Does the type of anesthetic agent affect remifentanil effect-site concentration for preventing endotracheal tube-induced cough during anesthetic emergence? Comparison of propofol, sevoflurane, and desflurane.

STUDY OBJECTIVE: To investigate whether the type of anesthetic agent administered affects the antitussive effect of remifentanil. DESIGN: Prospective randomized study. SETTING: Operating room of a university hospital. PATIENTS: 78 ASA physical status 1 and 2 women, aged 20 to 65 years, who were scheduled to undergo a thyroidectomy. INTERVENTIONS: Patients were randomly assigned to three groups to receive anesthesia with propofol (Group P), sevoflurane (Group S), or desflurane (Group D). The main anesthetics were titrated to maintain a target Bispectral Index for hypnosis of 40 to 60. Remifentanil was administered via effect-site target-controlled infusion (TCI). To determine the effective remifentanil effect-site concentration (Ce) to suppress coughing in each group, the up-and-down sequential allocation design was used. MEASUREMENTS: The half maximal effective concentration (EC50) values of remifentanil for preventing coughing in the groups were estimated using isotonic regression and compared among the groups. MAIN RESULTS: The EC50 of remifentanil for cough suppression in Group P [1.60 ng/mL (98.3% CI, 0.92-1.75 ng/mL)] was statistically lower than in Group D [1.96 ng/mL (98.3% CI, 1.81-2.50 ng/mL)]. The EC50 in Group S was 1.75 ng/mL (98.3% CI, 1.39-2.13 ng/mL), which was higher than in Group P and lower than in Group D, but did not differ significantly from either group. CONCLUSIONS: Remifentanil administration for cough suppression during emergence should be customized to the anesthetic agent.