What the dog blood pressure calculator does
This calculator takes your dog's measured systolic and diastolic blood pressure (in mmHg) and classifies the systolic reading into the four risk categories defined by the American College of Veterinary Internal Medicine (ACVIM) 2018 consensus statement on systemic hypertension. It also reports two derived cardiovascular numbers that veterinarians rely on: pulse pressure and mean arterial pressure (MAP).
The ACVIM categories describe how likely a blood pressure is to cause future target-organ damage, meaning damage to the eyes, kidneys, brain and heart. The scale runs from Category I (normotensive) through Category II (prehypertensive) and Category III (hypertensive) to Category IV (severely hypertensive).
How to use it
Enter the systolic blood pressure and the diastolic blood pressure from your dog's reading, both in millimetres of mercury (mmHg). Doppler devices, the most common tool in small-animal practice, usually report only the systolic value, while oscillometric monitors report both. For a reliable result, use the average of several readings taken while the dog is calm, and discard the first measurement. The calculator then shows the ACVIM category along with the pulse pressure and MAP.
The formula explained
The classification depends only on systolic blood pressure (SBP): below 140 mmHg is normotensive (Category I), 140 to 159 mmHg is prehypertensive (Category II), 160 to 179 mmHg is hypertensive (Category III), and 180 mmHg or above is severely hypertensive (Category IV).
Pulse pressure is the gap between the systolic and diastolic pressures:
$$PP = SBP - DBP$$Mean arterial pressure is the average pressure across one cardiac cycle. Diastole lasts longer than systole, so the diastolic value is weighted twice:
$$MAP = \frac{SBP + 2 \times DBP}{3}$$Worked example
Suppose an oscillometric monitor reads a systolic pressure of 165 mmHg and a diastolic pressure of 95 mmHg. The pulse pressure is 165 − 95 = 70 mmHg. The mean arterial pressure is (165 + 2 × 95) / 3 = 355 / 3 ≈ 118.3 mmHg. Because the systolic value of 165 mmHg falls between 160 and 179, the dog is classified as ACVIM Category III, hypertensive, with a moderate risk of target-organ damage.
Frequently asked questions
What is a normal blood pressure for a dog? Under the ACVIM 2018 guidelines a dog is normotensive when its systolic pressure is below 140 mmHg. Readings of 140 to 159 mmHg are considered prehypertensive and are worth rechecking on another visit.
How is a dog's blood pressure measured? It is measured non-invasively with a Doppler or oscillometric device and an inflatable cuff placed on a limb or the tail. Because dogs stress easily, vets take five to seven readings in a quiet room, discard the first, and average the rest to reduce the white-coat effect.
When should canine hypertension be treated? The ACVIM consensus suggests antihypertensive treatment for dogs with a systolic pressure at or above 160 mmHg, especially when there is evidence of target-organ damage. Readings of 180 mmHg or higher indicate a high risk and call for more urgent management by a veterinarian.
