Randomized Study of the Effect of Local Anesthetic Volume and Concentration on the Duration of Peripheral Nerve Blockade
Randomized Study of the Effect of Local Anesthetic Volume and Concentration on the Duration of Peripheral Nerve Blockade
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DOI：
10.1097/aap.0b013e3182580fd0
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发表时间：
2012-09-01
影响因子：
5.1
通讯作者：
White, Richard
中科院分区：
文献类型：
--
作者：
Fredrickson, Michael J.;Abeysekera, Amitha;White, Richard
背景和目的：超声引导减少了成功周围神经阻滞所需的局麻药量，但尚不清楚这是否会影响阻滞持续时间。我们研究了罗哌卡因体积和浓度对肌间沟阻滞持续时间的影响。方法：185 名患者被随机分配到 5 种罗哌卡因体积/浓度组合（0.75% 5、10 和 20 mL；0.375% 20 和 40 mL），术前在全麻肩部手术前通过肌间沟导管给药。疼痛发作时开始输注弹性体罗哌卡因。患者在 24 小时内接受询问，主要询问主要结果：首次疼痛的时间。由于区块失败率高得令人无法接受，5 mL 组被事后排除。使用多变量 Cox 回归来评估容量和浓度（各自校正另一个）对主要结果的影响。结果：作为时间函数的疼痛概率不仅与剂量相关，还与浓度校正的体积和体积校正的浓度相关：剂量的风险比（95% 置信区间） = 0.992 (0.987-0.997) (P = 0.002)，体积 = 0.959 (0.937-0.982) (P = 0.001)，浓度 = 0.852 (0.743-0.976) (P = 0.021)。据估计，将罗哌卡因的体积从 10 mL 增加到 40 mL 0.375%，会使中位（四分位数）阻滞持续时间从 10.0 (9.5-11.5) 小时增加到 15.0 (10.75-21) 小时。同样，将 20 mL 罗哌卡因的浓度从 0.375% 增加到 0.75% 估计会使中位（四分位数）阻滞持续时间从 10.75 (9.75-14.0) 小时增加到 13.75 (10.5-21.0) 小时。结论：阻滞持续时间受到局部麻醉剂量和浓度的影响，这一发现与当前超声引导下麻醉剂量减少的趋势越来越相关。区域麻醉。
Background and Objectives: Ultrasound guidance reduces the required local anesthetic volume for successful peripheral nerve block, but it is unclear whether this influences block duration. We investigated the ropivacaine volume and concentration effect on interscalene block duration.Methods: One hundred eighty-five patients were randomized to 5 ropivacaine volume/concentration combinations (0.75% 5, 10, and 20 mL; 0.375% 20 and 40 mL) administered preoperatively via an interscalene catheter before shoulder surgery under general anesthesia. An elastomeric ropivacaine infusion commenced at the onset of pain. Patients were questioned at 24 hours primarily for the primary outcome: time to first pain. Group 5 mL was excluded post hoc because of an unacceptably high block failure rate. Multivariate Cox regression was used to assess the effect of volume and concentration (each corrected for the other) on the primary outcome.Results: Probability of pain as a function of time was associated with not only dose, but also volume corrected for concentration and concentration corrected for volume: hazard ratio (95% confidence interval) for dose = 0.992 (0.987-0.997) (P = 0.002), volume = 0.959 (0.937-0.982) (P = 0.001), concentration = 0.852 (0.743-0.976) (P = 0.021). Increasing the volume of ropivacaine 0.375% from 10 to 40 mL was estimated to increase median (quartiles) block duration from 10.0 (9.5-11.5) to 15.0 (10.75-21) hours. Similarly, increasing the concentration of 20 mL ropivacaine from 0.375% to 0.75% was estimated to increase median (quartiles) block duration from 10.75 (9.75-14.0) to 13.75 (10.5-21.0) hours.Conclusions: Block duration is influenced by both local anesthetic volume and concentration, a finding of increasing relevance with the current trend to lower volumes for ultrasound-guided regional anesthesia.