INTRAVENOUS REGIONAL ANESTHESIA WITH 0.5-PERCENT ARTICAINE, 0.5-PERCENT LIDOCAINE, OR 0.5-PERCENT PRILOCAINE - A DOUBLE-BLIND RANDOMIZED CLINICAL-STUDY

Background and Objectives. The purpose of this study was to compare th e effectiveness of three local anesthetic agents for intravenous regio nal anesthesia in the upper limb. Side effects and plasma concentratio ns of the drugs in the doses administered for IVRA. were also studied. Methods. Thirty patients in ASA groups I and II received intravenous regional anesthesia for surgery of the upper limb. In a double-blind p rospective study, they were randomly allocated to receive one of three local anesthetics: articaine, lidocaine, or prilocaine. Patients rece ived 40 mL, of a 0.5% solution of the local anesthetic. The onset time of sensory block was assessed by pinprick and the extent of motor blo ck was was scored as 0-3. Plasma concentrations of local anesthetics w ere determined in all patients from serial arterial blood samples draw n at predetermined times before and after tourniquet release. Results. The onset time of sensory block was significantly shorter (2.5 minute s) in the articaine group than in the lidocaine group (11.1 minutes) o r the prilocaine group (10.9 minutes) (Scheffe, P < .05). Development of motor block was equal in all three groups (score 2). Estimation of plasma concentrations by high performance liquid chromatography showed that the peak level in all 30 patients was reached immediately after release of the tourniquet; plasma concentrations thereafter gradually declined. Maximum concentrations of articaine, lidocaine, and prilocai ne were, 1.85, 8.5, and 4.4 mu g/mL, respectively. No signs of local a nesthetic toxicity of the cardiovascular or central nervous systems we re seen. Conclusion. Articaine had the fastest onset of sensory block and the lowest peak plasma concentration of the three local anesthetic s when used for intravenous regional anesthesia.