Mogensen T, Simonsen L, Scott N B, Henriksen J H, Kehlet H
Department of Anesthesiology, Hvidovre University Hospital, University of Copenhagen, Denmark.
Anesth Analg. 1989 Aug;69(2):180-4.
The relationship between tachyphylaxis (measured as a decrease in the rate of regression of sensory levels of analgesia) during repeated epidural injections of lidocaine and both the distribution of lidocaine within the epidural space (as measured by spread of simultaneous injection of the tracer technetium-99m diethylenetriaminepentaacetate [99mTc-DTPA]) and elimination of lidocaine from the epidural space (as measured by serum concentrations of lidocaine) was investigated in 18 patients undergoing minor surgery during lumbar epidural analgesia. Twelve patients received four injections of 20 mL of 2% lidocaine at 2-hr intervals. Epidural distribution was assessed by injection of 99mTc-DTPA diluted in saline on the preoperative day and diluted in an equal volume of 2% lidocaine on the morning before surgery and again after the fourth injection of lidocaine 6 hr later. The distribution of 99mTc-DTPA in the epidural space was unchanged during the three measurements despite significant tachyphylaxis in both sensory analgesia and motor blockade (11 of 12 patients had sensory analgesia 2 hr after the first injection in contrast to only 3 of 12 patients during the third injection). In another six patients 20 mL of 2% lidocaine were injected three times at 2-hr intervals before surgery, with measurements of serum concentrations of lidocaine after the first and last injections. Despite tachyphylaxis (no patient had sensory analgesia 2 hr after the third injection), there was no difference in the rate of disappearance of lidocaine from the epidural space as assessed by plasma lidocaine concentration curves during the first and third injection (0.5 +/- 0.1 and 0.3 +/- 0.04 microgram.mL-1.min-1, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)
在18例接受腰椎硬膜外镇痛的小手术患者中，研究了重复硬膜外注射利多卡因期间快速耐受性（以镇痛感觉水平消退速率降低来衡量）与利多卡因在硬膜外间隙内的分布（通过同时注射示踪剂锝-99m二乙三胺五乙酸[99mTc-DTPA]的扩散来测量）以及利多卡因从硬膜外间隙消除（通过利多卡因血清浓度来测量）之间的关系。12例患者每隔2小时接受4次20毫升2%利多卡因注射。在术前一天通过注射稀释于盐水中的99mTc-DTPA来评估硬膜外分布，在手术前早晨以及6小时后第四次注射利多卡因后，将其稀释于等体积的2%利多卡因中再次评估。尽管在感觉镇痛和运动阻滞方面出现了显著的快速耐受性（12例患者中有11例在第一次注射后2小时有感觉镇痛，相比之下，第三次注射时12例患者中只有3例有感觉镇痛），但在三次测量期间，99mTc-DTPA在硬膜外间隙的分布没有变化。在另外6例患者中，术前每隔2小时注射3次20毫升2%利多卡因，在第一次和最后一次注射后测量利多卡因血清浓度。尽管出现了快速耐受性（第三次注射后2小时没有患者有感觉镇痛），但通过第一次和第三次注射期间血浆利多卡因浓度曲线评估，利多卡因从硬膜外间隙消失的速率没有差异（分别为0.5±0.1和0.3±0.04微克·毫升⁻¹·分钟⁻¹）。（摘要截断于250字）
