Cerebral oxygenation and cognitive decline

Slow rewarming has no effects on the decrease in jugular venous oxygen hemoglobin saturation and long-term cognitive outcome in diabetic patients

The purpose of this study was to examine the effects of rewarming rate on internal jugular venous oxygen hemoglobin saturation (SjvO(2)) during the rewarming period, and long-term cognitive outcome in diabetic patients. We studied 30 diabetic patients scheduled for elective coronary artery bypass graft surgery. As a control, 30 age-matched nondiabetic patients were identified. The diabetic patients were randomly divided into two groups: the Slow Rewarming group (n = 15) (mean rewarming speed: 0.22 degrees +/- 0.07 degrees C/min, mean +/- SD) or the Standard Rewarming group (Standard group) (n = 15) (mean rewarming speed: 0.46 degrees +/- 0.09 degrees C/min, mean +/- SD). After the induction of anesthesia, a fiberoptic oximetry catheter was inserted into the right jugular bulb to monitor SjvO(2) continuously. Hemodynamic variables and arterial and jugular venous blood gases were measured at nine time points. All patients underwent a battery of neurologic and neuropsychologic tests on the day before the operation and at 4 mo after surgery. The SjvO(2) values in the Standard group were decreased during the rewarming period compared with at the induction of anesthesia (P < 0.05). There was a significant difference in the SjvO(2) value in the Control group between standard rewarming and slow rewarming during rewarming periods (Standard Control group: 51% +/- 8%, Slow Control groups: 58% +/- 5%) (P < 0.05). However, there was no difference in the SjvO(2) value in diabetic patients between standard rewarming and slow rewarming during the rewarming period. The rewarming rates (odds ratio: 0.8; 95% confidence interval: 0.5-1.3; P = 0.6) had no correlation with cognitive impairment at 4 mo after the surgery. Diabetes (odds ratio: 1.6; 95% confidence interval: 0.9-2.6; P = 0.04) was a factor in relation to cognitive impairment at 4 mo after the surgery. We concluded that a slow rewarming rate had no effects on the reduction in SjvO(2) value and long-term cognitive outcome in diabetic patients.

IMPLICATIONS

We examined the effects of rewarming rate on internal jugular venous oxygen hemoglobin saturation in diabetic and nondiabetic patients during the rewarming period and long-term cognitive outcome. Slow rewarming could not prevent the frequency of the reduction in internal jugular venous oxygen hemoglobin saturation and adverse cognitive outcome in diabetic patients.