One Hour Post: Tourniquets
Good evening, folks. Time for a One Hour Post- I post I research, craft, write, and publish in under an hour. Today's topic was sent in by @exuberantocean:
Dressing a wound is something nurses get masters degrees in, so to make it something I could do in an hour, I decided to select tourniquets.
Tourniquets are devices used to stop bleeding in a limb. They are commercially available for purchase, but you can also improvise them without too much trouble.
What they look like:
Tourniquets are basically a strip of tough cloth with a windlass- basically a stick- that is used to tighten the cloth around a limb above where the bleeding is. The commercial ones look like this:
How they work:
Inside the upper part of every limb runs a really big artery. That artery's job is to carry blood at high pressure to the rest of the limb. If the artery (or a smaller artery in the lower part of the limb) gets torn or severed, a lot of blood can rush out of it very quickly, causing the person to be at risk of death from blood loss.
A tourniquet puts pressure on that artery- enough that it overcomes the pressure inside the artery (the top number in a blood pressure reading), preventing blood from flowing through it. The blood stops flowing through the artery and can no longer get to the part of the artery that is damaged, and bleeding stops.
When to use one:
There are basically two times you use a tourniquet. Time number one is when other methods to stop arterial bleeding have failed, and the person will die without it.
Tourniquets stop everything below the tourniquet from getting blood. Blood brings oxygen and glucose to a limb and removes metabolic waste. Muscle (the main blood-using thing in a limb) can go many hours without fresh blood before it begins to die, but when you use a tourniquet, a timer does start.
Ideally, you're trying to use direct pressure on a wound first. Direct pressure on an arterial bleed will deprive some tissue of blood (you have to compress the damaged part of the artery to stop bleeding, which will stop blood from getting anywhere downstream, but the artery is already not working well as an artery at this point, so some tissue is just gonna be SOL). Tourniqueting a limb will deprive a lot more tissue of blood, so it's technically the second option. Of course, if there's a spurting wound you can't get under control in a few seconds with pressure, tourniquet is definitely and always better than death.
The second reason you use a tourniquet is logistical. Tourniquets are going to stop bleeding quickly and reliably. So if there's a lot of bleeding people and few rescuers, the rescuers are going to be able to save more people slapping tourniquets on bleeds that maybe technically could have been stopped with pressure if they had been able to devote the time to any single wound. Also, if someone is bleeding somewhere a rescuer can't get to, like if a limb was crushed by a boulder, you can put the tourniquet around that limb and stop the bleeding without needing to be able to see the wound itself.
How to use one:
Take the (commercial) tourniquet and place the strap part around the upper part of the limb. You want the upper limb because there's only one artery there instead of two or more lower in the limb, and it's easier to compress against a single large bone. Tighten it down to finger tightness, then twist the windlass to put more and more pressure on the artery until bloodflow stops.
You know you're done tightening when the bleeding stops. Not slows down, stops completely. There should be no pulse below the site of the tourniquet. In commercial tourniquets there is usually a clip to keep the windlass in place once you've tightened it down enough. Here's a video:
Considerations:
If you put a tourniquet on someone because you could not stop bleeding and were afraid they were going to die, their artery is severely damaged and can't bring enough blood to the tissue below the site of the injury. They need surgery to repair the artery even if the tourniquet is removed. There is no version of this story where they don't get surgery and still get to keep the limb.
Also, without blood to carry it away, waste builds up in the muscle in the limb. When muscle starts to die, cells also release lots of electrolytes (potassium). This toxic soup stays in the limb until the tourniquet is removed, when it is released all at once. This is bad and needs to be accounted for medically.
I did this literally with 10 seconds to spare.
