Effects of exogenous intravenous glucose on plasma glucose and lipid homeostasis in anesthetized infants.

Background: Whether intravenous glucose administration to infants during anesthesia is necessary remains to be resolved. The current study was designed to investigate the effect of exogenous glucose infusion on plasma glucose and lipid homeostasis in infants undergoing minor surgery.

Methods: Sixty infants (inpatients, ASA physical status 1) between 1 and 11 months of age were divided randomly into three groups as follows: LR group, lactated Ringer's solution (LR) alone; D2LR group, 2% glucose in LR; and D5LR group, 5% glucose in LR. Anesthesia was induced and maintained with halothane and nitrous oxide in oxygen. All fluids were infused at a rate of 6 ml.kg-1.h-1 until 1 h after surgery. Plasma concentrations of glucose, nonesterified fatty acids, ketone bodies, insulin, and cortisol were determined at induction of anesthesia, at the end of surgery, and 1 h after surgery.

Results: No infants in the three groups had hypoglycemia (< 50 mg.dl-1) throughout the study. In the LR group, plasma glucose concentration remained unchanged perioperatively compared with the basal values (at induction), whereas in the D2LR group, it increased during surgery but remained normoglycemic. In the D5LR group, plasma glucose concentration increased markedly both during and after surgery. In 6 of 20 infants, plasma glucose was greater than 200 mg.dl-1 at the end of surgery. In 8 of 20 infants receiving glucose-free infusion, plasma glucose concentrations decreased at the end of surgery. In contrast, the plasma glucose concentration increased in infants receiving glucose infusion. In the LR group, plasma concentrations of nonesterified fatty acids and ketone bodies increased at the end of and after surgery, suggesting lipid mobilization. The base excess decreased in the LR groups as concentration of the ketone bodies increased. Plasma insulin concentrations increased in the D2LR and D5LR groups and decreased after surgery in infants receiving a glucose-free solution. No intergroup differences in plasma cortisol concentrations existed at any sample point.

Conclusions: These data indicate that, in otherwise healthy infants undergoing minor surgery, intravenous infusion of 2% glucose may be sufficient to maintain plasma glucose concentrations within physiologic ranges and to prevent a compensatory increase in lipid mobilization (lipolysis) when fluids are infused at a rate of 6 ml.kg-1.h-1. However, there are limitations in extrapolating the results to neonates.