Alpha agonists in anaphylaxis

[paramatt_]

Now I have done a little research on this topic, but was wondering if anyone out there in ambulance land has the ability to use alpha agonists in anaphylaxis that’s refractory to /in combination with adrenaline.

I recently had a patient in anaphylactic shock, I can’t remember all of the vitals, but she was poorly perfused, tachy, BP 65/50, decreased conscious state, mottled skin, urticarial, GIT upset, but no broncho spasm. She received IM adrenaline, 02, fluids, supine legs elevated, etc. Upon reassessment somewhere after the five minute mark, she still remained hypotensive and had a marginal increase in heart rate, though no ectopics. She got a second dose of IM adrenaline and dexamethasone. After this, she became increasingly tachy and began having multiple PVCs, developed a bit of a tremor, though still was hypotensive. All in all, it took a good 25 minutes and close to a 1000mls of pressure infused saline to get her stabilized....minus the tremor and anxiety

Aside from the potential use of an adrenaline infusion, there wasn’t much else we could offer this patient and I don’t think it would have been possible to avoid the cardiac effects anyways. With this being said, however, I kept thinking how a solely alpha-1 agonist such as phenylephrine or metaraminol might have been handy. I like to hear from anyone who has experience with these meds in similar situations

Many thanks

[Kiwiology]

You raise a very interesting point sir. There is no Ambulance Service I know of internationally that is doing this but I think MAS in Victoria (AU) is using aramine in patients with bradyarrhythmia. Isuprel and noradrenaline spring to mind as well.

I would strongly recommend an IV infusion of adrenaline over boluses of IM adrenaline. Large amounts of fluid are fairly common in this situation, probably the only patient I would still consider two big bore drips and squeezing fluid into is a patient with anaphylaxis.

[BushyFromOz]

You raise a very interesting point sir. There is no Ambulance Service I know of internationally that is doing this but I think MAS in Victoria (AU) is using aramine in patients with bradyarrhythmia. Isuprel and noradrenaline spring to mind as well.

Metaraminol is used here for poorly perfused SVT's refractory to reversion and hypotensive people arfter some clown mixes viagra and GTN together. Adrenaline infusion at 5mcg/min and then working up, but i dont think the metaraminol stabilises MAST cells like the adrenaline does, but im probably just making that up.

IMI adrenaline is all i have here. Crazy that yours had no bronchospasm, all of my Anaphylactic patients had dynamic hyperinflation and distributive shock which seriously stuffs up their preload, but it doesn't sound like thats the case with yours.

IM with Kiwi, this chick would get agressively fluid loaded from me, and with the exception of the Septic Shock patient i cant think of any other patient you would aggressively load like this. The last anaphylaxis i had took around 4.5 litres to come good - despite the adrenaline and the beta agonists for her bronchospasm she just didn't have anything left to pump..... she had nice puffy limbs though

http://www.semes.org/revista/vol21_3/11_ing.pdf

Pretty much sums up the topic

[croaker260]

I would strongly recommend an IV infusion of adrenaline over boluses of IM adrenaline. Large amounts of fluid are fairly common in this situation, probably the only patient I would still consider two big bore drips and squeezing fluid into is a patient with anaphylaxis.

Agreed...

IM EPi, followed by H1 and H2 anatagonist, Solu-medrol, an EPi Neb for laryngeo-edema and either repeated epi IM or an Epi drip for refractory hypotension. Fluids can easily exceed 2L in these situations.

While Nor-Epi (seldome carried around here) or high dose dopamine (20-30 mcg/kg/min) might be an option, I think we all agree that an Epi Drip would be your best bet here.

[chbare]

From my experience with anaphylaxis, I would probably not initially go to an epinephrine infusion. It takes time to mix it and delivering reliable doses in the field when so many EMS units do not have pumps is a potential problem. I would administer IM epinephrine first along with IV fluid boluses and steroids/H2 antagonists first, then move onto an epinephrine infusion if needed.

[Kiwiology]

The adrenaline infusion used here is pretty simple 1mg adrenaline in 1 litre NaCl given at 2gtt/s titrated doesnt take that long to mix probably no longer than drawing up and administering IM adrenaline and can be used for anaphylaxis, asthma and severe bradycardia

[Eydawn]

Simple to mix in that format, yes, but counting drops is in no way, in my opinion, an accurate way to titrate a correct dose. It changes enough on a patient in a non-moving hospital bed... I agree with Chbare that a pump is vital, and it is far preferable to go with the IM route in a moving vehicle.

I'm curious as to what the post-fluid bolus care is... do people end up in fluid overload once the anaphylactic shock has been mitigated? Do we ever see rebound pulmonary edema, especially in those clients already in heart failure? I honestly haven't seen enough anaphylaxis nor the followup care to know... but 4 litres is a LOT of fluid to be positive on!

Wendy

CO EMT-B

RN-ADN Student

[BushyFromOz]

Simple to mix in that format, yes, but counting drops is in no way, in my opinion, an accurate way to titrate a correct dose. It changes enough on a patient in a non-moving hospital bed... I agree with Chbare that a pump is vital, and it is far preferable to go with the IM route in a moving vehicle.

I'm curious as to what the post-fluid bolus care is... do people end up in fluid overload once the anaphylactic shock has been mitigated? Do we ever see rebound pulmonary edema, especially in those clients already in heart failure? I honestly haven't seen enough anaphylaxis nor the followup care to know... but 4 litres is a LOT of fluid to be positive on!

Wendy

CO EMT-B

RN-ADN Student

I should have been a bit more descript, not all of her circulating gvolume was third spaced, some went down the toilet too

[paramatt_]

Thanks for all the replies. Our guidelines outline the use of both IM and IV adrenaline, although IM is generally preferred. We are getting pumps shortly, which will obviously have its benefits.

In a patient that has extremely poor perfusion with brochospasm I would be more inclined to go the IV route, however, then comes the increased likelihood of the adverse B-1 effects, so I suppose a bit of risk vs benefit vs being able to manage the appropriate infusion rate all play into the discussion as well.

And Bushy, for what its worth I had a look at Therapeutic Guidelines (eTG), metaraminol is advocated in anaphylaxis with persistent hypotension. Not to say you guys will ever use it as such, but something worth noting

[BushyFromOz]

Thanks for all the replies. Our guidelines outline the use of both IM and IV adrenaline, although IM is generally preferred. We are getting pumps shortly, which will obviously have its benefits.

In a patient that has extremely poor perfusion with brochospasm I would be more inclined to go the IV route, however, then comes the increased likelihood of the adverse B-1 effects, so I suppose a bit of risk vs benefit vs being able to manage the appropriate infusion rate all play into the discussion as well.

And Bushy, for what its worth I had a look at Therapeutic Guidelines (eTG), metaraminol is advocated in anaphylaxis with persistent hypotension. Not to say you guys will ever use it as such, but something worth noting

I saw that too, i havn't looked into weather it stabilises MAST cells, will have to look into that tonight