Association between baseline cerebral oxygenation and postoperative outcomes in older noncardiac surgical patients: An exploratory observational study

Abstract

Background

Universal risk assessment strategies are needed to enhance perioperative care, especially for vulnerable patients at increased risk for adverse postoperative outcomes. Lower baseline regional cerebral oxygen saturation (rSO₂) was previously associated with increased mortality in cardiac surgical patients. We hypothesised that lower baseline rSO₂ could be a surrogate of increased vulnerability to adverse postoperative outcomes in older noncardiac surgical patients.

Methods

We conducted an exploratory secondary analysis of a prospective observational cohort study. Patients over 65 years scheduled for elective noncardiac surgery between 2017 and 2019 were included. Unilateral baseline rSO₂ was measured upon admission to the surgical ward. Our primary outcomes were morbidity and mortality rates within 30 days of the surgical procedure.

Results

Among 254 analysed patients (median [25th percentile, 75th percentile] age 73 [68, 78], 65 % males), 17 (7 %) were readmitted to the hospital within 30 days after surgery, and five died in this period (2 %). Baseline rSO₂ values were significantly associated with readmission (mean (SD), 58 (10) vs 65 (8), P = 0.003) and mortality (mean (SD), 51 (15) vs 64 (8), P < 0.001). Mortality prediction based on baseline rSO₂ revealed an AUC of 0.801 (p = 0.021).

Conclusions

The utility of baseline rSO₂ as a biomarker of adverse postoperative outcomes can potentially extend to noncardiac surgical patients, especially for older populations.