Decreasing the toxic potential of intravenous regional anaesthesia

In an attempt to reduce the dose of local anaesthetic agent during intravenous regional anaesthesia (IVRA) of the upper limb, we have used a forearm tourniquet in 12 adult volunteers. The volume of the forearm venous system was predetermined angiographically. We performed IVRA with three solutions of lidocaine (0.25, 0.375, 0.5 per cent) administered in a volume equal to the forearm venous system. Angiographic results indicate that: a forearm tourniquet provides adequate vascular isolation; the volume of the forearm venous system can be correlated with body weight; the progression of the fluid in the venous system follows a pattern that is similar for all patients with the small veins of the distal forearm and proximal hand being filled last. With this technique, lidocaine 0.5 per cent resulted in a dose of 1.5 mg.kg-1 and provided excellent analgesia. Lower concentrations were unsatisfactory. We conclude that the use of a forearm tourniquet allows reduction of the local anaesthetic dose to a non-toxic level and thus increases the safety of IVRA.     

Differential efficacy of intravenous lidocaine in alleviating ipsilateral versus contralateral neuropathic pain in the rat

In the this study we have investigated the threshold plasma concentration of lidocaine for reversal of mechanical ‘allodynia' in a neuropathic pain model in the rat, defined the concentration-dependent limits of that reversal and compared the acute reversal during intravenous drug infusion with the persistent relief of allodynia assayed 48 h later. Actions of i.v. lidocaine on ipsilateral and contralateral legs were also assessed. Forty rats were sorted into five groups (n=7–10) and underwent spinal root (L5–6) ligation to produce allodynia, as quantified by a lower force of von Frey hairs at the plantar hindpaw required to elicit paw withdrawal (PWT, paw withdrawal threshold). During surgery, intravenous catheters were placed for programmed lidocaine infusion and in some animals arterial catheters were also inserted for assaying lidocaine blood levels. PWTs were measured in ipsilateral and contralateral paws before and after ligation and during infusions which, beginning at 5 days after surgery, were conducted every other day to incrementing levels (1.1–9.7 μg/ml plasma). Ligation produced allodynia in ipsilateral paws (PWT=1.22±0.42 g (±SEM)) and in contralateral paws (PWT=4.99±0.61 g), both markedly lower than pre-operative control values for either paw (11.31±0.41 g). The ipsilateral allodynia was partially, but significantly and permanently reversed (to PWT=6–8 g) after a lidocaine infusion to 2.1 mg/ml in two separate groups (n=7, 8). Lower concentrations resulted in elevation of PWT during infusion but no sustained relief. The elevation of PWT during infusion at this threshold level among individual animals was positively correlated with the relief measured 48 h later, but higher lidocaine concentrations infused in subsequent dosings could exact no further sustained relief. The residual PWT level, after reversal by threshold lidocaine and greater, was constant for each individual rat tested over the next 14 days but varied substantially among individuals; some were restored to pre-operative PWTs and some were totally unresponsive to drug. Retrospective analysis revealed a significant and unanticipated correlation between the incidence of low pre-operative PWTs (<10 g) and a lack of sustained reversal of post-operative allodynia by lidocaine. Contralateral allodynia, despite its acute reversal during infusion to 2.1 μg/ml and higher, was not persistently relieved after infusion of lidocaine to any concentration. Repeated infusions to subthreshold levels (<2 μg/ml) did not provide persisting relief of allodynia on either side, and infusions of saline were impotent. These findings show that experimental allodynia results from multiple factors, only some of which are sensitive to lidocaine treatment, and that prolonged reversal of allodynia is limited in extent and likely influenced by pre-existing factors.     

Antihistaminic activity of carane derivatives in isolated guinea pig ileum

Local anesthetics (LAs) inhibit membrane depolarization by reducing sodium and potassium conductance, and subsequent displacement of calcium ions from binding sites seems to occur. Histamine release appears to be a secretory process in which calcium couples the stimulus to the exocytosis of histamine-containing granules. Furthermore, LAs are structurally similar to histamine H₁-receptor antagonists. Thus, LAs can be considered antihistaminic drugs.Previous pharmacological investigations have shown strong local anesthetic, anti-inflammatory and analgesic activity of the carane derivative KP-23. As it has previously been demonstrated that KP-23R, S and its R, S-diasteroisomers have an inhibitory effect on guinea pig ileum contractions, the aim of the present study was to determine and compare the antihistaminic effects of KP-23R, S and its individual isomers KP-23R and KP-23S on isolated guinea pig ileum.     

利多卡因对腹腔镜手术病人应激反应的影响

目的研究利多卡因对应激反应的影响。方法45例行腹腔镜胆囊切除术、ASAⅠ~Ⅱ级病人,随机分为3组P组靶控输注异丙酚诱导和维持麻醉;L1和L2组在靶控输注异丙酚诱导前分别静注利多卡因1、2mg/kg,并持续输注利多卡因1、2mg·kg-1·h-1维持。记录麻醉全程血液动力学变化、异丙酚靶浓度及停药至拔管时间;测定入室后、插管后即刻、切皮后10min、停人工气腹后和拔管后血皮质醇、胰高糖素、血管紧张素Ⅱ浓度。结果P组异丙酚靶浓度在各时点高于L1和L2组(P<0.05);皮质醇L2组在T1、T3、T4点明显低于P组(P<0.05);胰高糖素复合利多卡因两组在T2和T4显著低于P组(P<0.05);血管紧张素Ⅱ三组间比较差异无统计学意义。L1组和L2组苏醒时间较P组延长(P<0.05),L2组较L1组延长(P<0.05)。结论利多卡因可减轻应激反应,降低异丙酚效应室靶浓度,但延长苏醒时间。     

后腹腔镜二孔法肾囊肿去顶减压术的围术期护理

对30例单纯性肾囊肿患者采用后腹腔镜二孔技术肾囊肿去顶减压术。结果30例手术均获成功，住院4～6d，平均4．5d康复出院；随访3～6个月，B超检查无复发。提示高质量的术前准备、术后基础护理、引流管的护理，并发症的观察及护理可预防相关并发症的发生，促进患者康复。     

Intravenous lignocaine (lidocaine) infusion for the treatment of chronic daily headache with substantial medication overuse

Patients with chronic daily headache with medication overuse are difficult to treat, especially when the doses of analgesia are substantial. We have previously shown that intravenous lignocaine (lidocaine) infusion is useful in maintaining pain control while the offending analgesic agent is withdrawn in these patients. The published data on long-term efficacy of this treatment is limited. We undertook a retrospective survey of 71 consecutive patients admitted for lignocaine infusion (mean 8.7 days) for treatment of chronic daily headache, with substantial analgesic abuse. Ninety percent of patients had a history of migraine headaches. In 80% of patients codeine was the predominant agent implicated in the analgesic rebound headaches (mean 1053 mg/week) and 24% used ergotamine-containing medications (mean 16 mg/week). Thirty-one percent frequently used injected narcotics. At completion 90% reported that their daily headache was absent or improved, and the analgesic agent was withdrawn successfully in 97%. At six month follow-up, 70% of patients reported that their daily headache was absent or improved and 72% of patients remained free of the offending analgesic agent. Intravenous lignocaine is a useful treatment in the management of chronic daily headache with substantial medication overuse. The benefits of the program last for at least six months.     

Cutaneous and subcutaneous blood flow rates in paraplegic humans investigated by 133Xenon wash-out. Methodological considerations

Summary. In a methodological study including 14 paraplegics and seven normal controls cutaneous and subcutaneous blood flow rates were investigated by ¹³³Xenon wash-out after atraumatic labelling. In paraplegics, areas suffering pressure sores were included. The method was found applicable for the authors' purposes. In seven paraplegics median (95% confidence limits) cutaneous blood flow was 5–2 (2–4–8–5) ml (100 g min)“¹ and subcutaneous 4–3 (2–0–13–2) ml (100 g min)^-1. This did not differ from normal controls. In seven paraplegics with ischial pressure sores a trend for increased cutaneous blood-flow rates from areas adjacent to sores was obvious (P= 0–06). During 704 head-up tilt, elimination-rate constants were reduced by a factor of 0–54 (0–50–0–70). A proximal blockade or infiltration of the ¹³³Xenon depots with lidocaine did not inhibit employment of the method. The proximal block did not alter the local blood flow rate, but infiltration increased it in both paraplegics and normal individuals. Intra- and interdepot coefficients of variation were about 11% and 40% respectively. Interindividual coefficients of variation varied between 25% and 46%.     

利多卡因加液体石蜡用于男性导尿的观察

目的 观察利多卡因加液体石蜡在男性导尿中的效果。方法 将90例接受导尿的清醒男病人随机分为两组，观察组48例，在常规插尿管前自尿道外口注入利多卡因液体石蜡混合液，对照组42例，按常规导尿法插尿管。两组均以插尿管时患疼痛的主诉及插管时所遇阻力为判断指标。结果 两组在导尿时疼痛及插管阻力经x^2检验分别x^2=8.62,x^2=5.59,均P＜0．05,有显性差异。结论 利用卡因加液体石蜡用于男性导尿明显减轻插管时的疼痛，显提高导尿的成功率。     

The Influence of Sodium Channel Blockade on the Defibrillation Energy Requirements of Diphasic Versus Monophasic Shocks

The sodium channel-blocking actions of some Class I antiarrhythmic agents can increase the defibrillation energy requirements (DER) of monophasic shock waveforms. The influence of sodium channel blockade on biphasic shocks is less certain. The purpose of this study was to compare, in a randomized, placebo controlled study, the influence of lidocaine on the DER of biphasic and monophasic shock waveforms in a canine model of transvenous internal defibrillation. The DER was determined by the iterative increment-decrement protocol. Monophasic and biphasic shock DERs were tested at baseline and during lidocaine infusion (group A) or saline control (group B). Group A biphasic shock DERs increased significantly from a baseline of 12.1 ± 3.6 J to 19.1 ± 9.3 J when compared to group B (P = 0.005). In group A, the mean DER during lidocaine was significantly higher with monophasic shocks than biphasic shocks (29.6 ± 11.8 f vs 19.1 ± 9.3), respectively: P < 0.003), but the magnitude of change in biphasic versus monophasic shock DERs was not significantly different (F = 1.78; p = 0.193). There was a linear relationship between the baseline DER and the DER during lidocaine (r²= 0.63, P < 0.0001). Sodium channel blockade with lidocaine increases the DER of both monophasic and biphasic shocks. However, the DER of biphasic shocks during lidocaine are significantly lower than monophasic shock DERs, a finding that can be explained by the linear relationship between the baseline DER and the DER during lidocaine. These results may have favorable implications for the use of Class I antiarrhythmics with biphasic shock defibrillators.