Practical application of acceleromyography to monitor neuromuscular block in a horse.

The objective of this research was to address technical difficulties encountered while using sensory devices for tracking neuromuscular blockage in horses during intra-ocular surgery, proposing a practical application of acceleromyography.

Research Background

• The research revolves around a case wherein a horse needed to undergo a vitrectomy or removal of the vitreous from its eyes.
• To achieve an immobile eye, it was necessary to create a neuromuscular block for the horse. This makes the animal’s muscles unable to move.
• Standard procedures involve the use of acceleromyography (AMG) and train-of-four (TOF) stimulation to gauge the level of the block. In this procedure, the peroneal nerve in the horse’s limb is the one to be stimulated.

Problem Statement

• When performing the procedure, the researchers encountered a technical problem involving the length of the cables of a standard nerve stimulator (TOF-Watch SX).
• The cables were too short to be used effectively in the operation. The researchers decide to attach a straight metal stick to the horse’s hoof, with the transducer fixed at the end of this stick.

Execution of the Research

• The horse, put to lateral recumbency, had its non-dependent pelvic limb stabilized for maintaining movement only from the hoof in response to nerve stimulation.
• After implementing the procedure and administering a set dosage of atracurium, no TOF response was detectable within six minutes.
• 55 minutes post the administration, complete recovery was noted with a TOF ratio of 1.16.

Evaluation and Conclusion

• The method employed here was successful in providing a solution to the issue.
• The researchers note that visual assessment of TOF stimulation is sometimes used, but this is known to be inconsistent in detecting residual NMB.
• Facial muscles, often less sensitive to Neuromuscular Blocking Agents (NMBAs) in horses, may not provide accurate enough measurement of whether limb muscles are strong enough to support recovery.
• Thus, the results highlight the importance and effectiveness of AMG in monitoring neuromuscular blocks during surgery.