小型猪气管插管时异氟醚半数有效剂量的探索

Evaluation of inhalation induction of anesthesia for tracheal intubation in miniature pigs

目的本研究拟探讨小剂量舒泰(1.5 mg/kg)肌注复合异氟烷吸入用于保留自主呼吸的小型猪气管插管时50%和95%有效的异氟烷最小肺泡气浓度(50%and 95%minimum alveolar concentrations effective inhaled,MAC EI50and MAC EI95),为小型猪提供安全的麻醉插管方法。方法44例全身麻醉的巴马小型猪,肌注舒泰镇静后,面罩吸入异氟烷进行麻醉诱导,监测心率、血压、呼吸、体温、氧饱和度、呼末二氧化碳浓度和呼末异氟烷浓度。初始呼末异氟烷浓度设置为2.0%,采用Cooper’s评分评价气管插管满意度,采用Dixon’s改良序贯法测算剂量-效应关系。Probit回归法计算MAC EI50和MAC EI95及95%可信区间(confidence interval,CI)。结果小剂量舒泰复合异氟烷吸入诱导直接喉镜气管插管时,小型猪肺泡气浓度的MAC EI503.10%(95%CI 2.79%~3.56%),MAC EI953.77%(95%CI 3.41%~6.42%);在做好监测和气道管理预案的基础上,肺泡异氟烷浓度3.10%~3.75%,均能保证小型猪生命体征稳定。结论舒泰复合异氟烷吸入用于保留自主呼吸的小型猪气管插管是建立小型猪经口气道较好且安全的麻醉方法,具有推广价值。

Objective This study was performed to explore the use of intramuscular low-dose Zoletil(1.5 mg/kg)combined with isoflurane inhalation for tracheal intubation in miniature pigs while preserving spontaneous respiration by determining the 50%and 95%minimum alveolar concentrations effective inhaled(MAC EI50 and MAC EI95).The goal was to establish a safe anesthetic method for tracheal intubation in miniature pigs in which intubation is difficult.Methods Forty-four Bama miniature pigs underwent general anesthesia.Following sedation with an intramuscular injection of sufentanil,anesthetic induction was performed using mask inhalation of isoflurane with monitoring of the heart rate,blood pressure,respiration,body temperature,oxygen saturation,end-tidal carbon dioxide concentration,and end-tidal isoflurane concentration.The initial end-tidal isoflurane concentration was set at 2.0%.The tracheal intubation conditions and outcomes were evaluated using Cooper’s scoring system,and the dose-response relationship was calculated using Dixon’s up-and-down method.Probit regression was employed to calculate the MAC EI50 and MAC EI95 along with their 95%confidence intervals(CI).Results In tracheal intubation using direct laryngoscopy with induction by low-dose sufentanil combined with isoflurane inhalation in miniature pigs,the MAC EI50 was 3.10%(95%CI,2.79%~3.56%)and the MAC EI95 was 3.77%(95%CI,3.41%~6.42%).With proper monitoring and airway management planning in place,alveolar isoflurane concentrations ranging from 3.10%to 3.75%were able to maintain stable vital signs in the miniature pigs.Conclusions The use of Zoletil combined with isoflurane inhalation for tracheal intubation in miniature pigs,aimed at preserving spontaneous breathing,is a preferable and safe anesthetic method for oral airway management in miniature pigs with significant potential for widespread application.