Anesthesia Case of the Month.

The article presents a case involving the anesthesia of a 22-year-old horse who was diagnosed with lameness in the right forelimb. Detailed explanation of the clinical examination, anesthesia procedure, computed tomography (CT) scanning, and recovery attempts are given.

Clinical Examination and Diagnosis

• The horse was referred to the William R. Pritchard Veterinary Medical Teaching Hospital due to right forelimb lameness. A radiographic study was carried out on the horse’s each carpus, which indicated that the right carpus might have been injured.
• After discussing diagnostic and treatment options with the owner, it was decided to undertake a CT scan of the right carpus to better ascertain the injury’s extent. Alongside this, a carpal arthroscopy was considered as a follow-up procedure if necessary.

Anesthesia Procedure

• Before the anesthesia, the horse underwent a complete blood count (CBC) and serum biochemical analyses. Only mild hyperglycemia was found to be out of the normal range.
• The next day, the horse was anesthetized and CT was carried out. Food, but not water, was withheld from the horse for about 8 hours before anesthesia.
• A series of drugs were used to sedate and anesthetize the horse. The horse was mechanically ventilated with general anesthesia maintained by delivering isoflurane in oxygen, and IV fluids were administered throughout the anesthesia.
• Vitals such as blood pressure, heart rate, respiratory rate, arterial oxygen saturation, and end-tidal isoflurane concentration were monitored throughout the procedure. No cardiovascular or respiratory abnormalities were detected.

Computed Tomography (CT) and Treatment Decision

• The horse was positioned on a CT table and images of the carpus were obtained. Evaluating the CT results, it was decided that arthroscopy would not significantly benefit the horse, so they concluded to recover the horse from anesthesia and focus on medical management.

Recovery Period

• The horse was moved into a recovery stall with protection measures like a padded leather helmet and neoprene boots. Romifidine was given, and oxygen was provided via nasal tube once the horse started breathing spontaneously.
• The horse took around 20 minutes after being placed in the stall to stand independently, showing signs of explosive behavior, severe lack of coordination, and ataxia in the attempts. The incoordination and ataxia resolved after the horse had stood for an additional 30 minutes. The horse was then quietly walked back to its hospital stall.