PLASMA LIDOCAINE LEVELS DURING SUCTION-ASSISTED LIPECTOMY USING LARGEDOSES OF DILUTE LIDOCAINE WITH EPINEPHRINE

Liposuction, like many other plastic surgical procedures, is often per formed under local anesthesia. Drug toxicity is the most serious compl ication and the factor that limits the use of this form of anesthesia. Toxic effects are related to the peak concentration in plasma and dep end on the type of local anesthetic, the drug concentration, total dos e, site of injection, injection speed, and whether vasoconstrictors ar e used or not. This study evaluates the use of large volumes of subcut aneously injected 0.1% lidocaine with epinephrine 1:1,000,000 as the l ocal anesthetic procedure in 12 patients undergoing suction-assisted l ipectomy of the abdomen, flanks, and/or lower extremities. A total dos e of 1260 to 2880 mg lidocaine corresponding to 10.5 to 34.4 mg/kg was administered with an injection speed of 60 to 78 ml/min. The peak con centration of Iidocaine varied between 0.9 and 3.6 mu g/ml and occurre d between 6 and 12 hours postoperatively. For the given dose range, a linear correlation (r = 0.83) was found between the total dose of lido caine and the peak concentration in plasma. A dose increase of 1 mg/kg raised the peak concentration approximately 0.1 mu g/ml. Our data cle arly demonstrate that when using pH-adjusted 0.1% lidocaine with epine phrine subcutaneously for suction-assisted lipectomy, lidocaine can be administrated safely in significantly higher doses than recommended. When such high doses are used, the patient probably should be observed for at least 18 hours post-operatively.