EVALUATION OF THE TOURNIQUET LEAK DURING FOREARM INTRAVENOUS REGIONAL ANESTHESIA- Manual vs Automatic Pump Injection -

Background: The present study was conducted to compare the effect of pump injection versus manual injection on the venous pressure, during forearm intravenous regional anesthesia (IVRA) and the incidence and the magnitude of lidocaine leak, . Methods: A crossover randomized study of IVRA with a forearm tourniquet was conducted on 14 male healthy volunteers. This study was performed, once using manual injection of local anesthetic and once using automatic pump injection, on two separate sessions. In both techniques, 0.3 ml/kg lidocaine 0.5% was injected over 90 seconds. The occlusion pressure, continuous venous pressure and the serum lidocaine two minutes at end of injection, were recorded. Results: The mean occlusion pressure 161.6 (17.2) mmHg was always higher than the mean initial arm systolic blood pressure 131.711. The maximum venous pressure was significantly higher in the manual technique 176.7 (15.4) mmHg than in the pump technique 161.3 (12.3) mmHg (p = 0.04). The incidence of lidocaine leak was significantly lower (35.71%) in the pump technique compared to (78.5%) in the manual technique (p = 0.02). Moreover; the mean lidocaine plasma concentrations was significantly higher [0.86 (0.5) μg.ml-1] in the manual technique compared to [0.32 (0.4) μg.ml-1] the pump technique (p = 0.04). Conclusion: The use of pump injection for forearm IVRA could significantly decrease the maximum venous pressure, and decrease the incidence and the magnitude of lidocaine leak past the tourniquet.