It had been a pleasant day so far. The dachshund with congestive heart failure had started eating and wagging her tail again. The angry cat with eosinophilic keratitis, a disease that caused a huge white growth to cover one eye, had finally let his owners apply ophthalmic ointment. The lesion had almost completely resolved, restoring kitty’s vision and good mood. Another mother had remarked how nice my kids were. Someone else complemented my writing. I was feeling fine.
“Come in with Rhea,” I invited the owner of the elderly cat with chronic renal failure. A common syndrome in geriatric cats, many live for years despite impaired kidney function. The kidneys’ major job is to filter the blood and excrete waste products via the urine, but they have another crucial role, producing hormones that stimulate red blood cell production and regulate blood pressure. Therefore, cats with chronic renal failure should be periodically monitored for anemia and high blood pressure. Rhea was here to have her blood pressure checked.
What exactly is blood pressure? It is the force with which blood flows through the small vessels called capillaries that supply oxygen to the body. If pressure is too low, blood may not adequately perfuse essential organs including brain, heart, lungs, and kidneys. Low blood pressure is called hypotension and can be the result of many things including blood loss, trauma, anesthesia, dehydration, and medications. Prolonged hypotension can lead to kidney failure, brain damage, and death. If the pressure is too high, it’s called hypertension, also known as “the silent killer” because there may be no visible symptoms until it’s too late.
Hypertension increases risk of stroke in many species. It may lead to heart attack in humans. Hypertensive cats are particularly prone to retinal hemorrhage and detachment leading to blindness.
So when Rhea arrived, we pulled out the handy-dandy blood pressure machine I bought years ago. We always measure blood pressure before doing anything else stressful. An agitated patient may have a temporary increase in blood pressure that is simply situational and not indicative of actual disease. I dimmed the lights. Sometimes I play soothing New Age music. “She needs to lie on her side,” I instructed.
Rhea was not fond of this idea but in order to get the most accurate reading, the limb where we place the cuff should be approximately level with the heart. Measuring pressure with Rhea standing may give a falsely elevated reading, leading to unnecessary treatment. Measuring with the leg elevated above heart level might give a falsely low reading. As Rhea relaxed a little, I selected the right size cuff, wrapped it firmly around her foreleg, attached the tubing, and pressed Start.
Phffitttzzzzz. Whhhosssh. Aaaahhhhhh. The cuff would begin to inflate, the electronic display would flash numbers, then everything fizzled. I tried again. I checked my connections. I changed cuffs. Rhea was not impressed. Phfitzz, whhosssh, aahhh. My patient looked in fine fettle, but my blood pressure machine was dying.I tried not to show me dismay.
What’s the big deal, you ask? Just go buy a new sphygmomanometer, the technical name for that simple cuff they use at your doctor’s office. Or one of those home monitors you get at the drugstore for 20 bucks. Right? I’m afraid not.
In people, measuring BP is relatively simple. A cuff inflated around the arm occludes blood flow. Then a stethoscope is placed over the artery. As the cuff deflates, the nurse listens for the sound of blood pulsing to begin, and then to stop. Pressure is measured in millimeters of mercury (mm Hg.) Systolic pressure is generated when the big left ventricle of the heart contracts, sending blood pumping out into the body, and correlates to when the listener first hears a sound. Diastolic pressure is when the left ventricle relaxes and correlates to when the pulsing sound stops.
But in dogs and cats the sound of arterial blood flow is not audible with a stethoscope. We still use a cuff but then have to add one of two high-tech methods to “hear” that pulsing. Dopplers use ultrasonic waves to detect the flow and make it audible. Oscillometric devices use changes in pulsatile pressure oscillation to sense the changes in flow. A human sphygmomanometer goes for under 50 bucks. Veterinary monitors range from two to five thousand. Yup. Thousand. My blood pressure goes up just typing that.
Later that day, trying to get my machine repaired, I was informed it was “obsolete.” Sigh. In vet school 35 years ago, they barely mentioned hypertension. That was something specialists dealt with. As technology advanced, I took the leap and invested in this machine. Next the automatic x-ray processor replaced darkroom tanks of developer and fixer. Then I bought the pricey gadget that measures intra-ocular pressure, since I was tired of stressing about whether every red-eyed dog had glaucoma. Nowadays I wish I could afford digital radiographs, a more modern anesthesia set-up, maybe a computer and tablet for the exam room.
All this equipment…. It’s great, but it also makes me ponder how dramatically veterinary medicine has changed. The solo veterinarian, once the norm, has been largely replaced by big multi-veterinarian practices. Chains like VCA and Banfield have taken over many mainland hospitals. It’s a far cry from James Herriot, but by sharing equipment and resources among multiple doctors, such facilities can offer far more in state-of-the-art technical services than the old country vet. As I flip through catalogs looking at expensive new equipment, I wonder if I am as outdated as my blood pressure machine.
I recall James Herriot’s response when he was asked who his last patient was: “There was no last animal I treated. When young farm lads started to help me over the gate into a field or a pigpen to make sure the old fellow wouldn’t fall, I started to consider retiring.”
Then I shake it off. You can’t buy 30 years of experience in a catalog, and I can still climb over an occasional gate.