Accuracy and precision of oscillometric blood pressure in standing conscious horses

Background - Arterial blood pressure (BP) is a relevant clinical parameter that can be measured in standing conscious horses to assess tissue perfusion or pain. However, there are no validated oscillometric noninvasive blood pressure (NIBP) devices for use in horses. Animals - Seven healthy horses from a teaching and research herd. Hypothesis/Objective - To evaluate the accuracy and precision of systolic arterial pressure (SAP), diastolic arterial pressure (DAP), and mean arterial pressure (MAP) in conscious horses obtained with an oscillometric NIBP device when compared to invasively measured arterial BP. Methods - An arterial catheter was placed in the facial or transverse facial artery and connected to a pressure transducer. A cuff for NIBP was placed around the tail base. The BP was recorded during normotension, dobutamine-induced hypertension, and subnormal BP induced by acepromazine administration. Agreement analysis with replicate measures was utilized to calculate bias (accuracy) and standard deviation (SD) of bias (precision). Results - A total of 252 pairs of invasive arterial BP and NIBP measurements were analyzed. Compared to the direct BP measures, the NIBP MAP had an accuracy of -4 mm Hg and precision of 10 mm Hg. SAP had an accuracy of -8 mm Hg and a precision of 17 mm Hg and DAP had an accuracy of -7 mm Hg and a precision of 14 mm Hg. Conclusions and Clinical Relevance - MAP from the evaluated NIBP monitor is accurate and precise in the adult horse across a range of BP, with higher variability during subnormal BP. MAP but not SAP or DAP can be used for clinical decision making in the conscious horse.