右美托咪定对椎管内麻醉期间患者入睡时间和镇静效果的影响

The influence of dexmedetomidine on the time of falling asleep and the effect of sedation in patients during intrathecal anesthesia

目的探讨静脉输注右美托咪定（DEX）对下肢手术患者椎管内麻醉期间入睡时间和术中镇静效果的影响。方法拟在腰硬联合麻醉下完成下肢手术患者180例,ASA I-Ⅱ级,年龄20-65岁,椎管内麻醉效果满意后,所有患者均给予DEX负荷剂量0.5μg/kg,时间为10min,随机平均分为3组,A组持续输注DEX 0.2μg·kg^-1·h^-1,B组持续输注DEX 0.4μg·kg^-1·h^-1,C组持续输注DEX 0.6μg·kg^-1·h^-1。手术结束前30min停止右美托咪定输注,手术时间2-3h。记录给予DEX即刻（T0）、给药10、20、30、60min（T1-T4）及术毕（T5）时的血压、心率、BIS值及BIS值到达85时应用右美托咪定的时间（BIS85时间）,计算术中心动过缓、低血压及低氧合事件（Sp O2〈90%）等不良事件的发生率。结果与T0比较,3组T1-T5时MAP、HR、BIS值均降低（P〈0.05）;与T1比较,B组和C组T2-T5时MAP、HR、BIS值均降低（P〈0.05）;与A组比较,B组和C组T0、T1时MAP、HR、BIS值无统计学意义（P〉0.05）,T2-T5时MAP、HR、BIS值均降低（P〈0.05）,入睡时间明显缩短（P〈0.05）,B组心动过缓、低血压、低氧合事件发生率无明显差异（P〉0.05）,C组心动过缓、低血压、低氧合事件发生率增高;与B组比较,C组T3-T5时MAP、HR均降低（P〈0.05）,BIS值无明显改变（P〉0.05）,入睡时间明显缩短,心动过缓、低血压、低氧合事件发生率增高（P〈0.05）。结论下肢手术患者椎管内麻醉期间应用0.4μg·kg^-1·h^-1右美托咪定术中持续泵注,BIS值维持在66-76之间,患者处于舒适的自然睡眠状态,具有良好的镇静效应,血流动力学稳定。

Objective To explore the influence of dexmedetomidine on the time of falling asleep and the effect of seda-tion in patients who experienced the lower lamb operation during intrathecal anesthesia. Methods After an induction of in-trathecal anesthesia, 180 patients were injected dexmedetomidine 0.5μg/kg for 10 minutes and randomly divided into three groups：the group A were injected dexmedetomidine 0.2μg·kg^-1·h^-1,the group B were injected dexmedetomidine 0.4μg·kg^-1·h^-1, the group C were injected dexmedetomidine 0.6μg·kg^-1·h^-1. All the patients finished the infusion dexmedetomidine 30 minutes before the end of operation, the time of operation was 2-3h. Blood pressure, heart rate, BIS were recorded at the beginning of dexmedetomidine infusion（T0）, after 10,20,30,60min（T1-T4） and the end of operation（T5）. The time of falling asleep, and the incidence of bradycardia,hypotension and hyoxemia were recorded. Results Compared with T0, blood pressure, heart rate and BIS decreased in the three groups at T1-T5 （P〈0.05）. Compared with the group A, blood pressure, heart rate and BIS were decreased in the groups B and C at T2-T5 （P〈0.05）, the time of falling asleep was shorter （P〈0.05）. The incidence of bradycardia, hypotension and hyoxpemia had no significance in group B,but increased in group C. Compared with the group B, MAP and HR decreased at T3-T5 （P〈0.05）, the time of falling asleep was shorter, the incidence of bradycardia, hypotension and hyoxemia increased （P〈0.05） in the group C. Conclusion The infusion speed of dexmedetomidine is 0.4μg·kg^-1·h^-1 when the values of BIS at 66-77, patients who experienced the lower lamb operation during intrathecal anesthesia could have comfortable sedation like natural sleep and stable haemodynamics.