静脉预注右美托咪定对罗哌卡因蛛网膜下腔阻滞效应的影响

The effects of intravenous dexmedetomidine premedication on ropivacaine-induced subarachnoid blockade

目的观察静脉预注右美托咪定对罗哌卡因蛛网膜下腔阻滞效应的影响。方法选择拟行下肢手术的患者50例,ASAⅠ或Ⅱ级,随机均分为两组：右美托咪定组（D组）,静脉予以右美托咪定1μg/kg,10min输注完毕,随后以0.5μg·kg-1·h-1持续静注。观察10min,然后选择L2~3间隙穿刺行蛛网膜下腔阻滞,穿刺成功后以0.25ml/s恒定速度注入药物,药物为1%罗哌卡因12.5mg＋10%葡萄糖的混合液3ml;对照组（C组）,给以等量的生理盐水静脉输注10 min,余方法同D组。记录药物预注前（T0）、开始预注后（包括麻醉穿刺期间）10min（T1）、20min（T2）、30min（T3）、60min（T4）及术后即刻（T5）、10min（T6）、20min（T7）、30min（T8）、60min（T9）的HR和BP,记录Ramsay镇静评分、最高感觉阻滞平面消退至S1神经水平的时间、最大运动阻滞恢复至Bromage 0分的时间。结果 C组患者Ramsay镇静评分为（2.00±0.41）分,明显低于D组的（3.96±0.53）分（P〈0.05）。D组感觉阻滞时间（178.5±32.6）min,明显长于C组的（135.1±20.3）min（P〈0.05）,运动阻滞时间（148.2±41.8）min,明显长于C组的（110.6±28.4）min（P〈0.05）。结论静脉预注右美托咪定1μg/kg能延长0.5%罗哌卡因蛛网膜下腔阻滞感觉及运动阻滞时间,同时具有良好的镇静作用,能较好维持循环稳定。

Objective To determine the sedative effect and efficacy of intravenous dexmedetomidine premedication on ropivacaine-induced spinal blockade.Methods Fifty ASA Ⅰ or Ⅱ patients who would undergo elective surgery on limb were randomly allocated to two groups：the dexmedetomidine group（group D,n=25）and the control group（group C,n=25）.All patients had spinal anaesthesia at the level of L2~3through a midline approach with 0.5% ropivacaine 12.5 mg.Patients in group D received intravenously a dose of 1μg/kg dexmedetomidine over 10 min before spinal anesthesia.Patients in group C received normal saline infusion at the same amount and duration.The level of sedation,hemodynamic changes,and the regression time to reach S1 sensory level and Bromage 0motor scale were recorded.Results Patients in group C for Ramsay sedation score（2.00±0.41）,was obviously lower than that of（3.96±0.53）in group D（P〈0.05）.Sedation effect was good in group D and hemodynamics were stable in both groups.The duration of sensory block was longer in group D[（178.5±32.6）min]compared with group C[（135.1±20.3）min].The duration of motor blockade was longer in group D[（148.2±41.8）min]than in group C [（110.6±28.4）min].Conclusion Intravenous dexmedetomidine premedication prolonged the sensory and motor blocks of ropivacaine-induced spinal anesthesia with good sedation effect and hemodynamic stability.