January 2009: Slater, James P., et al. Cerebral Oxygen Desaturation Predicts Cognitive Decline and LongerHospital Stay After Cardiac Surgery. Ann Thorac Surg 2009; 87:36-45.

In the January 2009 Annals, Slater et al looked at postoperative cognitive decline in adult cardiac surgery patients (partially excerpted herein).  The authors note  an 11% to 75% incidence of postoperative cognitive decline among cardiac surgery patients in prior studies. Using the  INVOS Cerebral Oximeter (Somanetics Corp, Troy, MI) to measure regional cerebral oxygen (rSO2) saturation, the group examined whether decreased rSO 2 predicts cognitive decline and prolonged hospital stay after coronary artery bypass grafting(CABG).

The rSO 2 was monitored intraoperatively and patients were randomized to a blinded control group or an unblinded intervention group.Cognitive function was assessed preoperatively, postoperatively, and at 3months 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% by time (seconds). Multivariatelogistic 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 rSO 2 desaturation score greater than3,000%-second had a significantly higher risk of early postoperative cognitive decline [p = 0.024]. Patients with rSO 2 desaturation score greater than3,000%-second also had a near threefold increased risk of prolonged hospital stay (>6 days) [p = 0.007]. The authors concluded that intraoperative cerebral oxygen desaturation is significantly associated with an increased risk of cognitive decline and prolonged hospital stay after CABG.

This paper is part of an increasing body of evidence concerning the utility of intra and postoperative cerebral oxygenation monitoring, using a variety of methodologies. The effect of active intervention for changes in rSO2  merit further study.

Please read the article athttp://ats.ctsnetjournals.org/cgi/content/full/87/1/36 add your comments andexperience in the Dilemmas in Adult Cardiac Surgery Discussion Forum.