Objective: This study evaluated a device for blood pressure measurement using high definition oscillometry (HDO) for its acceptability and practicability in the horse. Furthermore, we evaluated whether this device can determine differences in blood pressure between healthy horses and horses with heart diseases and between different measurement times.
Material and methods: The study population consisted of 60 horses (aged 4-31 years). All horses underwent clinical examination, conventional echocardiography (including cardiac output measurement at the pulmonary artery), repeated noninvasive blood pressure measurement at the coccygeal artery (measurement of systolic [SAP], diastolic [DAP] and mean [MAP] arterial blood pressure) and Doppler sonographic measurement of arterial blood flow at the lateral digital artery. Thirty horses were considered to be cardiologically healthy based upon previous examination. In 30 horses, various heart diseases (mitral valve insufficiency, aortic valve insufficiency and atrial fibrillation) were diagnosed. The diurnal variations in blood pressure in 18 healthy horses and 18 horses with heart disease were determined in the morning and evening. In three horses suffering from atrial fibrillation, the blood pressure was determined before and after successful cardioversion.
Results: In healthy horses the following mean blood pressures were found: SAP 118 ± 21 mmHg, DAP 70 ± 19 mmHg and MAP 87 ± 19 mmHg. No significant difference was found between healthy horses and horses with heart diseases. An insufficiency of the aortic valve tended to result in a higher SAP (p = 0.05), whereas atrial fibrillation lowered blood pressure compared to healthy horses. With respect to the diurnal rhythm of the blood pressure, healthy horses displayed a slight increase in the systolic arterial pressure in the evening.
Conclusion: The HDO-sphygmomanometer facilitates a straightforward, indirect way to determine blood pressure that delivers meaningful values. However, the method is unsuited to monitor the development or therapy of cardiac diseases.
Keywords: Blood pressure measurement; cardiac output; high definition oscillometry technique; vascular Doppler sonography.