Antithrombin III activity in horses with large colon torsion.

This research sought to examine the changes in plasma antithrombin III (AT III) activity in four groups of horses under varying conditions, including in healthy horses, after surgery, and in those diagnosed with large colon torsion. The study found that AT III activity was not significantly affected by anesthesia or surgery in healthy horses, but a significant decrease was noted in horses with large colon torsion, suggesting that AT III activity may be a useful indicator for predicting survival in such horses.

Research Approach and Groups

• The researchers used a chromogenic peptide substrate assay to measure AT III activity in the blood plasma of horses in four different test groups.
• Group I consisted of healthy horses. Their AT III activity was tracked twice daily for seven consecutive days to establish typical levels of this protein in overall horse health.
• Group II and III were made up of healthy horses which had undergone general anesthesia and surgery – specifically median celiotomy. These horses’ AT III levels were monitored for a week post-surgery.
• Group IV consisted of horses pre-diagnosed with large colon torsion. Their AT III activity was also tracked.

Key Findings

• In healthy horses (group I), AT III activity levels remained constant over time. This means that in a healthy horse, AT III levels do not fluctuate dramatically.
• Groups II and III, which included horses that had undergone anesthesia and surgery, did not show a significant difference from base-line AT III activities. The implication here is that general anesthesia and surgery have minimal or no effect on plasma AT III activity.
• However, horses in group IV, with large colon torsion, exhibited a significant decrease in AT III activity. Importantly, AT III activity returned to preoperative values by the fourth day after surgery in those that survived. Conversely, in horses that did not survive, AT III activity remained below base-line values throughout the observation period.

Implications and Applications

• To a large extent, the research indicates that plasma AT III activity is not significantly affected either by halothane anesthesia or surgery, in horses.
• However, the research suggests a potential clinical use for AT III activity measurements. The observed decrease in AT III activity in horses with large colon torsion and the correlation with survival, may suggest that monitoring plasma AT III activity could potentially be useful in predicting the survival of horses affected by large colon torsion.