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Old 01-17-2013, 00:30   #5
Quiet Professional
Join Date: Oct 2007
Location: San Antonio, TX
Posts: 377
First off, thank you for your urgency in addressing what you see is a serious problem with regards to our combat wounded.

Just a few weeks ago one of our commanders came by and mentioned this device - both myself and one of our experienced (read: old) trauma nurses looked at each other and laughed.... and immediately thought about the MAST trousers that SWATSURGEON mentioned. The more things change, the more they stay the same....

Has your concern about pneumatic devices during helicopter transport ever been borne out in real life? Back when MAST trousers were popular did anyone notice people exsanguinating during helicopter rides?

Let's play with the concept behind Boyle's Law for a minute (OK all you DMTs, follow along <g>) - lets say a pneumatic device is applied to stop bleeding at 3000ft elevation (91 kPA air pressure). Helicopter then ascends to 8000ft to deliver casualty, at which elevation the air pressure is approx 75 kPA. You are talking about an 18% change in notional volume during that shift - or using old geometry formulas (Vol of sphere = 4/3 pi r^3) the diameter difference between those 2 containers is less than 8%! - which would result in a negligible change in the amount of pressure that was being applied to the artery (which is what we really care about).

Furthermore, whatever material you make your pneumatic device out of is NOT an ideal material - it has elastic properties that means some of the force caused by the pressure difference will NOT be reflected as a change in volume - the same reason an elastic balloon contains air under higher pressure than the air that surrounds it.

Anyway, I'm not a materials scientist, I'm just a manual laborer who really liked all the DMT stuff... My REAL criticism about pieces of equipment like this dates back to lessons hammered into me during the 18D course...

You are asking guys to tote along a bulky piece of equipment that has only one use. What are they going to have to leave behind due to this piece of equipment? Will they carry fewer Combat Gauzes or bags of hetastarch? Fewer bullets? If so, how often does this "Junctional Hemorrhage" occur? Yes, I saw the movie along with everyone else, and had nightmares about that injury just like every other 18D... but I question whether adding another piece of bulky equipment to the medical set is the answer. It doesn't matter whether we're talking about an Aid Bag being carried, or a foot locker on a MRAP, there are still strict limitations on the amount of stuff guys can drag along with them, and we cannot always justify giving them more things to carry - and it's harder to justify it when the piece of equipment we are asking them to carry will only do ONE TASK... and that one task happens very very rarely.

I hate to quash the obvious enthusiasm you have for your piece of equipment, but a "one-trick pony" piece of gear is gonna be a hard sell.

Sorry I can't watch your video (crappy bandwidth where I'm at), but I've seen just as many videos of Quick Clot or Combat Gauze stop bleeding from a transected femoral artery in a swine model, and done it myself quite a few times (again, swine & caprines only, thankfully) to know it may not work 100% of the time, but it works OFTEN, and that is a "piece of gear" that can be used for multiple uses, not just a single one.

(Thanks to Tom Sheridan and the rest of the 300F1 instructors for those great lessons....)
Ars Longa, vita brevis
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