When we go to the doctor, having our blood pressure taken is just routine. Why isn’t it for dogs and cats? For starters, blood pressure is perhaps the most difficult parameter to accurately measure in dogs and cats. It wasn’t until less than 15 years ago that reliable veterinary machines were developed. It used to be that only specialists measured blood pressure, but it is becoming the standard of care for general practitioners to have the ability as well. Animals do not commonly have aneurisms, heart attacks, or strokes like people do. They have their own set of problems that come with being hypertensive (having high blood pressure). Cats in particular can quickly go blind from hypertension, often secondary to kidney and/or thyroid disease. Dogs on certain medications must be monitored for hypertension as a side effect. It’s a good idea to measure blood pressure on all cats over the age of 12, and on dogs with kidney, heart, or bladder issues, to name a few.
How is Blood Pressure Measured?
If we were to use a blood pressure machine (a sphygmomanometer) designed for use on people on a dog or cat, the results would be meaningless. Animals have fur, their “arms” are below their heart, and they bear weight on them. All of these factors complicate blood pressure measurements. It’s therefore imperative to have not only the machine designed for veterinary use, but the cuffs as well. Because our patients come in a wide variety of sizes, we have six different sizes of cuff. After determining the cuff size, we attach it to the pet. Depending on the pet, we may put it on the front foot, back leg, or even the tail! Animals seem to tolerate it rather well. If it’s our first time measuring a particular pet, we’ll often measure multiple locations to decide which is most accurate and least annoying for the patient. Once we know what works for that patient, we use that protocol for any follow-ups.
Even though we bought what is currently one of the best devices in the industry, no machine is perfect. Standard procedure is to take three blood pressure readings. Yep, this is much more involved than the 20 second measurement at your doctor’s office! It can take 15 minutes to fit the cuff and measure blood pressure in a pet, so it is not a routine part of a physical exam in the veterinary world. (Heck, many clinics allow 15 minutes for your whole appointment!)
One thing to remember is we want to do it before anything gets too stressful. (Immediately after a nail trim would not be the time to take a blood pressure!) The wonderful part is, this test is best performed at home (being a house call vet, this works in my favor!). For cats in particular, the stress of going to a vet clinic alone will make them hypertensive! In fact, when I was first testing my machine on some pets, I thought it was malfunctioning because the animals had readings at the low end of normal. I had the company come out to test it not once, but TWICE! They confirmed it is accurate. Why the difference?
The “normal levels” that have been researched and published for dogs and cats are all done on pets in veterinary hospitals. No one has calculated what “normal” is for a pet NOT in a hospital. Animals are more stressed in that kind of setting than they would be by having blood pressure measured at home. Therefore, what’s considered “normal” is actually slightly higher than what it is at home. Without having to leave home, we’re able to get much more accurate readings.