Fialkov J A, McDougall E P
Department of Surgery, St Michael's Hospital, University of Toronto, Canada.
Ann Plast Surg. 1996 Jan;36(1):11-3. doi: 10.1097/00000637-199601000-00003.
The effect of warming local anesthetic on the amount of pain experienced during local infiltration was tested by comparing equal volumes of 40 degrees C- and 21 degrees C-infiltrates in each of 26 subjects. Six subjects were patients undergoing excision of two benign asymptomatic nevi in separate locations, and 20 subjects were healthy adult volunteers who were injected in bilateral antebrachial sites. The warmed and room temperature solutions were randomized to each side, so that each subject received both temperature injections in random order. All subjects and the injector were blinded. The rate of injection was time-controlled (0.05 ml/sec). Following both injections, subjects were asked to rate the pain experienced at each site. In addition, the subject was asked if there was no difference, a slight difference, or a substantial difference between the two sites. A two-tailed paired t-test was used to analyze the mean difference in pain scores for all subjects. Paired analysis of the pain scores for each subject eliminated intersubject variance of pain tolerance. The mean difference in pain score between the room temperature and warmed solutions was +1.5 (p < 0.0001). Of the 21 subjects (81%) who found the warmed solution less painful, 11 (52%) found the difference to be significant, while 10 (48%) found the difference to be slight. Two subjects (8%) found no difference between the two, while 3 subjects (11%) found the colder solution slightly less painful. We conclude that warming local anesthetic to 40 degrees C prior to subcutaneous injection is a simple, inexpensive means of reducing the pain of local infiltration.
通过比较26名受试者中分别注射等量40摄氏度和21摄氏度局部麻醉剂时局部浸润期间的疼痛程度，测试了局部麻醉剂升温的效果。6名受试者是在不同部位切除两个良性无症状痣的患者，20名受试者是在双侧前臂部位接受注射的健康成年志愿者。将温热溶液和室温溶液随机分配到身体两侧，以便每个受试者以随机顺序接受两种温度的注射。所有受试者和注射者均不知情。注射速度由时间控制（0.05毫升/秒）。两次注射后，要求受试者对每个部位的疼痛程度进行评分。此外，还询问受试者两个部位之间是否没有差异、有轻微差异还是有显著差异。使用双尾配对t检验分析所有受试者疼痛评分的平均差异。对每个受试者的疼痛评分进行配对分析消除了受试者间疼痛耐受性的差异。室温溶液和温热溶液之间疼痛评分的平均差异为+1.5（p<0.0001）。在认为温热溶液疼痛较轻的21名受试者（81%）中，11名（52%）认为差异显著，而10名（48%）认为差异轻微。两名受试者（8%）认为两者没有差异，而三名受试者（11%）认为较冷的溶液疼痛稍轻。我们得出结论，皮下注射前将局部麻醉剂加热至40摄氏度是一种简单、廉价的减轻局部浸润疼痛的方法。
