Racemic epi in allergic reaction

[DwayneEMTP]

If you take her appearance, respiratory rate, pulse rate, combined with her lower than expected blood pressure, particularly the systolic reading, all together, that should have had you for sure getting really good lung sounds before moving forward, and ;that might have given you some hints to go down a different path.

I'm not saying that it should, but in this patient the lower than expected b/p would have initially moved asthma attack to #2 on my differential with a, hopefully temporary, question mark for #1.

It feels like, and of course I don't know, but this is just sort of the vibe that I'm getting, that you're looking for 'points' that you can put together to make sure that you don't make the same mistake again. Maybe, try instead of looking for things to memorize, to build the physiological picture in your head. I think that if you do that, then you'll see that the b/p doesn't fit. The hole for that puzzle piece is there, but it's the wrong shape. In this case we all want really badly to hammer it into place, but you can't Brother...you have to keep looking (asking questions) for the right piece..

Excellent post, and I know that we've gone off in a direction that you didn't intend, so just raise the yellow flag and we'll try and get back on topic.

Thanks for your response above!

[Kiwiology]

The bug bite and reasonably rapid onset (20 minutes) are the huge clues that this is not an asthma attack.

[JakeEMTP]

As far as the cookbook medic the idea seemed sound at the time. Looking at it now I couldve accomplished the same method of killing two birds with one stone by doing the epi IM. With respirations at 40+ i'm starting to think the nebulized epi wouldve been useless because the tidal volume (or is it inspiratory volume? I need to double check that) wouldve been insufficient.

Hindsight is 20/20. That is what scenarios are for in class. I would have treated it as an allergic reaction as I stated above. Until you can control the respiratory rate, any nebulized medication is going to be futile. Breathing 40x/min is not conducive to a good neb. treatment.

[DFIB]

Also, and I'll ask that you believe that this isn't a criticism but a preference only....I like your posts, but could you break your larger posts up into smaller paragraphs? It just makes it easier for old People like the Mike's and DFIB to read. Me? No problem...I'm just trying to watch our for our brothers...

Old? "I'm as good once as I ever was"

[CytochromeP450]

chbare covered the pharmacology which was the root of your question, but I am going to play devils advocate...just because I can.

Based on the formula for normal blood pressure of [(Age x 2) + 90 = 102], and hypotensive being [(Age x 2) + 70 = 82] I am going to argue that she is normotensive. She does not have any hives or angioedema. It sounds like her symptoms are localized to her bronchioles...making me lean away from anaphylaxis.

Her heart rate and her respirations are elevated which should be expected from her respiratory distress. She has a history of asthma but no history of allergies (other than seasonal -- does anyone know if there is a correlation between these and anaphylactoid reactions?)

You said that she had a "bug bite" which I take to mean something entirely different from a HYMENOPTERA STING. One of which is a leading cause of anaphylaxis, the other I don't believe carries such a risk.

In terms of the contrast in onset between asthma and anaphylaxis...well...I can't quite come up with an argument for that. But I think my case still stands.

So I'm going to say that your working diagnosis wasn't as wrong as your instructor may have suggested, even though he had the "answer" in his hands and had the advantage of building things around it. Now I ask you...so she was maxed out on albuterol, but what other medication could you have given that has a mechanism of action that is still pretty specific to the bronchioles?

[croaker260]

We use standard epi nebs (5cc of 1: 1,000 , not racemic*) in anaphylaxis for acute laryngeal edema only, otherwise we use albuterol/atrovent nebs. Combining with CPAP might have been useful as well.

The epi neb (if indicated) is given in addition to any epi SQ/IM you may give.

We follow this up with Benadryl, Zantac, and Solu-medrol.

* side note: the WHO organization found little difference between racemic epi and epi 1:1,000 when nebbed for epiglottitis. We use standard epi nebs for epi-glottitis and any other form of laryngeo-edema, including burns or anaphylaxis.

Edited July 24, 2012 by croaker260

[DwayneEMTP]

...Based on the formula for normal blood pressure of [(Age x 2) + 90 = 102], and hypotensive being [(Age x 2) + 70 = 82] I am going to argue that she is normotensive....

And I'm going to play Angel's advocate, (I mean, the devil was already taken.) (Stop laughing DFIB, it's not that friggin' funny.)

First, I really hate these formulas (No disrespect intended, just my opinion) as they seem to have been designed for certain age categories, within certain weight ranges, under certain conditions. I did them in my head as a medic student but just couldn't make them jibe with real life and abandoned them.

But lets say that they are accurate. Your formula says that 102/s is normotensive for this child, but I'm assuming that that value is at rest. She's now slightly below that, which could also be her normal baseline, she's got a resp rate of 40 and a pulse rate of 140 so there's no question that this Babe is in severe distress, right? What is happening to all of the catecholamines that this distress will cause to circulate? How is a baseline normotensive finding a good thing in this patient? I don't believe that it is.

My guesss would be that the vasodilation secondary to the allergic reaction is keeping the b/p from elevating.

...She does not have any hives or angioedema. It sounds like her symptoms are localized to her bronchioles...making me lean away from anaphylaxis...

Did we get lung sounds at some point? It actually sounds like an anxiety attack, but again, we'd have to explain the lack of an elevated blood pressure secondary to her extreme anxiety to make that argument. Unless it's your feeling that this child's normal B/P in the 70's/s or so?

[DFIB]

And I'm going to play Angel's advocate, (I mean, the devil was already taken.) (Stop laughing DFIB, it's not that friggin' funny.)

I know an Angel. Angel Hernandez, he sells oranges for money.

[CytochromeP450]

Dwayne, you are starting to tear apart the straw man I had so carefully constructed to defend my claim!

So you are saying that based on the equation...

Blood pressure = Heart Rate x Stroke Volume x Systemic Vasclar Resistance

...that she is currently in a state of compensated shock, and that her blood pressue has not yet fallen because her heart rate increase had increased her cardiac output.

This makes me wonder: If a 50% decrease in SVR is matched by a 50% increase in heart rate, does blood pressue remain the same? Can you make the equation mathematically accurate by adding constants in front of each variable? Or is this only useful in demonstrating concept.

[DFIB]

This patient's MAP is 83 which is till acceptable although although worrisome for adults, especially if suspect of shock. I am not sure what the MAP values for a 6 year old are but I am assuming that they would be a little lower than for an adult.