Efficacy of Lidocaine for Pain Control in Subcutaneous Infiltration During Liposuction

Transcription

1 Body Contouring Efficacy of Lidocaine for Pain Control in Subcutaneous Infiltration During Liposuction Daniel A. Hatef, MD; Spencer A. Brown, PhD; Avron H. Lipschitz, MD; and Jeffrey M. Kenkel, MD Background: Liposuction remains the most commonly performed aesthetic surgical procedure in the United States. Preoperative infiltration of the subcutaneous tissues with a wetting solution has become standard. These solutions typically contain some amount of lidocaine for pain control. High doses of lidocaine have been demonstrated to be safe, but large amounts of this cardioactive agent during elective cosmetic procedures may be unnecessary. Objective: A study was designed to examine the effects of wetting solutions with lower concentrations of lidocaine on perioperative pain. Methods: Seventeen patients were prospectively randomized to subcutaneous infiltration with one of 3 different lidocaine concentrations: 10 mg/kg, 20 mg/kg, or 30 mg/kg. Intra- and postoperative lidocaine and monoethylglycinexylidide (MEGX) plasma concentrations were measured and the total intraoperative inhalation gas requirements and minimum alveolar concentrations were recorded. Postoperative pain medication requirements were recorded and morphine equivalents were calculated. Patient pain level was subjectively assessed by using a visual analog pain scale. Results: There was no difference in the intraoperative lidocaine or MEGX concentrations between any of the 3 groups. There was also no statistical difference between the 3 groups when comparing intraoperative inhalational gas requirement, postoperative morphine equivalence requirements, or subjective pain using the visual analog scale. Conclusions: Decreasing concentrations of lidocaine in infiltrative wetting solutions did not significantly affect intraoperative anesthesia requirements or postoperative pain with liposuction. Lower concentrations of lidocaine can effectively be used, use of any lidocaine may be unnecessary. Future investigations may examine whether total elimination of lidocaine yields similar results in terms of anesthesia requirements and postoperative pain. (Aesthetic Surg J 2009;29: ) From the Department of Plastic Surgery, University of Texas Southwestern Medical Center, Dallas, TX. According to the most recent statistics from the American Society for Aesthetic Plastic Surgery, lipoplasty is the most popular aesthetic surgical procedure performed in the United States. 1 Since the first official report of lipexeresis by Schrudde 2 in 1980, the surgical technique that we now call liposuction has undergone evolutionary advancement. Updating the previous description by Grazer, 3 it may now be said that modern lipoplasty is the fourth generation of suction liposuction technique (Table). Liposuction has reached the point where a great deal is understood about the basic techniques and aesthetic removal of fat through closed suction techniques; modern liposuction advancements have been focused on decreasing complications and safely facilitating larger amounts of lipoaspirate. The use of subcutaneous infiltrative solutions ( wetting solutions ) in the adipose tissue to be aspirated is now well accepted and widely used. Subcutaneous infiltration facilitates the removal of fat, 4 assists with pain control, 5,6 and (perhaps most importantly) reduces bleeding Although it does not contribute to the vasoconstrictive effect of these solutions, lidocaine has become a mainstay component of wetting solutions for the purpose of anesthesia. Many authors advocate the use of lidocaine because they believe that it eliminates the need for general anesthesia and may allow for extended postoperative pain relief. 5-7 Lidocaine concentrations in wetting solutions often exceed 35 mg/kg, which is well above the manufactur- 122 Volume 29 Number 2 March/April 2009 Aesthetic Surgery Journal

2 Table. History of liposuction Generation Early years Early pioneers Technique nomenclature Technical advancements First Mid-1960s Schrudde 2 Lipexeresis Uterine curettes to remove subcutaneous fat Second Mid-1970s Kesselring 4 Suction lipectomy Specialized cannulae with suction attached; dry technique Third Early 1980s Illouz 17 Lipolysis Popularized use of subcutaneous infiltration Fourth Mid-1980s Fodor 21 ; Hetter 22,23 ; Liposuction, lipoplasty Refinement of subcutaneous infiltration; evolution Klein 5,6 ; Pitman 26 and in technologies (ultrasound-assisted liposuction Pitman et al 40 ; Rohrich [UAL], etc.); advanced understanding of patient and Mathes, 41 Rohrich et al 42 physiology and technique limitations er s recommended dose of 4 to 7 mg/kg. These are large amounts of a drug with the potential for cardiac and neurologic toxicity. 11,12 Despite high total doses of infiltrative lidocaine, it has been shown that tissue levels of lidocaine are subtherapeutic within 8 hours postoperatively. 13 This calls into question previous recommendations regarding the standard use of lidocaine as a component of infiltrative fluids. In an effort to uncover whether or not lower levels of lidocaine can be tolerated, a study was designed to investigate the efficacy of decreased concentrations of lidocaine in subcutaneous infiltrative solutions used during liposuction. PATIENTS AND METHODS Patient Selection and Randomization An application was submitted to and approved by the Institutional Review Board at the University of Texas Southwestern Medical Center in Dallas, TX. The study was approved for 24 patients who would be undergoing liposuction anticipated to be of a volume greater than 1500 cc. The patients would be randomized into 3 groups of differing concentrations of lidocaine in superwet wetting solutions: 100 mg/l, 200 mg/l, and 300 mg/l. Patients were evaluated and asked to participate in the study if they were candidates for liposuction. All patients had received an American Society of Anesthesiologists Physical Status score of I or II. All patients were evaluated and considered candidates for surgery based on previously published exclusion criteria. 14 Intraoperatively, wetting solutions were mixed according to the group that the patient was randomized to: 10 ml, 20 ml, or 30 ml of 1% lidocaine with 1 mg of epinephrine in 1 ml solution added to 1 L of lactated Ringer s solution (1:1,000,000 epinephrine concentration). Postoperatively, patients were kept overnight with nursing supervision. All amounts of lidocaine administered were diligently recorded, including the lidocaine used in the wetting solution and the lidocaine used to minimize pain associated with propofol administration. Specimen Collection Blood samples were collected through a peripheral venous line. Intraoperatively, samples were collected by the anesthesiologist after induction and every 2 hours thereafter. Postoperatively, samples were collected by the patient s nurse every 4 hours. Per laboratory recommendations, blood samples were collected in ethylenediaminetetraacetic acid containing vials. The samples underwent immediate centrifugation at 3000 rpm for 10 minutes at 4 C. Plasma was stored at 80 C until lab analysis. Ten-milliliter samples from each bag of lipoaspirate were collected intraoperatively after homogenizing the specimen by inverting the bag a number of times. The samples were centrifuged at 3000 rpm for 10 minutes at 4 C and supernatant was stored at 80 C for later analysis. Blood samples were analyzed for mean plasma concentrations of lidocaine and monoethylglycinexylidide (MEGX), both in micrograms per liter. Anesthesia Requirement and Pain Assessments Anesthesiologists were blinded to the concentration of lidocaine that the patient received. Sevoflurane inhalational gas was used to maintain anesthesia in all cases and the total inhalational gas requirement was tabulated at the end of the operation. The total amounts of intraoperative inhalational anesthesia for each individual patient were used to calculate the minimum alveolar concentration (MAC) equivalents. Postoperative pain medication usage was diligently recorded and morphine equivalents were calculated for the total amounts of pain medications used by each individual patient. Patient pain was subjectively assessed at 2, 10, and 18 hours postoperatively using a standard Wong Baker FACES visual analog scale. Statistical Analysis All data were maintained in an Excel (Microsoft, Redmond, WA) database. All statistical analyses comparing the 3 groups were performed using a 3-factor analysis of variance and analyses comparing two groups were performed using the Student t-test, both from GraphPad online statistical software ( graphpad.com/quickcalcs/ttest1.cfm). Regression analysis using the Durbin Watson autocorrelation statistic was employed to detect for any correlation between the total amount of lipoaspirate and the anesthetic requirement as well as between lipoaspirate and the postoperative morphine equivalence requirement. These tests were also per- Lidocaine for Pain Control in Subcutaneous Infiltration Volume 29 Number 2 March/April

3 Figure 1. Mean peak plasma lidocaine per group per collection point. Figure 2. Mean peak monoethylglycinexylidide concentration per group per collection point. formed using online statistical software (courtesy Dr. P. Wessa; RESULTS Patient Outcomes The study was ended before 24 patients were enrolled because statistical analysis showed no statistical difference between the groups with regard to pain outcomes and no potential for change in this statistical outcome with completion of the final 7 approved patients. Fifteen women and 2 men completed the study. The mean patient age was 42 years (range, 24 to 56 years). The mean body mass index (BMI) was 27.8 kg/m 2 (range, 23.9 to 38.4 kg/m 2 ). There were no major complications in this group of patients. A review of the operative records revealed that no patient experienced a major episode of bradycardia or hypotension. Peak Plasma Lidocaine Levels Individual patient peak lidocaine levels were between 0.63 and 2.71 g/l. Some patient peak levels were reached within 2 hours postoperatively and others had peak plasma levels as late as 18 hours postoperatively (mean 8 hours). Figure 3. Mean anesthetic minimum alveolar concentration equivalence per group. The group with the overall highest mean peak plasma lidocaine level was the 30 mg/kg group, with a mean peak of 1.69 g/l (standard deviation [SD] 0.74). The 20 mg/kg group had the second highest mean peak, 1.07 g/l (SD 0.36). The 10 mg/kg group had the lowest mean peak, 0.77 g/l (SD 0.1; Figure 1). There was a statistically significant difference when comparing the levels for the 30 mg/kg and 10 mg/kg groups (P.05). Plasma Monoethylglycinexylidide Levels Individual patient peak MEGX levels were between 0.11 g/l and 0.77 g/l. Peak levels were reached at a mean of 16 hours postoperatively (range 4 to 24 hours). The 30 mg/kg group had the highest mean peak plasma MEGX level, 0.41 g/l (SD 0.16). The 10 mg/kg group had the lowest mean peak, 0.12 g/l (SD 0.02; Figure 2). There was a statistically significant difference when comparing the levels for the 30 mg/kg and 10 mg/kg groups (P.01). Intraoperative Anesthesia Requirements There was no statistical difference between the mean amounts of intraoperative inhalational anesthetic per group (Figure 3). The highest mean amount was seen in the 30 mg/kg group, which received an average of MAC equivalents. The lowest mean amount was seen in the 10 mg/kg group, which received an average of MAC equivalents. A 3-factor analysis of variance revealed no statistical difference (P.15). There was no correlation between total MAC requirement and amount of lipoaspirate (P.95). Postoperative Pain Mean postoperative morphine equivalence calculations were shown to be highest for the 30 mg/kg patient group, with mg. The 10 mg/kg group had a mean morphine equivalence of mg (Figure 4). There was no statistically significant difference between the means for the 3 groups (P.4). There was no correlation between postoperative morphine equivalence and amount of lipoaspirate (P.95). 124 Volume 29 Number 2 March/April 2009 Aesthetic Surgery Journal

4 Figure 4. Mean postoperative morphine equivalence per group. Patient subjective pain ratings revealed that pain was highest at 2 hours postoperatively, with an overall mean score of 4.62 (range 1 to 9). There was no statistical difference in patient pain when comparing the means of the groups at any of the 3 time points (Figure 5). DISCUSSION This study shows that lower doses of lidocaine in subcutaneous infiltrative solutions do not lead to higher levels of intraoperative anesthesia gas requirements, higher amounts of postoperative pain medication, or higher subjective pain ratings by patients. The study was ended before the full participation of 24 patients was reached because statistical analysis demonstrated that there was no difference between the groups. It could be argued by some that the results of this study cannot be applied globally, because very high doses of lidocaine ( 35 mg/kg) as seen with the tumescent technique were not employed. The authors would agree that using the true tumescent technique where this is the only form of anesthesia would clearly require high doses of lidocaine in the wetting solution. However, for the purposes of large-volume lipoplasty performed under general anesthesia with the standard superwet 1:1 infiltration, mg/kg concentrations of lidocaine are efficacious and 30 mg/kg concentrations are higher than necessary; in fact, lidocaine may not be necessary at all. The debate centering on the infiltration of operative areas to be defatted through lipoplasty has been going on since the early days of this procedure. Kesselring 4 and Fournier and Otteni 16 were early advocates of the dry technique. They argued that the use of infiltrative solutions distorted the tissues and created a situation in which it was more difficult to achieve an aesthetically pleasing result. Illouz 17 is credited as being the first to introduce the concept of using a subcutaneous wetting solution. He advocated injecting the area to be suctioned with hypotonic saline mixed with hyaluronidase. He called this technique lipolysis and believed that the hypotonic saline created an osmotic lipolysis of the adipocytes, facilitating their removal. Figure 5. Mean subjective pain ratings. Liposuction was introduced in the United States by Teimourian and Fisher 18 in In the early 1980s, the American Society of Plastic and Reconstructive Surgeons formed a task force to study this new technique. Much of the early suction lipectomy was done dry (ie., without the benefit of subcutaneous infiltration). This led to blood loss that sometimes amounted to 40% of the aspirate, nearly ubiquitous transfusions, and limited aspiration volumes. 16,19,20 In an effort to minimize complications secondary to aggressive large-volume liposuction, the superwet technique was introduced in the mid-1980s by Fodor. 21 He advocated the use of epinephrine for vasoconstriction and the infiltration of larger amounts of saline solution in a 1:1 ratio to the volume of aspirate. Hetter 22,23 was another early advocate of wetting solutions he used a solution containing both lidocaine and epinephrine. His work showed that the addition of epinephrine to these saline solutions was a major step forward, because this minimized blood loss and enabled higher volumes to be aspirated. In the late 1980s, Klein 24 introduced what is probably the most well-known version of infiltrative solution: the tumescent solution. This was a mixture of lidocaine, epinephrine, and sodium bicarbonate in saline. He reported essentially bloodless liposuction, with blood being around 1% of the aspirate volume. 5,6,24 Klein 24 was also among the first authors to examine the pharmacokinetics of lidocaine during liposuction. Using his technique, he reported peak plasma levels of lidocaine ranging between 0.38 and 1.86 mg/kg. He repeated this for experimental purposes in an infiltrated patient on whom he did not perform lipoaspiration and revealed that peak plasma lidocaine levels were 2.37 mg/kg. These peak levels were achieved long after surgery, between 11 and 14 hours postoperatively. Klein 23 showed that the level of pain control achieved with the tumescent technique alone allowed liposuction to be performed with no other adjunctive anesthesia and that it could be performed as an outpatient procedure. Clearly, patients who are undergoing more extensive procedures require longer postoperative observation not just for pain control, but also for the monitoring of potential blood loss, fluid shifts, and thromboembolism. 25 Lidocaine for Pain Control in Subcutaneous Infiltration Volume 29 Number 2 March/April

5 Lidocaine used in infiltrating solution has been advocated as an agent that will induce profound local anesthesia, thereby reducing not only postoperative pain, but also the amount of intraoperative systemic anesthesia. 5-7,9,22-24,26,27 Authors have questioned the value of lidocaine in subcutaneous infiltration, suggesting that the use of such large amounts of a pharmacologic agent that has well known cardiac and neurologic toxicity profiles during an elective cosmetic procedure may be unjustified. In 1999, Perry 28 published his experience with a prospective study evaluating postoperative pain when lidocaine was not used on a randomized operative side in 10 patients. It was shown that there was no difference in patients subjective pain ratings between sides and he concluded that lidocaine was completely unnecessary as an adjunct to subcutaneous infiltration in liposuction. Klein 29 contested this conclusion, arguing that the sample size was too small and the concentrations of lidocaine were not high enough to create the desired postoperative analgesia. Klein 29 believed that the operative risk during liposuction stems more from the use of general anesthesia and that this risk is higher than that of lidocaine. However, no valid evidence of this has ever been provided and a vague allusion to the risk of general anesthesia is not sufficient scientific empiricism. This argument remains to be adjudicated in the future. Like any pharmacologic agent, lidocaine is not without side effects. Lidocaine has a long history, being the first amide local anesthetic. It was first synthesized in the 1940s as an injectable local anesthetic. 30 It acts by preventing depolarization through reversible blockage of the sodium channels in the neuron cell membrane. 31 Lidocaine has been associated with serious cardiovascular side effects such as myocardial depression, hypotension, and cardiac arrhythmias. 30 Systemic administration of lidocaine decreases stroke volume, cardiac output, and heart rate; it increases systemic vascular resistance, pulmonary arterial pressure, and pulmonary capillary wedge pressure Lidocaine side effects are first seen at doses around 5 g/ml, with potentially fatal complications seen at 8 g/ml. 31 Lidocaine plasma concentrations of 7 mg/kg are commonly considered to be the upper limit of safety when used with epinephrine (vasoconstriction decreases the speed of its absorption) and this is widely recommended as the maximum dose. 35 It has been shown by many authors that plasma lidocaine levels are well below what is considered dangerous when used in wetting solutions for liposuction. In the first investigation into the pharmacokinetics of lidocaine in liposuction wetting solutions, lidocaine levels were completely undetectable. 36 In 1988, Lillis 7 reported on liposuction with lidocaine levels of 88 mg/kg without any side effects. As stated before, Klein reported some elegant studies 5,6,24 demonstrating that the peak plasma lidocaine was never greater than 2.37 g/ml. He used regression analysis to postulate that the safe level of lidocaine in tumescent solutions was 35 mg/kg. 5 Subsequently, Burk et al 37 demonstrated in a series of 20 patients that the peak level of plasma lidocaine was never greater than 2.13 g/ml and that peak lidocaine was at a mean of 12 hours postoperatively. In a 60-patient series, Ostad et al 38 demonstrated the safety of using 55 mg/kg doses of lidocaine. In this large series of patients with very high concentrations of lidocaine, they found no signs of toxicity. They demonstrated that peak plasma levels of lidocaine were found between 4 to 8 hours after tumescent infiltration and that small levels of lidocaine were still present in the blood at 24 hours postinfiltration. Lipoaspirate analysis showed that low levels of lidocaine were removed with lipoplasty. It was shown that lidocaine doses of up to 76.7 mg/kg were safe for lipoplasty. In spite of all of these data showing the safety of lidocaine in liposuction, the most extensive report of mortality in association with liposuction, published by Rao et al 39 in the New England Journal of Medicine, implicated lidocaine as the main culprit in 3 of the 5 deaths reviewed. These 3 patients experienced profound bradycardia and hypotension intraoperatively; it was felt that this was possibly associated with lidocaine toxicity. Although there is a great deal of evidence suggesting that plasma lidocaine levels will never come close to these kinds of dangerous levels, it was shown by Kenkel et al 13 that the pharmacologically active metabolite of lidocaine, MEGX, is present in the plasma in small amounts and reaches its peak much later than lidocaine, as many as 30 hours postoperatively. 22 There was also shown to be extreme individual variability in absorption of lidocaine, with patients absorbing between 45% to 93% of infiltrative lidocaine. Because of this unpredictability, it is not possible for a surgeon to predict how any specific patient will respond to these large doses of lidocaine. In this same study, Kenkel et al 13 showed that tissue levels of lidocaine are subtherapeutic within 8 hours postoperatively. If tissue levels of lidocaine are at such a low concentration so soon after surgery and the additive effect of lidocaine and MEGX are unclear, this raises the question of whether or not lidocaine is a useful adjunct to subcutaneous infiltration. In light of the results of this study, it is clear that lower concentrations of wetting solution lidocaine can be used without either placing the patient at a great deal of risk for discomfort or increasing operative anesthesia requirements. CONCLUSIONS This investigation proves that using concentrations of 10 mg/kg and 20 mg/kg of lidocaine in wetting solutions leads to no additional anesthesia requirements and no more perioperative pain than higher concentrations of 30 mg/kg. In light of the potentially toxic effects of lidocaine, surgeons are encouraged to attempt the use of lower concentrations. Studies are currently underway to examine whether lidocaine can be completely eliminated from subcutaneous infiltration altogether and whether local anesthetics with lower side effect profiles, such as ropivacane, might be useful alternatives. Future investi- 126 Volume 29 Number 2 March/April 2009 Aesthetic Surgery Journal

6 gations would optimally be randomized, prospective studies conducted at multiple institutions for greater power. These might focus on comparing the complications associated with the 3 major anesthetic techniques used for liposuction: local/tumescent solution only; local/tumescent with sedation; and general anesthesia. DISCLOSURES The authors have no disclosures with respect to the contents of this article. REFERENCES 1. American Society for Aesthetic Plastic Surgery Web site. Cosmetic surgery quick facts: 2005 ASAPS statistics. (Accessed 1/18/2008, at 448&section news-quickfacts.) 2. Schrudde J. Lipexeresis as a means of eliminating local adiposity. Aesthetic Plast Surg 1980;4: Grazer FM. Suction-assisted lipectomy, suction lipectomy, lipolysis, and lipexeresis. Plast Reconstr Surg 1983;72: Kesselring UK. Regional fat aspiration for body contouring. Plast Reconstr Surg 1983;72: Klein JA. Tumescent technique for regional anesthesia permits lidocaine doses of 35 mg/kg for liposuction. J Dermatol Surg Oncol 1990;16: Klein JA. Tumescent technique for local anesthesia improves safety in large volume liposuction. Plast Reconstr Surg 1993;92: Lillis PJ. Liposuction surgery under local anesthesia: limited blood loss and minimal lidocaine absorption. J Dermatol Surg Oncol 1998;14: Dolsky RL. Blood loss during liposuction. Dermatol Clin 1990;8: Samdal F, Amland PF, Bugge JF. Blood loss during liposuction using the tumescent technique. Aesthetic Plast Surg 1994;18: Tsai RY, Lai CH, Chan HL. Evaluation of blood loss during tumescent liposuction in Orientals. Dermatol Surg 1998;24: Davison R, Parker M, Atkinson AJ Jr. Excessive serum lidocaine levels during maintenance infusions: mechanisms and prevention. Am Heart J 1982;104(2 pt 1): Nisse P, Lhermitte M, Dherbecourt V, et al. Fatal intoxication after accidental ingestion of viscous 2% lidocaine in a young child [in French]. Acta Clin Belg Suppl 2002;1: Kenkel JM, Lipschitz AH, Shepherd G, et al. Pharmacokinetics and safety of lidocaine and monoethylglycinexylidide in liposuction: a microdialysis study. Plast Reconstr Surg 2004;114: Rohrich RJ, Beran SJ, Kenkel JM. Ultrasound-assisted liposuction. St. Louis, MO: Quality Medical Publishing, Fodor PB. Lidocaine toxicity issues in lipoplasty. Aesthetic Surg J 2000;20: Fournier PF, Otteni FM. Lipodissection in body sculpturing: the dry procedure. Plast Reconstr Surg 1983;72: Illouz YG. Body contouring by lipolysis: a 5-year experience with over 3000 cases. Plast Reconstr Surg 1983;72: Teimourian B, Fisher JB. Suction curettage to remove excess fat for body contouring. Plast Reconstr Surg 1981;68: Clayton DN, Clayton JN, Lindley TS, Clayton JL. Large-volume lipoplasty. Clin Plast Surg 1989;16: Courtiss EH, Choucair RJ, Donelan MB. Large-volume suction lipectomy: an analysis of 108 patients. Plast Reconstr Surg 1992;89: Fodor PB. Wetting solutions in aspirative lipoplasty: a plea for safety in liposuction. Aesthetic Plast Surg 1995;19: Hetter GP. The effect of low-dose epinephrine on the hematocrit drop following lipolysis. Aesthetic Plast Surg 1984;8: Hetter GP. The use of low concentration epinephrine. In: Hetter GP, editor. Lipoplasty: the theory and practice of blunt suction lipectomy, 2nd ed. Boston: Little, Brown, 1990: Klein JA. Anesthesia for liposuction in dermatologic surgery. J Dermatol Surg Oncol 1988;14: Hatef DA, Kenkel JM, Nguyen MQ, et al. Thromboembolic risk assessment and the efficacy of enoxaparin prophylaxis in excisional body contouring surgery. Plast Reconstr Surg 2008;122: Pitman GH. Tumescent technique for local anesthesia improves safety in large-volume liposuction (discussion). Plast Reconstr Surg 1993;92: Grazer FM. Suction-assisted lipectomy: indications, contraindications, and complications. In: Habal M, editor. Advances in plastic and reconstructive surgery, vol 1. Chicago: Year Book Medical Publishers, Perry AW, Petti C, Rankin M. Lidocaine is not necessary in liposuction. Plast Reconstr Surg 1999;104: Klein JA. Lidocaine is not necessary in liposuction (discussion). Plast Reconstr Surg 1999;104: Lofgren N. Studies on local anesthetics: xylocaine, a new synthetic drug. Stockholm: Hoeggstroms, Brunton LL, editor. Local anesthetics. In: Goodman s & Gilman s. The pharmacological basis of therapeutics, 11th ed. New York: McGraw-Hill, Groban L, Deal DD, Vernon JC, James RL, Butterworth J. Cardiac resuscitation after incremental overdosage with lidocaine, bupivacaine, levobupivacaine, and ropivacaine in anesthetized dogs. Anesth Analg 2001;92: Reiz S, Nath S. Cardiotoxicity of local anaesthetic agents. Br J Anaesth 1986;58: Moller R, Covino BG. Cardiac electrophysiologic properties of bupivacaine and lidocaine compared with those of ropivacaine, a new amide local anesthetic. Anesthesiology 1990;72: Lidocaine hydrochloride in dextrose [package insert]. Deerfield, IL: Baxter U.S., Gumucio CA, Bennie JB, Fernando B, Young VL, Roa N, Kraemer BA. Plasma lidocaine levels during augmentation mammaplasty and suction-assisted lipectomy. Plast Reconstr Surg 1989;84: Burk RW 3rd, Guzman-Stein G, Vasconez LO. Lidocaine and epinephrine levels in tumescent technique liposuction. Plast Reconstr Surg 1996;97: Ostad A, Kageyama N, Moy RL. Tumescent anesthesia with a lidocaine dose of 55 mg/kg is safe for liposuction. Dermatol Surg 1996;22: Rao RB, Ely SF, Hoffman RS. Deaths related to liposuction. N Engl J Med 1999;340: Pitman GH, Aker JS, Tripp ZD. Tumescent liposuction. A surgeon s perspective. Clin Plast Surg 1996;23: Rohrich RJ, Mathes SJ. Suction lipectomy. In: Jurkiewicz MJ, Krizek TJ, Mathes SJ, Ariyan S, editors. Plastic surgery: principles and practice. St. Louis, MO: Mosby, 1990: Rohrich RJ, Beran SJ, Fodor PB. The role of subcutaneous infiltration in suction-assisted lipoplasty: a review. Plast Reconstr Surg 1997;99: SUGGESTED READING Ala-Kokko TI, Löppönen A, Alahuhta S. Two instances of central nervous system toxicity in the same patient following repeated ropivacaineinduced brachial plexus block. Acta Anaesthesiol Scand 2000;44: Albright GA. Cardiac arrest following regional anesthesia with etidocaine or bupivacaine. Anesthesiology 1979;51: Coyle DE, Porembka DT, Sehlhorst CS, Wan L, Behbehani MM. Echocardiographic evaluation of bupivacaine cardiotoxicity. Anesth Analg 1994;79: Feldman HS, Arthur GR, Pitkanen M, Hurley R, Doucette AM, Covino BG. Treatment of acute systemic toxicity after the rapid intravenous injection of ropivacaine and bupivacaine in the conscious dog. Anesth Analg 1991;73: Rigler ML, Drasner K, Krejcie TC, et al. Cauda equina syndrome after continuous spinal anesthesia. Anesth Analg 1991;72: Lidocaine for Pain Control in Subcutaneous Infiltration Volume 29 Number 2 March/April

7 Ruetsch YA, Fattinger KE, Borgeat A. Ropivacaine-induced convulsions and severe cardiac dysrhythmia after sciatic block. Anesthesiology 1999;90: Scott DB, Lee A, Fagan D, Bowler GM, Bloomfield P, Lundh R. Acute toxicity of ropivacaine compared with that of bupivacaine. Anesth Analg 1989;69: Schell RM, Brauer FS, Cole DJ, Applegate RL 2nd. Persistent sacral nerve root deficits after continuous spinal anaesthesia. Can J Anaesth 1991;38: Supported by a grant from the Aesthetic Surgery Education and Research Foundation. Presented at the Annual Meeting of The American Society for Aesthetic Plastic Surgery, New York, NY, April 20, Reprint requests: Jeffrey M. Kenkel, MD, Department of Plastic Surgery, The University of Texas Southwestern Medical Center, 1801 Inwood Rd., WA4, Dallas, TX Jeffrey.Kenkel@UTSouthwestern.edu. Copyright 2009 by The American Society for Aesthetic Plastic Surgery, Inc X/$36.00 doi: /j.asj Volume 29 Number 2 March/April 2009 Aesthetic Surgery Journal