Blood pressure

[FrankM]

I recently had the personnel experience of observing major differences in how blood pressure is measured. My wife was at a specialist and he put their automatic blood pressure machine on her and let it cycle a few times. The systolic was 40 points higher than at her previous specialist, which was 20 points higher than what she gets from her general internist that uses a manual sphygmomanometer.

 

I commented that the systolic pressure was high, and the doctor responded, "the pressure is too high", this referring to the cuff pressure. Guess what blood pressure he recorded on her record?

 

I recently participated in a "health fair" where my blood pressure was measured, and the machine produced a very high reading and I asked to be tested with a manual device, which was available. It produced a normal reading well below the NIH "high blood pressure" value.

 

The U.S. NIH states:

"High blood pressure is a blood pressure reading of 140/90 mmHg or higher."

 

I commented to one of the other "health professionals" at the "health fair" about the difference in the manual versus automatic machine. He stated if you really want some wide variations get it tested at your local drug store where they have one of the machines sitting there for anybody to use.

 

If I were a drug manufacturer, selling drugs to reduce blood pressure, I would make sure the automatic machines were cheap enough that no doctor would take the time or find it profitable for a staff member to use a manual sphygmomanometer.

 

I wonder how many people have been put on "biology altering drugs" because of erroneous blood pressure measurements?

[FrankM]

Earlier this week had the opportunity to be present when a blood pressure test was being made and I asked the person giving it, a manual sphygmomanometer test, how high the pressure was pumped. The response was 160 unless there is a need to go higher because of a persons blood pressure.

 

The systolic was 120. The same person had a systolic of 190 from a machine test two weeks earlier. Would you rather be tested manually or by machine?

 

I repeat, "How many people are being put on biology altering drugs because their blood pressure readings (machine read) were high?"

 

From my limited contact with medical facilities, I find many are using automatic sphygmomanometers exclusively. Could this be associated with the dramatic increase in sales of blood pressure medication?

[Tormod]

Hey Frank

 

Forgive me for asking (it's early morning and I'm watching Disney Channel with my daughter! ) but are you suggesting that the blood pressure test in post #1 above was "faked" in that they used the equipment wrong?

 

Was the guy an actual doctor? If so I am surprised because as far as I'm aware they have ethical guidelines about the use of equipment. Any doctor who uses the equipment to provide "fake" results to promote use of medicine is obviously doing a poor job of being a doctor...

 

I did a quick google search and it confirmed what I already knew: most blood pressure meters (ie the sphygmomanometers) that are used profesionally these days have "comfort fit" wraps which automatically apply the correct pressure. These are often automatic and should be self-calibrating (which might be a worrying term...).

 

Obviously there is a link between the use of sphygmomanometers and blood pressure medicine. You could probably say there is a link between sphygmomanometers and a lot of other medication as well (I have my pressure checked every time I see my doctor to get asthma medicines, for example). I think we'd have to dig deep to find evidence of medical professionals *knowingly* making "mistakes" in order to increase sales.

 

That's not to say it doesn't happen, of course.

 

Just my 2c!

 

For those who wonder what sort of diabolic instrument we're talking about: :camera:

Sphygmomanometer - Wikipedia, the free encyclopedia

[FrankM]

No Tormod, the results are from medical facilities and doctors that are long established in the community. The one physician does not treat patients for high blood pressure, thus there is no incentive on his part to "fake" a result.

 

I have no explanation for the doctors comment, "the pressure is too high". I have been looking for something on the internet and I don't find anything. During the last test that registered high, the one I mentioned in the Private Message, I stood right in front of the machine and watched it intently while it went through several cycles.

 

I always noted that the results from the machines used in a certain hospital were always at least 20 mmg HG higher than those taken by the doctor office that used a manual sphygmomanometer, so this is not something right out of the blue.

 

What appears to be happening is that the excessive cuff pressure is causing vascular constriction that has not been completely relieved at the point systolic pressure is being taken, but by the time it takes to get to the diastolic the constriction has been reduced a little more.

 

You have to realize that the auto sphygmomanometers are a one-size-fits-all device. It doesn't matter if you are frail, thin, obese or muscular, they aren't smart enough to adjust the cuff pressure to accommodate the individuals physical characteristics.

 

I had my blood pressure measured just 3 months before I had participated in a health fair, which had a specific theme, and I was amazed that the auto machine they were using was 30 points higher than normal. They had a manual sphygmomanometer available and I asked to be tested with that, and it was 30 points lower than the auto machine. I wonder how many individuals will be scared into getting biology altering chemicals to lower their blood pressure as the result of the auto machine results?

 

I asked one of the other health professionals at the "health fair" about the auto machine and he is the one that said the "drug store" machines can vary dramatically. I suspect the machines in other facilities can vary enough to get a person tagged with "high blood pressure", when in fact it is normal.

 

What I need to determine now is if the auto sphygmomanometers in hospitals and doctors offices are periodically calibrated, and how this is done.

 

I have a request into a engineering forum, that has a medical device section, where I asked if there is a portable device that can be used to determine cuff pressure.

[CraigD]

I have a request into a engineering forum, that has a medical device section, where I asked if there is a portable device that can be used to determine cuff pressure.

There are a lot of them. Googling “digital manometer” will turn up lots of browsing material – such as these, which came up first for me.

 

I had a fairly nice one in 1985, from an employer - Long battery life, accurate (about +-0.5 mmHg), recording with a sampling rate <0.1 sec, easy to reset (pushbutton) max/min, with a serial interface and a bundled computer (DOS) program that would write the recorded data to convenient flat file.

 

Before considering this sort of testing, though, I recommend some common-sense consideration.

 

FrankM’s experience points out something I believe most clinicians, especially nurses and aids, know: automatic blood pressure readers are less reliable than a manual cuff, stethoscope and human ears. Even a well-maintained, high-quality automatic reader can error badly if confused by noise from accidental movement that would never fool even a distracted human.

 

I’d recommend he and his wife consider that BPs are not constant, but vary due to many normal and pathological causes. Years ago, one of my healthcare org’s in-house publications carried a summary of a clinician’s paper in which he noticed a roughly 10 mmHg change in average systolic BP due to the temporary relocation of his department from a the second to the first story of his medical center. This building has a central atrium with wide, inviting stairs, which apparently many patients used rather than waiting for an elevator, resulting in a significant skewing of average BPs, even though it was assumed that the usual waiting time was long enough for everyone’s BP to return to normal.

[FrankM]

Craig, thanks for the response. Actually the type of pressure measurement device I need is one that can measure the applied pressure of the cuff. I don't want to take the hoses off of someones sphygmomanometer and replace it with a manometer. I know of several locations in the small community I live in that has public use sphygmomanometers, and I would like to expose them to a pressure test. Ideally, I would like to be able to insert a compressible item into the cuff (connected to a pressure gauge or manometer), cycle the machine, and see its maximum applied pressure.

 

I have been reviewing the technical specifications on various sphygmomanometers and there are significant differences in how they do their job. Also, some come with different cuff sizes, but I don't deal with pediatricians so I don't know if they use a different cuffs sizes. The physician I deal with has a number of very frail elderly patients and their physical conditions puts them in the same category as a small child, but he uses the manual sphygmomanometer.

 

I have seen just one automatic model that actually limits the cuff pressure and increments it to be just above the systolic. I am sure there are more but I haven't found them yet.

 

Adult Mode: Initial inflation to 150 mmHg

Neo Mode: Initial inflation to 75 mmHg

Subsequent inflation to approximately 30 mmHg greater than previous systolic pressure.

 

I need to get the specific model numbers of the devices that I or my wife might be exposed to and see their specifications.

[UncleAl]

It's more fun than that! Official Truth started at 140 mm systole as "normal" bp for a middle aged male. That was dropped to 130 mm (do the gym hard 3x/week) and now 120 mm (ain't gonna happen without drugs).

 

You will die. Death by one cause is neither more nor less effective than death by ten causes. Do what you want within nominal bounds for quality of life. Weigh known side effects against presumptive benefits.

[FrankM]

Weigh known side effects against presumptive benefits.

 

I know too many older relatives that have chosen to take chemicals to alter their biology rather than curb their eating habits or to consider getting some exercise. Periodically one or more will complain about some side effect of their chemical habits and they get their physician to try something different. Their emails about their chemical juggling is a constant lesson in how their lifestyles are now dictated by this or that drug. Some of the side effects are absolutely scary; a close relative was advised to stay out of the sun, which is a problem for someone that lives in Arizona.

 

Blood pressure measurement techniques are not the only thing that an individual should watch, be informed about what one needs to do before blood tests. I only thing that I am told is that one should "fast" before certain blood tests, that is, don't eat or drink for at least 12 hours (except for water or coffee) before the test. Depending upon what "panel" they choose for the blood test, there are a number of other things one should not do. I was never told that hard physical exercise several days before certain standard tests will skew the results. The testing labs adjust the acceptable ranges for results based upon age, but they don't tell you the reason for this. It is presumed that if you are older you won't be doing really hard physical work for any extended period of time, thus it is assumed you have a serious problem if the tested value is out-of-range for your age group.

 

The doctor noticed one of the "skewed" values and suggested drugs to bring it down. All I had to do was avoid hard physical work in the week before the next test and it was then normal for my age group that are couch potatoes.

[FrankM]

All one needs to measure the pressure of an auto sphygmomanometer is a manual sphygmomanometer. I purchased a manual sphygmomanometer and mounted on an "arm", a 10 Oz (340 gm) soup can (empty). All one needs to do is pressurize the manual sphygmomanometer to about 80 mmHg, place it into the band of the auto sphygmomanometer, and hit On. Inflating the manual pressure bladder to about 80 mmHg gives it enough "body" to be pressurized by the auto sphygmomanometer. The initial pressurization of the auto sphygmomanometer can be read directly from the indicator on the manual sphygmomanometer.

 

Our home auto sphygmomanometer initial pressure was 210 mmHg.

 

As one ages the arteries and blood vessels become less flexible. When pressure is applied to an arm to constrict blood flow the arteries and blood vessels have been mashed to stop blood flow. Ideally, the pressure applied should be only that needed to stop blood flow, but many (how many?) apply much more pressure than needed. It appears that it takes longer for arteries and blood vessels to return to normal flow when excess pressures are applied.

 

I objected to the results of an auto sphygmomanometer test, as the results were way high from my past results. A manual test, where they don't pump up the pressure much beyond systolic (they can hear when this happens) indicated normal levels.

 

How many people do you know are on biology altering drugs because of an auto sphygmomanometer result?

[CraigD]

All one needs to measure the pressure of an auto sphygmomanometer is a manual sphygmomanometer. I purchased a manual sphygmomanometer and mounted on an "arm", a 10 Oz (340 gm) soup can (empty). All one needs to do is pressurize the manual sphygmomanometer to about 80 mmHg, place it into the band of the auto sphygmomanometer, and hit On. Inflating the manual pressure bladder to about 80 mmHg gives it enough "body" to be pressurized by the auto sphygmomanometer. The initial pressurization of the auto sphygmomanometer can be read directly from the indicator on the manual sphygmomanometer.

Clever! Assuming your test manometer (or would that be sphygmomanometermeter? ;)) is accurate, you could take it to various testers, and compare their performance.

 

I’d be curious to try such a test kit on some human takers of vital sign. Some of them really pump up the cuff before they start dropping it and listening for a pulse. I had a Red Cross staffer pump my cuff up 'til it pulled the Velcro lose so much that the cuff nearly fell off my arm when deflated – not to mention giving me numb, tingly fingers for the next few minutes!

As one ages the arteries and blood vessels become less flexible.

True

When pressure is applied to an arm to constrict blood flow the arteries and blood vessels have been mashed to stop blood flow. Ideally, the pressure applied should be only that needed to stop blood flow, but many (how many?) apply much more pressure than needed. It appears that it takes longer for arteries and blood vessels to return to normal flow when excess pressures are applied.

I’ve not noticed this. I don’t take BPs very often, but have taken them on people from under 1 to over 90 years old. You can get a bad reading if you let the pressure drop too quickly, “overshooting the mark” before you hear a pulse, and some people have faint pulses that are easy to mistake for other sounds, like slight movements of the arm, but I’m pretty sure that if it takes more than one pulse of blood to reopen your vessels, you’ve got some seriously dangerous blockage and adhesion!

 

Also, all of the human and automatic blood pressure testers I’ve seen inflate the cuff ‘til no pulse is heard, then slowly drop the pressure until first the systolic, then the diastolic pulse becomes audible. If the vessels were staying closed longer due to lack of flexibility or other causes, I think the reading would be in error by reporting a lower, not a higher pressure than it should.

 

I objected to the results of an auto sphygmomanometer test, as the results were way high from my past results. A manual test, where they don't pump up the pressure much beyond systolic (they can hear when this happens) indicated normal levels.

Your experience teaches a valuable lesson – if you think an error of any sort is being made in your medical treatment, speak up and insist the test or whatever be repeated. A good clinician should never object to this sort of input, and will be grateful for any action that could prevent an error. :D

 

There are a lot of potential factors that could cause a bad BP reading. Though, as I noted above, I don’t think inflexible vessels are likely to, something as simple as just not liking the automatic meter, or the clinician using it, could cause an actual, temporary spike in BP. As I related in post #5, as simple a thing as an extra flight of stairs between the door and the tester can have a significant skewing effect.

How many people do you know are on biology altering drugs because of an auto sphygmomanometer result?

I don’t know – I’d have to find or do a study to find out, and aren’t much involved in such things these days.

 

IMHO, the best safeguard against this possibility is to take your own BP at home, using whatever kit you like best, and call attention to an in-clinic reading that’s far from your usual. For the same reason, testing your friends can be a valuable service to them – my wife, a diabetic, makes it a point to test her friends’ blood sugars with her little test kit, and has found a few high reading in people who had no idea they might be diabetic.

[LaurieAG]

Actually the type of pressure measurement device I need is one that can measure the applied pressure of the cuff. I don't want to take the hoses off of someones sphygmomanometer and replace it with a manometer.

...

I have seen just one automatic model that actually limits the cuff pressure and increments it to be just above the systolic. I am sure there are more but I haven't found them yet.

 

Hi FrankM,

 

My father has had an automatic digital blood pressure monitor for a couple of years that has (cuff) inflation presets for 140, 170, 200 and 240. The specs give a measuring range of 0-280 mmHg, pulse 40-200 beats/min. The accuracy is +/- 3 mmHg for pressure and 5% for the pulse (Model OMRON M4, made in Japan).

 

If this automatic machine was under reporting I would be really worried because (for a male) my normal blood pressure is 90/60 with a pulse of 60-70 as measured on this machine. The lowest readings (after 10 hours sleep and breakfast) I have had was 82 and 81 over 51 and 51 (two tests) and I didn't even feel dizzy.