Elevated blood glucose is associated with poor outcome in the carbon-monoxide-poisoned rat

Levine-prepared, unanesthetized rats exposed to 2400 and 2700 ppm carbon monoxide (CO) for 90 min were used to examine the effect of acute CO poisoning on plasma glucose and insulin concentrations, and neurologic dysfunction. Body temperature and mean arterial blood pressure fell progressively during CO exposure. Glucose rose during initial CO exposure, then declined: glucose increased again after 2 h of room air recovery. Neurologic deficit, behaviorally-assessed after 4 h of recovery, was strongly correlated (r = 0.71, P less than 0.001) with glucose increase during the first 2 h of recovery. Recovery hyperglycemia was, in turn, correlated (r = 0.69, P less than 0.001) with the fall in glucose during the second half of CO exposure. Neurologic deficit was also correlated, but less strongly so, with hypoglycemia during CO exposure. Failure to rapidly regain body temperature during recovery was correlated with the post-CO rise in glucose concentration and with increased neurologic deficit. Plasma insulin activity was depressed immediately following CO exposure, and increased during recovery. CO-induced hypothermia was greater at 2700 than at 2400 ppm CO, as were post-CO recovery hyperglycemia, neurologic deficit and mortality, while body temperature recovery was less complete. The results provide evidence of an association between neurologic deficit and general morbidity following acute CO poisoning and the magnitude of post-CO hyperglycemia.