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July 11, 2012

Some IO Pearls

There's been some online chatter about IOs recently, and that got me thinking about a lot of the pearls I have picked up.

Some background: I think we should probably do more IOs, particularly on the non-sick patients. Ever placed a triple-lumen CVC on a patient just because you couldn't get an IV even with an ultrasound? That patient should get an IO instead. Fewer complications, easier & faster to place. My theory is that while drilling into bone is painful, that lasts a second or less, and poking around in a healthyish patient to place a TLC has to be worse.

Complications do happen, but if you do IOs right, the complication rate is low.

This is not a comprehensive list of everything you need to know before you IO. Just some tips that make IOs easier & safer.

n.b. this mostly assumes a powered device, such as the EZ-IO*

IO Pearls:

Placement should just feel right
It's hard to describe but the tactile sensation when you drill in just feels right (or wrong) as you get through the cortex into the medulla.

Spin before the skin
Otherwise, the skin gets all caught up in the spinning bit.

One shot per bone
The main danger of IO is extravasation (leading to soft tissue damage), and no matter how poor your first attempt, you probably popped a hole in the cortex. If you then place a working IO, it will leak out that hole, and badness will ensue.

BM is great but not necessary
Successful aspiration of a small amount of bone marrow "confirms" placement but is not 100% sensitive (NPV is poor); even if aspiration doesn't work, you should try flushing. Pay close attention to any sign of leak (and monitor those compartments...) -- maybe ultrasound is useful for checking for leaks? (I have no idea; someone should look into that).

Put in a 2 ml or so of lidocaine to numb up the marrow. This could hurt. Consider repeating if using for a while. Check your lido dosing as this is pretty much IV lidocaine.

Flush 10-20ml
This "primes" the marrow to allow for better infusion rates.

The big bad thing that can happen with an IO is compartment syndrome. Make sure this is checked, especially since most IO patients won't be able to complain of searing calf pain. You don't want to revive the arrested patient only to make his leg fall off.

24 hour limit
IOs should be removed as soon as possible (i.e. after alternate access achieved) but should be taken out before a full day.

To remove: pull STRAIGHT out
You can twist even though they're not threaded but...

Do NOT rock on removal
Rocking evidently causes bone cracks and kills puppies. Big no-no.

Tips from Matt:

The stylet is the worst sharp
The stylet from the IO needle is basically the sharpest needle in the world, with teeth. BE CAREFUL.

Lido isn't perfect
Understand that even after infusion of lido, injection is going to be very painful. May be difficult to use in a patient you were going to keep awake.

Pressors are OK 
Remember that IO is relatively safe for pressors, probably better than a bad peripheral.
"I have had a few residents ask me about sternal IOs, these are military items meant to be placed with no drill. They are a paddle like mechanism and are designed so that body armor can be opened and the IO can be placed. EZ IO drills are not for sternums under any circumstances. Does not seem like something that would need stating but I've been asked multiple times."
How-to Video:

This video is from Dena Asaad Reiter's excellent EMProcedures page:

*I don't get money from them (really)


  1. Hi Seth,

    Great post. Some great and insightful tips. The danger of the stylet in particular! Many people I know can testify to that one following a needle stick.

    The sternal IO or FAST-1 is available commercially but like you say mainly used by the army. The device looks like the worst Heaf test you could ever get but great for when your limbs are either mangled or missing. In that setting cook IO into iliac crest works well too. Good video below on FAST-1.


    One final thing I mentioned on twitter is that although I'm a huge advocate of the IO and have very low threshold for insertion, the definitive evidence for them being safer than CVCs is still not here.The number of IOs put in by even experienced doctors is low compared to CVCs. So although we infrequently hear about IO complications we must be aware the denominator is much lower. In experienced hands I feel a CVC maybe safer than an IO, especially if US is added to that experience. I've inserted many hundreds ++ of CVCs with minimal complications. For inexperienced hands I feel an IO is safer than a CVC. In my practice were I've inserted a plenty of IOs (but far more CVCs) I've had a compartment syndrome on one occasion. The case was a septic 2 year old trisomy 21 child with an anostomotic breakdown and faecal peritonitis following a reversal of Hartmans. She was mottle, blue, cold, shut down and in extremis. She had a first pass IO inserted in the tibia with no extravasation. She had an RSI through it as well as fluid resus and adrenaline infusion with no issues. Within 4hrs I changed it over to a RIJ CVC sited post op. With resuscitation she pinked up nicely and her limb mottling improved bar the one that had had the IO in. She went on to require a fasciotomy of that leg within 24hrs. So my only word of warning is that the complications may be out there we just need the numbers to get an accurate idea of the incidence. So for now I would not regard IOs as a relatively benign way of getting intravascular access.

    Kindest regards,

    Peter Sherren

    Ps Below are a multitude of case reports and series on compartment syndromes with IO insertion.







    And finally a dog study


  2. Thanks for the comment(s)!

    That's sobering & very sad story; we should certainly try to better measure the complication rate for IOs, and this is certainly something to be concerned about.

  3. What form of lidocaine are you using. Are you using lidocaine off crash cart, or are you just using 1 or 2% that you would typically use for local anesthetic ?

    1. I use lido from the crash cart. to be honest, I'm not sure whether the local lido is safe for intravascular use (and there's a good alternative) so I avoid it