The Gov agency that issues guidance on tourniquet types and use is the Committee on Tactical Combat Casualty Care which is a collaborative effort between the DOD, SOCOM, and the civilian trauma med community. They are the result of an effort to collect data and lessons learned from as many valuable sources as possible, but primarily from combat related injuries. Their protocols have revolutionized trauma medicine and dramatically changed the fatality rates for combat injuries.
In regards to tourniquets, they publish a list of approved devices that should be the first stop for anyone trying to find out what works. The devices they recommend have all been vigorously vetted and have proven themselves in real world application. For something that you would literally be betting your life on, that list should be the definitive answer. Below are a couple of links to point you at the latest guidance.
UPDATED list of CoTCCC-Recommended Limb Tourniquets as of 06 MAY 2019. Over the past year, the Committee on TCCC has conducted a comprehensive review of...
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For devices not on that list, weigh their size / weight / cost savings against the criticality of the circumstances in which they will be used.
There are multiple quality devices not on the list. Some are worth while, some are not.
For average Joe citizen who lives in a city / suburb where, in the event of a traumatic injury medical care (ambulance / EMT's / OR) will be at most 15-20 minutes away, a TQ that dramatically slows the flow of blood may suffice to save the person.
But in austere envirnments where surgical remediation of the injury is hours or more away, the blood loss must be stopped completely and remain that way until in the presence of appropriate care. And the device being used must work EVERY SINGLE time. Even after sitting in or on a pack or belt in less than coddling conditions.
A quality TQ from the approved list can usually be had for $30 or a little less.
This is entirely anecdotal, but I have heard from a few sources that the TQ's like the SWAT and RATS can be very effective in K9 or pediatric applications. Do your own diligent research on that though.
I used to fish offshore alot. I always knew a small life raft was the smart buy but the lack of space and the considerable expense allowed me to always mentally wiggle my way out of it. I did, however, always have the knowledge (whether I chose to acknowledge it or not) that if I ever found myself swimming and "in the food chain" 100+ miles offshore, the money saved would instantly be worthless.
I never had to face that consequence thank God, but the principle applies in many other places.
Please forgive the preachy nature of this. I've had the very, very good fortune to rub elbows with some truly amazing medics and they beat me about the head and shoulders with this until I "got it". Just trying to share the wealth.
Alibi:
deployedmedicine.com