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

Liposuction, like many other plastic surgical procedures, is often performed under local anesthesia. Drug toxicity is the most serious complication and the factor that limits the use of this form of anesthesia. Toxic effects are related to the peak concentration in plasma and depend on the type of local anesthetic, the drug concentration, total dose, site of injection, injection speed, and whether vasoconstrictors are used or not. This study evaluates the use of large volumes of subcutaneously injected 0.1% lidocaine with epinephrine 1:1,000,000 as the local anesthetic procedure in 12 patients undergoing suction-assisted lipectomy of the abdomen, flanks, and/or lower extremities. A total dose 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 concentration of Iidocaine varied between 0.9 and 3.6 mu g/ml and occurred between 6 and 12 hours postoperatively. For the given dose range, a linear correlation (r = 0.83) was found between the total dose of lidocaine 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 clearly demonstrate that when using pH-adjusted 0.1% lidocaine with epinephrine 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.