Pharmacokinetics and safety of lidocaine and monoethylglycinexylidide in liposuction: a microdialysis study

High doses of lidocaine are administered to patients undergoing liposuction. Monoethylglycinexylidide, the active metabolite of lidocaine, is 80 to 90 percent as potent as lidocaine, and its relative toxicity is approximately that of lidocaine. Monoethylglycinexylidide has not previously been measured in studies on lidocaine in liposuction. The aims of this study were to characterize systemic exposure to lidocaine and monoethylglycinexylidide and to measure lidocaine and monoethylglycinexylidide levels within the tissues. Five female volunteers between the ages of 29 and 40 years underwent liposuction. Lidocaine (1577 to 2143 mg, corresponding to 19.9 to 27.6 mg/kg) was infiltrated during the procedure. Levels of lidocaine and monoethylglycinexylidide in blood and lipoaspirate were assessed perioperatively. Tissue lidocaine and monoethylglycinexylidide levels were measured postoperatively using a microdialysis technique in vivo. The peak (maximal) concentration of lidocaine plus monoethylglycinexylidide was 2.2 to 2.7 microg/ml. Time to peak lidocaine plus monoethylglycinexylidide was 8 to 28 hours after infiltration began. Absorbed lidocaine was estimated to be 911 to 1596 mg; therefore, 45 to 93 percent (mean, 64 percent) of the infiltrated dose was ultimately absorbed. Lipoaspirate analysis showed that 9.1 to 10.8 percent (mean, 9.7 percent) of the infiltrated dose was removed during the procedure. Tissue lidocaine levels below 5 microg/ml were demonstrated from 4 to 8 hours postoperatively. The peak lidocaine plus monoethylglycinexylidide concentration was within safe limits in this group of subjects. Time to peak lidocaine plus monoethylglycinexylidide signifies a delayed peak and therefore a longer period of potential lidocaine toxicity than was originally thought. Microdialysis results demonstrated that tissue lidocaine levels may be subtherapeutic within 4 to 8 hours of the procedure. Investigation into factors controlling the resorption of lidocaine during liposuction is warranted in an effort to improve the duration of effect. Furthermore, considering the active metabolite monoethylglycinexylidide, longitudinal studies are necessary to determine whether improving the side effect profile of lidocaine by reducing the dose administered during liposuction may be possible without decreasing the perioperative analgesic effect.     

Effect of epinephrine on blood loss during liposuction.

Noncaseating granulomas present as a delayed foreign-body reaction to retained pencil-core fragments. The clinical appearance of the lesion can closely resemble melanoma. Surgeons who use pencils as surgical marking implements should be aware that there is a potential risk of developing late pencil-core granulomas. This risk can be reduced by carefully removing any pieces of pencil lead from the wound.     

The use of liposuction to contour cherubism

Yet another application of suction lipectomy equipment is presented to remove the pathologic tissue in cherubism. Owing to the variations of consistency of the material in this condition, this technique may not be successful in all patients, but it is certainly recommended when indicated.     

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.     

Combined use of ultrasonic liposuction with the pull-through technique for the treatment of gynecomastia

The authors present a method of treatment for gynecomastia that combines the use of two techniques of soft-tissue contouring. This method uses ultrasonic liposuction in conjunction with the pull-through technique of direct excision to effectively remove the fibrofatty tissue of the male breast and the fibrous breast bud through a single 1-cm incision. Fifteen patients were treated in this fashion, and each patient demonstrated a smooth, masculine breast contour with a well-concealed scar, which eliminates the stigma of breast surgery. The procedure is technically straightforward and provides consistent results. It is offered as an additional option for the treatment of gynecomastia.     

Pharmacokinetics of the progesterone-containing vaginal tablet and its use in assisted reproduction

Natural progesterone, which is devoid of androgenic activity, is widely used in assisted reproduction for luteal and pregnancy support. The vaginal route has become the most established way to deliver natural progesterone because it is easily administered, avoids liver first-pass metabolism, and has no systemic side-effects. The vagina has a large potential for absorption, and through the 'uterine first-pass effect' vaginal administration results in higher uterine progesterone concentrations. We have investigated the pharmacokinetics of natural progesterone in the form of a vaginal tablet. A single dose of 100 mg resulted in a mean C(max) of 31.53 +/- 9.15 nmol/l with a T(max) of 6.92 +/- 3.12 h. The terminal half-life was 16.39 +/- 5.25 h. The pharmacokinetic data are discussed in relation to dose, age, and estrogen priming. Single-dose pharmacokinetics of 100 mg of progesterone vaginal tablets and gelatin capsules were evaluated over 24 h. Results indicated a similar mean T(max) of 6.92 +/- 3.12 and 6.23 +/- 6.57 h, respectively. However, a significantly higher C(max) was achieved by the vaginal tablet (31.95 +/- 9.15 and 23.85 +/- 9.57 nmol/l, respectively, P < 0.05). Continuous use of vaginal progesterone did not influence the hormonal, liver, or lipid profiles evaluated. There was no case of endometrial hyperplasia. The vaginal tablet was found to be well-tolerated, safe, and easily administered. In conclusion, progesterone-containing vaginal tablets have good pharmacokinetic properties and should be used for progesterone supplementation in IVF.     

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.     

Outcome study in liposuction breast reduction

Liposuction as a primary modality of treating breast hypertrophy has been reported in the literature; however, many of these reports are small series and personal experiences. This report is the first outcome study to attempt to validate the effectiveness of liposuction as a primary method of breast reduction surgery. Questionnaires were sent to 117 patients who had undergone liposuction breast reduction surgery in our office during a 4-year period. Seventy-eight questionnaires were returned (67 percent response rate). The patients were asked about their complaints, their surgical results, and their satisfaction with the operation. Complaints such as neck and back pain, shoulder ruts, and intertrigo were improved or eliminated in the vast majority of patients. Women returned to work in 5 days on average and resumed full exercise in 2 weeks. Eighty percent of patients were either very or completely satisfied with their outcomes, 87 percent would choose the liposuction method again, and 92 percent would recommend the liposuction method to a friend. This study demonstrates that liposuction breast reduction is an effective method of breast reduction surgery.