Repeatability of Doppler ultrasonographic measurement of equine digital blood flow.

The study investigates the reliability and sensitivity of the Doppler ultrasonography technique for measuring blood flow in the lateral digital arteries and veins of Thoroughbred horses. The findings suggest that this technique is sufficiently reliable and sensitive to detect changes in blood flow in different physiological or pathological conditions or after drug administration.

Methodology

• The research utilized Doppler ultrasonography, a non-invasive medical testing technique that uses high-frequency sound waves to measure the amount of blood flow through the arteries and veins.
• The test was carried out on the forelimb lateral digital vessels of one Thoroughbred horse on six separate occasions, and in six different Thoroughbred horses on three different occasions. These tests were spaced at least 1 hour apart to gauge the within-horse and between-horse variations.
• The researchers aimed to find out if there were any significant differences in the measurements obtained from the right and left lateral digital vessels.

Results

• The study found that both the arterial and venous measurements demonstrated acceptable coefficients of variation (CV) within individual horses. These variations were below 11%, suggesting the measurements are reliable.
• The between-horse CV were also found to be acceptable for all parameters except two, the average velocity of the first peak of the arterial waveform (TaVa) and the average velocity of the remainder of the arterial waveform (TaVb).
• The within-horse intraclass correlation coefficients (ICC), which gauge the reliability of ratings within a subject, showed excellent repeatability for all parameters, excluding the venous diameter. Similarly, the between-horse ICC showed good to excellent reliability for all parameters, excluding TaVb.

Conclusion

• The research concludes that Doppler ultrasonography can accurately measure differences of 0.005 and 0.01 ml/min in digital arterial and venous flow, respectively. This is based on the measurements from six horses on three different occasions, with a statistical power of 80% and a significance level less than 0.05.
• This implies that the technique is sufficiently reliable and sensitive to detect changes in blood flow resulting from different physiological or pathological conditions, or the administration of drugs. This makes Doppler ultrasonography a useful tool for veterinary diagnostics.