年龄对硬膜外注射氯普鲁卡因药效学和药代动力学的影响

Effects of age on pharmacokinetics and pharmacodynamics of chloroprocaine epidural administration

目的探讨年龄因素对患者硬膜外注射氯普鲁卡因药效学和药代动力学的影响。方法择期连续硬膜外麻醉下下肢手术患者45例,根据年龄分为A组(≤45岁),B组(46～64岁)和C组(≥65岁),每组15例。以3%氯普鲁卡因6mg/kg行硬膜外阻滞。硬膜外注药后记录感觉和运动阻滞效果及不良反应发生情况。于注药后即刻、注药后3、6、9、12、15、20、30、45、60和90min采用高效液相色谱法测定血浆氯普鲁卡因浓度,计算药代动力学参数。结果与A组比较,C组最高感觉阻滞平面明显升高,感觉和运动阻滞维持时间明显延长(P<0.05)。硬膜外注药后90min时B组和C组氯普鲁卡因血药浓度高于A组(P<0.05)。结论随年龄增加,氯普鲁卡因阻滞平面升高,感觉和运动阻滞恢复时间延长,药物代谢减慢。

Objective To investigate the effects of age on pharmacodynamics and pharmacokinetics of chloroprocaine after epidural administration. Methods Forty-five patients scheduled for selective lower extremity surgery under epidural anesthesia were divided into 3 groups of A（≤45 years old）, B（46-64 years old） and C（≥65 years old） with 15 cases each. All patients received 3% chloroprocaine 6 mg/kg given epidurally. Planes of sensory and motor block were checked. Blood samples were taken from central vein at 0,3,6,9,12,15,20,30,45,60 and 90 rain after epidural administration for detecting plasma concentration of chloroprocaine by HPLC. The pharmacokinetic parameters were calculated. Results The cephalad spread of sensory block was significantly higher in group C than that in group A（P〈0. 05）. The duration of sensory and motor block was significantly longer in group C than that in group A（P〈0.05）. Plasma concentration of chloroproeaine at 90 min after epidural administration was significantly higher in groups of B and C than that in group A （P〈0. 05）. Conclusion As age increases, the block plane of chloroprocaine is heightened, duration of sensory or motor block is prolonged and the drug metabolism is delayed.