blood pressure cuffs

[Alan Lightstone]

good control of hypertension is probably one of the most important and easily accomplished things that can be done in modern medicine- the payback is HUGE.
Jeff

+1000 and then some.

[Patty Hann]

I read the article Alan linked to.

Wow. Clinic personnel may find it "too inconvenient" to ensure the proper size cuff is used. Just...Wow.

[Jim Becker]

And, of course, there’s this:
https://www.cnn.com/2023/08/07/healt...ess/index.html

Hah! I was just going to post this. We've had this struggle with our older daughter who is a "big woman" and I remain concerned that the XL cuff on her machine she has to use every day may still not be large enough.

[Dave Fritz]

My take aways - BP is a moving target. Get a physician you trust and do what they say. As the author, August Derleth once told me, "Not everyone with a reverse collar will get you into heaven and not every doctor will save your life."

[Alan Lightstone]

I just wrote a very long post that somehow got deleted. Aaargh!!!!!

I'm straying from the original post, but let me add some additional information from someone who has taken hundreds of thousands of BP readings from patients. In surgery, we typically take patient's blood pressures every 5 minutes on expensive, accurate BP machines with usually a choice of 3-4 different cuff sizes for adults, and more for kids. We are attuned to artifacts/bad readings and adjust as necessary.

When I need more accurate BP readings for more invasive surgery (like open heart surgery, lung surgery, major vascular surgery, trauma) I put an arterial line in the patient (think of a plastic IV catheter placed usually in a patient's radial artery in their wrist, but sometimes in their axillary artery, femoral artery, or even the aorta). This gives me far more accurate BP readings and second-by-second real-time readings, as well as makes it easy to take blood samples. We often have the BP cuff running concurrently (though less frequently) and the readings differ. It's comparing apples to oranges. Why don't we do this on everyone? It's invasive, painful (unless it's well anesthetized), and difficult to do unless you are well trained in it. I'm extremely good at it after decades of work, and ultrasound has made it far easier and quicker to do. What used to take sometimes minutes and minutes of work, I can usually now do in seconds. But enough patting myself on the back.

The point of this tome is that you need to think of BP readings as an estimate of what is going on in your body. Trends are the most helpful to look at (we can make you run, down tons of caffeine and make your BP high, but it's meaningless). If your physician thinks you have hypertension and should treat it, there is voluminous evidence in the medical literature as to how that is beneficial to your health.

I feel for large patients, who too small cuffs are placed on them and they get painful, inaccurate readings. It's a problem for sure.

[Patty Hann]

...

I feel for large patients, who too small cuffs are placed on them and they get painful, inaccurate readings. It's a problem for sure.

(There, Alan, I just deleted your post again ..well, most of it. But I digress...)

The "painful" part of using a too small cuff is, I would think, a minor problem compared to getting an inaccurate reading , which can have major consequences and ramifications.
So now the patient with "consistently high" BP readings is put on BP meds, when the real problem is the GP's staff "consistently used" too small of a cuff for Mr Linebacker.
What does taking BP meds do to a person with normal BP?
(I myself don't know, not being on BP meds, but I can't imagine any good comes of it.)

[Bill Howatt]

Item on some newscast a couple of days ago saying that a too large a cuff will tend to incorrect readings of low and a too small cuff will tend to incorrect readings of high. Apparently, the experts were surprised at the large magnitude of the errors so a correct cuff size is very important according to the study.

[Alan Lightstone]

...(snip)
What does taking BP meds do to a person with normal BP?
(I myself don't know, not being on BP meds, but I can't imagine any good comes of it.)

In most cases nothing bad, though it does cost money. In MOST cases. In some cases, bad things can happen. Obviously you only want to be on medicine if you need it and it makes things better, or prevents bad things from happening.

[Bill Howatt]

It probably depends on exactly what the medication is altering, but I lost some weight and my BP dropped (top number about 105) such that I was getting dizzy so the dose was cut back. I think some meds relax arteries and some others reduce the water in the body - the so-called pee-pill.

[Jeff Clode]

"Not everyone with a reverse collar will get you into heaven and not every doctor will save your life."
I love that!
I will make a plea that folks not get overwhelmed by the potential problems of measuring BP and miss the opportunity for appropriate treatment of hypertension. The issues with cuff size have been known since I was in medical school in the 70s - (nothing new here tho it does seem we have to “rediscover” stuff every so often for some reason). People with huge arms are often well served by using a validated wrist cuff - one which is from the validated lists and one which has been checked by their provider and is used in strict accordance with instructions.
The issue of BP variability is huge - it changes moment to moment. This is why home monitoring is so important - the more numbers you have the more accurate the averages are. The purpose of checking the cuff in the provider’s office is to see that you are getting a number congruent with the office cuff values. The absolute value at that moment is way less important than the fact that the should be within 5-10 points of each other. Then keep it simple- follow the instructions readily available on line - rest 5 minutes, no food or drink, no full bladder, no fights with SO, yada yada….check it once or twice at most, record it….rinse and repeat couple times per day until you see that the trend Alan is talking about is established. Don’t need to do both arms every time as long as they are similar when the diagnosis is made unless it floats your boat to do so…..
please don’t get frustrated - just measure and treat if appropriate. Your brain, heart, and kidneys will thank you

[Alex Zeller]

I asked the nurse at my doctor's office why she went so fast when doing things like weight and BP. She said they are just general numbers to see if there's a meaningful trend over the time between the last time it was taken. As long as it's close they are happy. Only if the BP is high will they do it a second time trying to be more accurate after having the patent try to relax. At work we have the same sort of sit on machine drug stores have but it's a little bit of a walk to get to it. I've never used it because I don't know how accurate it is without taking plenty of time after walking 10 minutes to it.

[Allan Dozier]

Question for Alan: For a thin patient with no hypertrophic muscles or obesity issues, given that the intra-arterial pressures differ from the external cuff pressures, are the external cuff measured ones consistently lower? Or all over the board? Again, for a thin armed individual.
The reason i ask is that the level of pressure that is considered harmful has been defined or determined over many years (and occasionally adjusted). I assume almost all of those readings were made with the cuff so if the measurements are consistent, isn't that the measurement that should be looked at? Do anesthesiologists use a different range of normal for intra-arterial pressures vs. the cuff measure? I would assume you couldn't extrapolate one to the other.

[Alan Lightstone]

Question for Alan: For a thin patient with no hypertrophic muscles or obesity issues, given that the intra-arterial pressures differ from the external cuff pressures, are the external cuff measured ones consistently lower? Or all over the board? Again, for a thin armed individual. The reason I ask is that the level of pressure that is considered harmful has been defined or determined over many years (and occasionally adjusted).

Some very interesting questions, there. I would say that the external cuff pressures are all over the board, but would likely be more accurate and precise for a thin armed individual, when measured by a quality automated machine or a skilled person with good hearing and good technique. The good technique part is important. Let's take the example of a patient either on a beta blocker, or natively bradycardic (slow heart rate). Lets arbitrarily use a HR of 55. So less than one heart beat every second. Now the person taking the BP is letting the pressure out of the BP cuff a little too quickly, as the patient is saying that it hurts them (pretty common scenario). If the operator is lowering the pressure more than 10mm a second, they could easily miss a heart beat and measure an artifactually high diastolic blood pressure. Easy to do this, and get an inaccurate reading. You can see why I'm more than a little partial to accurate automatic machines to do this. During my residency at Mass General (God, I'm getting old), they were just adopting automatic BP machines in the OR (the old Dynamaps). When we were on call at night, the first thing I would do is steal one of them from one of the operating rooms and take it with me wherever I had an operation that night. They were easier and more accurate to use.

I assume almost all of those readings were made with the cuff so if the measurements are consistent, isn't that the measurement that should be looked at?

Yes, I would assume (a safe assumption) that all of the recommended BP levels have been determined by measuring huge numbers of individuals with cuffs.

Do anesthesiologists use a different range of normal for intra-arterial pressures vs. the cuff measure? I would assume you couldn't extrapolate one to the other.

That is a very complicated question to answer. The simple answer to the above question is that we assume, if there is no or little artifact, that the arterial pressure is the correct reading.

But it is far, far more complicated. Let's take the example of a patient under general anesthesia, so unconscious. Usually the patients blood pressure drops during GA (general anesthesia). We often intervene to increase the blood pressure with vasopressors (constrict blood vessels) when the BP drops more than 20%. Tighter ranges are used for patients with known or suspected carotid or cardiovascular disease. If the patient doesn't have sufficient blocking of the pain response to parts of an operation, their blood pressure can rise. During parts of the procedure when nothing much is happening, the patient's blood pressure can drop. We strive for what we call "railroad tracks" - straight lines of BP readings that don't change from intended levels. It's by no means universally obtainable.

Now when doing many operations, often with orthopedic surgeons (see above quote about ox and IQ) https://gomerblog.com/2014/09/bones/...llLepfcQ61VyxE,
(An orthopedists view of the body - What's the purpose of the heart - it pumps Ancef (an antibiotic) to the bones. What's the purpose of the lungs - they provide oxygen so the heart can pump Ancef to the bones. What's the purpose of the brain - it tells the heart and lungs to pump Ancef to the bones. What's the purpose of the kidneys - they have no purpose. They excrete Ancef. But I digress... )

Anyway, back to the question. The orthopedists want us to intentionally lower the patient's blood pressure with medications to reduce blood loss, and improve their surgical view. (Intentional hypotension). This drives us crazy, as we are worried about the patient's brain and heart. They are focused on the surgical site (knee, hip, etc...) There are operations like cerebral aneurysm clipping that we also have to tightly control the BP, to avoid devastating consequences. Yeah, we are working hard not just sitting and reading a book while people are undergoing surgery. And I could write a book about cardiovascular surgery and BP control - many elements where the BP is intentionally raised or lowered, and long pump runs on a heart lung machine clearly do harm, necessitating sometimes heroic efforts at maintaining homeostasis.

[Jim Becker]

Professor Dr. SWMBO's close undergrad friend Selina is in your trade, Alan, coincidentally in the Boston area where you trained. (a contractor these days) She tells some interesting stories like that, too, relative to the surgeon's expectations vs reality.

[alan weinberg]

whenever the machine reading is strange we (yes, I’m a doctor, specifically urologist) use a stethoscope and manual sphygmomanometer, so if concerned, just buy those. Two minutes of training and you can be an expert even taking one’s own BP. Accurately.