Clinical Evidence

Cerebral Oxygen Desaturation Predicts Cognitive Decline and Longer Hospital Stay After Cardiac Surgery

Slater JP1, Guarino T, Stack J, Vinod K, Bustami RT, Brown JM 3rd, Rodriguez AL, Magovern CJ, Zaubler T, Freundlich K, Parr GV.



Previous studies have reported an 11% to 75% incidence of postoperative cognitive decline among cardiac surgery patients. The INVOS Cerebral Oximeter (Somanetics Corp, Troy, MI) is a Food and Drug Administration approved device that measures regional cerebral oxygen (rSO2) saturation. The purpose of this study is to examine whether decreased rSO2 predicts cognitive decline and prolonged hospital stay after coronary artery bypass grafting (CABG).


The rSO2 was monitored intraoperatively in a cohort of primary CABG patients. Patients were prospectively randomized to a blinded control group or an unblinded intervention group. Cognitive function was assessed preoperatively, postoperatively, and at 3 months using a battery of standardized neurocognitive tests. Cognitive decline was defined as a decrease of one standard deviation or more in performance on at least one neurocognitive measure. The rSO2 desaturation score was calculated by multiplyingrSO2 below 50% by time (seconds). Multivariate logistic regression models were used to assess cognitive decline and hospital stay. The change in cognitive performance was also assessed using a multivariate linear regression model.


Patients with rSO2 desaturation score greater than 3,000%-second had a significantly higher risk of early postoperative cognitive decline [p = 0.024]. Patients with rSO2 desaturation score greater than 3,000%-second also had a near threefold increased risk of prolonged hospital stay (>6 days) [p = 0.007].


Intraoperative cerebral oxygen desaturation is significantly associated with an increased risk of cognitive decline and prolonged hospital stay after CABG.

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