Effect of endotoxin administration on equine digital hemodynamics and Starling forces

Robert J. Hunt From the Departments of Large Animal Medicine (Hunt, Allen) and Physiology and Pharmacology (Moore) College of Veterinary Medicine, University of Georgia, Athens, GA 30602.

Search for other papers by Robert J. Hunt in
Current site
Google Scholar
PubMed
Close
 DVM
,
Douglas Allen From the Departments of Large Animal Medicine (Hunt, Allen) and Physiology and Pharmacology (Moore) College of Veterinary Medicine, University of Georgia, Athens, GA 30602.

Search for other papers by Douglas Allen in
Current site
Google Scholar
PubMed
Close
 DVM, MS
, and
James N. Moore From the Departments of Large Animal Medicine (Hunt, Allen) and Physiology and Pharmacology (Moore) College of Veterinary Medicine, University of Georgia, Athens, GA 30602.

Search for other papers by James N. Moore in
Current site
Google Scholar
PubMed
Close
 DVM, PhD

Click on author name to view affiliation information

SUMMARY

Using a pump-perfused extracorporeal isolated digital preparation, the effects of a 30-minute infusion of either saline solution (control) or endotoxin on equine digital hemodynamics and microvascular function were determined. Digital blood flow and arterial, venous, and capillary pressures were recorded at 15-minute intervals for 150 minutes. From these data, total vascular resistance and pre- and postcapillary resistances were calculated. Isogravimetric capillary filtration coefficient, vascular compliance, and the osmotic reflection coefficient were determined after the last hemodynamic measurements were taken.

Changes in hemodynamic values of control equine digits were not observed. During the 120 minutes after infusion of endotoxin, digital blood flow decreased 43%, and total vascular resistance increased 89%. Precapillary resistance increased 122%, but postcapillary resistance did not change significantly. Changes in vascular compliance or the capillary filtration coefficient were not observed in response to either treatment. The osmotic reflection coefficient, an index of permeability, did not differ significantly between digits of the endotoxin-treated and control groups. These data indicate that the increase in vascular resistance during endotoxemia may have been attributable to arterial/arteriolar constriction and that neither the permeability nor the surface area of the exchange vasculature within the digit was significantly affected by endotoxin. Although marked alterations in vascular function are seen after administration of endotoxin, these changes do not parallel those documented in association with experimentally induced laminitis.

SUMMARY

Using a pump-perfused extracorporeal isolated digital preparation, the effects of a 30-minute infusion of either saline solution (control) or endotoxin on equine digital hemodynamics and microvascular function were determined. Digital blood flow and arterial, venous, and capillary pressures were recorded at 15-minute intervals for 150 minutes. From these data, total vascular resistance and pre- and postcapillary resistances were calculated. Isogravimetric capillary filtration coefficient, vascular compliance, and the osmotic reflection coefficient were determined after the last hemodynamic measurements were taken.

Changes in hemodynamic values of control equine digits were not observed. During the 120 minutes after infusion of endotoxin, digital blood flow decreased 43%, and total vascular resistance increased 89%. Precapillary resistance increased 122%, but postcapillary resistance did not change significantly. Changes in vascular compliance or the capillary filtration coefficient were not observed in response to either treatment. The osmotic reflection coefficient, an index of permeability, did not differ significantly between digits of the endotoxin-treated and control groups. These data indicate that the increase in vascular resistance during endotoxemia may have been attributable to arterial/arteriolar constriction and that neither the permeability nor the surface area of the exchange vasculature within the digit was significantly affected by endotoxin. Although marked alterations in vascular function are seen after administration of endotoxin, these changes do not parallel those documented in association with experimentally induced laminitis.

All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 62 62 22
PDF Downloads 24 24 3
Advertisement