Acid-base balance parameters and a value of anion gap of arterial and venous blood in Malopolski horses

Abstract

The comparative study of the acid-base balance (ABB) parameters has been performed on 20 clinically healthy mature Małopolski horses. An arterial blood sample from the facial artery and a sample of venous blood from the external cervical vein were colected from each animal. In the samples tested, the blood pH, pCO₂, tCO₂, HCO₃-, concentration of Na+, K+, Cl-, and a value of the anion gap were determined. The difference among pCO₂, tCO₂, and HCO₃ - in both samples tested was statistically significant, whereas the pH of the arterial blood and the pH of the venous blood did not differ significantly. The anion gap in both types of blood did not differ significantly. Conclusions: 1) ABB parameters such as pCO₂, HCO₃-, and tCO₂ determined in the arterial and venous blood of the Małopolski horses differ from each other significantly. 2) In spite of the lack of the differences between pH of the arterial and venous blood, the ABB parameters in horses should be determined in the arterial blood, because the comparative study performed proves that the analysis of the ABB parameters determined for the venous blood of a healthy horse may lead to a wrong diagnosis of the compensated respiratory acidosis. 3) The mean value of anion gap in horses aged 8-12 years amounts to 20.9 mmol/l for the arterial blood and 19.93 for the venous blood; the difference between the two values is not statistically significant