Perivascular axillary block. I: blockade following 40 ml 1% mepivacaine with adrenaline

Perivascular axillary block was performed on 80 patients by a catheter technique. All patients had a standard dose of 40 ml mepivacaine 1% with adrenaline. Thirty minutes after the injection, the motor and sensory blockade was determined. Eighty-six per cent of the patients had a distinct motor blockade, whereas the remaining 14% had only a slight motor blockade. The sensory blockade was complete in 63%, whereas 37% had lack of analgesia in one or several cutaneous areas. Lack of analgesia was most often found in the cutaneous area of the axillary, musculocutaneous and radial nerves. The frequency of analgesia in the three areas of innervation was analysed with reference to the influence of the age, height and weight of the patient, and of differences in technique: paraesthesias, position of catheter, and unintended puncture of blood vessels. None of these variables seems to be important for the low frequency of analgesia in the three areas of innervation.