And we're back! In our last post, we discussed a number of approaches to the surgical airway, including the traditional "scalpel-hook-tube" method, the Seldinger technique, newer methods using bougies, and homemade/DIY/MacGyver approaches (a shout out to Emergency Medicine Ireland's Dr. Andy Neill for sharing his study on emergently using Bic Pens!). But what about kids? That's truly a beast of its own, so today is dedicated to our precious wee ones.
Clearly stating the obvious here: emergent pediatric airways are much less frequent than those in the adult world, and fortunately surgical airways in children are exceedingly rare. But you always have to remember that you cannot do a traditional cric on a child. Their cricothyroid membranes are just too small to accommodate an endotracheal tube, and you have an incredible high likelihood of damaging local structures. A paper we've referenced studied neonatal cadavers and found that in general their CTM's were about 2.8 mm tall, in comparison to the 2.0 ETT, which has an external diameter of 3.0 mm.
The exact cutoff age varies in the literature, anywhere from age five to age twelve. Generally speaking, if there's a kid, put your scalpel down. You could theoretically use this approach for adults as well, but they would require the jet ventilator--simply bagging them through the catheter won't generate adequate tidal volumes, and 15 L/min through the jet probably won't cut it either.
What you'll need is generally similar to the needle approach for kids: a 14 G angiocath with a 5 cc saline filled syringe (in a pinch, you can get this out of a central line kit), and some sort of adaptor for BVM (if that's your endpoint).
The big difference now is that you will need a jet ventilator--the system generally includes a hookup to high pressure wall O2 (generally at about 50 psi), tubing, an on-off valve/injector, a regulator, and a Luer lock to attach to your catheter (see below for images). Is this easily located in your shop? Best make sure that it is.
You'll start by identifying the laryngeal prominence, moving inferiorally to locate the CTM. In neonates and smaller children this may be difficult as their laryngeal prominence is not developed. In these instances, start low and move your finger up the tracheal rings until you've found the CTM. After cleaning, aim your needle caudad at about 30-40 degrees. Just like in our previous post, you'll want to aspirate to get air bubbles. And it should aspirate easily--any resistance suggests you're still in soft tissue. If your patient is awake (hopefully not), you can inject lidocaine via the syringe to suppress the cough reflex.
After that, just advance the catheter, and remove your needle. If you're going to be using a bag, toss on your adaptor (usually a 3 mL syringe MacGyvered into a 7.0 ETT adaptor--seen below), and start squeezing.
One big downside to using the standard angiocath is that it can kink relatively easy. An alternative, if you have it in your shop, is a non-kinking wire catheter, demonstrated here from the Walls text:
As for jet ventilating, you'll need to attach your apparatus and do some adjustments. To avoid barotrauma, you'll need to reduce the inspiratory pressures to less than 20-30 psi. This is where an expensive commercial device earns it weight in gold--you'll want a device that can reliably and easily do this quickly. You will want to set your flow rate at about 1 L/min per year of age, and then titrate up 1L/min based on how much chest wall movement you're seeing. Your control will either be a handle or a button, with several variations depicted below:
Due to their small lung volumes, the jet is generally contraindicated in kids younger than five. In these incidences, use the bag, ventilating carefully (but against a lot of resistance!) and with age appropriate equipment.
And now, here's your gratuitous Whit Fisher MacGyver video--this one features novel ways to jet ventilate when your equipment is not within grasp (along with some absolute ridiculousness):
As always, these writings on procedurology are for EDUCATIONAL PURPOSES ONLY. Do your own research, keep calm/carry on, and always do the right thing. You are the expert, and you are the one who will save a (young) life.
Thank you all for following! And thanks again to emcurious.com!
Check out the Part 1 Post:
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- Navsa, N. et al (2005). Dimensions of the neonatal cricothyroid membrane--how feasible is a surgical cricothyroidotomy? Pediatric Anesthesia, 15:402-406.
- Walls RM, ed. Manual of Emergency Airway Management, Section 2.
- Roberts and Hedges' Clinical Procedures in Emergency Medicine, 6th Edition. Chapter 6.
- Whit Fisher's YouTube Page