Department of Anesthesiology and Pain Medicine, Kangnam Sacred Heart Hospital, Hallym University College of Medicine, Seoul, Korea.
Korean J Anesthesiol. 2012 Jan;62(1):52-6. doi: 10.4097/kjae.2012.62.1.52. Epub 2012 Jan 25.
Bicarbonate, as an adjunct increasing the non-ionized form of local anesthetics, can reduce latency and prolong duration of regional nerve block. Warming of local anesthetics decreases pKa and also increases the non-ionized form of local anesthetics. We warmed ropivacaine to body temperature (37℃) and evaluated the sensory block onset time, motor block onset time and analgesic duration of axillary block.
Patients were consecutively allocated to two groups of 22 patients each. Ropivacaine 150 mg (30 ml) at 20℃ (room temperature) and 150 mg (30 ml) at 37℃ (body temperature) was injected in group 1 and group 2, respectively. Sensory block and motor block was assessed every 5 minutes, for 30 minutes after injection. The duration of analgesia was recorded after operation.
In group 2, the onset times of both sensory and motor block of the radial, ulnar, median and musculocutaneous nerves were significantly reduced, compared to group 1. Also, the number of blocked nerves was increased in group 2, within 30 minutes after injection. Analgesia lasted for 2 hours longer in group 2, compared to group 1, but the difference was not statistically significant (P > 0.05).
Warming of ropivacaine to 37℃ can reduce the onset time of both sensory and motor block, during axillary block.
作为局部麻醉剂非离子形式的附加物，碳酸氢盐可以减少潜伏期并延长区域神经阻滞的持续时间。局部麻醉剂的升温会降低 pKa 值，并增加局部麻醉剂的非离子形式。我们将罗哌卡因加热至体温（37℃），并评估腋路阻滞的感觉阻滞起效时间、运动阻滞起效时间和镇痛持续时间。
患者连续分配到两组，每组 22 例。在第 1 组和第 2 组中，分别注射 20℃（室温）下的 150mg（30ml）罗哌卡因和 37℃（体温）下的 150mg（30ml）罗哌卡因。注射后每 5 分钟评估感觉阻滞和运动阻滞，持续 30 分钟。记录术后镇痛持续时间。
与第 1 组相比，第 2 组桡神经、尺神经、正中神经和肌皮神经的感觉和运动阻滞的起效时间明显缩短。此外，在注射后 30 分钟内，第 2 组阻滞的神经数量也增加了。与第 1 组相比，第 2 组的镇痛时间延长了 2 小时，但差异无统计学意义（P>0.05）。
将罗哌卡因加热至 37℃可以缩短腋路阻滞时感觉和运动阻滞的起效时间。
