Effects of preoperative oral carbohydrate therapy on perioperative glucose metabolism during oral- maxillofacial surgery: randomised clinical trial.

BACKGROUND AND OBJECTIVES: Preoperative oral carbohydrate therapy has been suggested to attenuate postoperative insulin resistance. The purpose of this study was to investigate the effect of a carbohydrate-rich beverage given preoperatively on intraoperative glucose metabolism.

METHODS AND STUDY DESIGN: This study was a randomised, open-label, placebo-controlled trial. Patients undergoing oral-maxillofacial surgery were divided into two groups. In the glucose group, patients took glucose (50 g/278 mL, p.o.) 2 h before anaesthesia induction after overnight fasting; control-group patients took mineral water. Primary outcome was blood concentrations of ketone bodies (KBs); secondary outcomes were blood concentrations of free fatty acids, insulin and glucose. Concentrations were measured 2 h before anaesthesia (T0), induction of anaesthesia (T1), and 1 h (T2), 3 h (T3), and 5h after anaesthesia start (T4).

RESULTS: In the control group (n=11), KBs increased continuously from anaesthesia induction. In the glucose group (n=12), KBs were maintained at low concentrations for 3h after beverage consumption but increased remarkably at T3. At T1 and T2, concentrations of KBs in the glucose group were significantly lower than those in the control group (T1, p=0.010; T2, p=0.028). In the glucose group, glucose concentrations decreased significantly at T2 temporarily, but in the control group, glucose concentrations were stable during this study (T2, p<0.001: glucose vs control).

CONCLUSIONS: Preoperative intake of glucose (50 g, p.o.) can alleviate ketogenesis for 3 h after consumption but can cause temporary hypoglycaemia after anaesthesia induction.