Intraoperative tissue oxygenation and postoperative outcomes after major non-cardiac surgery: An observational study

BackgroundThe relationship between tissue oxygen saturation () and serious postoperative complications remains unclear. We tested the hypothesis that perioperative in patients undergoing major non-cardiac surgery is inversely related to serious surgical outcomes.MethodsWe enrolled 124 patients, ASA physical status ≤IV, having elective major non-cardiac surgeries with general anaesthesia. An InSpectra Model 650 StO₂ monitor (Hutchinson Technology, Hutchinson, MN, USA) was used to measure at the thenar eminence throughout surgery and for two postoperative hours. Our primary outcome was a composite of 30 day mortality and serious in-hospital complications. The secondary outcome was an a priori subset of the primary composite outcome representing infectious and wound-healing complications. Multivariable logistic regression was used to evaluate the associations between our primary and secondary outcomes and time-weighted average (TWA) and minimum. ResultsPatients were 61 (12), mean (sd) yr old. The minimum was inversely associated with our primary composite outcome (P=0.02). The estimated odds ratio (97.5% CI) of having any major postoperative morbidity was 0.82 (0.67, 1.00) for a 5% increase in the minimum. In contrast, TWA was not significantly associated with major postoperative morbidity (P=0.35). Furthermore, neither TWA (P=0.65) nor minimum (P=0.70) was significantly associated with wound complications. ConclusionsMinimum perioperative peripheral tissue oxygenation predicted a composite of major complications and mortality from major non-cardiac surgery. This is an observational association and whether clinical interventions to augment tissue oxygenation will improve outcomes remains to be determined.