Intraoperative cerebral oxygen desaturation is significantly associated with an increased risk of cognitive decline and prolonged hospital stay after CABG, according to a study in this month’s Annals of Thoracic Surgery.
Previous studies have reported an 11 to 75 percent incidence of postoperative cognitive decline among cardiac surgery patients. Using the Invos Cerebral Oximeter from Somanetics in Troy, Mich., to measure regional cerebral oxygen (rSO 2), the study’s authors examined whether decreased rSO2 predicts cognitive decline and prolonged hospital stay after CABG.
James P. Slater, MD, from the department of cardiac surgery at the Morristown Memorial and Gagnon Heart Hospital in Morristown, N.J., and colleagues said that the rSO 2 was monitored intraoperatively in a cohort of primary CABG patients. The patients were prospectively randomized patients to a blinded control group or an unblinded intervention group.
The researchers assessed cognitive function preoperatively, postoperatively and at three 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 rSO 2 desaturation score was calculated by multiplying rSO 2 below 50 percent by 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.
Slater and colleagues found a greater than two-fold increase in the odds of developing cognitive decline in patients who exceeded his cerebral de-oxygenation formula. Similarly, these patients experienced a nearly three-fold increase in the risk of having a longer hospital stay (greater than six days).