tourniquet: a device for stopping the flow of blood through a vein or artery, typically by compressing a limb with a cord or tight bandage.
Note the keyword "limb". Neck tourniquets are saved for use on murderers, terrorists, traitors, serial rapists, child molesters, politicians, telemarketers, people who drive 40 in the left lane, and any other of the most egregious criminals in society.
Historically, tourniquets were considered the Dark Arts in medicine, esp. field medicine, because you were "sacrificing a limb to save a life".
That's how they used to be, mainly because they were done with actual cord, wire, leather straps, and narrow bandages. And thusly set up, sacrificing a limb is exactly what they do.
Do NOT do that.
A) Because you're a dumb@$$ if you do.
B) Because we have far better materials, and much more knowledge, training, and recent experience, plus hugely better examples to work with nowadays.
Peer-reviewed medical journal articles, and better equipment, have documented conclusively that tourniquets applied in battlefield situations have been left in place for up to six hours, with no neurological or functional deficits noted afterwards. Six hours from application to removal in surgery is one helluva window for first aiders.
So how can you take advantage of it?
CAT
The original, and gold standard. For sale by North American Rescue for $30@.
You can put it on one-handed, crank the windlass until the bleeding stops, velcro it down, and drive on. One and done. You have four limbs; you would be well-advised to have four tourniquets handy, somewhere nearby. (Not all on your weapon, belt, etc., but one on the weapon, one on the belt, and two more nearby in a kit/pack/car would be a great way to go. When you need one, you'll need it right effing now, not in 10 or 45 minutes.)
How easy is it to use?
One-handed, total time (with slow instructions), 00:01:15 to apply, from on to done.
You should carry extras.
I probably have a dozen or two of these, including a couple of orange ones I use just for training.
Why so many?
Power tools: in the shop FAK.
Vehicle kits, each, and extras.
Chain saw: on the chaps belt.
Shooting range cart: a mittful of 'em.
Big Boy Military Rules: your tourniquet is for you, your buddy's tourniquet(s) are for him.
He doesn't have any? How much do you love him?? Srsly. Explain the facts of life to him, and wise him up.
You only have one? How much do you love yourself??
These have been around for years. They're already up to generation 7, or more (I forget). Older ones still work. Why are they generally single-use? Blood contamination/decon. Critical life support gear. You already wrote the time applied on the used one.
But after TSHTF, when re-supply is a critical problem, you may be less finicky about throwing them away after a single use vs. attempting to decon and re-use them.
***Important safety tip: Beware of Chinesium fake versions!***
They're out there, and in abundance, especially from the idiots at Amazon and affiliates. Buy yours from a reputable brick-and-mortar or online dealer. (Hint: "Reputable" does not mean "cheapest". That's a fool's economy.) I have a 5.11 store nearby, and NAR has a solid gold rep online. So do some others. But a Tupperware bin from Bubba's Qwality Medikal Emporium And Knives at the gun show is caveat emptor, unless you know Bubba personally, including his home address, and trust him with your life. YMMV.
And if you ever get stuck with one you can't get a refund for, smash it and burn it, just like you should for unfixably bad weapon magazines. Like fake $20 bills, don't palm off your bad counterfeit on some other unlucky schmuck. Take one for the team, and fold, spindle, and mutilate those POS fakes, with extreme prejudice.
If you find someone selling them, tell them.
If the seller doesn't offer a refund, or fold up their tent, out them ruthlessly and often until they do one or the other.
SOFT-TW
Same idea (not better per se, just different, IMHO) than the CAT, with an aluminum (versus hard nylon) windlass. And again, about $30 from Tac-Med.
Application? Pretty much the same.
Unlike the CAT, it comes pre-threaded. It's beefier. It has a belt-and-suspenders method to secure it. And comes in a couple more colors than the CAT.
It's also heavier, and tiny bit bulkier.
You pays your nickel, and you makes your choices. There's nothing wrong with either one, and I'd be fine using either one. I don't care which one you like better. It's a chocolate/vanilla question.
X8T
Stick it in and give it a spin. Click and crank.
Just another way to skin the cat. About $38 at Rescue Essentials.
Others
There are also straps, like the Touniq-Kwik/TK4, and the SWAT-T.
The TK4 is really just a strap that you shove something in and twist, which is a flashback to 1940.
The SWAT-T is really more like a phlebotomy tourniquet on steroids, allowing you to make a pressure dressing, but probably a lot less occlusion of bleeding possible than a CAT or SOF-T-TW, and if you try, you're warned not to pull it that hard by manufacturer materials and videos. But it could replace or supplement ACE wraps, etc., in a kit where space is at a premium.
Getting into the Stupid Zone, there's the SAM Junctional Tourniquet. It's a bona fide medical device, complete with BP cuff inflation bulb, and works for pelvic fractures and other hard-to-tourniquet spots like armpits. But that complexity makes it iffy in hard use, and more failure prone. Plus, with a price tag of $350-$400+, each, (yes, you read that right) it's geared towards hospitals, public agencies with deep pockets, and solo users with generally more money than brains.
There are probably eleventy others if you dig deep enough, which I won't. These are the best quality of what there is, and most of what's out there, until someone else builds a better mousetrap. IOW, unless you've markedly improved on anything listed, IDGAD. As it is, I wouldn't use some of the above, but the information is there for those who march to a different drummer (or have their choices dictated by fiat from on high).
All of the above have How-To videos available on YouTube, etc.
TL;DRs
1)Get tourniquetSSS.
Plural. From many, to a metric fuckton, depending on what you do or think (or fear?) you'll be doing.
2) Train On/Learn How To Use Them.
On every type you have. Including one-handed, for self-rescue.
Not just watching the videos.
3) Practice with them.
Frequently. Get a dedicated trainer model, and practice hands on. Nothing less will suffice for mastery, especially bearing in mind that you or someone else will be screaming, in excruciating pain, and gushing blood when you're doing it. This is NOT something you want to re-familiarize yourself with OJT on the day, under those conditions. Learn now, succeed later.
With ALL of your tribe. Family. Co-workers. Team. Neighborhood security group. Hunting buddies. Circle of fellow BSers. Everyone who knows how to use one is one more person who could save lives if things get sporty. Teach people in non-tactical circumstances: power tools, chainsaws, auto accident response, CERT/earthquake/disaster preparedness. You don't have to approach everything like Paul Blart - Mall Cop, Tacticool Timmy, or Gunkid with his Tactical Wheelbarrow(tm). Exsanguination happens all kinds of times and places.
4) Stock them EVERYWHERE.
For all of the above reasons. In job lots.
Imagine you were a bystander at the Route 91 Harvest Music Festival. Or a cab driver nearby afterwards. Not just the staff at Sunrise Med Center ER. You don't have to be able to save everyone. But what if you could save one person? What if it was a family member, or friend? What if they could save you, the next time?
Get busy.