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Intra-operative high inspired oxygen fraction does not increase the risk of postoperative respiratory complications

Alternating intervention clinical trial

Cohen, Barak*; Ruetzler, Kurt*; Kurz, Andrea; Leung, Steve; Rivas, Eva; Ezell, Jacob; Mao, Guangmei; Sessler, Daniel I.; Turan, Alparslan

European Journal of Anaesthesiology (EJA): May 2019 - Volume 36 - Issue 5 - p 320–326
doi: 10.1097/EJA.0000000000000980

BACKGROUND The WHO recommends routine intra-operative and early postoperative use of high inspired oxygen concentrations (hyperoxia). However, a high intra-operative inspired oxygen fraction (FiO2) might result in an increased risk of postoperative respiratory complications.

AIM To test the hypothesis that intra-operative FiO2 of 80% compared with 30% inspired oxygen decreases the postoperative ratio of arterial saturation to fraction of inspired oxygen (SpO2/FiO2). Secondarily, to evaluate whether an intra-operative inspired FiO2 of 80% increases the incidence of pulmonary complications.

DESIGN Posthoc subanalysis of a large alternating cohort trial.

SETTING Cleveland Clinic, Cleveland, United States, from 2013 to 2016.

PATIENTS Adults having colorectal surgery. Cases lasting less than 2 h, re-operations on the same hospitalisation, and cases with missing intra-operative or postoperative data were excluded.

INTERVENTION Maintaining intra-operative FiO2 at 30 or 80% and alternating this management every 2 weeks for a study period of 39 months.

MAIN OUTCOME Minimal SpO2/FiO2 ratio value in the postanaesthesia care unit. Secondary outcome was a composite of postoperative pulmonary complications throughout hospitalisation.

RESULTS A total of 5056 patients were included. Groups were well balanced on all demographic, baseline and procedural variables. Median time-weighted averages of intra-operative FiO2 in the 30 and 80% groups were 43% (IQR 38 to 54%, N=2486) and 81% (IQR 78 to 82%, N=2570), respectively. No difference was found in the lowest SpO2/FiO2 ratio (estimated median difference 0 [95% confidence interval: 0, 0], P = 0.91). The incidence of postoperative pulmonary complications was 16.3 and 17.6% in the 30 and 80% FiO2 groups, respectively (relative risk 1.07 [95% confidence interval: 0.95, 1.21], P = 0.25).

CONCLUSION Intra-operative hyperoxia did not change the postoperative SpO2/FiO2 ratio or the risk for pulmonary complications. Clinicians should not refrain from using hyperoxia for fear of provoking respiratory complications.

TRIAL REGISTRATION identifier: NCT01777568.

From the Department of Outcomes Research, Anesthesiology Institute, Cleveland Clinic, Cleveland, Ohio, USA (BC, KR, AK, SL, ER, DIS, AT), Division of Anesthesia, Critical Care and Pain Management, Tel-Aviv Medical Center, Sackler Faculty of Medicine, Tel-Aviv University, Tel Aviv, Israel (BC), Department of General Anesthesia, Anesthesiology Institute (KR, AK, JE, AT), Department of Anesthesia Hospital Clinic of Barcelona, IDIBAPS, Universidad de Barcelona, Spain (ER), Department of Diagnostic Radiology, Metrohealth Hospital, Case Western Reserve University, Cleveland, Ohio (SL) and Department of Quantitative Health Sciences, Cleveland Clinic, Cleveland, Ohio, USA (GM)

Correspondence to Alparslan Turan, MD, Department of Outcomes Research, Anesthesiology Institute, Cleveland Clinic, 9500 Euclid Ave P77, Cleveland, OH 44195, USA Tel: +1 216 445 9857; fax: +1 216 444 6135; e-mail:

Published online 8 March 2019

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© 2019 European Society of Anaesthesiology