Tourniquet Experiment

I have been wondering about how the effectiveness of modern tourniquets, like the CAT, compares to a traditional cravat and stick tourniquet.  I have also heard that an Israeli bandage makes a decent tourniquet if you use a stick to tighten it.  That made me wonder if an ACE bandage, which I have used on numerous occasions as an effective pressure dressing, would work as a tourniquet if you added a stick to use as a windlass.

The authority on tourniquets is the US Army Institute of Surgical Research (USAISR).  They have published numerous studies on the subject.  Their experiments sometimes use human subjects and measure arterial occlusion with a doppler device.

I couldn't find anything comparing the old fashioned cravat and stick, like I learned in basic training, to the new tourniquets.  I also wanted to see what an ACE and stick could do.  I didn't want to use human subjects.  I'm not planning on publishing my little experiment, other than on my own blog.  So I came up with the idea of using a football to simulate a thigh.  I deflated it to 2 psi (103 mm Hg), pretty close to normal human blood pressure, applied each tourniquet, and measured the pressure again.  Each of the 3 methods I tried, increased the pressure in the football to 3 psi (155 mm Hg).  High enough to exceed the arterial pressure in most humans.  There are numerous flaws in my methodology.  A football is not perfectly analogous to a thigh, my pressure gauge is not very accurate, etc.  However, nobody got hurt, and I think it gave a decent comparison, relative to each other, of how much pressure each tourniquet could give.  We know from USAISR's research that the CAT is effective.

Here is the CAT applied to the football.  Also shown is the pressure gauge.

Now a standard military issue triangular bandage NSN 6510-00-201-1755 (cravat) with a stick (3/8 x 6" oak dowel).  It generated just as much pressure, but you can see where the cloth rolled up, narrowing the width of the tourniquet.  This could potentially cause pain and tissue damage.

Now the ACE bandage (3") and stick.  I used a zip tie to secure the stick in place.  It also generated adequate pressure, but rolled up like the cravat.

Conclusions:  A cravat or an ACE bandage with a stick can be used to make an effective tourniquet.  They cannot be applied one-handed, limiting their application for self aid to an upper extremity injury.  They both roll up and narrow, likely causing pain and tissue damage.  Applying the tourniqet over clothing could limit this effect.

If you remember my prior post on making a budget IFAK, we could use some of the lessons learned in this experiment to make a pocket or EDC IFAK, like the Student of the Gun (SOTG) Pocket Lifesaver.  Knowing that a tourniquet can be made out an ACE bandage, we could eliminate the triangular bandage and limit the items in the kit to the following:

nasopharyngeal airway, 28 Fr
ABD pad or maxi pad
3" ACE bandage
3/8 x 6" oak dowel (maybe even 5")
36" of duct tape on a credit card

I am going to put together such a kit, vacuum pack it with a FoodSaver, and post some pics.  We'll see how convenient it is to carry around.

At $39.95, SOTG's Pocket Lifesaver is a good deal.  The cost is not much more than the cost of the RATS tourniquet and nasal airway that it contains.  I think their kit would be neater if the duct tape were on a credit card.  The RATS tourniquet can be applied one handed.  I'm not sure of its effectiveness.  They say that it is TCCC approved, but that is misleading.  See this article for the details on that.  I guess I will have to get one and test it on the football.  While I'm at it, I just might make a DIY tourniquet like the RATS from a Walmart bungee cord, and test it too.