右美托咪定辅助超声联合神经刺激仪引导神经阻滞麻醉在老年患者膝关节镜手术中的应用

Application of dexmedetomidine assisted nerve blocks guided by ultrasound joint nerve stimulator in elderly patients undergoing knee arthroscopy

目的探讨右美托咪定辅助超声联合神经刺激仪引导神经阻滞麻醉应用于老年患者膝关节镜手术中的安全性和有效性。方法选取择期行单侧膝关节镜手术的老年患者100例,美国麻醉医师协会分级Ⅱ或Ⅲ级,采用随机数字表法分为连续股神经复合股外侧皮神经阻滞组(对照组)和右美托咪定辅助神经阻滞组(研究组),每组50例。研究组于神经阻滞前经静脉泵注射右美托咪定,负荷剂量为0.5μg/kg,以0.9%氯化钠溶液稀释到20mL,在10min内注射完毕,并以0.2μg/(kg·h)持续经静脉泵注射至手术结束前30min;对照组以同样方法经静脉泵注射等容量0.9%氯化钠溶液。负荷剂量注射完毕后,两组分别在超声联合神经刺激仪引导下完成连续股神经复合股外侧皮神经阻滞。记录两组患者神经阻滞麻醉的操作时间和起效时间、有效阻滞例数。在静脉泵注射负荷量前(T_0)、负荷量注射结束(T_1)、麻醉结束(T_2)、手术开始即刻(T_3)、手术开始后15min(T_4)、手术开始后30 min(T_5)和手术结束时(T6)各时间点,记录患者的平均动脉压(MAP)、心率(HR)和脉搏血氧饱和度(SpO_2)。记录术中丙泊酚和芬太尼的使用情况,以及心动过缓、呼吸抑制、高血压等不良反应的发生情况。结果两组间患者的性别构成、年龄、BMI、神经阻滞麻醉操作时间和起效时间、有效阻滞构成的差异均无统计学意义(P值均>0.05)。两组患者均顺利完成手术,无中转全身麻醉的病例。研究组术中丙泊酚和芬太尼使用率均显著低于对照组(P值均<0.05)。两组患者在T_0和T_1时间点的MAP的差异均无统计学意义(P值均>0.05);对照组患者在T_2至T_4时间点的MAP均显著高于同组T_0时间点(P值均<0.05),在T_2至T6时间点的MAP均显著高于研究组同时间点(P值均<0.05)。两组患者间各时间点的HR和SpO_2的差异均无统计学意义(P值均>0.05)。两组间心动过缓发生率的差异无统计学意义(P>0.05),研究组呼吸抑制和高血压发生率均显著低于对照组(P值均<0.05)。结论右美托咪定辅助超声联合神经刺激仪引导连续股神经复合股外侧皮神经阻滞麻醉应用于老年患者膝关节镜手术中,能使患者术中循环、呼吸稳定,麻醉管理简便,且不良反应少。

Objective To investigate the safety and efficacy of dexmedetomidine assisted nerve blocks guided by ultrasound joint nerve stimulator in elderly patients undergoing knee arthroscopy. Methods One hundred elderly patients, American Society of Anesthesiologists （ASA） grade T1 or T5, scheduled for unilateral knee arthroscopy, were randomly allocated to two groups （n = 50） ： control group and test group. A loading dose of dexrnedetornidine 0.5 μg/kg diluted into 20 mL normal saline was infused within 10 minutes before nerve blocks in the test group, then dexmedetomidine was injected through venous pump at a constant speed of 0.2 μg/（kg · h） until 30 minutes before the end of surgery. The same volume of normal saline was infused in the same way in the control group. After the loading dose infusion, femoral nerve block combined with lateral femoral cutaneous nerve block was performed as guided by ultrasound joint nerve stimulator in both groups. Operation time and onset time of the nerve block, as well as the number of success cases were recorded. The mean arterial pressure （MAP）, heart rate （HR） and pulse oxygen saturation （SpO2） were recorded at each time point as follows., before （To） and at the end （T1） of the loading dose infusion, at the end of nerve blocks （T2）, at 0 （T3）, 15 （T4） and 30 （T5） min after incision, and at the end of surgery （T6）. The requirement for propofol and fentanyl and the incidences of bradyarrhythmia, respiratory depression and hypertension were also recorded during surgery. Results There were no statistical differences in terms of gender composition, age, body mass index （BMI）, operation time for nerve blocks, onset time of anesthesia, or success block rate between two groups （all P〈0.05）. No patient in either group was converted to general anesthesia, and surgeries proceeded smoothly in all patients. The requirement for propofol and fentanyl in the test group were significantly less than those in the control group （both P〈0.05）. No significant differences were found in the MAP at To and T1 between groups （both P〉0. 05）. MAP at T2 -T4 were remarkably elevated as compared with the baseline value at To in the control group （all P〈0. 05）. MAP at T2 -T6 in the control group were significantly higher than those in the test group （all P〈0. 05）. There were no significant differences in HR or SpO2 at any time point between two groups （all P〉0. 05） ; Neither was the incidence of bradyarrhythmia （P〉0. 05）. The incidences of respiratory depression and hypertension in the test group were significantly lower than those in the control group （both P〈0. 05）. Conclusion Dexmedetomidine can increase the efficacy of nerve blocks guided by ultrasound joint nerve stimulator when used for knee arthroscopy in the elderly patients, which shows stable hemodynamic performance, simple anesthesia management and less side effect. （Shanghai Med J, 2016, 39： 94-97）