Comparison of the Optimal Effect-Site Concentrations of Remifentanil for Preventing Cough during Emergence from Desflurane or Sevoflurane Anaesthesia

Abstract

To compare the effect-site concentrations of remifentanil target-controlled infusion (TCI) that produced 50% and 95% of the maximal effect (EC50 and EC95, respectively) for preventing cough during emergence from desflurane or sevoflurane anaesthesia, in patients undergoing elective thyroidectomy. Adults undergoing elective thyroidectomy were randomized to receive anaesthesia with desflurane or sevoflurane. The EC50 and EC95 values for remifentanil TCI were determined using Dixon's up-and-down method and probit analysis with sigmoid curve. In total, 48 patients aged 20-64 years were enrolled in the study. The EC50±SD of remifentanil TCI, determined by Dixon's up-and-down method, were 1.54±0.70 and 1.11±0.24 ng/ml for desflurane and sevoflurane, respectively. The EC95 of remifentanil TCI, analysed by probit analysis, were 2.88 ng/ml and 2.29 ng/ml for desflurane and sevoflurane, respectively. The effect-site concentration of remifentanil TCI for preventing cough during emergence from desflurane anaesthesia was not significantly higher than that observed for sevoflurane. During emergence from anaesthesia, variations in effect-site concentrations of remifentanil for preventing cough are of limited importance as they do not generate significant differences in results.