Perivascular axillary block III: blockade following 40 ml of 0.5%, 1% or 1.5% mepivacaine with adrenaline.

Perivascular axillary blockade was performed on 90 patients with the aid of a catheter technique. All blockades were performed by the same anaesthetist, who practised perivascular axillary blockade three or four times a day. The patients were randomly allocated to three groups. The injected volume of local anaesthetic was constant in each group: 40 ml mepivacaine with adrenaline. The concentration and, consequently, the amount (mg) were variable factors: 1/2% (200 mg), 1% (400 mg) and 1 1/2% (600 mg). Sensory and motor blockade were tested 30 min after each injection. All three groups showed a high incidence of analgesia (70%-100%) in all cutaneous segments, and none of the blockades showed total failure of the sensory blockade. The lowest incidence of sensory blockade was found in the areas innervated by the axillary, the radial and the musculocutaneous nerves, but no difference was found between the groups. However, the motor blockade was found to improve with increasing concentration of local anaesthetic solution.