Pain with IO use

[Quakefire]

One of my partners is getting ready to go back to school to become an Advanced Care Paramedic, and she has been doing an online A&P course ahead of time for a little extra study time during the course and she asked an interesting question. According to her text books the only place that has any nerve endings is in the periosteum, and yet we teach that the pain of insertion of an IO is much lower than the pain from the infusion. So she asked where the infusion pain comes from and I haven't the foggiest idea. I know there are people here much smarter than me so can anyone answer this question?

 

Dan

[Arctickat]

My understanding is that the pain is not associated with the injection site but more that the high pressures required for infusion result in discomfort  beyond the site. Think of it like this, when we give an IM injection the patient is left with discomfort for some time afterwards. This is because we've created an artificial hematoma with that 1 cc of fluid and it is putting pressure on the surrounding tissue. The situation is similar in IO. the tissues are being forced to deal with increased pressures that they are unaccustomed to. So it hurts.

[paramedicmike]

'Kat's got it.

[rock_shoes]

http://www.ncbi.nlm.nih.gov/pubmed/17229343

Nerve tissue abounds in the marrow space. The pressure from infusion Kat mentions causes extreme pain as a result. A very slow infiltration of lidocaine prior to the 10 to 20cc rapid flush to create an infusion "pocket" will help to numb the nerve tissue and dramatically reduce pain of infusion.

[Arctickat]

Wow, sometimes when I BS my way through an answer I'm actually right. I guess that's how I actually passed paramedork school.

[julia006]

You can identify the IO site that provides the least amount of pain and has the best fluid flow rate

Edited October 15, 2015 by julia006

[paramedicmike]

You can identify the IO site that provides the least amount of pain and has the best fluid flow rate

And what site would that be?  Care to explain what you mean by this?

[hertzvanrental]

Here in the UK (in my service, formerly Sussex, now SECAMB)  we got EZ-IO on every vehicle.  We also had lidocaine 1%. Recently it was removed because it was found to make very little difference. I have to admit that I agree. I have used the EZ-IO in conscious pts and even in some unconscious pts their leg will raise up when pushing fluids or meds despite lidocaine.

[rock_shoes]

Here in the UK (in my service, formerly Sussex, now SECAMB)  we got EZ-IO on every vehicle.  We also had lidocaine 1%. Recently it was removed because it was found to make very little difference. I have to admit that I agree. I have used the EZ-IO in conscious pts and even in some unconscious pts their leg will raise up when pushing fluids or meds despite lidocaine.

The key is patience. Once the slow infiltration of lidocaine is complete you have to wait a solid 4-5 minutes before flushing or doing anything else. 4-5 minutes on an ambulance call seems like an eternity so very few providers wait long enough.

If the patient is so crook you can't wait the 4-5 minutes you just have to accept you're going to cause significant pain. On the plus side, early administration of an appropriate benzo means the patient is unlikely to remember how much the flush sucked.

[hertzvanrental]

If the patient is ill enough to require an IO chances are they usually don't have 4-5 minutes spare. Especially if they are conscious and in agony. They want their morphine now not 5 minutes later. We got EZ-IO in 2005 with lido but  had lido removed last year so won't know about leaving it for 5 minutes. I thought it would be quicker onset. When I suture or use a digital nerve block I  find lido works very quickly