The effect of remifentanil on the minimum alveolar concentration of isoflurane in children - 20/05/15

Doi : 10.1016/j.jclinane.2015.03.026

Ben-zhen Chen, MD ^a,^b, Qin-jun Chu, MD ^c, Jing-rui Yu, MD ^d, Yu-sheng Yao, MD ^e, Ling Tan ^a,^{^⁎}
^a Department of Anesthesiology, West China Hospital, Sichuan University, Chengdu, Sichuan, China
^b Department of Anesthesiology, Sichuan Provincial Hospital for Women and Children, Chengdu, Sichuan, China
^c Department of Anesthesiology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China
^d Sichuan Provincial Hospital for Women and Children, Chengdu, Sichuan, China
^e Department of Anesthesiology, Fujian Provincial Hospital, Fuzhou, Fujian, China

^⁎Corresponding author. Department of Anesthesiology, West China Hospital, Sichuan University, No. 37, Guo Xue Xiang, Chengdu, Sichuan Province, 610041, China.

Sous presse. Épreuves corrigées par l'auteur. Disponible en ligne depuis le Wednesday 20 May 2015

Abstract

Study objective

To evaluate the effect of remifentanil on the isoflurane end-tidal concentration required to eliminate movement reaction upon surgical incision in children.

Design

Prospective, double blinded, serial study.

Setting

Operating room of a university-affiliated hospital.

Patients

Patients of ASA status 1 or 2, aged 4 to 7 years, scheduled for either inguinal hernia repair or orchidopexy surgery with general anesthesia.

Interventions and measurements

After endotracheal intubation, 108 children serially received 1 of 6 dose (nil, 0.05, 0.10, 0.15, 0.20, or 0.25 μg kg⁻¹ min⁻¹) of remifentanil. End-tidal isoflurane concentration was adjusted according to a Dixon's up-and-down approach. Twenty-five minutes after starting the remifentanil infusion, the surgical incision was performed. The response of patients was classified as either “response” or “no response.” Response was defined as a purposeful response in response to skin incision.

Main Results

The MAC of isoflurane were 1.50 ± 0.16%, 1.33 ± 0.27%, 0.93 ± 0.13%, 0.73 ± 0.27%, 0.63 ± 0.19%, and 0.60 ± 0.15% for remifentanil infusion rates of nil, 0.05, 0.10, 0.15, 0.20, and 0.25 μg kg⁻¹ min⁻¹, respectively.