Blood-volume determination with Evans blue dye in foals.
Abstract: The rate of disappearance of Evans blue dye from the blood after an intravenous injection was studied in young foals, between 4 and 105 days of age. This was found to be age dependant, especially during the first month, the initial dye disappearance being much faster than in the adult horse. This would mean an overestimation of plasma volume, using the single sampling technique, of about 5% during the first day of life, i.e. negligible from a practical point of view considering the standard error of estimation. The effect of exercise on the venous haematocrit was studied, too, in foals less than 3 months of age. There was a significant difference between mean values before and after exercise, and this difference seemed to increase with age, indicating an increasing erythrocytestoring capacity of the spleen. This means that even in young foals, the splenic function should be considered when determining the total blood volume from the plasma volume and the venous haematocrit. Försvinnandehastigheten av Evans blue dye från blodet efter en intravenös injektion undersöktes på 4–105 dagar gamla föl. Denna befanns vara beroende av åldern med snabbare färgförsvinnande under de första levnadsdagarna än vid vuxen åider. Detta innebär en överskattning av plasmavolymen om denna bestämmes med en enstaka provtagning efter blandningsfasens slut på ca 5 % under första levnadsdagen. Ur praktisk synpunkt är denna överskattning försumbar, då metodfelet uppgår till ca ± 4%. Vidare studerades effekten av arbete på hämatokriten på upp till 3 månader gamla föl. Hämatokriten var i medeltal signifikant högre efter arbete än före och denna skillnad tycktes växa med stigande ålder. Delta antyder en med åldern ökande lagringskapacitet i mjälten av erytrocyter och att mjältfunktionen måste tas i beaktande vid bestämning av totala blodvolymen från plasmavolym och venhämatokrit även på unga föl.
Publication Date: 1979-01-01 PubMed ID: 443134PubMed Central: PMC8322919DOI: 10.1186/BF03546624Google Scholar: Lookup
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- Journal Article
Summary
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This research examines age-dependent rates of decreasing Evans blue dye in the blood of young foals after injection, and the impact of exercise on venous haematocrit. The findings suggest rapid disappearance of dye in newborn foals and increasing capacity of the spleen to store red blood cells with age, thus affecting blood volume determination.
Evans Blue Dye in Foals
- The study focused on the rate of disappearance of Evans blue dye from the blood after it was injected intravenously in young foals aged between 4 and 105 days.
- Results indicated that the dye’s disappearance is age-dependent, particularly in the first month, as neonatal foals presented a significantly faster initial dye disappearance rate compared to adult horses.
- This implies that the single-sampling technique to estimate plasma volume may overestimate it by approximately 5% on the first day of life. However, given the standard error of estimation, this percentage is deemed negligible from a practical standpoint.
Effect of Exercise on Venous Haematocrit
- In addition to studying dye disappearance, this research also explored the impact of exercise on venous haematocrit values in foals that were less than three months old.
- There was a significant variance in the mean haematocrit values before and after exercise; this difference seemed to increase as a function of age.
- The results suggest an increased capacity of the spleen to store erythrocytes (red blood cells) as the foals age, implying a need to consider the splenic function when determining total blood volume from plasma volume and venous haematocrit, even in young foals.
Implications of the Research
- Thresholds of plasma volume estimation established in adults may not be valid for newborns or very young individuals due to their faster disappearance of the Evans blue dye.
- Exercise causes a significant change in blood composition in foals—particularly, red blood cell count—likely due to the spleen’s erythrocyte storage function, which is increasingly utilised as the foals age.
- Thus, splenic function, age, and activity level should be taken into account when calculating total blood volume based on plasma volume and venous haematocrit in young foals.
Cite This Article
APA
Persson SG, Ullberg LE.
(1979).
Blood-volume determination with Evans blue dye in foals.
Acta Vet Scand, 20(1), 10-15.
https://doi.org/10.1186/BF03546624 Publication
Researcher Affiliations
MeSH Terms
- Age Factors
- Animals
- Azo Compounds
- Blood Volume Determination / veterinary
- Evans Blue / metabolism
- Hematocrit
- Horses / blood
- Physical Exertion
References
This article includes 7 references
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- Persson S. On blood volume and working capacity in horses. Studies of methodology and physiological and pathological variations.. Acta Vet Scand 1967;:Suppl 19:9-189.
- Persson S G B. Value of haemoglobin determination in the horse. Nord. Vet.-Med. 1969;21:513–523.
- Persson SG, Ekman L, Lydin G, Tufvesson G. Circulatory effects of splenectomy in the horse. I. Effect on red-cell distribution and variability of haematocrit in the peripheral blood.. Zentralbl Veterinarmed A 1973 Aug;20(6):441-55.
- Persson SG, Ekman L, Lydin G, Tufvesson G. Circulatory effects of splenectomy in the horse. II. Effect on plasma volume and total and circulating red-cell volume.. Zentralbl Veterinarmed A 1973 Aug;20(6):456-68.
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