Association between tissue oxygenation and myocardial injury in patients undergoing major spine surgery: a prospective cohort study

OBJECTIVE: To describe the association between intraoperative tissue oxygenation and postoperative troponin elevation in patients undergoing major spine surgery. We hypothesised that a decrease in intraoperative skeletal muscle tissue oxygenation (SmO(2)) was associated with the peak postoperative cardiac troponin value. DESIGN: This is a prospective cohort study. SETTING: Single-centre, University of California San Francisco Medical Center. PARTICIPANTS: Seventy adult patients undergoing major elective spine surgery. PRIMARY AND SECONDARY OUTCOME MEASURES: High-sensitivity troponin T (hsTnT) was measured in plasma preoperatively and on the first and second day after surgery to assess the primary outcome of peak postoperative hsTnT. Secondary outcomes included MINS and intensive care unit (ICU) admission within 30 days. Skeletal cerebral tissue oxygenation and SmO(2) was measured continuously with near-infrared spectroscopy during surgery. The primary exposure variable was time-weighted area under the curve (TW AUC) for SmO(2). RESULTS: Mean age was 65 (33–85) years and 59% were female. No significant association was found between TW AUC for SmO(2) and peak hsTnT (Spearman’s correlation, r(s)=0.17, p=0.16). A total of 28 (40%) patients had MINS. ICU admission occurred in 14 (40%) in lower vs 25 (71%) in upper half of patients based on TW AUC for SmO(2), p=0.008. CONCLUSIONS: Decrease in SmO(2) was not a statistically significant predictor for peak troponin value following major spine surgery but is a potential predictor for other postoperative complications. TRIAL REGISTRATION NUMBER: NCT03518372.