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When to believe the pulse oxymeter, when not?


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I would not feel comfortable administering TNK without a 12 lead, but yes I can diagnose an MI without an ECG.

How?

And what percentage of the patients you think are having an MI will later be confirmed to be having an MI by troponin or ECG changes? And what percentage of the patients that you do not believe are having an MI will later be shown to be having one?

To counter your argument, you have a 60 year old male with a hx of 2 MIs, complaining of crushing chest pain, 10 out of 10, with radiation to left arm, who is also hypertensive. Your monitor dies, are you going to withhold NTG and MS ?

If the hx is suspicious for TAA, I might well hold the NTG, and go for fentanyl instead of MS. But I don't think this is what you're talking about, although some consideration needs to be given to this if the patient is hypertensive on presentation.

In the situation you describe I would administer the NTG and MS, but I would be concerned about the possibility of an undiagnosed RVMI. Nothing about the presentation you describe necessarily screams MI. There's a good possibility this could be angina, and despite the anginal-pattern pain, this could still be of non-cardiac origin.

::Raises hand::

Well, you never said anything about troponin levels.

Crap.

Well, you knew what I meant, and you'd agree that a troponin alone is not enough for TNK. :)

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If you're saying this just to get a rise out of us, congratulations. If you're saying this because you believe it, please stop working in EMS.

Systemet, it is called experience. And I have not misdiagnosed one that I can think of in 2011, so I am batting closer to 100%, but will only claim 99% for now (in case I remember one later). I can

You should not be allowed to use a pulse-oximeter until you have run at least 100 respiratory calls, and have assessed all of those properly with just your ears, eyes, and brain. You should be able t

A couple of things....

First, yeah, I was a bit altered when I wrote that....

Second, I think I've lost track of the conversation somewhere as I don't see the arguments of those claiming that we should use no machines, only that a provider should get at least the basics of clinical assessment before being allowed to add them to their care. I've seen many, myself included that have been grateful many, many times to have all of the tools. The problem is that I've seen no providers that started out as strong clinicians that didn't remain strong when adding the machines, but I've seen few that learned to use machines first and then became strong clinicians. Though of course my exposure to either group is fleeting, the motivations during that short time seemed to be telling.

Systemet, don't ECGs miss near, or greater, than 50% of acute MIs? That's not a great percentage it seem to make your argument, though it's likely I'm missing your point in regards to Flaming's post. I've many times treated on the assumption of an acute MI without clear ECG verification to later have that assumption proved correct.

So just to be clear, my argument isn't really against machines so much as developing decent clinicians at our level before introducing them. One group seems to use them as a tool, the other as a crutch, and I think most often mental crutches are bad. I think that there is no question that it's optimum to give good tools to a good clinician. But I think we do damage by allowing weak providers to believe that they are good clinicians because they can compare numbers on a machine to their protocols.

But it does raise a question in my mind...as we've had a million threads laughing at the hosemonkeys for their constant stream of trauma pics with the automated BP cuff hooked up on trauma patients, do you all then trust your automated BP cuffs too? I'm not being facetious as maybe I'm missing the boat on this.

As late as the LP12 it seemed to be, when comparing values during long transports, that that automated cuffs are either pretty reliable on some patients, or just crap. Why it would be patient dependent, or if that is even true, I have no idea. It's just what I've seemed to have observed.

Also, as I'm still recovering from my predeployment premedication with tequila, if none of this makes sense either then I'm using that as an excuse...

Dwayne

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Systemet, don't ECGs miss near, or greater, than 50% of acute MIs? That's not a great percentage it seem to make your argument, though it's likely I'm missing your point in regards to Flaming's post. I've many times treated on the assumption of an acute MI without clear ECG verification to later have that assumption proved correct.

Yep. Varies a little depending on which leads you're looking at, but it's around the 40% mark. My point, which I made poorly, is that flaming's sense of intuition is probably batting at <40%.

Where the ECG does win, is at specificity. If you see a true STEMI pattern, in most leads, there's a 90% or greater chance that there's an actual infarction happening. This may occur in the period before detectable enzyme level arise, and is sufficient to give thrombolytics, or do PCI. This is an example of a machine we trust very very regularly, as a rule-in. I am certain that flaming's random guess that this patient is having an MI is <90% specific. [i am sure, Dwayne, that you're aware of all of this, but I'm putting this information out there for the basic providers.]

While the ASA is certainly very important, the NTG and MS are adjunctive therapies with minimal proven benefit (some small amount of evidence exists for a negative effect of MS in NSTEMI, but it might just be noise in the data). No one's going around giving tPA without a positive 12-lead, because "this might be a STEMI".

Perhaps this clears it up a little. Perhaps I'm just completely incoherrent today. Oh well. :bonk:

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All are excellent points, and I get exactly what you're saying.

I think that this thread, and your previous post particularly where you mention withholding tPA without a 12 lead, is painting a perfect picture of the complete provider. That we can't be what we maybe should be if we lean to heavily on our tools, but certainly would be relatively crippled without them.

Pretty cool...

Dwayne

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That we can't be what we maybe should be if we lean to heavily on our tools, but certainly would be relatively crippled without

I strongly agree with that. I think you've put it much better than I managed.

I know that my physical examination skills are fairly weak. I'm not that great at heart sounds. I have a very hard time identifying all but the clearest murmurs. I have great difficulty measuring JVP. I know there are many areas where an MD, an RT, an ICU or ER RN is just going to be plain better than me, because they see a greater number of particular groups of patients.

For most of us working EMS, we don't see that many people, and we don't see that many people with unusual pathologies. If I worked in a CICU for a year as an RN (I'm not one), I'm sure I'd be a lot better at discussing heart sounds, or having a really confident idea of what a subtle pericardial friction rub sounds like.

There are undoubtedly lots of medics out there that are better at physical examination than me. But I'd bet there's probably a lot that are worse too. We (with few exceptions) take relatively short training programs, don't get a ton of time in specialty wards, and we don't see a lot of the really rare presentations that get concentrated in some of these places.

I wonder sometimes why we feel that our physical examination and history taking skills are so much better than everyone elses's, that we know, with an absolute certainty that that chest pain patient is having an MI, and that it's not a TAA, or a cholecystitis, or something. Why as a group, we tend to feel that we can identify drug seekers better than the hospital staff (usual something along the lines of poor + poorly differentiated abdo pain + dares to request the narcotic analgesia that worked last time +/- ethnic minority --> obvious drug seeker), or that our mid back pain patient is a PE (no D-dimer, no V/Q, no real considered thoughts about risk factors, etc.) and so on. There seems to be this pervasive attitude that somehow we are weaker if we admit that there's a huge amount of diagnostic uncertainty in what we do, and we are not experts. If something is giving an ER doc pause for thought, then maybe we should tread cautiously in the same situations. Why do we feel that we're the only group that can't improve our diagnostic ability with the aid of technology, as if paramedic programs were perfected in 1979. I've never been able to answer this question, but I have a feeling that this attitude is one of the major stumbling blocks in our evolution towards a profession.

My apologies for a semi-rant, that absolutely wasn't directed at anyone in particular (especially you Dwayne). I just needed to vent a little.

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All are excellent points, and I get exactly what you're saying.

I think that this thread, and your previous post particularly where you mention withholding tPA without a 12 lead, is painting a perfect picture of the complete provider. That we can't be what we maybe should be if we lean to heavily on our tools, but certainly would be relatively crippled without them.

Pretty cool...

Dwayne

That is the point I was attempting to make, but missed the mark. Thanks for someing it up so well.

thrutheashes

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..

I wonder sometimes why we feel that our physical examination and history taking skills are so much better than everyone elses's, that we know, with an absolute certainty that that chest pain patient is having an MI, and that it's not a TAA, or a cholecystitis, or something. Why as a group, we tend to feel that we can identify drug seekers better than the hospital staff (usual something along the lines of poor + poorly differentiated abdo pain + dares to request the narcotic analgesia that worked last time +/- ethnic minority --> obvious drug seeker), or that our mid back pain patient is a PE (no D-dimer, no V/Q, no real considered thoughts about risk factors, etc.) and so on. There seems to be this pervasive attitude that somehow we are weaker if we admit that there's a huge amount of diagnostic uncertainty in what we do, and we are not experts. If something is giving an ER doc pause for thought, then maybe we should tread cautiously in the same situations. Why do we feel that we're the only group that can't improve our diagnostic ability with the aid of technology, as if paramedic programs were perfected in 1979. I've never been able to answer this question, but I have a feeling that this attitude is one of the major stumbling blocks in our evolution towards a profession.

My apologies for a semi-rant, that absolutely wasn't directed at anyone in particular (especially you Dwayne). I just needed to vent a little.

When you say 'we as a group' I'm not sure if you mean 'we' at the City or 'we' as in prehospital EMS?

I've not seen this so much I think, though much of my EMS career has been spent working in non typical services and locations so it's likely that I wouldn't.

I don't think that my history taking and assessments are better than anyone elses, but I do tend to believe that they are better than many of the medics I've worked with. But I do get your point about us seeming more confident in our working diagnosis than many in hospital providers, and often more than we have a right to be.

I wonder though if it's really that way, or perhaps only appears that way when we discuss. I know I make people batshit sometimes for wanting to get to EXACTLY what happened when compared to my assessment and DDx. I've often asked an ER doc about a patient to hear get a flippant, "Not sure, we'll see what the labs say." And I get that as, not only is he way smarter than I am, but he's also surrounded by other really smart people and has the luxury of time on all but the most hinky of patients.

The flip side of course, and what I believe that you're addressing, is the medic that automatically knows what's going on. "Seen it all, done it all...blah, blah." I do think that that is a way of shoring up one's self esteem in the face of ignorance. "I don't know, but if I sound certain enough no one will know." Unfortunately it often works. Some of the more respected medics I know gained respect by posturing instead of solid medicine. In fact I've been gifted with that on more occasions that I'd like to admit.

I've never worked anywhere that I had 5 or 10 minute transports. Not ever. So I think that there is a big part of me that wants to know that I can still do my job when the monitor doesn't work, or the pulse ox is 'missing.'

I had a basic partner that I drove a little bit crazy. He'd check the ambulance for the collapsable cot, the stair chair, etc, etc. I didn't really care about any of those things. I'd say, "If we have them, great. If not, then we'll figure out another way to solve the problem, right?" One night he said, "Jesus Christ! It's like you want to make problems for yourself just so you can see if you're smart enough to solve them!"

And I think he was right..it made me stop and think, and I came to realize that I was afraid of not being able to think my way out of problems so I would make situations where it was necessary so that I could verify to myself that I would always be smart enough, no matter what went to shit. Again, I think in the end that that made me a better provider and that my patients didn't suffer from being carried out on a quilt instead of a soft cot, or a dinning room chair instead of a stair chair.

But I'm also happy that I don't have the need to play such games any more. :-)

There is no doubt that machines make me a better provider...I just want to try and be the strongest and most competent provider that I can be without them. And that is different. I feel driven to try and learn to notice and assess facial expressions and body movement, anxiety levels and skin color/condition before putting my hands on people. Not sure why, but there you have it.

Does it make me a better medic, or is it just some stupid game I play? No idea....

Dwayne

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Dwayne - I agree with your history taking and evaluation assessment. I have ridden with medics where the basic discovered the lower right quadrant rebound pain, took the time to get the complete history, uncovered a patient with TB from his med list and documented previous surgeries from scars.

Good history taking is about sleuthing the information with care. Most can do it well if they take the time, many don't.

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When you say 'we as a group' I'm not sure if you mean 'we' at the City or 'we' as in prehospital EMS?

I hadn't really thought about the distinction between the two to be honest. I think I was speaking more to EMS in general, which of course is coloured by my own experiences and the particular providers I've met, and systems I've dealt with.

I've not seen this so much I think, though much of my EMS career has been spent working in non typical services and locations so it's likely that I wouldn't.

This is great. I've been lucky to work with some awesome people as well. I've also worked with some people who weren't very good. There's been a real range.

I don't think that my history taking and assessments are better than anyone elses, but I do tend to believe that they are better than many of the medics I've worked with. But I do get your point about us seeming more confident in our working diagnosis than many in hospital providers, and often more than we have a right to be.

Do you really think so, I mean the part about us "hav[ing] a right to be?". I kind of feel like, as a group, we tend to underestimate the uncertainty involved in what we're doing. It seems like things would be all backwards if I'm bringing a guy into an EM doc with 9 years of medical training, on top of an undergrad, and I'm more likely to be right than him or her.

For example, unless I have a field troponin kit, which few services have, I have no way to diagnose a NSTEMI. I don't have any meaningful way to detect a PE. I can suspect CVA, but can't really differentiate it from a TIA, because we don't have CT scanning. My patients can be hyperkalemic, if they have a particularly suspicious ECG and history, but can I really claim to diagnose other electrolyte disturbances? I can observe findings that might point towards them, but it's hard to really sit down and say, "this patient here is hypomagnesemic because of ....". Or conversely, this patient isn't.

Sometimes it feels like we have a pretty narrow range of diseases we can identify, or at least find supporting evidence for, and we try and pigeon-hole the patients into these categories, often inappropriately.

I wonder though if it's really that way, or perhaps only appears that way when we discuss. I know I make people batshit sometimes for wanting to get to EXACTLY what happened when compared to my assessment and DDx. I've often asked an ER doc about a patient to hear get a flippant, "Not sure, we'll see what the labs say." And I get that as, not only is he way smarter than I am, but he's also surrounded by other really smart people and has the luxury of time on all but the most hinky of patients.

Well he may not be smarter than you, he just may be more educated. I've seen lots of educated people do lots of stupid things, trust me. I would argue, in a friendly way, that sometimes we have a lot more time on our hands than we think. Sometimes there just end up being a number of differentials that we can't exclude, that have a similar probability, then we end up stuck in the same situation, waiting for technology to provide other findings, or forced by the possible severity of the situation to do what we feel has the best risk/benefit.

Obviously you know if the doc is being flippant or not. I can't disagree with you over that from the other side of an electron beam, and it would be foolish for me to try. But the attitude of gathering further information before committing to a diagnosis seems quite reasonable.

The flip side of course, and what I believe that you're addressing, is the medic that automatically knows what's going on. "Seen it all, done it all...blah, blah." I do think that that is a way of shoring up one's self esteem in the face of ignorance. "I don't know, but if I sound certain enough no one will know." Unfortunately it often works. Some of the more respected medics I know gained respect by posturing instead of solid medicine. In fact I've been gifted with that on more occasions that I'd like to admit.

I think those are the sort of people I was really thinking more about. When I started as a medic I was quite young, and had to really fight for respect. I was lucky not to screw up too badly in my first couple of years, and eventually got to a place where I didn't care so much about being respecting, and around that point, it felt like people started respecting me more. I think a lot of us have probably walked that path. But I have had to deal with a lot of people who are very dogmatic, and that have the attitude that the winner of any argument is the person who aggressively defends their position as loudly as possible while showing anger and emotion. The "he who shouts loudest is right" philosophy.

I've never worked anywhere that I had 5 or 10 minute transports. Not ever. So I think that there is a big part of me that wants to know that I can still do my job when the monitor doesn't work, or the pulse ox is 'missing.'

I've worked in places as an EMT where it was possible to transport for several hours -- BLS services doing 911 as well. But as a medic, I've usually been within a half hour or so of some sort of approximation of a hospital, and an hour or two from a real one. The bulk of my experience has come in urban / suburban areas with shorter transport times, some of which have been in the 5 to 10 minute range. But, then, with redirect systems, and all the craziness that happens, I've done 45 minute transports in urban areas too. I won't even start about hallway nursing... :)

I think that some of the generalisations about rural and urban practice have some validity, but I think they're also often distorted by the perspective of past experience. City medics have a reputation for being burnt out, under-treating, and running everyone to the ER. Or at least I used to hear this complaint from people in the rural regions a lot. But the counter-argument you often get from urban practitioners is that they simply see a large volume of patients, and that they're being conservative with their treatments because (i) there's only so much benefit in exposing the patient to a potentially risky intervention if they're a few minutes from an ER fellow and a real hospital with trauma surg, and specialty ICUs, and (ii) they feel that they see a wide range of presentations, and are more comfortable with which patients are truely sick and need aggressive interventions, and feel the rural guys over-treat.

I think you still run into these situations in the city, as well. You can still show up at a code and have your laryngoscope die, or your monitor stop working. I don't know why I'm defending urban practitioners, perhaps because a large proportion of my time in EMS was spent being one. But I met good and bad people in both settings, and can't say that either population of providers seemed that much better than the other, on average.

(cut some stuff out, hope it's ok)

There is no doubt that machines make me a better provider...I just want to try and be the strongest and most competent provider that I can be without them. And that is different. I feel driven to try and learn to notice and assess facial expressions and body movement, anxiety levels and skin color/condition before putting my hands on people. Not sure why, but there you have it.

Does it make me a better medic, or is it just some stupid game I play? No idea....

No, I think that's part of being a competent provider. I think a lot of what people describe as "sixth sense" is just keying in on subtle aspects of a patient's presentation that reminds you of something you've seen before (sometimes it still steers you in the wrong direction, of course, but c'est la vie).

I used to play a game with students occasionally. Just sitting in the truck or in the station, we'd run through a scenario, and I'd randomly declare a piece of kit "out of bounds", and tell them it wasn't working, or was missing. They'd often protest about this being unfair, but it was surprising how many things it was possible to do without or improvise around.

Enjoying the conversation, all the best.

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So what happens to providers when their equipment fails. Waht about that catastrophic failure where all the battery powered devices fail? What are your steps now. You have no battery powered equipment!!!

In a professional environment and as a professional provider (and this is even true for a professional but unpaid volunteer setting) I would expect at least a basic form of risk management:

  1. Have tools that are good and certified for professional use. No cheap lay use-at-home crap.
  2. Get them regularly checked, calibrated, cleaned or whatever the technical manual and manufacturer regulations say.
  3. Check them on shift start. Check them as they should be checked (see manual).
  4. Fast check them before application.
  5. Know them, their scope and exceptions.
  6. Have fall-back options available (my LP12 pulse ox sensor failed, I used my handheld pulse ox - sure not possible with every thing in every situation)
  7. Have replacements available. If battery powered: have extra batteries with you. Know how to change them.
  8. Have improvisation fall-back options available. Know their limitations. (hmmm...difficult with pulse ox).
  9. Know how to do stuff without the tool. Know YOUR limitations then.

It scares me when I hear someone doesn't know if his ambulance is fully stocked or if something is defective/not available (could happen, but at least the team should know it). Every professional car repairman follows the points above, especially the availability of good and fitting tools. Would the professional car repairmen change a tire without a torque wrench, just because he knows how to? Most probably not. Why should a professional medic not rely on his tools as that what they are: tools, to perform his job better?

The topics above cover a lot of organizational problems (ensure a stock of fresh batteries, replacement tools at station, ...). This, too, is an indicator for a professional service.

If a provider can't do anything without tools or uses his tools in a wrong way or isn't able to use his tools as true support for his diagnosis, then there's something wrong with that provider, not with the tools.

My case#2 was a good example for a straight cascade of diagnosis using tools, leading from a bit sick looking man to a high risk patient by several steps:

  • manual assessment: 4 x oriented, bit pale, no pain, bit nausea, known history of heart disease, "sick since the night before", "just went up to the bathroom, sure can I go!", "no real problem, my wife called you because she always is so anxious!", "maybe just a flu".
  • pulse: 70/min, very arrhytmic (hm...OK)
  • blood pressure: 150/0 (Huh?!?!!)
  • ECG 3 lead: A-fib (ah!)
  • ECG 12 lead: Left branch block, rate 140/min (oh!!!)

Pulse ox and blood glucose level just ruled out some side problems. But without a 12 lead there would be no real indication, that this man is probably short before a V-tach/V-fib. You now could argue that everyone with a probable heart failure (could be everyone!) should be treated like a raw egg, but that leads to a somewhat inefficient point of view ("scoop and run with everyone") and should be outdated long enough.

What if I have nothing with me for some reason? Well, I can help anyway since the most important tools are permanently attached to me: my hands and my brain. But I can use a lot of other tools, too, and I would hate to have them not, not available or not working maybe just because I was too lazy to check them at shift start for beeing so cool and educated and that I don't need them anyway, if they don't work. Why do I bother to carry them around in the first place then?

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