The Pharmacokinetics of Lidocaine after Tracheal Administration during General Anesthesia / 대한마취과학회지

ABSTRACT

Spinal Anesthesia employing 0.5% plain bupivacaine was administered to 40 patients scheduled for lower limb or perineum sThe plasma concentrations and pharmacokinetic parameters of lidocaine were studied in 4 patients under general anesthesia(halothane, or enflurane-N20-O2) following the introduction of an 1% lidocaine endotracheal spray(1.5mg/kg) through an epidural catheter. Poak plasma lidocaine levels were reached in 5 to 15 minutes and were within the nontoxic range. The pharmacokinetics of lidocaine in these patients can be described by a two-compartment model with a rapid alpha distribution(T 1/2 alpha 8.66+/-2.24 min.), and an extensive apparent volume of idstribution(1.32+/-0.46 1/kg) similar to that observed in normal subjects. The half-life of absorption was 3.65+/-1.21 minutes. However, the elimination half-life(T 1/2 beta 173.25+/-32.41 min.) was prolonged and the total plasma clearance( 6.15+/-3.25 ml/min/kg) was decreased. This potent inhalation anesthetic agent may reduce the hepatic blood flow and would be expected to reduce the plasma clearance of lidocaine by reducing the delivery of plasma lidocaine. This study suggests that tracheal administration of lidocaine will produce effective plasma lidocaine levels in many clinical situations as will intravenous administration.