EFFECT OF TRANSCUTANEOUS ELECTRICAL NERVE-STIMULATION ON ONSET OF AXILLARY PLEXUS BLOCK

We examined the effect of high frequency transcutaneous electrical ner ve stimulation on the onset of brachial plexus block. Three groups of patients scheduled for surgery of the hand had a local anaesthetic blo ck performed with 40 ml mepivacaine 1.5% using the axillary approach. After injection of the local anaesthetic transcutaneous electrical ner ve stimulation was applied for 15 min either to the median nerve or th e ulnar nerve; no stimulation was applied in the control group. Before and for 45 min after, the injection of local anaesthetic touch percep tion, pin prick, motor strength and skin temperature were tested by a blinded investigator in the areas supplied by the median, musculocutan eous, radial and ulnar nerves. There were no differences in the onset of block between the group. Thus, the frequency-dependent action of lo cal anaesthetics could not be demonstrated.