Accuracy and Precision of Noninvasive Blood Pressure in Normo-, Hyper-, and Hypotensive Standing and Anesthetized Adult Horses

Background: Blood pressure, is relevant to the diagnosis and management of many medical, cardiovascular and critical diseases. The accuracy of many commonly used noninvasive blood pressure (NIBP) monitors and the accuracy of NIBP measurements in hypo- and hypertensive standing horses has not been determined. Hypothesis/Objectives: The objective of this study was to investigate the accuracy of an oscillometric BP monitor in standing horses before and during pharmacologically induced hyper- and hypotension and to compare results in standing and anesthetized horses. Animals: Eight standing mares from a research herd (SG) and eight anesthetized horses from a hospital population (AG). Methods: Prospective experimental and observational studies. Invasive blood pressure (113P) and NIBP, corrected to heart level, were, measured simultaneously. In the SG hyper- and hypotension were induced by administration of phonylephrine (3 mu g/kg/min IV for 15 minutes) and acepromazine (0.05 mg/kg IV), respectively. In the AG NIBP and IBP were recorded during regular hospital procedures. Results: There was a significant correlation between mean NIBP and IBP in standing (R = (1.88, P <.001) and anesthetized horses (R = 0.81, P <.001). The mean bias (lower, upper limit of agreement) was 16.4( 16.1, 48.9) mmHg for mean BP in the SG and 0.5(-22.3, 23.2) mmHg in the AG. The NIBP device was capable of identifying the increase and decrease in BP in all horses, but in the SG significant correlation between NIBP and IBP was only detected for the normotensive phase. Conclusion and Clinical Importance: While the evaluated oscillometric BP device allowed estimation of BP and adequately differentiated marked trends, the accuracy and precision were low in standing horses.