BACKGROUND: The aim of this study was to compare the anesthetic techniques for preventing postoperative nausea and vomiting (PONV) in the patients undergoing thyroidectomy.

METHODS: Sixty patients of ASA status I or II, undergoing thyroidectomy were studied. Patients were allocated randomly to one of three groups. Group 1 (n = 22): anesthesia was induced by propofol (2 mg/kg) and maintained with desflurane and 50% nitrous oxide in oxygen. Group 2 (n = 22): anesthesia was induced and maintained propofol and alfentanil using a computer controlled infusion system in 60% medical air in oxygen. Group 3 (n = 16): anesthesia was induced propofol using computer controlled infusion system in combination 50% nitrous oxide in oxygen. The incidence of PONV was assessed at 6 and 24 hours after the surgery and standardized by Rhodes index of nausea, vomiting and retching (RINVR) score.

RESULTS: In group 3, the incidence of PONV within the first 6 hours after surgery, was significantly lower as P < 0.05. But, there was no statistical differences among the three groups in the 6 to 24 hours' RINVR score after surgery.

CONCLUSIONS: The use of propofol for induction and maintenance with combination 50% N2O is the most effective technique at preventing PONV among the three groups within the first 6 hours after thyroidectomy. This study found no statistically significant difference between the RINVR score, using desflurane-N2O and propofol-alfentanil.