Glucose Homeostasis (14)

Similar results were found by Sebel et al with hypothermic CPB. Yokota et al observed decreased plasma GH levels during hypothermic CPB but GH peaks preceded and followed CPB. Differences in anesthetic and perfusion techniques may account for these differences.
In the present study, epinephrine and norepinephrine levels did not increase before CPB, probably due to high-dose fentanyl anesthesia. During and after CPB, these catecholamines increased in both groups. However, normothermic CPB was accompanied by higher levels than during hypothermic CPB. This difference was not observed in a previous study, possibly because a lower fentanyl dose was used. Our data are in agreement with Chemow et al who showed that anesthetized baboons during non-CPB hypothermia over 33°C presented with increased catecholamines, but that catecholamines declined between 31° and 29°C. A similar evolution was observed during hypothermic CPB.
During rewarming after hypothermic CPB, a 28 percent increase in blood glucose was accompanied by a 374 percent increase in insulin level. This suggests an insulin resistance with an insulin/blood glucose ratio of 10.2 vs 5.1 in the normothermic group. It may be partly explained by concomitant increases in norepinephrine, glucagon and cortisol levels by 20, 58 and 34 percent, respectively. A fivefold reduction in glucose utilization also suggested an insulin resistance in a previous study.