Changes of Plasma Lidocaine Concentration with Intravenous Injection in General Anesthesia / 대한마취과학회지

ABSTRACT

BACKGROUND: Lidocaine is the first amide local anesthetic and used for attenuating cardiovascular responses to endotracheal intubation. This study was conducted to observe changes of plasma lidocaine concentrations and pharmacokinetic parameters of lidocaine in patients who received different doses of lidocaine intravenously. METHODS: 23 adult patients under general anesthesia were divided into 3 groups. Each group patients were received intravenous lidocaine bolus dose of 1, 2, 3 mg/kg, respectively. Serial arterial blood samples were drawn upto 30 minutes and plasma lidocaine levels were determined by immunofluorescence assay. RESULTS: When lidocaine was injected intravenously, peak plasma concentrations measured at 30 seconds were 20.10+/-8.09 microgram/ml, 37.43+/-16.42 microgram/ml and 59.85+/-21.00 microgram/ml respectively on 1, 2, 3 mg/kg lidocaine group. Half-life of lidocaine was not significantly different with increased dose but AUCs(Area Under the Curves) of lidocaine were significantly increased with increased dose (p<0.001). CONCLUSIONS: Overall, plasma lidocaine concentration was reached within 30 secs and peak plasma lidocaine concentration was above 10 microgram/ml in all groups, so systemic toxicity may be developed in all groups. And careful monitoring may be needed until 1, 2, 3 min, respectively because the time when the plasma lidocaine concentrations were reached under 10 microgram/ml is 1, 2, 3 min, respectively.