Sunday, October 26, 2003 - 10:15 AM

Lidocaine, Catecholamine, Electrolyte and Cardiovascular Parameters During Liposuction

Jeffrey M. Kenkel, MD, Avron Lipschitz, MD, Spencer A. Brown, PhD, Greene Shepherd, PharmD, Evan Sorokin, MD, and Rod J. Rohrich, MD.

Objective: Patients are exposed to a number of stressors during liposuction including fluid shifts and high epinephrine and lidocaine doses. Little is known about the cardiovascular and hepatic responses to liposuction. Consequently, we examined the safety of liposuction by assessing multiple physiologic factors. The aims of our study were 1) to serially measure hemodynamic parameters perioperatively during liposuction; 2) to chronologically document fluctuations in electrolyte concentrations and liver functions throughout the time course; and 3) to quantify peri- and postoperative plasma lidocaine and catecholamine levels.

Method: Five (5) ASA 1 and ASA 2 female volunteers were consented and underwent moderate to large volume liposuction. Wetting solution contained lidocaine [21.4 (3.1) mg/kg, mean (SEM)] and epinephrine [7.3 (1.5) mg]. Heart rate (HR), blood pressure, pulmonary arterial pressure (PAP) and cardiac index (CI) were monitored. Serum levels of sodium, potassium, chloride, AST, ALT, urea, creatinine, albumin, protein, epinephrine (E), norepinephrine (NE), and lidocaine were measured preoperatively, hourly intra operatively and postoperatively (every 4 hrs) for 24 hrs. A plasma lidocaine concentration time curve was constructed and analyzed using the trapezoidal method to determine area under the curve that represents total lidocaine absorbed.

Results: The hemodynamic response to liposuction was characterized by an increase in CI (57%), HR (47%) and PAP (44%) (p<0.05). Maximum E levels were seen 5 6 hours post induction and NE was raised throughout the investigation period. Intra-operatively, a significant correlation between CI and E concentrations was shown (p<0.011). Serum albumin, protein and sodium levels were decreased (p<0.0001) postoperatively which is associated with hemodilution. Lidocaine levels peaked at 8 12 hrs post induction with maximum concentration of 2.4 mg/mL. Based on the area under the curve and population models of lidocaine clearance, the average absorbed dose was 1045 (94) mg 58% of administered dose. ALT and AST levels were increased 92% and 886% respectively by liposuction (p<0.0001).

Discussion: Intraoperative enhancement of cardiac function was significant with the effects of E countering general anesthesia, operative hypothermia and potential cardiosupression of lidocaine. Increased cardiac function may in part be due to hemodilution observed postoperatively. The estimated absorbed dose of lidocaine indicates that a large portion of the administered dose is being absorbed into systemic circulation. Thus liposuction does not remove the majority of lidocaine administered during the procedure. Elevated serum aminotransferase levels may be indicative of hepatic injury secondary to lidocaine metabolism. Lidocaine concentrations were below toxic levels (5 mg/mL). Future research is required to determine infusion doses of E that both restrict operative bleeding at the liposuction site, but also do not challenge cardiac health of the patients.