Studies on the physiopathology of chronic obstructive pulmonary disease in the horse. IV. Blood gas and acid-base values at rest.

This research article examines the differences in blood gas and acid-base values between healthy horses and those suffering from Chronic Obstructive Pulmonary Disease (COPD). It particularly focuses on whether these parameters can be related to intracardiac and pulmonary arterial pressures and the effect of fitness training on these values in racehorses.

Comparison between healthy and COPD horses

• Using a Radiometer Blood Micro-system 2, the researchers examined 38 healthy horses and 20 horses with COPD, a disease that obstructs airflow from the lungs.
• The mean values for partial pressure of arterial oxygen (PaO2), arterial carbon dioxide (PaCO2) and mixed venous carbon dioxide (PvCO2) were compared between the groups. Significant differences were found, highlighting the effect of COPD on the blood gas and acid-base values in horses.

Analysis of racehorses in training

• The research also investigated how these blood gas and acid-base parameters varied in Thoroughbred horses undergoing fitness training.
• The mean values and standard deviations for these parameters were documented, providing a reference point for future studies on the impacts of fitness training on these values in horses. The parameters studied were the levels of arterial and venous oxygen, carbon dioxide, and blood pH.

Relationship between clinical data, blood gas values, and pressures

• A key objective of the study was to determine the correlation between clinical data (particularly respiratory frequency, which is often increased in COPD), blood gas values, and intracardiac and pulmonary arterial pressures in horses with COPD.
• The results indicated that in COPD horses, the arterial oxygen pressure (PaO2), arterial carbon dioxide pressure (PaCO2), and the arterial pH were significantly correlated with the respiratory frequency, suggesting that these parameters could potentially be used as indicators of disease severity or progression.
• In COPD subjects, there were likely significant correlations between pulmonary diastolic pressure (the pressure in the pulmonary artery when the heart is resting between beats) and both arterial oxygen pressure and pH, highlighting the interplay between lung and heart function in the presence of this disease.
• There was also a highly significant correlation found between PaO2, pHa and PaCO2, indicating a potential relationship between blood oxygen, carbon dioxide levels and pH in horses with COPD.