Desflurane을 이용한 흡입 마취 중 기도내 삽관 시 혈역학적 변화를 억제하는 Remifentanil의 목표 농도

Abstract

Background: Anesthesia induction with desflurane is troublesome because of frequent sympathetic hyperactivity during desflurane administration. We supposed that low concentration of desflurane combined with target-controlled infusion (TCI) of remifentanil would eliminate desflurane-related complications and provide hemodynamic stability during desflurane induction. An up-and-down study was planned to find target effect-site concentration of remifentanil to block hemodynamic response to endotracheal intubation, the highest level of stimulus during anesthesia induction, during administration of desflurane 1 MAC. Methods: Remifentanil TCI was initiated before desflurane administration. When the preset target was achieved, spontaneous inhalation of desflurane 1 MAC was performed until patients became unconscious. Laryngoscopic tracheal intubation was facilitated with rocuronium injection. Starting concentration of remifentanil and test space were 5 and 1 ng/ml, respectively. Criteria for up-and-down was 20% increase of mean arterial pressure or heart rate after intubation. Median effective concentration (EC50) of remifentanil was calculated from 6 independent pairs. Complications related with remifentanil and desflurane were assessed during the study. Results: We studied 20 patients using 2-5 ng/ml of effect-site concentrations of remifentanil. The EC50 of remifentanil was 3.7 ng/ml. Loss of consciousness was achieved at 125 ± 22 s after desflurane inhalation, irrespective of combined remifentanil concentrations. Remifentanil-related complication was not observed. Transient cough was seen in one patient who received 2 ng/ml of remifentanil. Conclusions: We demonstrated that uncomplicated induction with desflurane was possible by the use oftarget-controlled remifentanil. EC50 of remifentanil to block hemodynamic response to tracheal intubation was 3.7 ng/ml during inhalational induction with 1 MAC desflurane.