Thoughts on using pulse ox for BP?

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bunkie

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http://www.ems1.com/ems-products/co-screening/articles/680842-The-Other-Side-of-Pulse-Oximetry/

One easy way to palpate a blood pressure is to place the pulse oximeter probe on a digit in the extremity in which you're taking a blood pressure. Wait for a steady waveform and decent saturation reading, then inflate your BP cuff.

Watch the numbers as the waveform disappears, and when it reappears during deflation. Those numbers are roughly equivalent to the systolic blood pressure reading you'd obtain during conventional palpation of a blood pressure.
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I was reading some articles and read over this. Any thoughts on this?
 
Considering that is takes longer for the SPO2 to react to the change, there is no way to get an accurate reading this way.

Is it that hard to take a real BP or at least feel for a pulse?
 
bunkie said:
http://www.ems1.com/ems-products/co-screening/articles/680842-The-Other-Side-of-Pulse-Oximetry/



I was reading some articles and read over this. Any thoughts on this?
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I would think it'd be faster getting the BP by palpation, instead of relying on a piece of equipment that typically underperforms from many different factors.

Training your hands for sensitivity will reap more benefits than relying on an additional gadget to do a task it was not intended for.

On the other hand... I've never seen this done before.
 
reaper said:
Considering that is takes longer for the SPO2 to react to the change, there is no way to get an accurate reading this way.

Is it that hard to take a real BP or at least feel for a pulse?
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I didn't think so. But I considered the fact that maybe the writer of the article came up with it as a solution to not being able to hear over road noise? I was just wondering about it. I do fine with good old fashioned bp's.
 
I can not believe this guy posted something like that. All he would have to do is visit any ICU where a patient has a manual BP cuff, arterial line and pulse ox to notice the discrepancies.
 
Roughly equivalent?
 
I read this technique(if u want to call it that) a while back and tried it just to see how well it worked... yep... didn't work well at all. I would never recommend this.

I really dont see any advantage of using the pulse ox to try and obtain a blood pressure. If you can't feel a radial pulse chances are the pulse ox isn't going to detect pulsation either.
 
VentMedic said:
I can not believe this guy posted something like that. All he would have to do is visit any ICU where a patient has a manual BP cuff, arterial line and pulse ox to notice the discrepancies.
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steven "kelly" Grayson does it again.

The same man who brought us the modified scrotal lead!

Reporting that a practitioner was unable to palpate a blood pressure due to weak pulse, vehicle movement or any other condition is preferable to using a technique that is wrought with inaccurate and unreliable readings and is frequently difficult to use. As a profession I think that inventing ways, that are unreliable and unproven, are in the past. EMS personnel treat 'tricks of the trade' as something to be proud of. We should look at what we do as a profession with an eye toward performing what has been proven not what may seem 'cool' and trendy. If you believe that the use of a pulse oxymeter provides an indication of blood flow to an extremity prove it empirically. You may be instrumental in taking away the image of EMS as being 'cowboys' and move towards it being a profession.
 
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VentMedic said:
If you are treating a patient, do you want to defend "roughly equivalent"?

Would you have the backing of the pulse ox manufacturer for this use?
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I suggest you use a pulse ox to obtain a pulse oximetry and a blood pressure cuff to obtain a blood pressure. Are these two procedures so time consuming for some that we need little tricks to save a few seconds.
 
CAOX3 said:
I suggest you use a pulse ox to obtain a pulse oximetry and a blood pressure cuff to obtain a blood pressure. Are these two procedures so time consuming for some that we need little tricks to save a few seconds.
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Did you read my post?

I do NOT recommend using this method.
 
I don't trust a field pulse ox to measure accurately even that which it's intended to measure. I'll stick to using a stethoscope to get blood pressures.

If you're going to do this, you might as well just watch your BP cuff and note when the needle starts bouncing with the pulse.

And no, I don't recommend that method either, I hasten to add.
 
One has to consider that each pulse ox brand is different. Right now Masimo is considered one of the best for its motion filtering technology. However, there is still much research to be done with the sensitivity and uses for the perfusion index. Right now the majority of their PI research is for neonates.

We did switch to Masimo and it took a significant amount of our budget to do so.
 
VentMedic said:
One has to consider that each pulse ox brand is different. Right now Masimo is considered one of the best for its motion filtering technology. However, there is still much research to be done with the sensitivity and uses for the perfusion index. Right now the majority of their PI research is for neonates.

We did switch to Masimo and it took a significant amount of our budget to do so.
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Is there a relationship between PI and PPG as measured by pulse ox? I've seen PPG mentioned in a Crit-care book, but I've not come across PI much...although I know almost nothing about both, but it seems on brief inspection that the two readings might be based on similar data. I understand that PI is a relative measurement of pulse strength and that PPG is volumetric, or change in volume, but it seems like that is basically the same way of expressing the same information..

Is there a reason why we can't simply press a 'mode' button and switch our pulse oxs to take these readings, other than just the fact that the feature wasn't previously added?

Would these readings be of any value in the prehospital setting (what, briefly, is the clinical application of the two values)?
 
Melclin said:
I understand that PI is a relative measurement of pulse strength and that PPG is volumetric, or change in volume, but it seems like that is basically the same way of expressing the same information..

Is there a reason why we can't simply press a 'mode' button and switch our pulse oxs to take these readings, other than just the fact that the feature wasn't previously added?

Would these readings be of any value in the prehospital setting (what, briefly, is the clinical application of the two values)?
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Terms:
PPG: Pulsatile Photoplethysmographic

PI: Perfusion Index

Some of these factors would also depend on the algorithm used for the PPG amplitude. I've got to admit this is getting into a technical area where I may not be able to adequately explain it or even begin to explain it.

Masimo can change it algorithm with the more sophisticated models to adapt in low perfusion and can give an indication for the PI and the wavelengths.

The issue would be would the PPG and algorithm be appropriate for motion and skin considerations to adequately monitor PI. Motion is probably the biggest issue in prehospital as many of the situations studied were in controlled OR or ICU environments. Neonates has also been relatively easy to study due to their skin density. Masimo has some good articles from their studies on their website.

PI
http://www.masimo.com/Rainbow/pdf/LAB3410F%20-%20PI.pdf

PVI (masimo's own term)
http://www.masimo.com/pvi/index.htm


A decent article although it doesn't get into great detail for the technical aspect.
http://www.rtmagazine.com/issues/articles/2002-08_03.asp
 
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bunkie said:
http://www.ems1.com/ems-products/co-screening/articles/680842-The-Other-Side-of-Pulse-Oximetry/



I was reading some articles and read over this. Any thoughts on this?
Click to expand...

You have got to be kidding me. I don't see why you would want to palpate at all in the first place. The Good Lord gave us two good ears, a stethescope, and a BP cuff for a reason. Auscultate. I don't like palpated blood pressures.

Short cuts are are only halfway doing doing something. Halfway also means half-arsed.

Just my opinion.
 
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There was a mention of this exact technique in a recent text on transport medicine, I can't recall the title, its at home, remember reading it while preparing for the FP-C exam.

Air and Surface Patient Transport: Principles and Practice.
 
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