Should we teach / use the Shock Index?

[Steve Whitehead]

I'm considering whether I should teach the concept of the "shock index" to new EMT's. I like the concept for several reasons. I also think it has some failings.

Plus:

1) Good demonstration of the relationship between pulse and blood pressure in identifying shock. (New students like to compartmentalize information.)

2) Would help newer EMTs recognize early decompensation when complicating factors (like beta-blocker use) affect the complete vital sign picture.

3) MIght help recognition of occult bleeding.

4) Good platform to lead into teaching about putting the vitals signs in context for the patient. (Diffcult to teach new EMTs)

Minus:

1) Might give new EMT's the idea that they should be puling out a calculator and doing math while they are involved in patient care.

Is this concept worthwhile in prehospital care? Should we be learning it at the EMT basic level?

[Kaisu]

In the minimal hours required for EMT-B certification? Hardly likely my friend. There isn't even time in that curriculum to explain what BP is.

[chbare]

Is there strong evidence that suggests it is useful or gives us the ability to make clinical decisions?

[Vorenus]

Strikes me as pretty much useless. It only demonstrates what you should notice anyways (decrease of BP, increase of HR) and puts it into a formula.

It may be useful in the classroom to explain the correlation between BP and HR, but I don`t see any use for it in a prehospital enviroment.

[DwayneEMTP]

I don't see the value in it as a tool either, though don't read that as a belief that it has none. As a teaching tool, it's hard to say without understanding the correlation of the numbers to hemodynamic/perfusion status.

Is there a better description of the relative value of the numbers other than what's given? "0.5-0.7 is believed to be a normal shock index." I don't really know what that means...The value considered normotensive and/or non shocky?

Could you possibly give a quick primer with patient examples showing how it might be applied? Again, I'm not making fun of it at all, I just don't get it, but I also, after significant consideration, see no value in the GCS that so many do either.

When I ran numbers that might worry me, depending on patient presentation, such as p120, s140 when imagining a compensating patient, or p125 s156 it gave me numbers near the "normal shock index" range, though I would be concerned about those patients being compensated, possibly significantly so.

Maybe it's just my little brain works but I'm happier with a 90/40, 130, patient because at least I'm confident that I'm not waiting for the compensation failure but have a relatively 'solid' baseline from which to work and trend.

I've also found that attempting to berate patients that I'm confident are about to crump, but present fairly well hemodynamically, into conforming to my expectations has limited value, if any. Though I've seen no studies on the subject.

Anyway, again, way to long winded, but the point is meant to be that perhaps it's my relative comfort with decompensated patients over badly injured/ill compensating patients that causes me to miss the value of the calculation.

I would argue though that if the concept can be shown to have some predictable relationship to overall perfusion status that the value at the EMT level would be limited unless you're drawing students much more qualified than those that I've been exposed to.

The majority, again, in my limited experience, are most interested in finding an Iphone app that will give them values each time memorization or calculation is confronted. (In no way am I pretending that I wasn't that same student, though Iphones were not an option when I became a basic) I would personally like to see that relationship severed.

Interesting discussion I think...

[Kiwiology]

No I think it's pretty useless, I have never heard of it, none of my Anaesthetist contacts have ever heard of it

Now Columbus hadn't heard the earth wasn't flat either but still in the pre-hospital environment what good is it going to do? Change whether we give the bro hit by a bus a litre of fluid? No. Change whether he meets major trauma criteria? No. Do anything of any value whatsoever, oh look $4 pizzas at Dominos now that is value, no.

Edited April 27, 2012 by Kiwiology

[DwayneEMTP]

But Kiwi, the question wasn't only whether or not it should be taught as a diagnostic aid, but if it should be taught as an adjunct teaching aid to help clarify other more complex issues of perfusion at the EMT level.

Why are you guys so quick to say that this is shit? It's an intelligent question presented in a respectful intelligent manner...Perhaps in your infinite wisdom maybe you can explain from a physiologic perfusion point of view why it makes no sense?

Maybe I'm just getting City burnout, but these kinds of posts are really starting to piss me off...

But I guess if it's not going to change treatment, then it can't possibly have any value...or have you maybe spent a shitload of time battling that ridiculous statement in the past?

[Kiwiology]

But Kiwi, the question wasn't only whether or not it should be taught as a diagnostic aid, but if it should be taught as an adjunct teaching aid to help clarify other more complex issues of perfusion at the EMT level.

Perfusion is not a difficult concept to grasp, I mean I'm a complete bloody retard and I didn't haz teh problem with it

Hmm ... capillary hydrostatic pressure you say; what in the fuck is that?

Why are you guys so quick to say that this is shit? It's an intelligent question presented in a respectful intelligent manner...Perhaps in your infinite wisdom maybe you can explain from a physiologic perfusion point of view why it makes no sense?

I said some arbitrary number nobody has heard of is pretty useless; its not a like a Glasgow coma score or a blood pressure it's just some random ass number

In shock itself blood pressure is a very poor indicator of the degree of shock and gone are the days that we used blood pressure as a primary indicator of severity of volume depletion. Somebody who is on a big bag of blood pressure lollies may have shock without significant hypotension or may be overly hypotensive because of the blocking of the reflex mechanisms by which the body will attempt to maintain blood pressure.

Heart rate is kind of the same, some bloke who is on beta blockers for a nunngered ticker can have shock without tachycardia

So that right there means that shock index number you get is going to be skewed

But I guess if it's not going to change treatment, then it can't possibly have any value...or have you maybe spent a shitload of time battling that ridiculous statement in the past?

A fair point but I don't see this number being of any value honestly

[chbare]

Perfusion is actually quite difficult and certain aspects are ill defined. Remember, one of the greatest unsolved problems today is how to derive the Navier Stokes equations from first principles and really develop a sound understanding of concepts such as turbulent flow. Being that we have areas in our body where Reynolds numbers are high, we have turbulence. This is one of many things we do not fully understand.

[Asysin2leads]

Putting in my own vital signs from my physical, HR = 90, BP = 105/72, gives me a shock index of 0.86. My heart rate was a little higher that morning, and my BP on the lower side. I had exercised strenuously the night before and skipped breakfast. I was probably a little dehydrated, but according to the shock index, I should have been in bad shape, right? MAP, of course, is a far better indicator of perfusion, particularly the central perfusion pressure, rather than systolic, diastolic, or heart rate. For my own vitals, my MAP would have been 81.7, well within the normal range, so in this case the shock index is not reflective of perfusion.

I'd rather EMT-B's not worry so much about the number, and more about when to push the panic button and engage in rapid transport or meet up with ALS. It drives me up the wall that some EMT and first aid textbooks still list loss of radial pulses and diaphoresis as a "warning sign of shock." Nuh, uh, homey, if you've lost your radial pulses you're actually headed in to Stage 3 hypovolemic shock and you are in bad shape. Reinforce the subtle warning signs of shock, the tachycardia, the restlessness, the air hunger, etc. I think that would be more beneficial.