Adverse reactions in horses that underwent general anesthesia and cervical myelography.

This research study investigates the adverse reactions in horses that have undergone general anesthesia and cervical myelography, a process that involves injecting contrast material into the horse’s spinal column. It is observed that such reactions occur more frequently in horses that have a longer general anesthesia time as well as those that have been subjected to higher volumes of contrast-medium. The most common type of adverse reaction observed are neurological.

Objective of the Study

• The study was designed to understand the adverse reactions (AAR) in horses having undergone general anesthesia and cervical myelography.
• It aims to find out if there is a correlation between the volume of cerebrospinal fluid (CSF) changes (caused by CSF removal or contrast material addition) and the presence of AAR.
• The study also sought to determine any relationship between the frequency of AAR and the neurologic grade of horses before myelography.
• The researchers also investigated the potential effect of anti-inflammatory and osmotic agents in managing nonspecific hyperthermia.
• The study involved a multi-institutional, retrospective, observational design.

Methodology

• Researchers included 278 horses that had undergone myelography at five different institutions from 2000 – 2012.
• Data was retrospectively collected and analysed.

Findings

• Out of the 278 horses, adverse reactions were noted in 34% (95 horses). These were associated with longer durations of general anesthesia and a higher volume of contrast-medium used in the procedure.
• 5 out of the 278 horses (2%) were euthanized due to these adverse reactions.
• Adverse neurological reactions were the most common type of adverse reaction occurring in 5% (15/278) of horses immediately after myelography and 18% (42/235) in the post-myelography period.
• There appeared to be no clear link between the prevalence of adverse reactions and the neurologic grade of horses before myelography.
• Nonspecific hyperthermia, a condition of abnormally high body temperature, was observed in 11% (25/235) of the horses. No associative relationship was found between this condition and the use of anti-inflammatory drugs and osmotic agents.

Conclusions

• Adverse reactions after anesthesia and cervical myelography occurred in one-third of the horses, and were generally mild and self-limiting. They were associated with increased contrast-medium volume and longer anesthesia time.
• Despite these observations, researchers were unable to make procedural recommendations due to the small odds ratios associated with each 1 mL increase in contrast material and each 1 minute of additional anesthesia time.