The use of high-dose lidocaine in wetting solutions for lipoplasty

The use of lidocaine as a local anesthetic has been limited to 7 mg/kg. The authors question whether amounts of lidocaine greater than the recommended dosage may be safely used in the patient undergoing lipoplasty of the torso and knees. Six patients were used as a sample and a wetting solution of 750 mg or 1,000 mg of a .25% lidocaine solution containing 1:400,000 epinephrine was injected into the surgical site. The ratios of milligrams of lidocaine to kilograms of body weight varied from 9.1 to 13.8. Serum lidocaine levels were measured at frequent intervals. Because of many factors, including poor vascularity of subcutaneous fat, vasoconstrictive effect of epinephrine, and aspiration of a portion of the lidocaine, blood levels of lidocaine in the patients never exceeded 1.0 microgram%. We conclude that lidocaine, 9 to 14 mg/kg, results in peak serum lidocaine levels of only 0.5 to 0.8 microgram%.