[Mixtures of different local anesthetics for subaxillary plexus anesthesia]

In a prospective clinical study, 76 patients were scheduled for subaxillary plexus block in order to investigate onset time, duration of action and quality of motor and sensitive blockade of various mixtures of local anaesthetics. Sixty-one patients were allocated to four groups. Each of them received 15 ml of bupivacaine 0.5% with either 15 ml of lidocaine 1% (n = 14), of mepivacaine 1% (n = 16), of prilocaine 1% (n = 15) or of etidocaine 1% (n = 15). Fifteen patients (control group) received only 30 ml bupivacaine 0.5%. The investigation showed that in comparison with the control group the mixtures of the intermediate-acting local anaesthetics led to significantly shorter times of onset and duration. Within these three groups we did not find any significant differences regarding onset time and duration of action. But regarding the quality of motor block, the mixture of bupivacaine and lidocaine was less effective than the other combinations, of which the mixture of bupivacaine and prilocaine showed the best motor block. The combination of the two long-acting local anaesthetics bupivacaine and etidocaine had the longest effect and, therefore, this mixture is a real alternative to subaxillary block via catheter technique. Specific electric stimulation of the radial nerve leads to higher success rate of subaxillary plexus block.