![]() These are just a few examples as to why direct arterial blood pressure (DABP) monitoring, proven to be the most accurate method of measuring blood pressure in both human and veterinary patients, is considered the gold standard.ĭirect (invasive) blood pressure monitoringĪlthough a thorough understanding of the regional anatomy and an advanced skill level are necessary to place arterial catheters, their use for DABP monitoring has many advantages when used in critically ill or high-risk anesthetic patients. However, no indirect device has met these criteria for use in conscious dogs or cats. … for the diagnosis of systemic hypertension, the indirect device used should be one that is commonly employed or designed for veterinary use, and has been previously validated in conscious animals of the species of interest. The apparent inability to accurately gauge blood pressure in veterinary patients using currently available indirect methods led the American College of Veterinary Internal Medicine Consensus Panel to proclaim the following (Cowgill 2006): The results of this study found that 1) in normal dogs, “spot” blood pressure measurements may not accurately reflect the patient’s physiologic or pathologic state as accurately as time-averaged blood pressure readings over larger segments of the day 2) although blood pressure trends were accurately predicted among the indirect oscillometric methods tested, each one provided unique values that were not consistently comparable to the validated standard and 3) as compared to the referenced measurements, there were wide deviations in recorded blood pressure values when trained and experienced personnel in a clinical setting used oscillometric or Doppler techniques. Experienced personnel using Doppler (Parks Model 811-BTS) methods to record systolic pressures ranged from 18% to nearly 28% lower than the referenced measurements, demonstrating the lowest level of accuracy. All brands compared in one head-to-head study (using Cardell ® 9401 and Dinamap ® 1846 SX oscillometric devices) ranged consistently 10% (or as much as 20–30%) lower than the direct, telemetric recordings (Durham 2005 Cowgill 2006 Love and Harvey 2006). It has been demonstrated that although the heart rate can be reliably and repeatedly predicted there is great variability regarding the indirectly obtained measurements of the diastolic, systolic, and mean arterial pressures as compared to the telemetrically acquired direct blood pressure (Data Sciences International, DSI) readings obtained within a given (3–4 minutes) time frame in a conscious dog. There are two techniques available for measuring blood pressure- directly utilizing invasive methods or indirectly via noninvasive methods such as Doppler ultrasonography and DINAMAP (Device for Indirect, Noninvasive, Automatic Mean Arterial Pressure) oscillometric devices (Waddell 2004, Durham 2005). Proceedings Western Veterinary Conference (Waddell L. Normal arterial pressure values.īlood pressure monitoring for the critically ill. The mean arterial pressure (MAP) is determined by the following equation: Pulse pressure is a result of the difference between the systolic and diastolic pressures. Systole represents cardiac contraction, and diastole occurs during cardiac filling. Normal arterial blood pressure values for dogs and cats are indicated in Table 11.1. Furthermore, many other factors can impact blood pressure homeostasis, including chemoreceptors, hormonal influences, and the renal sensing systems (Durham 2005 Tefend 2007). Baroreceptors located in the carotid sinus and aortic arch help regulate blood pressure through the sympathetic nervous system control centers. Additionally, blood volume is a major determinant of blood pressure (Durham 2005). Blood pressure itself may be defined as “the lateral force on the arterial wall” (Love and Harvey 2006). Cardiac contractility, preload, and afterload are all factors that can influence the stroke volume. The stroke volume is the amount of blood ejected with one contraction of the heart. The heart rate is the speed at which the heart is pumping, or the number of contractions per minute. Cardiac output is determined by a combination of the heart rate and stroke volume. Total peripheral resistance is defined as the resistance to blood flow created by the peripheral arterial system as well as capillary beds. Blood pressure is determined by total peripheral resistance and cardiac output. In summary there are two factors that affect blood pressure and two factors that affect cardiac output ( Fig. ![]()
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