Safety of supplementing axillary brachial plexus blocks

The incidence of failed local anesthetic axillary blockade varies but can be as high as 20-30%. The authors propose to evaluate the safety of supplementing an axillary block with mepivacaine 30 min after the initial injection. An axillary blockade was performed on 10 healthy patients scheduled for forearm or hand surgery using a new catheter technique. Mepivacaine 1% with epinephrine (7 mg/kg) was administered initially and followed 30 min later by half the original dose (3.5 mg/kg). Plasma levels of mepivacaine were estimated at frequent intervals for 5 h after the initial injection. There were no symptoms or signs of local anesthetic toxicity, and plasma levels of mepivacaine remained below those that usually caused symptoms. In conclusion, the authors conclude that mepivacaine 1% with epinephrine (10.5 mg/kg) can be safely administered in divided doses into the axillary sheath within a 31-min period.