Impairment of postural stability following perivascular axillary block with mepivacaine

Perivascular axillary block was performed on 10 patients using a catheter technique. All patients received a standard dose of 50 ml mepivacaine 1% with adrenaline 1:200 000. Using a quantitative Romberg-test performed on a computerized force-plate system, postural stability was tested before and 40 min after the local anesthesia. There was a significant increase in body-sway following axillary block (P less than 0.01). Nine out of 10 patients had an increased sway-tendency, an average of 31%. A proportionate increase in postural imbalance has been found in normal persons after alcohol consumption, when blood levels were 0.8 mg/ml.