Comparison of clinical judgment, Doppler ultrasound, and fluorescein fluorescence as methods for predicting intestinal viability in the pony.

This research investigates the effectiveness of three methods – clinical judgment, Doppler ultrasound, and fluorescein fluorescence – in predicting the viability of intestines under strangulation obstruction in ponies.

Study Design and Methodology

• The study was carried out on anesthetized ponies. Strangulation obstruction was artificially induced for durations of 2 and 3 hours by clamping specific segments of the jejunum, a part of the small intestine, and the related veins and arteries.
• This obstruction was created in four segments in each of seven ponies that were allowed to survive 12 hours, two segments in a pony that was kept alive for 1 hour, and one segment in each of 10 ponies allowed to survive for 42 days after the end of strangulation periods.
• Fifteen minutes after the cessation of the obstruction, the viability of the test intestine segments was evaluated using three methods – clinical judgment, fluorescein fluorescence, and Doppler ultrasound.

Results

• The test segments appeared normal in long-term survivor ponies during necropsy, so all segments were deemed viable.
• The overall accuracy of the methods used for predicting viability was compared. Doppler ultrasound was found to have an accuracy of 88%, significantly higher than 53% each for clinical judgment and fluorescein fluorescence. This difference in accuracy was statistically significant (with a P-value less than 0.005).
• The lower accuracy of clinical judgment and fluorescein fluorescence was mainly due to their tendency to classify the segments under venous strangulation obstruction (which blocks the outflow of blood from a section of the intestines) as non-viable. Both methods scored non-viability in 90% of these segments.
• In contrast, Doppler ultrasound was significantly more accurate, with 94% accuracy in venous strangulation obstruction segments.

Conclusion

• The study concluded that Doppler ultrasound was a superior method for predicting intestinal viability following induced strangulation obstruction in the experiment involving ponies. More specifically, it was significantly more accurate in cases of venous strangulation obstruction, where both clinical judgment and fluorescein fluorescence faltered.
• These findings can potentially contribute to improving clinical practices regarding diagnosis and treatment decisions in cases of intestinal strangulation in ponies and other equine species.