Department of Anaesthesiology, Perioperative Medicine and Intensive Care Medicine
Department of Radiology, Paracelsus Medical University, Müllner Hauptstrasse 48, 5020 Salzburg, Austria.
Br J Anaesth. 2016 Mar;116(3):405-12. doi: 10.1093/bja/aev550.
Ultrasound guidance allows for the use of much lower volumes of local anaesthetics for nerve blocks, which may be associated with less aberrant spread and fewer complications. This randomized, controlled study used contrast magnetic resonance imaging to view the differential-volume local anaesthetic distribution, and compared analgesic efficacy and respiratory impairment.
Thirty patients undergoing shoulder surgery were randomized to receive ultrasound-guided interscalene block by a single, blinded operator with injection of ropivacaine 0.75% (either 20 or 5 ml) plus the contrast dye gadopentetate dimeglumine, followed by magnetic resonance imaging. The primary outcome was epidural spread. Secondary outcomes were central non-epidural spread, contralateral epidural spread, spread to the phrenic nerve, spirometry, ultrasound investigation of the diaphragm, block duration, pain scores during the first 24 h, time to first analgesic consumption, and total analgesic consumption.
All blocks provided fast onset and adequate intra- and postoperative analgesia, with no significant differences in pain scores at any time point. Epidural spread occurred in two subjects of each group (13.3%); however, spread to the intervertebral foramen and phrenic nerve and extensive i.m. local anaesthetic deposition were significantly more frequent in the 20 ml group. Diaphragmatic paralysis occurred twice as frequently (n=8 vs 4), and changes from baseline peak respiratory flow rate were larger [Δ=-2.66 (1.99 sd) vs -1.69 (2.0 sd) l min(-1)] in the 20 ml group.
This study demonstrates that interscalene block is associated with epidural spread irrespective of injection volume; however, less central (foraminal) and aberrant spread after low-volume injection may be associated with a more favourable risk profile.
This study was registered with the European Medicines Agency (Eudra-CT number 2013-004219-36) and with the US National Institutes' of Health registry and results base, clinicaltrials.gov (identifier NCT02175069).
超声引导下进行神经阻滞时，可以使用更低容量的局部麻醉剂，这可能与麻醉剂扩散异常和并发症减少有关。本随机对照研究使用对比磁共振成像来观察不同容量局部麻醉剂的分布，并比较了镇痛效果和呼吸功能障碍。
30 名接受肩部手术的患者被随机分为两组，每组 15 名，由一名单独的、盲法操作者进行超声引导下的肌间沟阻滞，注入罗哌卡因 0.75%（20 或 5ml）加造影剂钆喷替酸二葡甲胺，然后进行磁共振成像。主要结局是硬膜外扩散。次要结局是中央非硬膜外扩散、对侧硬膜外扩散、膈神经扩散、肺活量测定、膈超声检查、阻滞持续时间、术后 24 小时内疼痛评分、首次使用镇痛药时间和总镇痛药用量。
所有阻滞均能快速起效，并提供充分的术中及术后镇痛，各时间点疼痛评分无显著差异。两组各有 2 例（13.3%）发生硬膜外扩散；然而，20ml 组更频繁地出现椎间孔和膈神经扩散以及广泛的肌内局部麻醉剂沉积。膈神经麻痹的发生率也增加了一倍（8 例比 4 例），且 20ml 组的峰值呼吸流量从基线的变化更大[Δ=-2.66（1.99 sd）比-1.69（2.0 sd）l min（-1）]。
本研究表明，无论注射剂量如何，肌间沟阻滞都会引起硬膜外扩散；然而，低容量注射后较少的中央（椎间孔）和异常扩散可能与更有利的风险状况相关。
该研究在欧洲药品管理局（Eudra-CT 编号 2013-004219-36）和美国国立卫生研究院注册和结果数据库，clinicaltrials.gov（标识符 NCT02175069）进行了注册。
