Palpation- and ultrasound-guided brachial plexus blockade in Hispaniolan Amazon parrots (Amazona ventralis)
Article first published online: 29 OCT 2012
© Published 2012. This article is a U.S. Government work and is in the public domain in the USA
Veterinary Anaesthesia and Analgesia
Volume 40, Issue 1, January 2013
How to Cite
da Cunha, A. F., Strain, G. M., Rademacher, N., Schnellbacher, R. and Tully, T. N. (2013), Palpation- and ultrasound-guided brachial plexus blockade in Hispaniolan Amazon parrots (Amazona ventralis). Veterinary Anaesthesia and Analgesia, 40: n/a. doi: 10.1111/j.1467-2995.2012.00783.x
- Issue published online: 18 DEC 2012
- Article first published online: 29 OCT 2012
- Received 27 May 2011; Accepted 23 September 2011
- local anesthesia;
- nerve evoked muscle potentials;
Objective To compare palpation-guided with ultrasound-guided brachial plexus blockade in Hispaniolan Amazon parrots.
Study design Prospective randomized experimental trial.
Animals Eighteen adult Hispaniolan Amazon parrots (Amazona ventralis) weighing 252–295 g.
Methods After induction of anesthesia with isoflurane, parrots received an injection of lidocaine (2 mg kg−1) in a total volume of 0.3 mL at the axillary region. The birds were randomly assigned to equal groups using either palpation or ultrasound as a guide for the brachial plexus block. Nerve evoked muscle potentials (NEMP) were used to monitor effectiveness of brachial plexus block. The palpation-guided group received the local anesthetic at the space between the pectoral muscle, triceps, and supracoracoideus aticimus muscle, at the insertion of the tendons of the caudal coracobrachial muscle, and the caudal scapulohumeral muscle. For the ultrasound-guided group, the brachial plexus and the adjacent vessels were located with B-mode ultrasonography using a 7–15 MHz linear probe. After location, an 8-5 MHz convex transducer was used to guide injections. General anesthesia was discontinued 20 minutes after lidocaine injection and the birds recovered in a padded cage.
Results Both techniques decreased the amplitude of NEMP. Statistically significant differences in NEMP amplitudes, were observed within the ultrasound-guided group at 5, 10, 15, and 20 minutes after injection and within the palpation-guided group at 10, 15, and 20 minutes after injection. There was no statistically significant difference between the two groups. No effect on motor function, muscle relaxation or wing droop was observed after brachial plexus block.
Conclusions and clinical relevance The onset of the brachial plexus block tended to be faster when ultrasonography was used. Brachial plexus injection can be performed in Hispaniolan Amazon parrots and nerve evoked muscle potentials were useful to monitor the effects on nerve conduction in this avian species. Neither technique produced an effective block at the doses of lidocaine used and further study is necessary to develop a useful block for surgical analgesia.