Dexamethasone for postoperative nausea and vomiting prophylaxis: effect on glycaemia in obese patients with impaired glucose tolerance

BACKGROUND AND OBJECTIVE: Dexamethasone given to prevent postoperative nausea and vomiting may produce significant hyperglycaemia in the perioperative period. The effect of dexamethasone on patients with impaired glucose tolerance is unknown. METHODS: Thirty obese patients with impaired glucose tolerance undergoing laparoscopic Roux-en-Y gastric bypass surgery were studied in a double-blind fashion. Patients were randomly distributed into two groups: the dexamethasone group (n = 15) received dexamethasone 8 mg intravenously after induction of anaesthesia; the control group (n = 15) received isotonic saline. Fingerprick capillary blood glucose concentrations were measured at baseline and every 2 h during the first 12 h after the start of surgery. RESULTS: In both groups, all blood glucose concentrations measured after the beginning of surgery were higher than baseline values. However, the dexamethasone group showed higher glucose concentrations than the control group from the 6th to the 12th hour of the study. In addition, the maximum blood glucose value in the dexamethasone group (10.4 +/- 1.6 mmol l(-1)) was higher than in the controls (8.8 +/- 1.7 mmol l(-1)) (P < 0.05). CONCLUSION: Dexamethasone, 8 mg, intravenously administered at the beginning of laparoscopic bariatric surgery in patients with impaired glucose tolerance is associated with significantly increased postoperative blood glucose concentrations.