetic, degree of nausea, and severity of pain.Main ResultsThere was no overall difference in the frequency of PONV at the early and late assessment periods among the three groups. G80 patients had significantly less vomiting than Group G30 at two hours, 3% (1/36) vs. 22% (8/36), respectively, P = 0.028. Nausea scores, rescue antiemetic use, pain scores, and opioid consumption did not differ among the groups.ConclusionHigh intraoperative FIO2 of 0.8 and FIO2 of 0.5 do not prevent PONV in patients without antiemetic prophylaxis. An intraoperative FIO2 of 0.8 has a beneficial effect on early vomiting only.