[Effect of different injection technics on the blood level of lidocaine following intravenous regional anesthesia].

Nine volunteers received two intravenous regional anaesthetics in the right arm. The first anaesthetic consisted of an injection of 0.5% lignocaine (0.5 ml/kg body wt.), immediately followed by 0.9% NaCl (0.5 ml/kg body wt.). The second anaesthetic consisted of 0.25% lignocaine (1.0 ml/kg body wt.). Just prior to pressure release of the cuff and 30 s, 2, 5, 10, and 20 min afterward, venous blood samples were taken from the contralateral cubital vein in both groups. Lignocaine blood levels were determined by the fluorescence polarization method with the Abbott-TDx. As expected, in the first 2 min after cuff deflation, the blood levels were significantly lower in the first group. However, the peak levels did not differ significantly between groups (5-10 min). Therefore, one can expect slightly less toxicity using the combined injection technique. No significant systemic side effects of the drug were observed. On the basis of this investigation, 0.5% lignocaine (0.5 ml/kg body wt.) followed immediately by 0.9% NaCl (0.5 ml/kg body wt.) can be recommended for IV regional anaesthesia, as this seems to be less toxic than the diluted lignocaine that is usually used.