Mortality predicted by preinduction cerebral oxygen saturation after cardiac operation

Area of Science:

• Cardiovascular Surgery
• Neuroanesthesia
• Critical Care Medicine

Background:

• Intraoperative decline in regional cerebral oxygen saturation (rSO2) is linked to central nervous system injury.
• Individual variations in cerebral oxygen saturation limit its clinical monitoring utility.
• Low preoperative rSO2 is a potential predictor of adverse outcomes in cardiac operations.

Purpose of the Study:

• To compare the sensitivity and specificity of preinduction rSO2 as a predictor of adverse operative events.
• To compare preinduction rSO2's predictive accuracy against the Society for Thoracic Surgeons (STS) risk index.

Main Methods:

• Included 2,097 white patients undergoing cardiac operations (2010-2012).
• Group 1 (1,496 patients) had preinduction rSO2 ≥ 60%; Group 2 (601 patients) had rSO2 < 60%.
• Compared predictive accuracy using statistical techniques, including receiver operating characteristic (ROC) curve analysis.

Main Results:

• Patients with rSO2 < 60% had significantly higher STS mortality risk scores (4.0 vs 2.0, p<0.001).
• Lower rSO2 (< 60%) was associated with higher operative mortality and identified as an independent predictor (p<0.001).
• ROC analysis showed rSO2 (AUC: 0.71) was slightly less accurate than STS score (AUC: 0.85) for mortality prediction.

Conclusions:

• Preinduction rSO2 measurement is less complex than STS score calculation.
• rSO2 is only slightly less accurate than the STS score in predicting operative mortality.
• rSO2 may be a valuable tool when STS score calculation is not feasible.