Document Type


Publication Date



This article has been peer reviewed. It is the authors' final version prior to publication in Journal of Clinical Anesthesia Volume 22, Issue 7, November 2010, Pages 492-498. The published version is available at DOI: 10.1016/j.jclinane.2009.10.013. Copyright © Elsevier Inc.


Study objective: To assess the efficacy of intraoperative different inspired oxygen fractions (FIO2) of 0.8 and 0.5 when compared with standard FIO2 0.3 in prevention of postoperative nausea and vomiting (PONV).

Design: A prospective, controlled, randomized, double-blind study.

Setting: General hospital, postanesthesia care unit (PACU) and gynecologic floor room. Patients: 120 ASA physical status I and II women, aged 21 to 76 y, undergoing elective gynecologic laparoscopic surgery.

Interventions: Patients were randomized to receive gas mixture of 30% oxygen in air (FI O2=0.3, group G30), 50% oxygen in air (FIO2=0.5, group G50) or 80% oxygen in air (FIO2=0.8, group G80), n=36 in each group. A standardized sevoflurane general anesthesia, postoperative pain management and antiemetic regimen were used.

Measurements: The incidence of nausea, vomiting or both was assessed for early (0-2h) and late PONV (2-24h) along with the use of rescue antiemetic, degree of nausea and severity of pain.

Main results: There was no overall difference in the incidence of PONV at early and late assessment periods among the three groups. Patients in G80 had significantly less vomiting than G30 at 2 hours, 3% (1/36) vs. 22% (8/36), respectively, P=0.028. Nausea scores, rescue antiemetic use, pain scores and opioid consumption were not different among the groups.

Conclusion: High intraoperative FIO2 of 0.8 and FIO2 of 0.5 does not prevent PONV in patients without antiemetic prophylaxis. Intraoperative FIO2 of 0.8 has beneficial effect on early vomiting only.