Optimal dose and duration of glucose administration during fasting period preceding surgery in rabbits

We examined preoperative glucose administration to establish what dose and cutoff point were optimal for suppression of lipolysis and prevention of hypo- or hyperglycemia.

Rabbits were preoperatively fasted and simultaneously received glucose at a constant rate of 0, 0.1, 0.2, 0.3, or 0.4 g.kg(-1).h(-1) in fluid infusion for 3 h. Plasma glucose, immunoreactive insulin activity, nonesterified fatty acids, and ketone bodies were measured 0, 1.5, 3 and 4 h after the start of infusion, and hepatic glycogen content was assessed 1 h after cessation of infusion.

Fluid infusion without glucose decreased plasma glucose. Glucose administration at more than 0.2 g.kg(-1).h(-1) caused hyperglycemia (>200 mg.dl(-1)) in the infusion period; the differences were significant compared with the value at zero time or in the 0 g.kg(-1).h(-1) group (P < 0.01). The highest dose also raised plasma immunoreactive insulin activity, which was significantly higher than in the 0 g.kg(-1).h(-1) group (P < 0.01) at the midpoint of the infusion period. Plasma nonesterified fatty acids increased in all groups. The changes were, however, significantly reduced in both the 0.3 and 0.4 g.kg(-1).h(-1) groups (P < 0.05 and P < 0.01, respectively) by the end of infusion. All these effects of glucose supply, including suppression of lipolysis, disappeared regardless of dose within 1 h after the cessation of infusion.

These results suggest that the optimal dose for preoperative glucose infusion, in order to preserve carbohydrate or fat metabolism, is 0.1-0.2 or 0.3 g.kg(-1).h(-1), respectively, and indicate that administration should not be discontinued until the start of surgery.