Treatment of Anaphylaxis vs Protocols

[NYMedic828]

This has been bugging me for a while now and I can't seem to make sense of it.

Here in NYC our triad of medications for anaphylaxis are

Benadryl
Epi
Dexamethasome/methylprednisolone

We also can give albuterol for wheezing.

Benadryl is given for any suspected allergic reaction. If there is airway compromise or potential for it, we go right to epi 0.3 IM.

Corticosteroids are only to be given in the presence of decompensated shock in conjunction with rapid fluid replacement.

My question is

Why don't we give combivent for anaphylaxis like all other respiratory treatment? Is it because we are mainly concerned with the larger airways and atrovent works more at the lower level?


Also, just to be certain. We only give corticosteroids in the presence of decompensated shock, instead of Benadryl. This to my understanding is because of the immunosuppressant effects of corticosteroids which inherently block histamine and other immune regulated responses. Is this correct?

 

[Veneficus]

Why don't we give combivent for anaphylaxis like all other respiratory treatment? Is it because we are mainly concerned with the larger airways and atrovent works more at the lower level?

Because of the mechanisms.

Albuterol will antagonize b2 receptors.

ipatropium cholinergic.

In anaphylaxis and subsequent shock, there will be a catecholamine response, which will cause b2 smooth muscle constriction, however, the other effects of the cholinergic will be needed. So you are basically blocking the unwanted effects and keeping the beneficial ones.

Especially if you are giving epi.

You don't need anticholinergic effect, so there is no need to administer a med you don't need. (which is of course a medication error)

Also, just to be certain. We only give corticosteroids in the presence of decompensated shock, instead of Benadryl. This to my understanding is because of the immunosuppressant effects of corticosteroids which inherently block histamine and other immune regulated responses. Is this correct?

For this you need to understand the 4 types of hypersensitivity reactions and it is too much for me to type here. Type I is histamine mediated, so an antihistamine will work.

The type iv or sometimes called, delayed sensitivity reactions, are not suppressed by histamine blockers, however they are suppressed by steroids.

In anaphylaxis type I and type IV are the ones of greatest concern from the immunilogical standpoint.

Mag sulfate also suppresses T-cells, so in the type iv that is a viable treatment also, though usually only used in asthma patients.

An excellent description of all of this can be found in this book:

http://www.amazon.com/Robbins-Cotra...1219/ref=sr_1_1?ie=UTF8&qid=1332338151&sr=8-1

 

[Veneficus]

In anaphylaxis and subsequent shock, there will be a catecholamine response, which will cause b2 smooth muscle constriction, however, the other effects of the cholinergic

That should read adrenergic, my fault, couldn't edit it so this will have to be the fix.

 

[Brandon O]

Because of the mechanisms.

Albuterol will antagonize b2 receptors.

ipatropium cholinergic.

I think you misspoke here; this is backwards. Albuterol is a B2 agonist and ipratropium is an anticholinergic.

 

[NYMedic828]

Yea I'm confused now...

Last I knew albuterol is a b2 agonist and atrovent is an anticholinergic

Why would the adrenergic catecholomine response cause bronchoconstriction?

Don't we want as much adrenergic stimulation as possible to reverse bronchoconstriction and vasodilation, hence the purpose of injecting high potency epi?

And In that regards wouldn't an anticholinergic aid in suppressing the cholinergic to give the adrenergic more power?

 

[Veneficus]

I think you misspoke here; this is backwards. Albuterol is a B2 agonist and ipratropium is an anticholinergic.

Yea, I did, thanks. I really need to start doing one thing at a time.

my fault entirely. Should have reread this before posting.

 

[Veneficus]

Yea I'm confused now...

Last I knew albuterol is a b2 agonist and atrovent is an anticholinergic

Why would the adrenergic catecholomine response cause bronchoconstriction?

it does cause bronhcodilation, I misspoke as I was doing multiple things at once and of course none of them well.

Albuterol should stimulate bronchdilation locally.

Yes you do want as much adrenergic stimulation as possible.

Again, my fault.

 

[NYMedic828]

Ok thank goodness.

My mind was about to explode ur not exactly one to be wrong about these matters lol.

So why would locally suppressing the anticholinergic to facilitate a stronger adrenergic response not be beneficial?

 

[Veneficus]

Ok thank goodness.

My mind was about to explode ur not exactly one to be wrong about these matters lol.?

I am wrong from time to time, especially when I am reading one topic, responding to a different topic and somebody starts talking to me about a third and none of them are related. (as happened to me today) I think I messed up all of them, but the last was most important so I had to fix that first.

So why would locally suppressing the anticholinergic to facilitate a stronger adrenergic response not be beneficial?

According to Goodman & Gillman's ipatropium has almost no effect on leukotriene receptors.

There is also a warning in prescribing information that in combination with epi will cause an increase in heart rate synergistically and potential arrhythmias.