Looking for old thread on BP myths

[emtannie]

I seem to remember a thread quite some time ago that talked about teaching newbies and students "the right way" vs "the way it has always been done."

One of the posts in that thread was regarding obtaining a patient's BP. There was some discussion on "the way it has always been done" technique of watching for the needle bounce as a non-scientific way of obtaining BP's.

I have tried the search function and came up with over 1700 possibilities, so I am hoping someone remembers this thread.

I am looking for this information as I need to prove to a co-worker that the "needle bounce" is not an evidence-based method of obtaining BP.

Thanks!

[Richard B the EMT]

This is anecdotal, so is probably not much help, but even when doing a BP of XXX over "Palp", it still is when the sound is auscultated, or pulse palpated, as most of us with experience taking BPs know the needle bounces a lot from pumping up to the sounds being audible.

On the other hand, I have had no needle jump at all until after I have first heard the sounds through the stethoscope, on some patients.

Just remember that there are actually only 2 things that can and will affect a BP: Anything, and Everything!

[fiznat]

This thread?

http://www.emtcity.com/phpBB2/viewtopic.php?t=7470&

Most of it is a steaming pile of crap imho... It doesn't matter whether BP readings are odd or even because either are within the range of SIGNIFICANCE on the instrument.

[crotchitymedic1986]

and that whole thing about if you have a radial pulse, you have a b/p higher than 90 is all BS too.

[JPINFV]

This thread?

http://www.emtcity.com/phpBB2/viewtopic.php?t=7470&

Most of it is a steaming pile of crap imho... It doesn't matter whether BP readings are odd or even because either are within the range of SIGNIFICANCE on the instrument.

You mean like this post I made?

Of course this entire conversation is even more of a moot point when you stop and realize that must manual cuffs have a margin of error of +/- 3 mmHg anyways. This means that your blood pressure can be anywhere in a 7 mm range (3 in each direction plus the number you got). It gets even worse when looking at a change in BP because that change would have to change more than 6 mm in a single direction (example, starting with a BP of 100, a new BP at 106 is not significant because 103 is within both margins of error. This is an extreme example).

http://www.emtcity.com/phpBB2/viewtopic.php?p=102475#102475

Interesting how no one debunked my use of statistics.

[fiznat]

You mean like this post I made? ....

No I agree with you JPINFV. Even if odd numbers are unacceptable (which is a ridiculous premise in the first place), it doesn't matter anyways because the cuffs have a margin of error that far exceeds the degrees we are discussing. And so, my original comment stands: the thread is crap.

and that whole thing about if you have a radial pulse, you have a b/p higher than 90 is all BS too.

This is mostly true btw, even though ATLS still uses palpable pulses as a guideline for BP measurements. I don't disagree that clinical signs can sometimes give us a good idea about the blood pressure, but the exact "it must be over 80 if I feel a radial" is bunk.

Some science to back it up: http://www.bmj.com/cgi/content/full/321/7262/673

[fiznat]

Another article evaluating the accuracy of BP cuffs. They tested 645 of them, which I think is a pretty decent sample size.

http://www.scielo.br/pdf/abc/v74n1/2202.pdf

And another: http://ccn.aacnjournals.org/cgi/content/full/22/2/123

Of the aneroid sphygmomanometers tested, 51% of those used in private practice and 56% of those used in hospitals were found to be not accurately calibrated. Of these, the magnitude of inaccuracy ranged from 4 to 8mm Hg in 70% and 51% of the devices, respectively...

Even if we HEAR the sounds absolutely perfectly (which we dont, and I imagine this has an even higher margin of error), we are looking at a difference of four to eight points in blood pressure simply due to the CUFF. Add in user error, ambient noise, and stethoscope problems, and I guarantee we're looking at at least 10-15 points in error.

People ought to realize that noninvasive blood pressures are estimations only.

[JPINFV]

No I agree with you JPINFV.

Oh, sorry, I was asking if that agreed with the, "It doesn't matter whether BP readings are odd or even because either are within the range of SIGNIFICANCE on the instrument," not the "Steaming piles of crap" part.

[emtannie]

This thread?

http://www.emtcity.com/phpBB2/viewtopic.php?t=7470&

Thanks fiznat, but that wasn't the one I was looking for.

My request stems from a comment a co-worker made.... stating that if you can't auscultate a BP, or palpate it, you can attach the cuff, inflate it, and then watch the needle... and when you see the first "bounce" of the needle, you have the systolic pressure. After I went :shock: I decided I should come up with something to refute that.

And, sidenote for anyone who wants to post that whoever this EMS person is should get off the truck.... this co-worker is not EMS... but is an ER RN....

[mobey]

If you cannot auscltate or palpate a BP, you need to move your patient :wink:

Remember there is more than one place to take a BP