0.5％罗哌卡因用于超声引导下肋锁间隙臂丛神经阻滞的半数有效容量

目的采用序贯法测定0.5%罗哌卡因用于前臂尺骨骨折患者超声引导下肋锁间隙(CCS)臂丛神经阻滞的半数有效容量(EV_(50))。方法选择2018年2—8月行前臂尺骨折手术患者40例,在超声引导下行CCS臂丛神经阻滞。从预试验中出现阳性反应的其中一个较大容量22 ml开始试验,相邻容量梯度变化为1.2 ml。若前一例患者阻滞30 min内疼痛完全缓解视为阻滞成功,下一例患者罗哌卡因容量下降一级;若阻滞30 min内疼痛未完全缓解视为失败,下一例患者罗哌卡因容量上升一级,获得7个拐点研究结束。采用概率回归法计算0.5%罗哌卡因用于前臂尺骨骨折患者超声引导下肋锁间隙臂丛神经阻滞的EV_(50)及其95%可信区间(CI)。结果 40例患者中23例(58%)阻滞成功,0.5%罗哌卡因EV_(50)为17.9 ml(95%CI 15.5～20.3 ml)。结论超声引导下0.5%罗哌卡因用于前臂尺骨骨折患者肋锁间隙臂丛神经阻滞半数有效容量EV_(50)为17.9 ml。

Median effective volume of 0.5% ropivacaine employed in the ultrasound-guided brachial plexus block through costoclavicular space

Objective Sequential method was adopted to measure the median effective volume (EV50) of 0.5% ropivacaine in ultrasound-guided brachial plexus block through costoclavicular space in the patients with ulnar fractures.
Methods Forty patients with ulnar fracture were given a ultrasound-guided brachial plexus block from February to August in 2018. The initial dose was 22 ml which showed positive reaction in the preliminary experiment. The volume gradient was 1.2 ml. If the pain was completely relieved in 10 minutes, the brachial plexus of the patient was regarded as successfully blocked and the next patient would be given a lower volume of ropivacaine. Otherwise, the next patient would be given a higher volume of ropivacaine until we got 7 inflection points. Probability regression method was adopted to calculate the EV50 and the 95% confidence interval (CI) of the 0.5% ropivacaine.
Results Twenty-three patients (57.5%) of patients were successfully blocked, EV50 of 0.5% ropivacaine was 17.9 ml (95%CI 15.5-20.3 ml).
Conclusion The median effective volume of 0.5% ropivacaine in ultrasound-guided brachial plexus block through costoclavicular space in the patients with ulnar fractures is 17.9 ml.