The relationship between digital perfusion pressure and hoof lamellar blood flow in isoflurane-anesthetized horses.

This research study details an investigation into the connection between digital perfusion pressure (DPP) and hoof lamellar blood flow (LBF) in horses. It found out that the LBF is not solely determined by passive pressure-flow relationships and that systemic hypertension may not adequately increase dermal LBF in horses.

Concept Definitions

• Digital Perfusion Pressure (DPP): This measures the difference between the mean arterial pressure at the hoof coronet and the interstitial pressure inside the hoof.
• Lamellar Blood Flow (LBF): This is the rate of blood flow within the hoof lamina in horses.

Research Methodology

• The research was conducted on six horses which were induced and maintained with anesthesia using isoflurane with a target mean arterial pressure (MAP) of 60 mmHg.
• The researchers measured arterial, venous, and hoof interstitial pressures in each pelvic limb of the horses.
• The LBF was measured during dobutamine infusions at three different targeted MAP levels: low (60 mmHg), medium (80 mmHg), and high (100 mmHg).
• After euthanizing the horses, hoof lamina was collected for isolation of the fluorescent microspheres that were used to measure LBF.

Findings and Conclusions

• With an effort to minimize intra-individual variability, the pressures and flows measured at the medium and high levels were divided by the respective measurements taken at the low level. This resulted in the creation of indexed variables – ΔLBF and ΔDPP.
• The study found a negative correlation between ΔLBF and ΔDPP.
• The researchers concluded that LBF in horses is not solely determined by passive pressure-flow relationships. This implies that other factors apart from blood pressure may influence blood flow in the hoof lamina of horses.
• Additionally, the study noted that systemic hypertension (or high blood pressure) may not increase dermal LBF in horses.