Warm steaming enhances the topical anesthetic effect of lidocaine

Warm steaming has been used for hydrating the skin, thereby increasing its permeability. We studied whether skin pretreatment with a steamed towel (at 45 degrees C) for 5 min could enhance the anesthetic effect of a topical lidocaine tape in 14 female volunteers. After each volunteer received the skin pretreatment on one of the forearms, lidocaine tape was applied for 30 min on both the treated and the untreated forearms. Superficial anesthesia was scored by recording the number of painful experience during 5 pinpricks delivered with a 27-gauge needle. To assess anesthesia of the deeper layer, single insertion of a 27-gauge needle to a depth of 3 mm was made and pain was scored by a visual analog scale (VAS). There were significant reductions in the scores of superficial anesthesia (median [range]: treated arm, 2 [0-5], versus untreated arm, 4 [1-5]; P < 0.01) and the VAS scores of deeper insertion (median [range]: treated arm, 4.5 [0-8], versus untreated arm, 8 [2-10]; P < 0.01). In conclusion, the application of a warm steamed towel enhanced the anesthetic effect of a topical lidocaine tape. IMPLICATIONS: We showed that the skin pretreatment with a steamed towel (at 45 degrees C) enhanced the anesthetic effect of a topical lidocaine tape in female volunteers.     

Local anesthetic effect of tramadol, metoclopramide, and lidocaine following intradermal injection

Background and Objectives. We observed clinically that tramadol and metoclopramide appear to have local anesthetic action. Tramadol is a central-acting analgesic. Metoclopramide is a commonly used antiemetic. The local anesthetic effect of tramadol in reducing propofol injection pain has never been mentioned, although it was speculated with metoclopramide. Methods. We conducted a double-blind, placebo-controlled study by injecting tramadol or metoclopramide intradermally in 10 healthy volunteers (5 men, 5 women; age 25–56 years). Each subject received 0.5 mL of four solutions in random order on the volar side of the forearm. These solutions were 25 mg tramadol, 5 mg metoclopramide, 5 mg lidocaine, and 0.5 mL normal saline. Pain on injections and the degree of local anesthesia (tested by pinprick, light touch, and cold) at each site was reported on a 0–3 scale at designed time intervals. Results. Like 1% lidocaine, tramadol and metoclopramide demonstrated loss of sensation for pinprick, light touch, and cold for 15 minutes after intradermal injection (P < .01). Conclusions. Intradermal tramadol or metoclopramide can produce local anesthetic effect.     

Allergic response to metabisulfite in lidocaine anesthetic solution

True allergies to local anesthetics are rare. It is common for practitioners to misdiagnose a serious adverse event to local anesthetics as an allergic reaction. The most likely causes for an allergic response are the preservative, antioxidant, or metabolites and not the anesthetic itself. This case report illustrates the need for practitioners to understand the many potential allergens in local anesthetics and to correctly diagnose patients that are truly allergic to the local anesthetic.     

硬膜外麻醉时可乐定和肾上腺素对麻醉效果和血清利多卡因浓度的影响

目的　研究硬膜外麻醉时 ,利多卡因溶液中加用可乐定或肾上腺素对血清利多卡因浓度和硬膜外麻醉效果的影响。方法　将 3 0例 ASA ～ 级下腹或下肢择期手术患者随机分为三组 :1组为利多卡因空白对照组 ,单纯 2 %利多卡因 6mg· kg- 1 硬膜外注射 ;2组为肾上腺素对照组 ,2 %利多卡因 6m g· kg- 1 加肾上腺素 5μg· ml- 1 硬膜外注射 ;3组为可乐定试验组 ,2 %利多卡因 6mg·kg- 1 加可乐定 5μg· m l- 1 硬膜外注射。测定感觉和运动阻滞的起效和恢复时间 ,并采集动脉血检测血清利多卡因浓度。结果　利多卡因溶液中加用可乐定 ( 1∶ 2 0万 ) ,可使硬膜外麻醉起效加快、作用间期延长 ,并能降低血清利多卡因浓度 ,其作用类似于利多卡因溶液加用同等浓度的肾上腺素。结论　可乐定作为一种血管活性因子可应用于硬膜外麻醉 ,以减少利多卡因的毒副作用     

The anesthetic potency of lidocaine in the rat.

The anesthetic effect of lidocaine was evaluated in rats by determining the change in anesthetic requirement of cyclopropane MAC that was produced by blood concentrations of lidocaine in the clinically useful range. A linear reduction in anesthetic requirement was produced with concentrations up to 1 mug/ml. Further increases in lidocaine up to 5.5 mug/ml resulted in no further decrease in cyclopropane requirement. Lidocaine was found to contribute a maximum MAC fraction of 0.4.     

不同剂量罗哌卡因联合利多卡因对腹股沟疝无张力修补术后麻醉效果及应激反应的影响

目的探讨不同剂量罗哌卡因联合利多卡因用于腹股沟疝无张力修补术,对患者术后应激反应的影响。 方法选择2020年2至10月内蒙古包钢医院收治的拟在局部麻醉下行腹股沟疝无张力修补手术患者80例,随机分为复合组和对照组,每组各40例。对照组给予0.25%罗哌卡因联合1%利多卡因进行麻醉,复合组给予0.75%罗哌卡因联合1%利多卡因进行麻醉。比较2组患者各时段应激反应指标[皮质醇、白细胞介素-6（IL-6）]水平、Ramsay镇静评分、疼痛视觉模拟（VAS）评分、术后患者苏醒状况与术中不良反应情况。 结果术后2组患者术前1 d（T0）时,术后2 h（T1）和术后4 h（T2）的VAS评分与治疗前相比呈下降趋势,术后各时间段复合组的VAS评分比对照组更低（P<0.05）;所有患者应激反应指标对比,T1时2组血清皮质醇、IL-6水平较T0时期增高,但复合组低于对照组（P<0.05）,在T2时间段2组患者应激反应指标水平比T1时间段下降,且复合组应激反应水平比对照组低（P<0.05）。与对照组相比,Ramsay镇静评分显著降低（P<0.05）。2组患者术后苏醒情况比较,复合组苏醒时间短于对照组（P<0.05）;术中不良反应发生率复合组（1/40）明显低于对照组（7/40）（P<0.05）。 结论0.75%罗哌卡因联合1%利多卡因对腹股沟疝术后的患者有显著的镇痛效果,可以降低炎症,不良反应少,有临床推广的意义。     

Potential toxicity from prolonged anesthesia: a case report of a thirty-hour anesthetic

Selection of anesthetics for prolonged administration must include consideration of potential toxicity resulting from extended exposure. This report deals with a patient undergoing a 30-hour anesthetic that included nitrous oxide (N2O) and isoflurane (9.7 MAC-hours). Serial serum inorganic fluoride levels obtained in the perioperative period demonstrated a peak fluoride level of 12.6 mumols occurring 27 hours after isoflurane was discontinued. Although higher than previously reported fluoride levels following isoflurane anesthesia in healthy adults (4 mumols), the current results are below those levels associated with renal abnormalities after prolonged enflurane anesthesia (34 mumols). In addition to outlining basic care guidelines for patients undergoing a prolonged anesthetic, this report discusses potential toxicity from prolonged exposure to both N2O and isoflurane. It concludes that isoflurane can be tolerated in doses up to 10 MAC-hours without fluoride toxicity but cautions against the use of N2O for periods longer than 24 hours.     

Humidification of anesthetic systems for prolonged procedures.

The desirability of humidification of anesthesia systems for prolonged surgical procedures has been documented previously. Dry anesthetic gases damage the ciliated epithelium and cause respiratory heat loss. Chalon suggests that from 12 to 16 mg. of water/L. of gas is necessary to prevent damage to the tracheal epithelium. This study describes a method of obtaining values of from 21.5 plus or minus 0.4 to 39.3 plus or minus 0.1 mg. of water/L. by cycling the fresh gas flow through the carbon dioxide (CO2) absorber before exposure to the patient.     

Mitochondrial injury and caspase activation by the local anesthetic lidocaine

BACKGROUND: Lidocaine, a local anesthetic, can be neurotoxic. However, the cellular mechanisms of its neurotoxicity at concentrations encountered during spinal anesthesia remain unclear. METHODS: The authors examined the mechanisms of lidocaine neurotoxicity in the ND7 cell line derived from rat dorsal root ganglion. Individual neurons were assayed by flow cytometry or microscopy using fluorescent probes of plasma membrane integrity, mitochondrial membrane potential, caspase activity, phospholipid membrane asymmetry, and mitochondrial cytochrome c release. RESULTS: In the ND7 cell line, lidocaine at 185 mm x 10 min to 2.3 mm x 24 h caused necrosis or late apoptosis. Equimolar Tris buffer and equipotent tetrodotoxin controls were not toxic, indicating that neither osmotic nor Na-blocking effects explain lidocaine neurotoxicity. The earliest manifestation of lidocaine neurotoxicity was complete loss of mitochondrial membrane potential within 5 min after exposure to lidocaine at a concentration of 19 mm or greater. Consistent with these data, 37 mm lidocaine (1%) induced release of mitochondrial cytochrome c into the cytoplasm, as well as plasma membrane blebbing, loss of phosphatidylserine membrane asymmetry, and caspase activation, with release of mitochondrial cytochrome c to the cytoplasm within 2 h. Treatment with z-VAD-fmk, a specific inhibitor of caspases, prevented caspase activation and delayed but did not prevent neuronal death, but did not inhibit the other indicators of apoptosis. CONCLUSIONS: Collectively, these data indicate that lidocaine neurotoxicity involves mitochondrial dysfunction with activation of apoptotic pathways.     

Comparison of anesthetic effect between 0.375% ropivacaine versus 0.5% lidocaine in forearm intravenous regional anesthesia

BACKGROUND AND OBJECTIVES: Ropivacaine was shown to provide superior postblock analgesia to lidocaine in intravenous regional anesthesia (IVRA) in voluntary studies. The objective of this study was to compare the anesthesia efficacy, postblock analgesia, and local anesthetic-related side effects between ropivacaine and lidocaine when forearm IVRA was used. METHODS: Fifty-one patients undergoing outpatient hand surgery were randomized to receive forearm IVRA with either ropivacaine 0.375% or lidocaine 0.5%. The volume was 0.4 mL/kg up to 25 mL. Sensation to pinching by forceps and motor function was assessed at 5-minute intervals up to 15 minutes. After tourniquet deflation, verbal pain rating score (VRPS) at 15-minute intervals for the first 2 hours and time for first analgesic in the first 24 hours were evaluated. RESULTS: Eleven patients were excluded from the study with 20 patients remaining in each group. Onset time of anesthesia (6.5 +/- 2.9 minutes v 8.0 +/- 4.1 minutes for lidocaine and ropivacaine groups, respectively) and motor block were similar. In the postoperative period, VPRS was significantly lower in the ropivacaine group in the first 60 minutes (median, 0; P <.05) with significantly more patients in the ropivacaine group pain free (VPRS, 0) up to the first 90 minutes (P >.05). More patients in lidocaine group requested analgesic in the first 2 hours postblock, and only patients in the lidocaine group required supplemental IV morphine in the recovery room. Twenty-four hour analgesic consumption was the same. No local anesthetic-related side effects were observed. CONCLUSIONS: We conclude that 0.375% ropivacaine provides effective anesthesia and superior postoperative analgesia compared with 0.5% lidocaine when forearm IVRA is used.     

Cardiac electrophysiologic properties of bupivacaine and lidocaine compared with those of ropivacaine, a new amide local anesthetic

Ropivacaine is a new amino-amide local anesthetic whose anesthetic profile appears similar to that of bupivacaine. Moreover, in intact animals ropivacaine was reportedly less arrhythmogenic than bupivacaine. These experiments evaluated the cardiac transmembrane electrophysiologic effects of ropivacaine compared with those of lidocaine and bupivacaine in an isolated rabbit Purkinje fiberventricular muscle preparation. Only bupivacaine (3-5 micrograms/ml, 0.92-1.5 x 10(-5) m) significantly decreased Purkinje fiber maximum diastolic potential. Action potential amplitude and maximal rate of depolarization (Vmax) were significantly decreased by all agents in the following order: bupivacaine, ropivacaine, lidocaine. High concentrations of bupivacaine and ropivacaine caused premature depolarizations during phase 3 in some preparations. In addition, bupivacaine altered the action potential configuration by producing "notching" not seen with either ropivacaine or lidocaine. This may reflect effects caused by changes in Ca2+, K+, or electrotonic effects. Ropivacaine and bupivacaine (30 micrograms/ml, 9.2 x 10(-5) m) and lidocaine (100 micrograms/ml, 3.74 x 10(-4) m) caused Purkinje fiber inexcitability and Purkinje fiber-ventricular muscle conduction block. However, the duration of PF inexcitability following exposure to ropivacaine and lidocaine was significantly shorter than in bupivacaine-treated preparation. Duration of PF-VM conduction block also tended to be shorter for ropivacaine than bupivacaine, but significantly longer than lidocaine. In general, ropivacaine is less potent than bupivacaine but more potent than lidocaine in terms of its depressant effect on cardiac excitation and conduction.     

Use of a charged lidocaine derivative, tonicaine, for prolonged infiltration anesthesia

BACKGROUND AND OBJECTIVES: We tested the hypothesis that the duration of cutaneous anesthesia elicited by the permanently charged compound N-phenylethyl lidocaine (tonicaine) would be longer than that elicited by its parent structure, lidocaine, and that it would be less affected by epinephrine (epi), after subcutaneous injection in rats, as a model for infiltration anesthesia. METHODS: Subcutaneous injections were performed on the shaved dorsal skin of rats with either tonicaine or lidocaine (0.1% or 0.5%, n = 8 in each group) with and without epi (1:200,000). Inhibition of the cutaneous trunci muscle reflex was quantitatively evaluated by a blinded observer by the number of times pinpricks failed to elicit the nocifensive motor response out of a total of 6 pinpricks applied to the injected area. RESULTS: Duration of complete nociceptive blockade in the 0.5% tonicaine and lidocaine groups was 619 +/- 47 and 58 +/- 2 minutes, respectively; duration of full recovery in these groups was 1,106 +/- 19 and 86 +/- 3 minutes, respectively. Epi increased the duration of complete block in the 0.5% tonicaine and lidocaine groups to 750 +/- 13 and 97 +/- 11 minutes, respectively, and the duration of full recovery to 1,185 +/- 13 and 172 +/- 6 minutes, respectively. Skin toxicity was seen only in the 0.5% tonicaine with epi group (3 of 8 rats). CONCLUSIONS: Tonicaine is a substantially longer lasting local anesthetic with a delayed onset of action compared with lidocaine and may be useful in situations where long duration of infiltration block is desirable.     

复方利多卡因乳膏对喉罩插入不良反应的抑制作用

目的 观察复方利多卡因乳膏乳癌改良根治术中喉罩插入时不良反应的抑制作用.方法 择期行全麻乳癌改良根治术的患者80例,ASA Ⅰ～Ⅲ级,随机均分为复方利多卡因乳膏喉罩组(A组)和石蜡油喉罩组(B组),将复方利多卡因乳膏和石蜡油涂抹于喉罩表面.麻醉诱导后插入喉罩,记录麻醉诱导前、喉罩插入前、喉罩插入即刻及喉罩插人后3 min患者SBP、DBP、HR,以及术后咽痛或咽部不适的发生率.结果 与喉罩插入前和A组比较,B组喉罩插入即刻和喉罩插入后3min时SBP、DBP明显升高,HR明显增快(P<0.01).A组患者术中呛咳和术后咽痛、咽部不适感发生率明显低于B组(P<0.05).结论 复方利多卡因乳膏能有效抑制全麻乳癌改良根治术中喉罩插人所引起的咽反射和术后咽痛.