• Sam Ireland

The EPI Mixer - Should EMS Use Push Dose Pressors?


The patient absolutely cannot wait. Their blood pressure has been dropping for the last several minutes and there is no doubt in your mind that you must intervene. You have a choice to make. Should you grab...

PUSH DOSE EPI

x1 Cardiac EPI

x1 Bag of 0.9% NS

x2 Needles

x1 10cc syringe

Or are you going to grab...

EPI DRIP

x1 Cardiac EPI

x1 Bag of 0.9% NS

x1 Needle

x1 IV pump tubing and pump

Lately in FOAMed there has been talk about the pros and cons of each method of pressor delivery. I recently listened to the EMCRIT update about push dose pressors, which got me thinking about EMS application of this method. Most of the talk about push dose pressors centers around in-hospital use. I don't usually pay too much attention to in-hospital vs pre-hospital, since EMS has such a broad range of capabilities. However, when it comes to the use of push dose pressors, this is one area where the availability of equipment and medications plays a big role in the treatment you choose. 

If you do choose the push dose epi as first line treatment as opposed to the infusion, be aware that it is not a replacement. It is simply a bridge until an infusion can be started. With this in mind, does it make sense for EMS to be utilizing push dose pressors? 

I've used EPI as an example in this post, but you could easily substitute norepinephrine if that is the push dose pressor you are considering using. 

My Challenge to you! 

I propose a challenge to you! Get in the back of your ambulance and time yourself to see how long it takes you to make either a push dose EPI or an EPI drip. The timer starts when you make the decision to initiate pressor treatment, and stops when the patient gets the medication. This will tell you if a push dose epi would even be appropriate for you to consider. And by all means, post your videos and share them with us here at FOAMfrat! Should you use the one that you can mix up faster?? We will consider the issue of familiarity with each in a minute. First, let me tell you about my own experience. 

MY own experience

I decided to do the experiment mentioned above. In my experiment, I already had a driver line of saline infusing into my fake patient. The only thing I had to do was mix either the drip or push dose vial and administer it into the driver line. The results? 

PUSH DOSE EPI

The push dose vial took me 1:47 to mix and administer. Not bad. 

EPI INFUSION 

The infusion took me 2:05. Only 18 seconds longer than the push dose vial. 

Now I have to ask myself, is the 18 seconds worth the extra work? My work is not done after I mix the push dose epi vial, I still have to mix an infusion soon after. If I take the extra 18 seconds, my work is done because my end goal is obviously to get the patient on an infusion. Check out the video I made of this experiment! 

Video:

The Issue of Familiarity 

If you're not at all familiar with the idea of push dose pressors, you probably shouldn't try it out for the first time when a patient is crashing right in front of you. This is something you should thoroughly practice in simulation prior to implementation in the field, and have all the logistics on lockdown. Since this is a not a standard way of mixing EPI, it can be easy to screw up the concentration. 

In EMS, most of us are very familiar with the standard EPI drip. 4 mcg / mL by mixing 1mg into a 250 mL bag. We usually start at a mid range dose like 5 mcg/min to avoid the over abundance of beta 2 dilation action, and take advantage of the opposing alpha 1 stimulation that happens above the mid range dose. This is pretty straight forward. Put it on the pump, titrate to MAP. 

With push dose epi, there are a few more considerations. Are you going to remember to administer another dose in a minute or two? Are you sure you mixed it right? Did your driver line actually deliver the dose yet? How much should you push? How long should you want to readminister? These are all things you should have a solid answer to before switching your first delivery method. 

As a side note, people have asked me if it would be within their medical guidelines to use push dose epi instead of an epi drip. Since the medication should be administered in the manner of an infusion (just with your brain and hand being the IV pump) I do not see why it should be viewed any differently. Perhaps your organization would have a different view of this issue. 

Logistics 

Whichever one you choose, here is the logistics of how to prepare each one. 

A Push Dose EPI is 1mL of cardiac arrest EPI (1mg in 10mL) into 10mL of 0.9% normal saline. This makes a concentration of 10mcg/mL. This can be accomplished by first drawing up 1mL (100 mcg) of cardiac arrest EPI (the 1mg in 10mL solution). Once you expose the top of the cardiac arrest PFS, a needle can be placed into it and medication can be drawn out. Next, draw up 9mL of 0.9% NS to make a 10mcg/mL solution. 

An EPI infusion will require 1mg of EPI to be placed into a 250mL bag. This will make a 4mcg/mL concentration. 

The manual calculation would be: Desired mcg/min x 60 / Concentration = mL/hour.

For example, a desired 5 mcg/min would be: 5 x 60 / 4 = 75mL/hour. 

Dosing chart: 

Many people weight base their epi (probably the better option). This should be done as mcg/kg/min. 

Example: mcg x kg x 60 / concentration = mL/h that you enter on your pump. 

Making a personal choice 

You have to make a decision of what you are going to do before you are in the situation where you must make a choice. For myself, I have decided that making a push dose epi, having to manage that push dose, and then having to make an infusion in addition to that push dose, is too much work and the logistics do not make sense to me. I would rather use the infusion right off of the bat and mentally offload all the extra work. In EMS we usually wear multiple hats on a call. We do not have as many people helping us as a physician may in a hospital setting. We must make decisions that are not only best for our patient, but ones that do not cognitively overload us. Each provider must test out what would be right for them and figure out the logistics to execute top notch patient care efficiently. 

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