Lidocaine Levels During the First Two Hours of Infiltration of Dilute Anesthetic Solution for Tumescent Liposuction: Rapid Versus Slow Delivery

BACKGROUND: Tumescent anesthesia for liposuction with dilute lidocaine has been well documented to result in peak serum levels 4-14 hours after infiltration. Pharmacokinetic studies have shown that the rate of lidocaine absorption is related not only to dilution, but also to the speed of subcutaneous infiltration. Early studies with a more concentrated solution of lidocaine (1.0%) have shown that with rapid infusion, peak plasma levels may occur within 30 minutes. OBJECTIVE: To determine whether rapid absorption of lidocaine may occur during infusion of tumescent solution by varying the rate of infusion of dilute lidocaine solution (0.05% or 0.1%) and observing serum levels of lidocaine within the first 2 hours of the procedure. METHODS: Eighteen patients participated in this study and were infused with a standard liposuction tumescent formula consisting of lidocaine either 0.05% or 0.1%. The rates of infusion of tumescent anesthesia ranged from 27.1 mg/min up to 200 mg/min infused over a period of 5 minutes to 2 hours. Total lidocaine infused ranged from 7.4 to 57.7 mg/kg. Serum levels of lidocaine were taken every 15 minutes during the first hour of the procedure and repeated at 2 hours. RESULTS: In all 18 patients, lidocaine levels remained significantly below the toxic range and were always less than 2.0 microgram/ml. In 11 patients, lidocaine levels at all time intervals were less than 0.5 microgram/ml. In seven patients, the lidocaine levels ranged from 0.6 to 1.9 microgram/ml at varying intervals. There was no correlation between the maximum dose of lidocaine (mg/kg) or rate of lidocaine delivered (mg/ml) with plasma levels of lidocaine. CONCLUSION: Despite variability, the serum levels of lidocaine remained well within safety limits during infusion of tumescent solution and the first hours of the procedure when infused in rates up to 200 mg/min with spinal needles and/or small diameter multiholed infusion cannulas.     

双侧大腿环形吸脂术中肿胀麻醉利多卡因用量分析

目的:探讨局部肿胀麻醉技术下进行双侧大腿环形吸脂手术中利多卡因用量及是否存在中毒反应。方法:148例全部为女性,年龄19～56岁,平均(30.01±7.91)岁,肥胖指数13.43～43.59,平均23.37±6.82。采用左大腿前、右大腿前、左大腿后、右大腿后侧四个部位环形序贯吸脂术,统计手术中肿胀液的注射量、利多卡因用量以及吸出脂肪和肿胀液数量。连续观察术中、术后病人的临床反应和生命体征。结果:肿胀液注入皮下脂肪数量为3000～9000ml,平均(6009.80±1482.51)ml。吸出皮下脂肪数量1500～7000ml,平均(3105.74±1068.24)ml。术中抽出肿胀液200～3300ml,平均(1312.50±549.92)ml,约占注入量的5%～41.67%,平均(21.84±6.95)%。注入皮下脂肪之利多卡因剂量为27.69～88.42mg/kg,平均(59.45±13.62)mg/kg。术中出血极少,生命体征稳定,术中及术后未见眩晕、耳鸣、幻听、金属味、口周麻木、定向障碍、抽搐、惊厥等利多卡因药物中毒的临床症状。术后站立包扎时个别患者有体位性低血压表现,平卧即可恢复正常。术后大腿围径和形态均有不同程度改善,效果满意。结论:在双侧大腿环形吸脂手术中,采用分部位序贯吸脂方法,可以有效避免利多卡因中毒发生,达到安全有效的结果。     

Prilocaine Plasma Levels and Methemoglobinemia in Patients Undergoing Tumescent Liposuction Involving Less Than 2,000 ml

Background As a reaction to reported adverse outcomes after lidocaine infiltration in tumescent liposuction, prilocaine has gained increasing popularity. Previous studies investigating large-volume liposuction procedures found maximum prilocaine levels and methemoglobinemia up to 12 h postoperatively, suggesting that liposuction should be performed as a hospital procedure only. The aim of this study was to determine prilocaine plasma levels and methemoglobinemia in patients after low- to average-volume liposuction for the purpose of defining the required postoperative surveillance period.Methods In 25 patients undergoing liposuction involving less than 2,000 ml prilocaine levels and methemoglobinemia were measured over 4 h postoperatively. Liposuction was conducted after the tumescent technique using a 0.05% hypotonic prilocaine solution with epinephrine.Results The average prilocaine dose was 6.8 + 0.8 mg/kg, with a maximum dose of 15 mg/kg. The peak prilocaine plasma level of 0.34 g/ml occurred 3 h after the infiltration. The mean methemoglobinemia at this time point was 0.65%. Only one patient demonstrated a slightly elevated methemoglobin level of 1.4%, but lacked any clinical signs of methemoglobinemia. The prilocaine recovery in the aspirate averaged 36 ± 4%, indicating that a large amount is removed by suctioning.Conclusions The patients did not experience high plasma levels of prilocaine or methemoglobinemia undergoing liposuction involving less than 2,000 ml using a 0.05% hypotonic prilocaine solution. The authors therefore conclude that this procedure can be performed safely with a monitoring period of 12 h.     

吸脂术中大剂量使用利多卡因的血药浓度监测及意义

目的 探讨作为局部麻醉剂的利多卡因在肿胀法脂肪抽吸术中的有限剂量是多少，既能达到良好的镇痛效果，又有安全地使用而不产生毒副作用。方法 对１４例大剂量使用低浓度利多卡因作为局麻药的脂肪抽吸术的术中和术后血清利多卡因浓度以免疫荧光测定法进行了动态监测，作出其时间－浓度曲线，并与临床表现相对照。结果 在此类手术中，利多卡因在０．１ｍｇ／ｍｌ的浓度下，加入１／１百万￣１／２百万肾上腺素，其用量可达３５ｍｇ     

肿胀吸脂术疗效与并发症分析

目的　探讨肿胀吸脂术的疗效与并发症的预防。方法　应用肿胀技术对 2 69例进行腹部、大腿等部位吸脂术 ,利多卡因总量最大 3 0 0 0mg ,43mg kg ,吸脂最大量为 475 0ml。结果　本组有术后吸脂部位不平、血清肿等并发症 ,但没有出现利多卡因中毒及肺栓塞等严重并发症 ,大部分受术者对术后效果满意。结论　肿胀吸脂术是一种安全有效的减肥方法。术中需注意操作技巧 ,以预防或减少并发症的发生     

Tumescent anaesthesia

Tumescent anaesthesia describes the practice of injecting a very dilute solution of local anaesthetic combined with epinephrine and sodium bicarbonate into tissue until it becomes firm and tense (tumescent). It was initially described in the field of liposuction but now surgical applications for the technique are widely varied ranging across vascular surgery, breast surgery, plastic surgery and ENT procedures. It is widely used in both hospital- and office-based environments and may form the sole method of anaesthesia for surgery. Advantages include a reduction in blood loss through both epinephrine-induced vasoconstriction as well as hydrostatic compression from the tumescent effect. Sodium bicarbonate reduces pain associated with the injection of an acidic local anaesthetic solution. Due to the unique pharmacokinetic profile of this technique lidocaine doses of 35 mg/kg bodyweight have been shown to be safe for liposuction procedures.Tumescent lidocaine is absorbed very slowly from subcutaneous tissues producing lower, and more delayed, peak blood levels compared to other routes, as well as extended postoperative analgesia. Slow systemic absorption allows the rapid hepatic plasma clearance of lidocaine to maintain safe local anaesthetic blood levels. This slow absorption from subcutaneous tissue has been likened to a depot injection. Careful attention must be given to appropriate local anaesthetic dosage alterations in cases of co-administration with agents affecting hepatic drug clearance or conditions reducing liver blood supply. Adherence to these pharmacological principles has produced an exemplary safety record for this technique to date.     

腰腹部吸脂大容量肿胀麻醉安全性分析

目的:探讨以肿胀麻醉技术一次性吸出3000ml以上脂肪的手术安全性。方法:73例女性,年龄19～62岁,一次性吸出腰腹部脂肪3000～7700ml。统计手术中肿胀液的注射量、利多卡因用量。连续观察术中、术后病人的临床反应和生命体征。结果:肿胀液注射量4000～11500ml,利多卡因用量38.10～92.00mg/kg体重。术中麻醉效果满意,出血少,未见血压降低、呼吸困难、头痛、耳鸣等症状。术后发生体位性低血压11例,发生率15.07%,平卧和补液后即恢复。受术者体形均有明显改善,多数患者体重下降,效果满意。结论:在肿胀麻醉技术下一次性吸出大量腰腹部皮下脂肪是有一定风险的,术后应常规留院观察12h以上。     

吸脂术中大剂量使用利多卡因的血药浓度监测及意义

目的探讨作为局部麻醉剂的利多卡因在肿胀法脂肪抽吸术中的极限剂量是多少,既能达到良好的镇痛效果,又能安全地使用而不产生毒副作用。方法对１４例大剂量使用低浓度利多卡因作为局麻药的脂肪抽吸术的术中和术后血清利多卡因浓度以免疫荧光测定法进行了动态监测,作出其时间浓度曲线,并与临床表现相对照。结果在此类手术中,利多卡因在０１ｍｇ／ｍｌ的浓度下,加入１／１百万～１／２百万肾上腺素,其用量可达３５ｍｇ／ｋｇ体重而血清高峰浓度仍在安全范围内,无中毒症状,既可减轻病人的疼痛,又可减少出血,提高安全性,增加脂肪抽吸量。结论本研究为肿胀法吸脂术中大剂量使用利多卡因的临床实践提供了理论依据。     

Tumescent technique for local anesthesia

Tumescent local anesthesia was originally used in liposuction but is also carried out for other plastic, cosmetic, dermatological procedures and for surgery of the venous system, often in outpatients. For this purpose, large amounts of fluids containing diluted lidocaine or prilocaine and epinephrine are infused subcutaneously. In this review of the literature, this technique is assessed in view of potential anesthesiological complications such as intoxication with lidocaine, prilocaine, overdosage of epinephrine or overload with fluids. While originally a lidocaine dosage of 35 mg/kg b.w. was considered to be safe, dosages were then increased to 55 mg/kg b. w. and even 90 mg/kg b. w. without data showing the safety of such high doses. Published data of plasma concentrations were obtained from small numbers of patients, showing that the concentrations were below 5 microg/ml which is considered the nontoxic range. The maximum levels were observed after 4 - 12 hours, if epinephrine was used. In a few patients, however, the values had not yet begun to decrease at the end of the 23 hours observation period. Replacing lidocaine by prilocaine shifts the problem of toxicity to that of the formation of methemoglobine, which can reach levels of more than 10 %. Data about effects of high-dose epinephrine in the literature are sparse, but tachycardia, arrhythmias and hypertension remain a major concern. Although fluids are applied subcutaneously, an overload with fluids may occur. Cases of lung edema have been reported, however, hypovolemia caused by a loss of fluid into the third space cannot be excluded. Because of these possible complications, tumescent local anesthesia should be employed in outpatients with great care. Patients should be monitored during the procedure and for a sufficient period of time thereafter by adequately trained staff. Patients with cardiac or pulmonary risk factors should not undergo tumescent local anesthesia.     

Small-dose dopamine increases epidural lidocaine requirements during peripheral vascular surgery in elderly patients

We studied 20 patients over the age of 65 yr undergoing prolonged peripheral vascular surgery under continuous lidocaine epidural anesthesia, anticipating that the increased hepatic metabolism caused by small-dose IV dopamine would lower plasma lidocaine concentrations. Subjects were assigned (random, double-blinded) to receive either a placebo IV infusion or dopamine, 2 microg. kg(-1). min(-1) during and for 5 h after surgery. Five minutes after the IV infusion was started, 20 mL of 2% lidocaine was injected through the epidural catheter. One-half hour later, a continuous epidural infusion of 2% lidocaine at 10 mL/h was begun. The epidural infusion was temporarily decreased to 5 mL/h or 5 mL boluses were added to maintain a T8 analgesic level. Arterial blood samples were analyzed for plasma lidocaine concentrations regularly during and for 5 h after surgery. Plasma lidocaine concentrations increased continuously during the epidural infusion and, despite wide individual variation, were similar for the two groups throughout the observation period. During the observation period, the mean maximal plasma lidocaine concentration was 5.8 +/- 2.3 microg/mL in the control group and 5.7 +/- 1.2 microg/mL in the dopamine group. However, the mean hourly lidocaine requirement during surgery was significantly different, 242 +/- 72 mg/h for control and 312 +/- 60 mg/h for dopamine patients (P < 0.03). At the end of Hour 4, the last period when all 20 patients were still receiving the epidural lidocaine infusion, the total lidocaine requirement was significantly different, 1088 +/- 191 mg for the control group and 1228 +/- 168 mg for the dopamine group (P < 0.05). Despite very large total doses of epidural lidocaine (1650 +/- 740 mg, control patients, and 1940 +/- 400, dopamine patients) mean maximal plasma concentrations remained below 6 microg/mL, and no patient exhibited signs or symptoms of toxicity. We conclude that small-dose IV dopamine increased epidural lidocaine requirements, presumably as a consequence of increased metabolism. IMPLICATIONS: We tested dopamine, a drug that increases liver metabolism of the local anesthetic lidocaine to determine if it would prevent excessively large amounts of lidocaine in the blood during prolonged epidural anesthesia in elderly patients. Dopamine did not alter the blood levels of lidocaine, but it did increase the lidocaine dose requirement to maintain adequate epidural anesthesia.     

吸脂术中大剂量使用利多卡因的血药浓度监测及意义

目的探讨作为局部麻醉剂的利多卡因在肿胀法脂肪抽吸术中的极限剂量是多少,既能达到良好的镇痛效果,又能安全地使用而不产生毒副作用。方法对14例大剂量使用低浓度利多卡因作为局麻药的脂肪抽吸术的术中和术后血清利多卡因浓度以免疫荧光测定法进行了动态监测,作出其时间-浓度曲线,并与临床表现相对照。结果在此类手术中,利多卡因在0.1mg/ml的浓度下,加入1/1百万～1/2百万肾上腺素,其用量可达35mg/kg 体重而血清高峰浓度仍在安全范围内,无中毒症状,既可减轻病人的疼痛,又可减少出血,提高安全性,增加脂肪抽吸量。结论本研究为肿胀法吸脂术中大剂量使用利多卡因的临床实践提供了理论依据。     

Skin Retraction After Liposuction in Patients Over the Age of 40

BACKGROUND: A commonly held misperception regarding liposuction in patients over 40 years of age is that the skin will not retract and redrape following removal of the fat. OBJECTIVE: In order to evaluate tissue retraction in the abdomen, neck, and arms in patients undergoing liposuction after 40 years of age, the following study was conducted. METHOD: A total of 58 patients ranging in age from 40 to 75 years underwent liposuction. Thirty had liposuction of the abdomen, 20 had liposuction of the neck, and 8 had liposuction of the arms. Measurements in inches and weight in pounds were recorded before and at 1, 3, and 6 months after the procedure. RESULTS: Ninety percent of the patients were women. The rest of the patients were men. The average age of the patients undergoing liposuction of the abdomen was 55 years old. The average supranatant fat extracted from these patients was 1725 ml, with an average lidocaine dose of 36 mg/kg of body weight. The patients who had liposuction of the abdomen demonstrated an average weight loss of 5 lb and a decrease of 3 inches in waistline 6 months after the procedure. For those patients who had liposuction of the neck, the average age was 57 years old. The average supranatant fat extracted from these patients was 75 ml, with an average lidocaine dose of 4 mg/kg of body weight. The patients who had liposuction of the neck decreased an average of 1.3 inches in circumference without any weight change 6 months after the procedure. For those patients having liposuction of the arms, the average age was 44 years. The average supranatant fat extracted from these patients was 525 ml, with an average lidocaine dose of 16 mg/kg of body weight. The patients who had liposuction of the arms had an average of 0.5 inch decrease in circumference without any weight change 6 months after the procedure. The cosmetic results were good to excellent. Our highest lidocaine dose occurred in a patient having suction of the abdomen and was 71 mg/kg of body weight. No patients experienced any objective or subjective signs of lidocaine toxicity. CONCLUSION: Tumescent liposuction of the abdomen, neck, and arms is a safe alternative for contour improvement with good cosmetic results in patients over 40 years of age.     

Plasma determination of lidocaine and bupivacaine after caudal anesthesia in children

Serum concentrations of lidocaine and plasma concentrations of bupivacaine were measured so as to assess the risk of systemic toxicity following their administration by the caudal route in children, and study their pharmacokinetic profiles according to age. The serum concentrations of lidocaine were measured by immuno-enzymology in 37 children (23 +/- 13 kg) during the first hour after administration of 7 mg . kg-1. The plasma concentrations of bupivacaine were measured by high performance liquid chromatography in 40 children (18.03 +/- 8.90 kg) during the first hour after administration of 2.5 mg . kg-1. The greatest concentrations observed between 15 and 30 min after the injection were of 2.40 +/- 0.86 micrograms . ml for lidocaine and 0.93 +/- 0.44 microgram . ml-1 for bupivacaine. Higher values were observed in infants weighing less than 12 kg where they reached 2.89 +/- 0.72 and 1.52 +/- 0.68 micrograms . ml-1 respectively. These results showed that caudal anaesthesia with lidocaine (7 ml . kg-1) and bupivacaine (2.5 ml . kg-1) was a safe technique for children, giving average plasma concentrations inferior to toxic values. However, it seemed prudent not to give more than the prescribed doses in the small infant.     

When One Liter Does Not Equal 1000 Milliliters: Implications for the Tumescent Technique

BACKGROUND: Tumescent anesthesia has revolutionized the practice of liposuction. Inherent to the tumescent technique is the use of large volumes of dilute solutions of lidocaine with epinephrine instilled into subcutaneous fat deposits. Precise formulation of the tumescent anesthesia is essential to liposuction technique. OBJECTIVES: To determine the actual volumes of fluids contained in intravenous (IV) 1 L bags of saline used for tumescent anesthesia, to calculate volumes supplied in 50 cc stock solutions of 1% lidocaine, and to measure the amount of fluid retained by peristalic pump tubing used for infiltration. METHODS: The amount of saline contained in fifteen 1 L saline bags from three different manufacturers was calculated using graduated cylinder methodology. The volume of tumescent anesthesia retained by peristaltic pump tubing was calculated by expelling the contents of the filler tubing and measuring it. The actual amount of 1% lidocaine contained within fifteen 50 ml "stock" 1% lidocaine bottles from different manufacturers and with different lot numbers was calculated by transferring the contents into graduated cylinders. RESULTS: One liter IV bags of physiologic saline contained an average volume of 1051 ml (range 1033-1069 ml). The 50 ml bottles of 1% lidocaine with epinephrine contain an average of 54 ml of anesthetic (range 52.5-55 ml). Infusion tubing for use with peristaltic pumps may retain 46-146 ml of tumescent anesthesia. CONCLUSION: One liter IV bags of normal saline contain more than 1 L, having an average volume of 1051 ml. Common methods of preparation of 0.05% lidocaine with 1:1,000,000 epinephrine and sodium bicarbonate can increase the total amount of fluid in the tumescent anesthesia to 1112 ml for 0.05% solutions and preparation of a 0.1% solution contains an average volume of 1162 ml. The fluid contained in each bag may be increased over labeling by as much as 11-16%. Final concentrations of lidocaine in tumescent anesthesia may be reduced due to extra fluids. A 0.05% lidocaine solution may have a final lidocaine concentration of 0.045% and a 0.1% lidocaine solution may have an actual concentration of 0.086%. Lidocaine concentrations may be reduced by as much as 10-14%. Extra anesthesia fluid is also contained within stock 50 ml bottles of 1% lidocaine. Dermatologic surgeons should be aware of extra fluid possibly contained within tumescent anesthetic preparation, be aware of the extra anesthesia supplied in standard 1% lidocaine bottles, and possible decreased concentration of lidocaine within the final tumescent anesthesia.     

Ventilatory response to CO2 following intravenous and epidural lidocaine

The authors determined the effects of intravenous infusion and epidural administration of lidocaine on the control of ventilation in two groups of eight healthy unpremedicated subjects. In the intravenous group, an injection of 1.5 mg/kg lidocaine was followed by an infusion at a rate of 60 micrograms X kg-1 X min-1 for 30 min. The slope of the ventilatory response to CO2 was significantly increased (P less than 0.05) from its control value (2.65 +/- 1.22 1 X min-1 X mmHg-1 [mean +/- SD]) at the end of the infusion (58%), while plasma lidocaine level was at 3.14 +/- 0.82 microgram/ml. The correlation between individual plasma lidocaine levels and the changes in the slope of the ventilatory response to CO2 was significant (r = 0.58, n = 24, P less than 0.01). In the epidural group, after the administration of 5 mg/kg of lidocaine, the slope of the ventilatory response to CO2 increased significantly (P less than 0.05) from its control value (1.52 +/- 0.75 1 X min-1 X mmHg-1) at 15 (+22%) and 25 min (+42%), while plasma lidocaine levels were at 1.79 +/- 0.42 and 2.22 +/- 0.47 microgram/ml, respectively. In both groups, resting minute ventilation and end-tidal CO2 values remained unchanged. These results suggest that epidural lidocaine has a stimulating effect on the ventilatory control mechanisms that results from the systemic effect of the drug.     

Does epidural anesthesia have general anesthetic effects? A prospective, randomized, double-blind, placebo-controlled trial

BACKGROUND: Clinically, patients require surprisingly low end-tidal concentrations of volatile agents during combined epidural-general anesthesia. Neuraxial anesthesia exhibits sedative properties that may reduce requirements for general anesthesia. The authors tested whether epidural lidocaine reduces volatile anesthetic requirements as measured by the minimum alveolar concentration (MAC) of sevoflurane for noxious testing cephalad to the sensory block. METHODS: In a prospective, randomized, double-blind, placebo-controlled trial, 44 patients received 300 mg epidural lidocaine (group E), epidural saline control (group C), or epidural saline-intravenous lidocaine infusion (group I) after premedication with 0.02 mg/kg midazolam and 1 microg/kg fentanyl. Tracheal intubation followed standard induction with 4 mg/kg thiopental and succinylcholine 1 mg/kg. After 10 min or more of stable end-tidal sevoflurane, 10 s of 50 Hz, 60 mA tetanic electrical stimulation were applied to the fifth cervical dermatome. Predetermined end-tidal sevoflurane concentrations and the MAC for each group were determined by the up-and-down method and probit analysis based on patient movement. RESULTS: MAC of sevoflurane for group E, 0.52+/-0.18% (+/- 95% confidence interval [CI]), differed significantly from group C, 1.18+/-0.18% (P < 0.0005), and from group I, 1.04+/-0.18% (P < 0.001). The plasma lidocaine levels in groups E and I were comparable (2.3+/-1.0 vs. 3.0+/-1.2 microg/ml +/- SD). CONCLUSIONS: Lidocaine epidural anesthesia reduced the MAC of sevoflurane by approximately 50%. This MAC sparing is most likely caused by indirect central effects of spinal deafferentation and not to systemic effects of lidocaine or direct neural blockade. Thus, lower concentrations of volatile agents than those based on standard MAC values may be adequate during combined epidural-general anesthesia.     

Plasma concentrations of lidocaine and its principal metabolites during intermittent epidural anesthesia

Plasma concentration-time courses of lidocaine and its principal metabolites (monoethylglycinexylidide, MEGX, and glycinexylidide, GX) were studied during intermittent epidural injections of lidocaine HCl in eight female patients (ASA status 1). The initial dose (320-400 mg without epinephrine) followed by top-up injections of about 60% of the mean initial dose every 35-55 min resulted in a plasma accumulation of lidocaine: the peak concentration increased from 2.30 +/- 0.46 (mean +/- SD) microgram/ml following the first injection and 3.34 +/- 0.76 microgram/ml after the second, to 4.11 +/- 0.72 microgram/ml following the third. The maximum concentrations of MEGX and GX were 0.66 +/- 0.22 and 0.28 +/- 0.08 microgram/ml, respectively. A pharmacokinetic model could successfully fit the entire plasma concentration-time profile of lidocaine during repeated epidural injections (r2 = 0.886 to 0.983). Such pharmacokinetic variables as elimination half-life (t1/2, 2.33 +/- 0.43 h), apparent volume of distribution divided by bioavailability (Vd/F, 2.51 +/- 0.61 l/kg), and clearance divided by bioavailability (Cl/F, 11.65 +/- 1.21 ml X kg-1 X min-1) obtained from the female patients were in reasonable agreement with those reported from healthy females receiving the intravenous lidocaine HCl. A computer-aided simulation generated from using the mean kinetic data in a 50-kg woman predicted that plasma lidocaine concentration would reach the postulated toxic range (approximately equal to 6 microgram/ml) after the fourth supplementary dose under a similar dosing scheme as performed in this study. In conclusion, an accumulation of lidocaine in plasma occurs during a usual intermittent epidural dosing.(ABSTRACT TRUNCATED AT 250 WORDS)     

Research on the effect of atenolol on lidocaine pharmacokinetics in rats

The aim was to determine the influence of atenolol on lidocaine pharmacokinetics in rats for one hour interval of time (average of a dental intervention). The study was carried out on 2 groups of Wistar rats treated with saline solution (0.5 ml/kg), respectively with atenolol (1.5 mg/kg), administered orally 24 hours and 3 hours before intraperitoneal administration of lidocaine (1.5 mg/kg). Blood samples were collected before and 5, 10, 20, 30, 60 minutes after lidocaine administration. Lidocaine plasma concentrations were determined by HPLC. Some pharmacokinetic parameters of lidocaine were statistically significant higher (p < 0.05, ANOVA) for the rats treated with atenolol compared with control group: Cmax (196.97 +/- 2.15 ng/ml vs. 125.29 +/- 2.90 ng/ml), AUD (7734.07 +/- 129.06 ng/ ml x min vs. 4478.57 +/- 296.61 ng/ml x min), AUC1 after 5 minutes (314.23 +/- 6.59 ng/ml x min vs. 190.71 +/- 19.75 ng/ml x min). Tmax was 20 minutes, similar for both groups. CONCLUSION: local anesthesia with lidocaine might be enhanced in the presence of atenolol compared to controls.     

Perioperative intravenous lidocaine has preventive effects on postoperative pain and morphine consumption after major abdominal surgery

Sodium channel blockers are approved for IV administration in the treatment of neuropathic pain states. Preclinical studies have suggested antihyperalgesic effects on the peripheral and central nervous system. Our objective in this study was to determine the time course of the analgesic and antihyperalgesic mechanisms of perioperative lidocaine administration. Forty patients undergoing major abdominal surgery participated in this randomized and double-blinded study. Twenty patients received lidocaine 2% (bolus injection of 1.5 mg/kg in 10 min followed by an IV infusion of 1.5 mg. kg(-1). h(-1)), and 20 patients received saline placebo. The infusion started 30 min before skin incision and was stopped 1 h after the end of surgery. Lidocaine blood concentrations were measured. Postoperative pain ratings (numeric rating scale of 0-10) and morphine consumption (patient-controlled analgesia) were assessed up to 72 h after surgery. Mean lidocaine levels during surgery were 1.9 +/- 0.7 microg/mL. Patient-controlled analgesia with morphine produced good postoperative analgesia (numeric rating scale at rest, 相似文献   

Impact of Large-Volume Liposuction on Serum Lipids in Orientals: A Pilot Study

Recent advances in liposuction techniques now make it possible to remove considerable amounts of subcutaneous adipose tissue. However, the metabolic consequences of this procedure are not well documented. The aim of this study was to identify the effects from the surgical removal of subcutaneous fat on the body weights and serum lipids of patients who have undergone large-volume liposuction. In this study, eleven consecutive patients with a minimum aspirate volume of 5,000 ml were evaluated, and their serum lipids were measured at a postoperative 2-month follow-up assessment. Tumescent fluid was infiltrated using the superwet technique. The liposuction device used was a Liposlim power-assisted liposuction system. The amount of solution infiltrated and the volume of aspirate were measured. Pre- and postoperative serum lipids, body weights, and body mass indices were compared. Statistical analysis was performed on lipid profile changes and aspirate volumes using Spearman's correlations. The average volumes of infiltrate and aspirate were 7,241 and 6,790 ml, respectively. Mean body weight decreased from 64.5 +/- 18.8 to 59.9 s +/- 17.8 kg (p < 0.01). The change in body weight per 1 l of aspirate volume was 0.67 +/- 0.10 kg/l. The mean body mass index dropped from 23.8 +/- 4.4 to 22.0 +/- 4.2 kg/m(2) (p < 0.01), and the mean total serum cholesterol levels from 168.2 +/- 23.6 to 162.9 +/- 26.5 mg/dl, an average of 3.2%. The mean low-density lipoprotein (LDL) decreased from 94.3 +/- 20.5 to 89.5 +/- 19.0 mg/dl, a 5.1% drop, and the mean high-density lipoprotein (HDL) decreased from 55.8 +/- 9.5 to 53.7 +/- 10.7 mg/dl, a 3,8% drop. The mean HDL/LDL proportion increased from 62.6 +/- 20.9% to 63.5 +/- 22.4%, averaging 1.4%. However, no significant correlation was found between the aspirated volume of fat and lipid profile change. In conclusion, over a 2-month period, large-volume liposuction reduced weight and total cholesterol level and increased the HDL/LDL ratio. The authors hope to discover whether the therapeutic impact of liposuction is long-lasting, and to determine whether it reduces the morbidity and mortality associated with obesity.