Plasma concentrations of monoethylglycinexylidide during and after breast augmentation

MEGX (monoethylglycinexylidide) is the main metabolite of lidocaine and is 83 percent as potent as an antiarrhythmic drug and with the same toxicity as lidocaine. In this study, plasma levels of MEGX were measured in 10 other wise healthy women during and after breast augmentation. A total dose of 825 to 1,280 mg of lidocaine of 0.2% and 0.5% lidocaine with epinephrine corresponding to 16.3 to 21.8 mg/kg (mean, 18.2 mg/kg) was injected in the spatium between the pectoralis muscle and the mammary gland. The peak plasma concentrations of MEGX varied between 0.40 and 0.99 microg/ml (mean, 0.49 microg/ml) and occurred between 8 and 12 hours (mean, 9.1 hours), postoperatively. In three patients, the concentration of MEGX was still increasing after 12 hours. In comparison, the peak plasma concentrations of lidocaine varied between 0.96 and 3.12 microg/ml (mean, 1.49 microg/ml) and occurred between 4 and 12 hours (mean, 7.3 hours) after the end of the injection. The peak lidocaine + MEGX concentrations varied between 1.45 and 3.58 microg/ml (mean, 2.02 microg/ml) and occurred between 5 and 12 hours (mean, 8.5 hours), postoperatively. These data suggest that MEGX might contribute to lidocaine toxicity when high doses of lidocaine are injected. The substantial interindividual variation strongly indicates that recommendations about maximum safe doses of lidocaine should be made with caution.     

Plasma concentrations of lidocaine and alpha1-acid glycoprotein during and after breast augmentation

Plasma levels of lidocaine and the main binding proteins of lidocaine in plasma alpha1-acid glycoprotein (AAG) and albumin were measured in 10 otherwise healthy women during and after breast augmentation. A total dose of 825 to 1280 mg of 0.2% and 0.5% lidocaine with epinephrine corresponding to 16.3 to 21.8 mg/kg (mean 18.2 mg/kg) was injected in the spatium between the pectoralis muscle and the mammary gland. The peak plasma concentrations of lidocaine varied between 0.96 and 3.12 microg/ml (mean 1.49 microg/ml) and occurred between 4 and 12 hours (mean 7.3 hours) postoperatively. The plasma concentration of AAG varied between 0.42 and 1.73 g/liter (mean 0.49 g/liter, normal range 0.54 to 1.17 g/liter). There was a significant correlation between the plasma concentration of AAG and lidocaine. The mean concentration of albumin was 37.2 g/liter, ranging from 33 to 42 g/liter (normal range 35 to 50 g/liter). No patient showed signs of lidocaine toxicity. These data indicate that a dose of 20 mg/kg of lidocaine with epinephrine probably is safe in breast augmentation when the drug is administrated as described in this study. There are significant individual differences in the plasma concentration curves between patients, partly explained by different concentrations of AAG. Further studies with a larger number of patients are needed to establish definitive recommendations of safe maximal doses.     

Pharmacokinetics and safety of epinephrine use in liposuction

Patients are routinely exposed to high-dose epinephrine infiltration during large-volume liposuction. Because of the serious cardiovascular side-effect profile of catecholamine overdose, the authors examined the safety of larger-volume liposuction by assessing epinephrine pharmacokinetics. Five female volunteers with American Society of Anesthesiologists physical status of I or II, aged 29 to 40 years and weighing 75.9 to 95 kg, underwent liposuction. The wetting solution contained 7.3 mg (SEM, 0.7 mg) of epinephrine, corresponding to 0.09 mg/kg (0.04 mg/kg). Total plasma epinephrine and norepinephrine concentrations were assessed by high-performance liquid chromatography. Approximate exogenous epinephrine absorption was calculated after correction for estimated endogenous epinephrine production. Pharmacokinetic assessments were performed using standard equations. The total plasma epinephrine peak occurred at the final intraoperative reading (5 hours after induction) and was 323 pg/ml (24.8 pg/ml), three to four times maximum baseline resting levels. The norepinephrine level was slightly elevated throughout the study period, with a reversal of the normal epinephrine/norepinephrine ratio (<0.5:1) demonstrated intraoperatively (>5:1). Estimated time to peak exogenous epinephrine level ranged from 1 to 4 hours from the start of infiltration. Area under the plasma concentration versus time curve was approximately 2089 to 2610 pg x hour/ml. Peak exogenous epinephrine concentration was estimated to be 286 to 335 pg/ml. Clearance was 764,508 ml/hour and volume of distribution was 0.4 liter/kg (0.006 liter/kg). Total absorbed epinephrine was estimated, 1.8 mg to 2.2 mg, equivalent to 25 to 32 percent of the infiltrated dose. The reversal of the normal epinephrine/norepinephrine ratio and the fact that norepinephrine levels were within normal range implied that the majority of plasma epinephrine measured was exogenously infiltrated and not endogenously synthesized. On the basis of these observations, pharmacokinetic analyses were performed. Although unequivocal toxic epinephrine levels were not demonstrated, epinephrine peaks were three to four times the maximum observed in normal resting patients. Peak levels were comparable to those observed during major physiologic stresses, such as exercising to exhaustion, open abdominal surgery, or cross-clamping the aorta during surgical repair. Furthermore, epinephrine has been associated with myocardial infarction, arrhythmias, and fatal asystole in susceptible patients at these levels. Patients should be carefully screened for clinical evidence of hemodynamic and cardiac pathology before larger-volume liposuction is undertaken, as it may result in unnecessary high risk for patients who have preexisting cardiovascular disorders. Healthy American Society of Anesthesiologists physical status I or II patients should have sufficient cardiac reserve to tolerate these catecholamine levels.     

Electrolyte and plasma enzyme analyses during large-volume liposuction

Substantial fluid shifts occur during liposuction as wetting solution is infiltrated subcutaneously and fat is evacuated, causing potential electrolyte imbalances. In the porcine model for large-volume liposuction, plasma aspartate aminotransferase and alanine transaminase levels were elevated following liposuction. These results raised concerns for possible mechanical injury and/or lidocaine-induced hepatocellular toxicity in a clinical setting. The first objective of this human model study was to explore the effect of the liposuction procedure on electrolyte balance. The second objective was to determine whether elevated plasma aminotransferase levels were observed subsequent to large-volume liposuction. Five female volunteers underwent three-stage, ultrasound-assisted liposuction. Blood samples were collected perioperatively. Plasma levels of sodium, potassium, venous carbon dioxide, blood urea nitrogen, chloride, and creatinine were determined. Liver function analyte levels were measured, including albumin, total protein, aspartate aminotransferase, and alanine transaminase, alkaline phosphatase, gamma-glutamyl transpeptidase, and total bilirubin. To further define intracellular enzyme release, creatine kinase levels were measured. Mild hyponatremia was evident postoperatively (134 to 136 mmol/liter) in four patients. Hypokalemia was evident intraoperatively in all subjects (mean +/- SEM; 3.3 +/- 0.16 mmol/liter; range, 3.0 to 3.4 mmol/liter). Hypoalbuminemia and hypoproteinemia were observed throughout the study (baseline: 2.9 +/- 0.2 g/dl; range, 2.6 to 3.5 g/dl), decreasing to 10 to 40 percent 24 hours postoperatively (2.0 +/- 0.2 g/dl; range, 1.7 to 2.1 g/dl). Aspartate aminotransferase, alanine transaminase, and creatine kinase levels were significantly elevated after the procedure (190 +/- 47.1 U/liter, 50 +/- 7.7 U/liter, and 11,219 +/- 2556.7 U/liter, respectively) (p < 0.01). Release of antidiuretic hormone and even mildly hypotonic intravenous fluid infiltration have long been known to cause hyponatremia postoperatively. Intraoperative hypokalemia is associated with hypocarbia and respiratory alkalosis and the elevated epinephrine levels observed in the concurrent study. Factors having the greatest initial impact on diminished serum albumin and protein levels postoperatively are redistribution and hemodilution. Subsequent diminished viscosity may significantly affect postoperative hemodynamics. Elevated aspartate aminotransferase, alanine transaminase, and creatine kinase levels are associated with skeletal muscle injury, adipocyte lysis, and/or hepatic damage. Therefore, tissue injury is associated with large-volume liposuction as observed in several cellularly released enzymes. Future clinical studies are required to determine the degree of injury and specific tissues that are damaged or sensitive to mechanical trauma and/or drugs used in large-volume liposuction.     

Simultaneous determination of local anesthetics including ester-type anesthetics in human plasma and urine by gas chromatography–mass spectrometry with solid-phase extraction

The present study describes the simultaneous determination of seven different kinds of local anesthetics and one metabolite by GC–MS with solid-state extraction: Mepivacaine, propitocaine, lidocaine, procaine (an ester-type local anesthetics), cocaine, tetracaine (an ester-type local anesthetics), dibucaine (Dib) and monoethylglycinexylidide (a metabolite of lidocaine) were clearly separated from each other and simultaneously determined by GC–MS using a DB-1 open tubular column. Their recoveries ranged from 73–95% at the target concentrations of 1.00, 10.0 and 100 μg/ml in plasma, urine and water. Coefficients of variation of the recoveries ranged from 2.3–13.1% at these concentrations. The quantitation limits of the method were approximately 100 ng/ml for monoethylglycinexylidide, propitocaine, procaine, cocaine, tetracaine and dibucaine, and 50 ng/ml for lidocaine and mepivacaine. This method was applied to specimens of patients who had been treated with drip infusion of lidocaine, and revealed that simultaneous determination of lidocaine and monoethylglycinexylidide in the blood and urine was possible.     

The tumescent technique: the effect of high tissue pressure and dilute epinephrine on absorption of lidocaine

Injection of lidocaine into the subcutaneous tissues by the tumescent technique results in a delayed absorption of the local anesthetic and has allowed clinicians to exceed the maximum recommended dose of lidocaine without reported complications. However, little knowledge exists about the mechanisms that permit such high doses of lidocaine to be used safely with this technique. The presence of low concentration epinephrine and the increased tissue pressure resulting from the tumescent injection have both been implicated as important factors, but neither has been studied in patients whose results were not altered by the variability of the suction procedure. The purpose of this work was to determine the effect of tissue pressure during tumescent injection and presence of low concentration epinephrine on the absorption of lidocaine from subcutaneous tissues in human volunteers. Twenty healthy female human volunteers were randomized into four study groups. After body fat measurements, all subjects received an injection of 7 mg/kg of lidocaine into the subcutaneous tissues of both lateral thighs. The injected solution consisted of 0.1% lidocaine and 12.5 meq/liter sodium bicarbonate in normal saline with or without 1:1,000,000 epinephrine. Tissue pressure was recorded during injection using a specially designed double-barreled needle. The time required for injection was also recorded. Subjects in group 1 received lidocaine with epinephrine injected by a high-pressure technique. Group 2 subjects received lidocaine with epinephrine injected by a low-pressure technique. Group 3 subjects received lidocaine without epinephrine injected under high pressure. Group 4 subjects received lidocaine without epinephrine injected under low pressure. Following injection, sequential blood samples were drawn over a 14-hour period, and plasma lidocaine concentrations were determined by gas chromatography. No suction lipectomy was performed. Maximum tissue pressure during injection was 339 +/- 63 mmHg and 27 +/- 9 mmHg using high- and low-pressure techniques, respectively. Addition of 1:1,000,000 epinephrine, regardless of the pressure of injected fluid, significantly delayed the time to peak plasma concentration by over 7 hours. There was no significant difference in the peak plasma concentration of lidocaine among the four groups. Peak plasma concentrations greater than 1 mcg/ml were seen in 11 subjects. Epinephrine (1:1,000,000) significantly delays the absorption of lidocaine administered by the tumescent technique. High pressure generated in the subcutaneous tissues during injection of the solution does not affect lidocaine absorption. The delay in absorption may allow time for some lidocaine to be removed from the tissues by suction lipectomy. In addition, the slow rise to peak lidocaine concentration in the epinephrine groups may allow the development of systemic tolerance to high lidocaine plasma levels.     

Evaluation of tissue changes following intramuscular infiltration of lidocaine in rainbow trout Oncorhynchus mykiss

Rainbow trout Oncorhynchus mykiss were infiltrated with either saline or lidocaine adjacent to the dorsal fin to assess histopathological changes. Infiltration was done as if it were being used as a local anaesthetic. Tissue lesions and associated tissue healing were examined over a period of 30 days. Most changes occurred at the cranial site of where the solution was first infiltrated. The infiltration of a dose of 10 mg kg^?1 of lidocaine appears to have damaged the skeletal muscle and connective tissues more than a similar volume of saline, especially during the first 15 days. The primary changes included haemorrhage, inflammation and muscle degeneration and necrosis. By day 30 post‐infiltration inflammatory lesions were either nearly or completely absent, signs of myofibre regeneration were noted in only one fish. This experiment shows local anaesthetics and saline can produce localized tissue damage, especially during the first 2 weeks post infiltration. Care should be taken to allow the fish to heal for at least 30 days and probably more, no matter the solution administered, especially if giving repeated injections or infiltrations at the same site.     

Quantitative analysis of lidocaine hydrochloride delivery by diffusion across tissue expander membranes.

Permeability of Silastic tissue expander shells to lidocaine was studied to investigate the feasibility of intraluminal lidocaine injection for pain relief during soft-tissue expansion. Both intact expanders and an apparatus using isolated Silastic membrane segments were used to partition solutions of various lidocaine concentrations, and the rate of diffusion was quantitatively measured using a fluorescence polarization immunoassay. Lidocaine flux was found to follow Fick's law of passive diffusion with respect to time, surface area, and concentration gradient for the first 9 hours, with a permeability coefficient of 10.3 +/- 2.6 micrograms (h.cm2.percent)-1 (mean +/- SD) and diffusion coefficient of 7.5 x 10(-7) cm2/min for an average membrane thickness of 473 +/- 23 microns. After 9 hours, the lidocaine flux decreased exponentially, although the concentration gradient across the membrane remained essentially the same order of magnitude. Plasma proteins in the outer bathing solution and methylparaben used as a preservative in the standard lidocaine formulation had no influence on the change in transport flux with time. At the end of the linear portion of the diffusion curve, less than 2 percent of the total intraluminal lidocaine had crossed the membrane. Potential toxicity in the event of implant rupture limits the maximum total lidocaine dose to approximately 500 mg within an expander at any one time. Within these limits, the capacity for lidocaine delivery of 500 mg lidocaine by a 640-cc tissue expander would be only 6 mg during the first 9 hours after administration.(ABSTRACT TRUNCATED AT 250 WORDS)     

Hemodynamic physiology and thermoregulation in liposuction

Little is known about the physiology of large-volume liposuction. Patients are exposed to prolonged procedures, general anesthesia, fluid shifts, and infusion of high doses of epinephrine and lidocaine. Consequently, the authors examined the thermoregulatory and cardiovascular responses to liposuction by assessing multiple physiologic factors. The aims of their study were to serially determine hemodynamic parameters perioperatively, to quantify perioperative and postoperative plasma epinephrine levels, and to chronologically document fluctuations in core body temperature. Five female volunteers with American Society of Anesthesiologists' physical status I and II underwent moderate- to large-volume liposuction. Heart rate, blood pressure, mean pulmonary arterial pressure, cardiac index, and central venous pressure were monitored. Serum epinephrine levels and core body temperature were assessed perioperatively. The hemodynamic responses to liposuction were characterized by an increase in cardiac index (57 percent), heart rate (47 percent), and mean pulmonary arterial pressure (44 percent) (p < 0.05). Central venous pressure was not significantly altered. Maximum epinephrine levels were observed 5 to 6 hours after induction. Significant correlations between cardiac index and epinephrine concentrations were shown intraoperatively (r = 0.75). All patients developed intraoperative low body temperatures (mean 35.5 degrees C). An overall enhanced cardiac function was observed in patients subsequent to large-volume liposuction. The etiology of the altered cardiac parameters was multifactorial but may have been attributable in part to the administration of epinephrine, which counters the effects of general anesthesia and operative hypothermia. Additional explanations for raised cardiac output may be hemodilution or emergence from general anesthesia. Elevated mean pulmonary arterial pressure may be a result of subclinical fat embolism demonstrated in previous porcine studies, although fat was not observed in urine. The unchanged central venous pressure levels indicate that young healthy patients with compliant right ventricles can accommodate the fluid loads of large-volume liposuction. Overall hemodynamic parameters remained within safe limits. Within these surgical parameters, patients should be clinically screened for cardiovascular and blood pressure disorders before liposuction is undertaken, and preventative measures should be taken to limit intraoperative hypothermia.     

Effect of liposuction on skin perfusion

Clinical reports of full-thickness skin necrosis have raised concern about the thermal and dermal ischemic effects of ultrasound-assisted liposuction. The purpose of this study was to evaluate skin perfusion in patients treated with ultrasound-assisted liposuction or suction-assisted liposuction. Patients (n = 75) were studied prospectively in the perioperative period surrounding their suction-assisted liposuction (31 patients) or ultrasound-assisted liposuction (64 patients). The laser Doppler flowmeter was used to monitor skin perfusion in the treated regions preoperatively, intraoperatively, and postoperatively at a series of time intervals. The effects of the anesthetic, wetting solution, and type of liposuction (suction-assisted liposuction or ultrasound-assisted liposuction) on skin perfusion were measured. Anesthetic induction significantly increased measured skin perfusion. Wetting solution infusion significantly decreased skin perfusion (-57.4 percent +/- 2.0) by 15 minutes postinfusion. Skin perfusion in the ultrasound-assisted liposuction group was significantly greater than that of the suction-assisted liposuction patients at 1 hour, 1 day, and 1 week postoperatively; however, by 2 to 5 weeks, no difference in skin perfusion was noted and skin perfusion had returned to preoperative levels in both groups. Although skin perfusion in the suction-assisted liposuction group was significantly lower than in the ultrasound-assisted liposuction group in the early postoperative period, no differences in skin perfusion between the groups were noted beyond 1 week postoperatively, suggesting that neither technique impairs perfusion.     

Capillary gas chromatographic method for the measurement of small concentrations of monoethylglycinexylidide and lidocaine in plasma

The major metabolite of lidocaine, monoethylglycinexylidide (MEGX) is currently used as a dynamic marker of liver function. It has been proven, in recent advances, that the determination of MEGX formation after intravenous injection of lidocaine was an effective means of assessing liver dysfunction in critically ill patients. An accurate and sensitive gas chromatographic method has been developed for the determination of small quantities of MEGX formed in such cases. The procedure involves a solid-phase extraction and injection of the extract (splitless mode) into a gas chromatograph equipped with a capillary column and nitrogen–phosphorus detector. The limit of detection is 1 ng/ml and the limit of quantification is 2.5 ng/ml. The response is linear up to 50 ng/ml. The inter- and intra-assay coefficients of variation for MEGX and lidocaine are between 5 and 9%. This method can be used for the determination of small concentrations of MEGX in plasma and could be applied to analysis of small amounts of many other nitrogenous molecules.     

Comparison of transthecal digital block and traditional digital block for anesthesia of the finger

A randomized, double-blind study was performed in 50 patients to compare the transthecal and traditional subcutaneous infiltration techniques of digital block anesthesia regarding the onset of time to achieve anesthesia and pain during the infiltration. All the patients had sustained injury involving two or four fingers of the hand. Each patient served as his or her own control, having one finger infiltrated with the transthecal technique and the other with the subcutaneous infiltration technique. Time to loss of pinprick sensation and pain (at the time of the infiltration and 24 hours postoperatively) were assessed using a visual analogue scale and verbal response score. A total of 104 blocks (52 transthecal and 52 subcutaneous infiltration) were performed. All of these blocks were successful. Mean time to achieve anesthesia with the transthecal block was 165 seconds, compared with 100 seconds for the subcutaneous infiltration block. The mean analogue pain score was higher for transthecal blocks than for subcutaneous infiltration blocks (3.2 +/- 0.19 versus 1.6 +/- 0.14). Twenty-four hours postoperatively, 24 patients who had the transthecal block experienced pain at the injection site of the digit. However, none of the patients who received the subcutaneous infiltration block complained of pain at the digit. The technique of anesthesia preferred by patients for their finger was the subcutaneous infiltration block, because it causes less pain. Our results confirm the efficacy of the transthecal block for achieving anesthesia of the finger; however, because it is a more painful procedure, it is not recommended.     

Perioperative management of cosmetic liposuction

Recent qualms about the safety of aesthetic lipoplasty may be attributable more to support system flaws than to technical process deficiencies. The authors here focus on perfunctory patient monitoring when sedative or analgesic drugs are given, cavalier infiltration of mega-dose lidocaine, cursory intraoperative patient observation by team members with conflicting responsibilities, anesthesia providers unfamiliar with the unique surgical physiology of liposuction, hurried-discharge policies that virtually ignore the residual depressant effects of sedatives and analgesics, and compressive dressings that impair postoperative chest-wall expansion and venous return. Whereas pulmonary embolism remains the leading process cause of morbidity from liposuction, complications from austere resource allocation to dedicated patient monitoring should be largely preventable. Not all lipoplasties require an anesthesia provider but-when heavy sedation, mega-dose lidocaine, or both, are projected-a trained team member dedicated exclusively to patient safety and comfort should be a minimum patient care standard. The potential role of lidocaine cardiotoxicity in tumescent anesthesia is widely underappreciated and that of hypothermia goes mostly unrecognized. These, plus largely preventable or potentially correctable perioperative events such as pulmonary edema, fluid imbalance, or improperly administered sedative and analgesic drugs, demand upgrading and expansion of monitoring, resuscitative, and recuperative facilities in physician offices. In fact, ASPS guidelines urge that anesthesia services be engaged for dedicated patient care whenever "major" liposuction or conscious sedation is projected, because liposuction is neither as benign nor as simple a procedure as heretofore reputed. To assess objectively the operative and anesthetic risk of obesity, document body mass index for the preoperative record; morbid obesity (body mass index >/= 35.0), for instance, is a known risk multiplier for sedatives and analgesics. Other system issues such as the dynamic profile of high-dose lidocaine pharmacokinetics, the deportation of fat globules in the bloodstream, and the incidence of intraoperative hypothermia remain as unresolved topics for interdisciplinary, multi-institutional clinical research.     

The effects of norepinephrine and prostaglandin E1 on pharmacokinetics of lidocaine in isolated perfused rat liver

We hypothesized that depression of liver function by norepinephrine can be improved by prostaglandin E1. Isolated perfused rat liver was selected as an experimental model, since the flow rate can be regulated in it. Twenty-one rats were randomly allocated to three groups: control, norepinephrine, and norepinephrine and prostaglandin E1 groups. The liver was perfused in a recirculating system at a constant flow rate of 20 ml/min. After administration of two milligrams of lidocaine in each group, lidocaine and monoethylglycinexylidide concentrations in the recirculating system were measured. Lidocaine pharmacokinetics were analyzed using the SAAM II program, including metabolic rate from lidocaine to monoethylglycinexylidide using time-concentration curves. Norepinephrine significantly increased perfusion pressure and the area under the time-concentration curve for lidocaine. Norepinephrine decreased the clearance and the elimination rate constant of lidocaine compared with those in the control group. Although administration of prostaglandin E1 after infusion of norepinephrine did not significantly change perfusion pressure, it significantly (p < 0.05) improved metabolic rate, clearance and the elimination rate constant of lidocaine in the isolated rat liver model.     

Fatal outcomes from liposuction: census survey of cosmetic surgeons

Troubling reports of adverse outcomes after liposuction prompted a census survey of aesthetic plastic surgeons. All 1200 actively practicing North American board-certified ASAPS members were polled by facsimile, then mail, regarding deaths after liposuction. Patient initials together with case summaries precluded data replication yet assured patient anonymity and preserved surgeon privacy. Incomplete returns or ambiguous findings were authenticated, where feasible, by direct follow-up. Total number of lipoplasties performed by plastic surgeons was interpolated from the ASPRS procedure database for the survey time frame of 1994 to mid-1998. Lacking reliable annual case volume estimates, deaths from lipoplasties performed by non-ABPS surgeons were excluded from the actual mortality rate computation but were included in cause-of-death ranking statistics. Responding aesthetic plastic surgeons (917 of 1200) reported 95 uniquely authenticated fatalities in 496,245 lipoplasties. In this census survey, the mortality rate computed to 1 in 5224, or 19.1 per 100,000. A virtually identical 20.3 per 100,000 mortality rate was obtained in a 1997 random survey commissioned by the parent society. Pulmonary thromboembolism remains as the major killer (23.4+/-2.6 percent); lacking consistent medical examiners' toxicology data, the putative role of high-dose lidocaine cardiotoxicity could not be ascertained. Where so stated, many deaths occurred during the first night after discharge home; prudence suggests vigilant observation for residual "hangover" from sedative/anesthetic drugs after lengthy procedures. Taken together, these two independent surveys peg the late 1990s mortality rate from liposuction at about 20 per 100,000, or 1 in every 5000 procedures. Set beside the 16.4 per 100,000 fatality rates of U.S. motor vehicle accidents, liposuction is not an altogether benign procedure. We do not have comparable mortality data for lipoplasties performed by non-ABPS-certified physicians.     

Acetaminophen distribution in the rat central nervous system

Based on the evidence that the antinociceptive effects of acetaminophen could be mediated centrally, tissue distribution of the drug after systemic administration was determined in rat anterior and posterior cortex, striatum, hippocampus, hypothalamus, brain stem, ventral and dorsal spinal cord. In a first study, rats were treated with acetaminophen at 100, 200 or 400 mg/kg per os (p.o.), and drug levels were determined at 15, 45, 120, 240 min by high performance liquid chromatography (HPLC) coupled with electrochemical detection (ED). In a second study, 45 min after i.v. administration of [3H]acetaminophen (43 microCi/rat; 0.65 microg/kg), radioactivity was counted in the same structures, plus the septum, the anterior raphe area and the cerebellum. Both methods showed a homogeneous distribution of acetaminophen in all structures studied. Using the HPLC-ED method, maximal distribution appeared at 45 min. Tissue concentrations of acetaminophen then decreased rapidly except at the dose of 400 mg/kg where levels were still high 240 min after administration, probably because of the saturation of clearance mechanisms. Tissue levels increased with the dose up to 200 mg/kg and then leveled off up to 400 mg/kg. Using the radioactive method, it was found that the tissue/blood ratio was remarkably constant throughout the CNS, ranking from 0.39 in the dorsal spinal cord to 0.46 in the cerebellum. These results, indicative of a massive impregnation of all brain regions, are consistent with a central antinociceptive action of acetaminophen.     

Large-volume liposuction complicated by retroperitoneal hemorrhage: management principles and implications for the quality improvement process

Large-volume liposuction can be associated rarely with major medical complications and death. The case of exsanguinating retroperitoneal hemorrhage that led to cardiopulmonary arrest in an obese 47-year-old woman who underwent large-volume liposuction is described. Extensive liposuction is not a minor procedure. Performance in an ambulatory setting should be monitored carefully, if it is performed at all. Reporting of adverse events associated with outpatient procedures performed by plastic surgeons should be mandated. Hemodynamic instability in the early postoperative period in an otherwise healthy patient may be due to fluid overload, lidocaine toxicity, or to hemorrhagic shock and must be recognized and treated aggressively. Guidelines for the safe practice of large-volume liposuction need to be established.     

The key to long-term success in liposuction: a guide for plastic surgeons and patients

Patients need to have realistic expectations for a long-term successful body contour result. There are four key elements for long-term successful improvement in body contour, and the patient is responsible for the first three: exercise, a proper diet, and other positive lifestyle changes; and successful body contouring. An extensive survey requesting information about the procedures, areas of liposuction, lifestyle habits, and satisfaction was mailed to 600 patients who had liposuction surgery performed between 1999 and 2003. One hundred and eight surveys were undeliverable and 209 completed surveys were returned (34.8 percent of 600 mailed surveys and 42.5 percent of 492 delivered surveys). Data were analyzed by a binary logistic regression with backward elimination. Weight gain (versus no weight gain) was used as the dependent variable. The results showed that regardless of whether the patient did or did not gain weight, both groups reported being very satisfied (30 percent and 48 percent, respectively) or satisfied (43 percent and 34 percent, respectively) with their procedure. Among the weight gain patients, 72 percent would still have the procedure again, compared with 82 percent of responders who did not gain weight. When asked if they would recommend the procedure to family or friends, 90 percent of responders who did not gain weight would recommend the procedure whereas only 74 percent of responders who did gain weight would recommend the procedure (p < 0.001). Among those patients who gained weight, only 29 percent thought their appearance was excellent or good (compared with 79 percent of those who did not gain weight). Among the 57 percent of patients who did not gain weight, 35 percent report exercising more postoperatively (compared with only 10 percent in the weight gain group, p = 0.002) and 50 percent report eating a healthier diet (22 percent in the weight gain group report eating a healthier diet, p = 0.002). In the weight gain group, 67 percent report no change in their diet regimen and only 17 percent thought their productivity increased (compared with 25 percent among the no weight gain group, p = 0.002). Successful body contouring surgery requires a patient to embrace positive lifestyle habits. The results of this survey have been used to create a quantitative decision-making framework or a "road map" for patients and plastic surgeons to use for navigating toward successful long-term results.     

Effect of propranolol on lidocaine pharmacokinetics

The study aimed at investigating an effect of propranolol on lidocaine pharmacokinetic parameters, especially elimination rate and total clearance rate. The study was carried out in 8 rabbits with cross-over technique. The animals were examined twice. Sequence of therapy was established randomly. Some group of the animals were given propranolol and lidocaine first while the remaining animals were given lidocaine alone. Sequence of drugs administration was changed after one week. Propranolol was given in a single dose of 0.05 mg/kg b.w. intravenously. Lidocaine was injected in a single dose of 3 mg/kg b.w. during 5 minutes i.v. after a 30-minute interval. All drugs were injected into ear vein. Blood for assays was collected 8 times within 6 hours after lidocaine administration. TDx system manufactured by Abbott was used for drug concentration assay with immunofluorescence polarization method. One-compartment open model was used for calculations. The results were analysed with Student t-test for pairs. Significant decrease in AUC, marked decrease in distribution volume and total body clearance following lidocaine and propranolol were noted. The study has shown that there is interaction between propranolol and lidocaine leading to a decrease in total body lidocaine clearance.     

Comparative lipoplasty analysis of in vivo-treated adipose tissue

A comparative histologic and chemical analysis was undertaken of adipose tissue treated in vivo with traditional, ultrasound-assisted, and external ultrasound-assisted lipoplasty. A series of six healthy women undergoing elective liposuction according to the superwet technique using a 1:1 infiltration ratio with the estimated quantity of fat to be removed was included in the study. Four separate regions on each patient were treated independently in vivo with traditional liposuction, internal ultrasound-assisted liposuction, or external ultrasound-assisted liposuction for 7 minutes. External massage was used as a control. Four separate specimens of adipose tissue from each patient were assessed for cellular disruption using blinded histologic evaluation. The remainder of tissue was centrifuged to separate the aqueous phase from the cellular components and then spectrophotometrically analyzed for creatinine kinase and glycerol 3-phosphate dehydrogenase activity as markers of cellular disruption. Histologic analysis confirmed 70 to 90 percent cellular disruption with internal ultrasound-assisted liposuction. Suction-assisted and external ultrasound-assisted liposuction showed 5 to 25 percent disruption, whereas massage controls showed only 5 percent. Only internal ultrasound-assisted liposuction showed 5 to 20 percent thermal liquefaction. Absorbance analysis showed creatine kinase activity (sigma units) greatest in ultrasound-exposed tissue. Both external and internal ultrasound-assisted liposuction gave creatine kinase levels 28 to 33 percent greater than suction-assisted liposuction, which varied only 10 percent from controls. Glycerol 3-phosphate dehydrogenase activity was 44 percent greater for internal ultrasound-assisted liposuction than that detected with suction-assisted liposuction. Glycerol 3-phosphate dehydrogenase activity with external ultrasound-assisted liposuction and massage did not vary much from each other, at only 14 percent and 11 percent activity compared with internal ultrasound-assisted liposuction, respectively. Histologic and enzyme analysis of the different types of liposuction and their effect on adipocyte cellular disruption revealed no significant effect of external ultrasound or massage on the adipocytes. Further experimental studies are necessary to evaluate the role and efficacy of alternative techniques for body contouring.