右美托咪定不同给药途径对二次剖宫产术硬膜外麻醉效果影响的比较

Comparison of dexmedetomidine administered via different routes for epidural anesthesia during second cesarean section

目的比较右美托咪定不同给药途径对二次剖宫产术硬膜外麻醉的效果。方法选择单胎足月妊娠拟在硬膜外麻醉下行二次剖宫产术的产妇60例，ASA分级Ⅰ或Ⅱ级，年龄22～38岁，体重58～84 kg，采用随机数字表法分为静脉输注右美托咪定联合硬膜外注射罗哌卡因组（VDER组）、硬膜外注射罗哌卡因混合右美托咪定组（ERD组）和硬膜外注射罗哌卡因组（ER组），每组20例。硬膜外穿刺术毕给予试验量排除脊麻后，VDER组硬膜外给予0.75%罗哌卡因15 ml混合0.9%生理盐水2 ml，同时静脉输注1 μg/kg右美托咪定，输注时间10 min；ERD组硬膜外给予0.75%罗哌卡因15 ml混合1 μg/kg右美托咪定2 ml；ER组硬膜外给予0.75%罗哌卡因15 ml混合0.9%生理盐水2 ml。记录硬膜外麻醉起效时间、最高平面、达最高阻滞平面时间及感觉阻滞时间。硬膜外注药完毕后30 min时评估Ramsay镇静评分和术中牵拉反应程度分级；观察低血压、心动过缓、呼吸抑制和寒战的发生情况，记录胎儿娩出前使用瑞芬太尼的例数及新生儿1和5 min时的Apgar评分。结果与VDER组和ER组比较，ERD组硬膜外麻醉起效时间、达最高阻滞平面时间缩短，感觉阻滞时间延长（P〈0.05）；与ER组比较，VDER组和ERD组镇静满意率高，瑞芬太尼使用率降低，术中牵拉反应轻，呼吸抑制和寒战的发生率降低（P〈0.05）；新生儿1和5 min时Apgar评分比较差异无统计学意义（P〉0.05）。结论静脉与硬膜外途径应用右美托咪定均可增强二次剖宫产硬膜外麻醉的效果，且对新生儿无不良影响；硬膜外给予右美托咪定混合罗哌卡因，麻醉起效快，感觉阻滞时间长，有利于术后镇痛。

Objective To compare dexmedetomidine administered via different routes for epidural anesthesia during second cesarean section.Methods Sixty parturients who were at full term with a singleton fetus, of American Society of Anesthesiologists physical statusⅠor Ⅱ, aged 22-38 yr, weighing 58-84 kg, undergoing a second caesarean section under epidural anesthesia, were divided into 3 groups（n=20 each）using a random number table： IV infusion of dexmedetomidine combined with epidural injection of ropivacaine group（VDER group）, epidural injection of a mixture of ropivacaine and dexmedetomidine group（ERD group）and epidural injection of ropivacaine group（ER group）. The epidural puncture was performed at L2, 3.After identification of the epidural space and a negative aspiration test for blood or cerebrospinal fluid, the mixture of 0.75% ropivacaine 15 ml and 0.9% normal saline 2 ml was injected epidurally, and dexmedetomidine 1 μg/kg was intravenously infused for 10 min at the same time in VDER group; the mixture of 0.75% ropivacaine 15 ml and 1 μg/kg dexmedetomidine 2 ml was injected epidurally in ERD group; the mixture of 0.75% ropivacaine 15 ml and 0.9% normal saline 2 ml was injected epidurally in ER group.The onset time of epidural block, maximum level of epidural block, time to reach the maximum epidural block and time of sensory block were recorded.Ramsay sedation scores were assessed at 30 min after the end of epidural administration, and intraoperative traction reaction was also assessed.The development of hypotension, bradycardia, respiratory depression and shivering was observed.The number of patients in whom remifentanil was used before delivery and Apgar scores at 1 and 5 min after birth were recorded.Results Compared with VDER group and ER group, the onset time and time to reach the maximum epidural block were significantly shortened, and the time of sensory block was prolonged in ERD group（P〈0.05）. Compared with ER group, the rate of satisfactory sedation was significantly increased, the number of patients in whom remifentanil was used before delivery was decreased, the degree of intraoperative traction reaction was mitigated, and the incidence of respiratory depression and shivering was decreased（P〈0.05）, and no significant change was found in Apgar scores at 1 and 5 min after birth in VDER and ERD groups（P〉0.05）.Conclusion Both IV and epidural dexmedetomidine can enhance the efficacy of epidural anesthesia during second cesarean section, producing no adverse effects on neonates; epidural injection of a mixture of ropivacaine and dexmedetomidine provides faster onset and prolonged time of sensory block, which is helpful for postoperative analgesia.