Abstract

The tumescent technique for local anesthesia permits regional local anesthesia of the skin and subcutaneous tissues by direct infiltration. The tumescent technique uses large volumes of a dilute anesthetic solution to produce swelling and firmness of targeted areas. This investigation examines the absorption pharmacokinetics of dilute solutions of lidocaine (0.1% or 0.05%) and epinephrine (1:1,000,000) in physiologic saline following infiltration into subcutaneous fat of liposuction surgery patients. Plasma lidocaine concentrations were measured repeatedly over more than 24 hours following the infiltration. Peak plasma lidocaine levels occurred 12-14 hours after beginning the infiltration. Clinical local anesthesia is apparent for up to 18 hours, obviating the need for postoperative analgesia. Dilution of lidocaine diminishes and delays the peak plasma lidocaine concentrations, thereby reducing potential toxicity. Liposuction reduces the total amount of lidocaine absorbed systemically, but does not dramatically reduce peak plasma lidocaine levels. A safe upper limit for lidocaine dosage using the tumescent technique is estimated to be 35 mg/kg. Infiltrating a large volume of dilute epinephrine assures diffusion throughout the entire targeted area while avoiding tachycardia and hypertension. The associated vasoconstriction is so complete that there is virtually no blood loss with liposuction. The tumescent technique can be used with general anesthesia or IV sedation. However, with appropriate instrumentation and surgical method, the tumescent technique permits liposuction of large volumes of fat totally by local anesthesia, without IV sedation or narcotic analgesia.