Comparison of the Effect Site Concentration of Remifentanil for Preventing Cough During Emergence Between Male and Female Patients With Thyroidectomy

The clinical studies demonstrate more powerful analgesic effect among female to both μ- and κ-opioid agonist (Fillingim et al. 2004). The antitussive effect of opioid is mediated predominantly by μ-, κ-opioid receptors (Kamei J. 1996). Therefore, the investigators hypothesized that there are sex differences in the antitussive responses to opioid. It has been reported that target-controlled infusion (TCI) of remifentanil can reduce cough against endotracheal tube during emergence from general anesthesia. Some studies, reporting the EC50 and EC95 of remifentanil in effect-site TCI for preventing cough during emergence in different sex and surgeries (B. Lee et al. 2009, E.M.Choi et al. 2012), showed differences in EC50 and EC95. The purpose of this study was to find out EC50 and EC95 of remifentanil in effect-site TCI for preventing cough during emergence in each sex and to evaluate whether there were sex differences in EC50 and EC95 of remifentanil in effect-site TCI or not.