Intraoperative blood glucose levels in neurosurgical patients : an evaluation of two fluid regimens.

ABSTRACT

Based on the evidence that hyperglycaemia aggravates ischaemic cerebral injury, it has been suggested that blood glucose levels be kept within 200 mg/dL during intracranial neurosurgery. Hypoglycaemia, however, can be a serious problem if glucose-containing solutions are avoided during the first four hours, as suggested in some studies. In order to explore the possibility of administering glucose in moderation so that the blood glucose levels are within acceptable limits, but at the same time the risk of hyoglycaemia is eliminated, we compared two intraoperative fluid regimens. Of the 52 neurosurgical patients studied, 32 patients received alternately 500 ml of 5% dextrose in normal saline and Ringer's lactate (DNS/RL Group) and 18 patients received alternately 500 ml of Ringer's lactate and normal saline (RL/NS Group). Blood glucose concentrations were determined at the end of each unit of fluid, until the patient received 4 units of fluid. In the DNS/RL group, blood glucose values peaked with the administration of each unit of DNS and tended to return towards the baseline with the subsequent RL, but remained higher than the previous control value. In the RL/NS group, there was a progressive increase in blood glucose values throughout the study period, but the increase was not statistically significant. The blood glucose levels were significantly different between the two groups after each unit of fluid except at the end of the fourth unit. Two patients in the RL/NS group had hypoglycaemia. In conclusion, the DNS/RL regimen maintains blood glucose levels within acceptable limits while avoiding the risk of hyperglycaemia. Withholding glucose completely, lowers blood glucose levels, but carries a risk of hypoglycaemia in some patients.