Thoughts on using pulse ox for BP?

[VentMedic]

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.

The arterial line and its waveform have been mentioned in some CC classes. If there are problems with BP management, we (RRT, RN) will insert an A-Line before flight. If we are having that much problem with pulses and BP, the pulse ox will be of little use. Also, if a person is on pressors, such as they commonly are on CCT and Flight, the peripherial vasoconstriction will also skew the ability of the pulse ox. For these patients we will use a earlobe probe which will be of no use for BPs either.

However, if anyone has ever been in an ICU to observe an A-line wave, pulse ox pleth and a manual BP, you will see the variation.

 

[VentMedic]

It also looks like Grayson has been doing some defending and clarifying of his article in the comments section below the article. I'm sure he's probably on a couple of other EMS forums as well defending it.

 

[Ambulance_Driver]

Defending the practice in other forums?

Nah, not really. I was given an assignment to do some "out of the box" thinking on clinical treatment tips. For the first three topics, I chose auscultatory percussion of long bone fractures, assessing tactile vocal fremitus, and alternative uses of pulse oximetry.

First, I think the pulse oximeter is a vastly misused piece of equipment, and secondly, I think there are other ways to utilize it, with the caveat that you shouldn't place absolute faith in the results you get. At best, it's a stopgap measure, a trick you try when nothing else works. I thought the article had made that clear, but apparently not.

I enjoy the discussions, actually. You guys are pointing out some flaws in my reasoning, and I appreciate that. That's what the comments section after the post is for, as well as discussion forums like this one.

On the other hand, let me offer a few clarifications:

1. The consensus seems to be that I recommend this trick for everyday use. I don't. I try it when I can't auscultate or palpate one conventionally. It's pretty rare that I can't palpate a pulse when the plethysmograph gets a good tracing, but it *has* happened.

2. I don't walk into an ER and confidently state, "The patient's BP is XX systolic," when I've done this. Instead, I do what I usually do when I can't obtain a decent BP, which is to say, "I could palpate or auscultate a BP (due to whatever reason), but I did manage to get one number this way (by the method described)."

To my mind, that's better than saying, "Couldn't get a BP," although I'm not shy about saying just that. Sometimes you simply can't. Heck, there have been times when I've said, "Blood pressure? Hell, I'm still working on airway!"

3. My ears suck, from childhood trauma and two tympanoplasties to years of shooting without ear protection, I have measurable deficits through all frequency ranges in both ears, but more so on the left. As a result, I'm one of those stethoscope snobs who has to carry his own high dollar scope, and guards it with his life. The other thing that necessitates is that I auscultate my blood pressures on scene, because road noise makes it almost impossible to hear in my sickest patients.

So yeah, once I'm in the rig, I palpate pressures a good bit, or use the NIBP. I always figured it went without saying that I auscultated a pressure with my own ears (or a partner I trusted), before I used either of those methods.

It's all good in theory to advise someone to never palpate a blood pressure, or if you do, "train your fingers to be more sensitive," but that breaks down in real life. When you can't hear for whatever reason, you palpate a blood pressure. And if you've never unsuccessfully tried to feel a radial pulse in a patient you *knew* had one, my hat's off to you, because either you haven't been working on a rig long, or your fingers are more sensitive than mine. If the latter is the case, a career as a concert violinist might make you more money than a medic. You're wasting your talents here.

4. When I'm titrating pressors, I prefer to have an art line. But since the docs sending those patients have this nasty habit of not bowing to my wishes every time, I frequently transport them without one. When that happens, refer to point #3. And when I get a NIBP reading that doesn't fit the trend or seems grossly wrong, also refer to #3. If necessary, I'll have my partner pull the rig over so that I can get a decent shot at auscultating a pressure. In other words, I use whatever works.

5. The modified scrotal lead remains an excellent trick to play on rookies. Try it some time!

 

[Melclin]

1. The consensus seems to be that I recommend this trick for everyday use. I don't...

Well that certainly needs to be clarified. I didn't read it that way, and it seems like plenty of other people didn't either.

 

[Ambulance_Driver]

Well,that certainly needs to be clarified. I didn't read it that way, and it seems like plenty of other people didn't either.

You know, I was going to post a direct quote from the article to refute that, but...

... I can't find it. Even worse, I can't blame it on editing, because it doesn't read that way in the original version either. So you're right, I didn't make that clear.

Thanks for pointing that out.

 

[Melclin]

Well,that certainly needs to be clarified. I didn't read it that way, and it seems like plenty of other people didn't either.

You know, I was going to post a direct quote from the article to refute that, but...

... I can't find it. Even worse, I can't blame it on editing, because it doesn't read that way in the original version either. So you're right, I didn't make that clear.

Thanks for pointing that out.

Waaaaait....an experienced medic politely acknowledging curt but constructive criticism from a student...whats your angle?...is it world domination?...its world domination isn't it.

 

[Ambulance_Driver]

ROFLMAO...

I have my moments. When my legion of flying monkeys completes my quest for world domination, I'll make sure you are on the protected rolls.

 

[Tincanfireman]

Welcome to EMTLife, by the way...

 

[Lifeguards For Life]

ROFLMAO...

I have my moments. When my legion of flying monkeys completes my quest for world domination, I'll make sure you are on the protected rolls.

welcome Supermedic!