The effect of a priming epidural injection of adrenaline on epidural blockade with bupivacaine

Twenty-four patients receiving epidural anaesthesia were studied to test the hypothesis that 1:200,000 adrenaline administered into the epidural space 5 minutes before 20 ml bupivacaine 0.5% would improve nerve block and delay systemic absorption of the local anaesthetic. Group A/B received 20 ml adrenaline 1:200,000 5 minutes before 20 ml bupivacaine 0.5%, group S/BA 20 ml saline followed by 20 ml bupivacaine 0.5% with 100 micrograms adrenaline, and group S/B saline 20 ml followed by 20 ml plain bupivacaine 0.5%. Mean maximum plasma concentrations of bupivacaine tended to be lower in the adrenaline groups. A delay in the time to peak plasma concentration of bupivacaine was noted in the A/B group; this indicated that priming with adrenaline may be effective at delaying early systemic uptake of the local anaesthetic. In both adrenaline groups a more prolonged epidural block and increased efficacy were noted, although this was only significant for the duration of block at T6 (p = 0.023) and duration of motor block at Bromage level 1 (p = 0.016) in group A/B. There seems little clinical advantage in administering adrenaline 5 minutes before bupivacaine.     

Serum bupivacaine concentrations following wound infiltration in children undergoing inguinal herniotomy

Serum bupivacaine concentrations were measured in 12 children who underwent elective herniotomy and who received analgesia in the form of wound infiltration. Mean (SD) peak concentration was 0.36 (0.14) micrograms/ml and time to peak concentration was 14.6 (7.2) minutes after infiltration of 1.25 mg/kg of bupivacaine. These concentrations are lower than those associated with other local anaesthetic blocks and well below potentially toxic levels. Wound infiltration provides a simple, effective and safe method of providing postoperative analgesia for hernia repair in children.     

Profound motor blockade with epidural ropivacaine following spinal bupivacaine

Ropivacaine, a relatively new amide local anaesthetic, reputedly produces less motor block than equivalent doses of bupivacaine, potentially combining high-quality analgesia with the ability to ambulate. We report two cases of prolonged, profound motor block with patient-controlled epidural analgesia using 0.1% ropivacaine, following spinal bupivacaine for Caesarean section. As there was no evidence of inadvertent intrathecal ropivacaine administration or of any neurological injury, we hypothesise that epidural ropivacaine may interact with intrathecal bupivacaine to prolong its effect.     

Topical bupivacaine and etidocaine analgesia following fallopian tube banding

The purpose of this study was to compare the effectiveness and safety of etidocaine and bupivacaine for postoperative analgesia after laparoscope sterilization. The study was performed in 22 healthy patients who received either one per cent etidocaine, 2 mg.kg-1, or bupivacaine 1.5 mg.kg-1 in a double-blind, randomized fashion. The local anaesthetic was dropped onto the fallopian tubes from uterus to fimbriae before tubal occlusion. To establish safety, blood concentrations of the parent drug and its metabolites were measured before application and at 1, 3, 6, 10, 15, 30, 60 and 120 min. The mean peak concentrations were 501.8 +/- 71.3 (SEM) for etidocaine with a range of 225 to 905 ng.ml-1. For bupivacaine, the mean peak concentration was 468 +/- 73.8 SEM with a range from 191 to 1005 ng.ml-1. The mean values are one eighth of the toxic convulsive dose for humans. Etidocaine was metabolized at a faster rate than bupivacaine with a rapid appearance of 2-amino-2'-butyroxylidide (ABX). The bupivacaine metabolite 2,6-pipecoloxylidide (PPX) was detected in low concentrations in the 60-minute samples. We conclude that the topical application of either etidocaine or bupivacaine is a safe procedure in the doses and concentrations used during general anaesthesia for laparoscopic tubal banding.     

Cardiovascular effects of epidural local anaesthetics

The cardiovascular effects of 20 ml 0.75% bupivacaine with adrenaline 5 micrograms/ml injected epidurally were compared with those of 20 ml 0.75% ropivacaine with adrenaline. Cardiovascular measurements were performed with a transthoracic electrical bioimpedance monitor. The maximum mean arterial blood pressure decreased significantly from baseline values after both solutions, but the decrease after 20 minutes was more pronounced with bupivacaine (21%) than with ropivacaine (9.6%). Stroke volume increased significantly in both groups (52% for bupivacaine and 29% for ropivacaine). Cardiac output increased significantly from baseline values 2 minutes after epidural administration; the mean of the maximum increase was 64% for bupivacaine and 53% for ropivacaine (NS). The mean of the maximum increase of the ejection fraction was 13% in the bupivacaine group and 9% in the ropivacaine group, but was only significantly different from baseline values following bupivacaine. There was no difference in the onset time or height of the sensory block between the groups. The cardiovascular changes can be ascribed to sympathetic blockade and to systemic absorption of the local anaesthetics and adrenaline.     

布比卡因加芬太尼硬膜外阻滞对分娩的影响

目的：探讨低剂量布比卡因加芬太尼硬膜外阻滞镇痛对分娩的影响。方法：用0．125％布比卡因加芬太尼2．5μg／ml硬膜外阻滞镇痛的69例初产妇为镇痛组，与未行镇痛术69例同等条件的初产妇对照，用随机单盲方法进行临床观察。结果：低剂量布比卡因与芬太尼联合用药使硬膜外阻滞镇痛有效率达100％，并改善它缩性质，协调宫缩即缩短活跃期宫缩持续时间；松弛盆底肌肉，减轻抬头下降受阻，加速宫口开大及胎头下降（P＜0．01），缩短活跃期及第二产程（P＜0．01），减少胎儿宫内窘迫、产生出血及难产率。结论：0．125％布比卡因加芬太尼2．5μg／ml用于硬膜外阻滞镇痛是一种安全、有效无痛分娩术。     

甲磺酸罗比卡因腰麻在膝关节镜检术中的应用

目的:探讨甲磺酸罗比卡因腰麻用于膝关节镜检术的安全性与有效性。方法:选择择期行膝关节镜检术ASA～级的患者40例,随机分为两组,甲磺酸罗比卡因(R)组、布比卡因(B)组,每组20例。局麻药的配方分别为R组1.192%甲磺酸罗比卡因重比重液2.4mL,B组0.75%布比卡因重比重液2.4mL,两组均取L3～4间隙行蛛网膜下隙阻滞穿刺,待脑脊液出现后注入局麻药,观察记录两组痛觉阻滞起效时间、痛觉阻滞的最大范围及平面固定时间、痛觉阻滞维持时间。采用改良的Bromage分级评定运动阻滞,记录运动阻滞起效时间、最大运动阻滞分级及时间、完全阻滞的患者数、运动阻滞的持续时间、自主排尿时间及术后尿潴留的发生率,连续记录给药后5、10、15、30、60min时的血压、心率及麻黄素和阿托品的追加使用情况、同时记录不良反应和并发症的发生情况。结果:与B组相比,R组痛觉阻滞起效慢,最高阻滞平面较低但持续时间较长,R组运动阻滞起效慢但持续时间短,自主排尿时间早,血流动力学稳定,不良反应少。结论:1.192%甲磺酸罗比卡因重比重液以其血流动力学稳定、不良反应少可安全用于腰麻的实施。     

应用丁哌卡因于臂丛神经阻滞

注局麻药液丁哌卡因<20ml(占255人次的2/3)入锁骨上方围血管围神经间隙进行臂丛神经阻滞,在相等的基础上(包括穿刺中阳性指示如异感和针干搏动等),比较0.375％丁哌卡因(96人次)与1.0％利多卡因和0.2％丁卡因混合液,(159人次)两者局麻效应强度,证明0.375％丁哌卡因是优于而不是逊于混合液,而且丁哌卡因的阻滞有效期长,一般可达8-10h。讨论中强调了阻滞操作技巧要完善,管理要得当,否则结论难以置信。此外有73次应用了超剂量的丁哌卡因或混合液,不论独用或合并,掌握得当均可无碍。     

Intervertebral epidural anaesthesia in paediatric surgery: success rate and adverse effects in 650 consecutive procedures

The success rate and occurrence of adverse effects are reported in a retrospective study of 650 (99 sacral, 468 lumbar, 76 thoracic and seven cervical) paediatric epidurals performed, mostly (91%) under light general anaesthesia, by several anaesthetists. Seventeen-gauge Tuohy and 20-gauge (Potts-Cournand® and Tuohy) needles were used. Anaesthetic solutions used were 1% lignocaine, 0.5% bupivacaine and a mixture of equal volumes of 0.5% bupivacaine with either 1% lignocaine or 1% etidocaine, all containing 1:200 000 adrenaline. The epidural space was identified by loss-of-resistance technique (LORT) with normal saline, air or CO₂. Up to five attempts were occasionally necessary. LORT using fluid resulted in more subarachnoidal penetrations than the LORT using air (P < 0.05) which was easy and reliable but produced patchy anaesthesia (‘painful gaps') in 4.2% of patients. CO₂-LORT was as easy and reliable as air-LORT and did not result in painful gaps. Lateral and mid-line insertion routes were equally suitable whatever the level of approach. Twenty-gauge needles, especially Tuohy needles, resulted in significantly less dural punctures in young children. The spread of the local anaesthetic correlated with the volume injected and the height of the epidural approach. Epidural anaesthesia had little haemodynamic effects. Administration of epidural morphine improved the duration of postoperative pain relief but undesirable effects occurred in up to 50% of patients. Low doses of naloxone (2–5 μg?kg^?1.h^?1) counteracted most adverse effects, avoiding urinary retention and delayed apnoea. Anaesthetists and residents without experience in paediatric anaesthesia had a good success rate in performing the techniques (under supervision of an experienced anaesthetist). At the same time, experience in regional anaesthesia would significantly boost the confidence of the anaesthetist in managing such cases. The authors recommend using CO₂ instead of air in the LORT.