右美托咪定镇静下瑞芬太尼抑制光棒插管反应的药效学观察

Pharmacodynamics of Remifentanil Required to Prevent Lightwand-guided Tracheal Intubation Response under Dexmedetomidine Sedation

目的测定瑞芬太尼在右美托咪定镇静下抑制光棒插管反应的半数有效效应室浓度(EC50)。方法择期乳腺肿瘤手术患者36例,年龄18~59岁,ASAⅠ~Ⅱ级,体重指数﹤30 kg/m2。入室后统一用18G套管针开放下肢静脉,静卧15 min后开始静脉输注负荷剂量右美托咪定1. 0μg/kg (10 min泵完),后以0. 5μg/(kg·min)持续泵入,待患者意识消失,脑电双频指数值降至60~65时,靶控输注瑞芬太尼(Minto模型),第1例患者瑞芬太尼初始效应室浓度为3. 0 ng/m L,待效应室浓度与血浆浓度达到平衡,利用非窥喉光棒技术经口气管内插管。入选样本从发生插管阳性反应的前一例阴性反应病例开始计算。瑞芬太尼的效应室浓度采用改良序贯法进行试验,相邻效应室靶浓度之间比率为1. 20。结果瑞芬太尼在右美托咪定镇静下抑制光棒插管反应的EC50为2. 85 ng/m L,95%可信区间为2. 61~3. 12 ng/m L。结论右美托咪定镇静下瑞芬太尼抑制光棒插管反应的半数有效效应室浓度为2. 85 ng/m L。

Objective To measure 50% effective concentration( EC50) of remifentanil required to prevent lightwand-guided tracheal intubation response under dexmedetomidine sedation. Methods 36 patients with selective breast tumor surgery were enrolled in the study,aged ranging from 18 to 59 years old,with ASAⅠ~ II level and body mass index < 30 kg/m2. After the lower extremity vein was opened by 18 G cannula,the patients lay in a supine position for 15 min before being given infusion of loading dose of 1. 0 μg/kg dexmedetomidine( finished in 10 min),followed by a continuous infusion of 0. 5 μg/( kg·min) dexmedetomidine. When the patients were in no consciousness and the Bispectral index( BIS) fell to 60 ~ 65,remifentanil was administered using target-controlled infusion( Minto model). For the first patient,the initial effective concentration of remifentanil was 3. 0 ng/m L,and then lightwandguided tracheal intubation was performed through the mouth after effective concentration was balanced with the plasma concentration.The selected samples were calculated from the previous negative case with positive intubation reaction. The effective concentration of remifentanil was tested by modified sequential method,and the ratio of adjacent effective concentration was 1. 20. Results The EC50 of remifentanil required to prevent lightwand-guided tracheal intubation response under dexmedetomidine sedation was 2. 85 ng/m L,and 95% confidence interval was 2. 61 ~ 3. 12 ng/m L. Conclusion Accompanied by dexmedetomidine sedation,the EC50 of remifentanil required to prevent lightwand-guided tracheal intubation response is 2. 85 ng/m L.