Effects of perioperative oxygen concentration on oxidative stress in adult surgical patients: a systematic review

BackgroundThe fraction of inspired oxygen (FiO2) administered during general anaesthesia varies widely despite international recommendations to administer FiO2 0.8 all anaesthetised patients reduce surgical site infections (SSIs). Anaesthetists remain concerned that high administration intraoperatively may increase harm, possibly through increased oxidative damage and inflammation, resulting in more complications worse outcomes. In previous systematic reviews associations between SSIs have been inconsistent, but none examined how affects perioperative stress. We aimed address this uncertainty by reviewing the available literature.MethodsEMBASE, MEDLINE, Cochrane databases were searched from inception March 9, 2020 for RCTs comparing higher with lower quantifying stress adults undergoing noncardiac surgery. Candidate studies independently screened two reviewers references hand-searched. Methodological quality was assessed using Collaboration Risk Bias tool.ResultsFrom 19 438 initial results, seven trials (n=422) included. Four reported markers Caesarean section (n=328) three elective colon surgery (n=94). bias low (four studies) moderate (three studies). Pooled results suggested associated greater malondialdehyde, protein-carbonyl concentrations reduced xanthine oxidase concentrations, together antioxidant such as superoxide dismutase total sulfhydryl levels although status unchanged.ConclusionsHigher be elevated However, limited specifically biomarkers oxidation. Given current clinical controversy concerning therapy, further research is urgently needed area.