This page is concerned with clinical pharmacology of the tumescent technique for local anesthesia using large volumes of very dilute lidocaine (local anesthetic) and epinephrine (vasoconstrictor that shrinks capillaries).
The word tumescent means swollen and firm. With the tumescent technique such a large volume of dilute lidocaine is injected into the targeted fatty tissues that those areas become tumescent (swollen and firm). The tumescent technique produces profound local anesthesia of the skin and subcutaneous fat that lasts for many hours.
Safety of the Tumescent Technique
Safety of the tumescent technique is remarkable. No deaths have ever been reported in association with the tumescent technique for liposuction totally by local anesthesia. Most serious liposuction complications seem to be associated with excessive liposuction or multiple simultaneous unrelated surgeries, and the use of general anesthesia or narcotic analgesics. The amazing safety record of liposuction totally by local anesthesia was surprising because the technique uses dosages of lidocaine (local anesthetic) that were considered potentially toxic. The mystery of this unexpected safety was solved by studying the pharmacokinetics of tumescent lidocaine.
Pharmacokinetics
This is the science that studies the concentration, pathway and fate of drugs as they travel through the body. For example, the pharmacokinetics of tumescent lidocaine is concerned with measuring the concentration of lidocaine in the blood, and how this concentration changes over time. The toxicity of a local anesthetic is a function of its peak plasma concentration which in turn depends on several factors including the total milligram per kilogram dose, and the rates of systemic absorption and elimination.
Safe Dose
A safe dose of tumescent lidocaine is estimated to be 45 mg/kg for thin patients, and 50 mg/kg for average to overweight patients. (Tumescent Technique, by J. Klein, Mosby Publishers, 2000).