We have assessed prospectively the time to readiness for surgery following axillary block (sum of block performance and latency times) in 80 patients. The brachial plexus was identified using a nerve stimulator, and anaesthetized with 45 mL of mepivacaine 1% with adrenaline 5 micrograms mL-1. In group 1 (single injection) the whole volume of mepivacaine was injected after locating only one of the plexus nerves. In group 2 (multiple injections) at least three plexus nerves were located, and the volume of mepivacaine was divided between them. Sensory block was assessed by a blinded observer every 10 min. Patchy analgesia was supplemented after electrolocating the unblocked nerves after 20, 30 or 40 min. The patient was pronounced ready for surgery when analgesia was present in all areas to be operated upon, which always included the three nerves to the hand. The single injection technique required less time for block performance (mean 5.5 min) than multiple injections (mean 9.5 min), P < 0.0001. However, latency of the block was longer and the requirement for supplemental nerve blocks was greater, after single injections (33 min and 57%) than after multiple injections (15.5 min and 7%, respectively), P < 0.0001. As a result, readiness for surgery was achieved faster in group 2 (25 min), than in group 1 (38.5 min), P < 0.0001. After supplementation, block effectiveness was 100% in group 1 and 98% in group 2 (NS). The frequency of adverse effects (vessel puncture or paraesthesia) was similar in both groups. No neurological sequelae were observed. We conclude that the multiple injection technique takes longer to perform than single injection, but that readiness for surgery is faster because of shorter block latency and better spread of analgesia.

Readiness for surgery after axillary block: Single or multiple injection techniques Summary (mean 9.5 min), P<0.0001. However, latency of the block was longer and the requirement for sup-We have assessed prospectively the time to readiness plemental nerve blocks was greater, after single infor surgery following axillary block (sum of block jections (33 min and 57%) than after multiple injections performance and latency times) in 80 patients. The (15.5 min and 7%, respectively), P<0.0001. As a result, brachial plexus was identified using a nerve stimulator, readiness for surgery was achieved faster in group 2 and anaesthetized with 45 mL of mepivacaine 1% with (25 min), than in group 1 (38.5 min), P<0.0001. After adrenaline 5 g mL −1 . In group 1 (single injection) the supplementation, block effectiveness was 100% in whole volume of mepivacaine was injected after locgroup 1 and 98% in group 2 (NS). The frequency of ating only one of the plexus nerves. In group 2 (muladverse effects (vessel puncture or paraesthesia) was tiple injections) at least three plexus nerves were similar in both groups. No neurological sequelae were located, and the volume of mepivacaine was divided between them. Sensory block was assessed by a observed. We conclude that the multiple injection techblinded observer every 10 min. Patchy analgesia was nique takes longer to perform than single injection, supplemented after electrolocating the unblocked but that readiness for surgery is faster because of nerves after 20, 30 or 40 min. The patient was proshorter block latency and better spread of analgesia. nounced ready for surgery when analgesia was pres-Keywords: anaesthetic techniques, regional, brachial ent in all areas to be operated upon, which always plexus, axillary approach, peripheral nerve stimincluded the three nerves to the hand. The single ulators; anaesthetics, local, mepivacaine. injection technique required less time for block performance (mean 5.5 min) than multiple injections

Wake-up tests can be conducted faster and better with midazolam-flumazenil sequence compared with propofol.

SUMMARY