广东医学2012，Vol.33Issue(16)：2479-2483,5.
氯胺酮对右美托咪定靶控输注患者镇静意识消失时浓度效应关系的影响
Effects of ketamine on concentration-response relationship of dexmedetomidine with respect to the loss of consciousness via target-controlled infusion
摘要
Abstract
Objective To investigate the effects of ketamine on concentration - response of dexmedetomidine with respect to the loss of consciousness via target-controlled infusion ( TCI ). Methods Sixty patients ( ASA Ⅰ~Ⅱ ) undergoing lower abdominal or extremity operations under combined spinal-epidural anesthesia were randomly divided into 2 groups ( n = 30 ): Group D ( dexmedetomidine alone ) and Group KD ( dexmedetomidine and ketamine ). Patients in Group D were further randomized to 5 subgroups ( n = 6 in each ), in which the subjects received dexmedetomidine via TCI at the respective target plasma concentrations of 0. 54, 0. 64, 0. 76, 0. 90 and 1. 07 ng/mL. Meanwhile, patients in Group KD were randomized 5 subgroups ( n = 6 in each ), in which the subjects with pretreatment of ketamine 0. 4 mg/kg and sustained by 5 μg/kg/min intravenously, received dexmedetomidine via TCI at the respective target plasma concentrations of 0. 30, 0. 37, 0. 46, 0. 57 and 0. 70 ng/mL. The loss of response to verbal command ( OAA/S scores ≤ 2 ) and eyelash stimulation was used as the standard of definite unconsciousness. The number of unconscious patients in each group was recorded during the first 30 mins. Bispectral index ( BIS ), heart rate ( HR ), blood pressure ( BP ), SpO2 , OAA/S scores and eyelash stimulation were monitored during the study. A quantal response model ( probit analysis ) was used to calculate the concentration-effect curve and predict plasma EC50 and EC95 of dexmedetomidine. Results Dexmedetomidine induced significant increase of unconsciousness ratio and reduction of BIS values in concentration-dependent manners ( P < 0. 05 ). The EC50 and EC95 of loss of consciousness of dexmedetomidine were 0. 445 ng/mL and 0. 603 ng/mL in Group KD, which were significantly lower than those ( 0. 738 ng/mL and 0. 990 ng/mL, respectively ) in Group D ( P <0. 05 ). A paralleled but left - shift concentration - effect curve was observed in Group KD when compared to that in Group D. Compared to the baseline, the MAP of both groups significantly decreased after 15 min in Subgroup 3, 4 and 5 ( P < 0. 05 ). So did the HR at 5min in the Subgroup 3 , 4 and 5, and at 10 min in the Subgroup 1 and 2 of the Group D. Compared to the baseline, the HR significantly decreased between 20 to 30 min in the Subgroup 4 and 5 ( P <0. 05 ). Conclusion Dex provides concentration-dependent sedative effect on anesthesia, and low dose ketamine enhances this via reduction of target plasma concentration of Dex.关键词
右美托咪定/靶控输注/意识消失/浓度-反应关系Key words
dexmedetomidine/ target controlled infusion/ loss of consciousness/ concentration - response relationship引用本文复制引用
邬子林,周志飞,佘守章,许立新..氯胺酮对右美托咪定靶控输注患者镇静意识消失时浓度效应关系的影响[J].广东医学,2012,33(16):2479-2483,5.基金项目
广东省医学科研基金资助项目(编号:A2011477),广州市医药卫生科研基金资助项目(编号:201102A213071) （编号:A2011477）
