A new brachial plexus block technique in dogs

To evaluate the feasibility and efficacy of a new technique of brachial plexus anesthesia in dogs.

Prospective, experimental study.

Twelve adult mongrel dogs, six males and six females weighing 14.8 ± 1.75 kg.

The animals were sedated with acepromazine 0.05 mg kg^-1 and anesthetized with propofol (6 mg kg^-1, IV bolus) followed by an infusion of 212 μg kg^-1 minute^-1. The brachial plexus block technique was performed utilizing the brachial artery as an anatomic landmark, the needle was inserted from the axilla and a nerve stimulator was used to ensure the accuracy of needle placement. Bupivacaine (0.375% with 5 μg mL^-1 epinephrine) was used at a dose rate of 4 mg kg^-1. Dogs underwent mid-diaphyseal osteotomies of the humerus followed by intramedullary pin fixation.

Onset time to motor and sensory block were 9.70 ± 5.52 and 26.20 ± 8.86 minutes, respectively. Analgesia lasted for 11.11 ± 0.47 hours. The block was effective in 91.6% of the animals, being verified by anesthesia of the whole front limb distal to the shoulder. One animal became hypotensive after the block and did not undergo the surgery at that time. In the remaining 10 animals the heart and respiratory rates, blood pressure, blood gas parameters and plasma bicarbonate concentration did not show any statistically significant alterations during the surgical procedure.

This brachial plexus block technique is effective in most cases to provide surgical analgesia for the front limb distal to the shoulder.

Various surgical procedures in the front limb can be performed with a regional anesthetic technique without the use and concomitant risks of general anesthesia in dogs. Long-lasting analgesia associated with this technique may also provide a valuable tool for the management of pain in the forelimb.