Plasma lidocaine levels during augmentation mammaplasty and suction-assisted lipectomy

Many plastic surgical procedures are dependent on or aided by the use of local anesthetics. Drug toxicity, although uncommon, is the most feared complication of this technique. There are multiple factors that lead to varying drug levels. These include drug concentration, speed of injection, rate of degradation, total dosage, site of injection or application, rate of administration, and the adjunctive use of vasoconstrictors. This study evaluates the use of subcutaneously injected lidocaine in patients undergoing suction-assisted lipectomy and augmentation mammaplasty. Lidocaine in the concentration of 0.5% containing either 1:100,000 or 1:200,000 epinephrine was used in doses up to 500 mg. Serial lidocaine levels were then obtained up to 1 1/2 hours after injection utilizing two different assay techniques. Our findings demonstrate consistently nondectable serum lidocaine levels despite the use of doses in excess of recommended "safe" amounts. This suggests that under specific circumstances and with certain operative procedures, lidocaine dosing can be liberalized.