Remember, severe extremity bleeding, while common on a battlefield or in a tactical situation, is extremely rare in an expedition setting. Tourniquets are more likely to be needed when machines—chain saws, chippers, wood splitters, farm machinery, etc.—are used in remote setting or when responding to a serious vehicle accident. Given their relatively small size, lightweight construction, and low cost, it makes sense to carry a commercial tourniquet if you are a member of a paramilitary group (police, warden, ranger, etc.), working with farm or logging equipment, or in your vehicle first aid kit, not so much in your expedition kit.
It’s important to note that improvised tourniquets have been shown to be generally ineffective due to the time it takes to locate the necessary supplies and apply it, and the skill required to engineer it. A venous tourniquet—one that shuts down the venous system but not the arterial system—is not effective and can reduce core blood volume and lead to a compartment syndrome. Most rescuers are surprised at the amount of force required to block arterial flow to the extremity. If you think you might need an improvised tourniquet, carry a commercial tourniquet instead.
If you choose to carry a commercial tourniquet, you need to practice and master its use before you rely on it in a field situation. Below are some guidelines for using a one of the commercial tourniquets shown in this article:
- Carry two tourniquets. Failure is possible (the windlass or buckle may break), and two side-by-side tourniquets are often required to shut down arterial blood flow in the upper leg.
- Store the tourniquet in an accessible place away from direct sunlight to prevent UV degradation and failure.
- Place the tourniquet 2-3 inches above (proximal to) the wound, pull the initial strap through the buckle as tight as possible, and tighten until you cannot feel the distal pulse. At least three complete turns on the windlass is needed for an upper extremity, more pressure—e.g. more turns—is necessary to stop arterial blood flow in the upper leg.
Once a tourniquet is in place, evaluate it in a controlled situation within two hours. Tourniquets left in place for greater than six hours may cause significant tissue damage. There are three steps for a successful conversion.
- Step 1. Before loosening the tourniquet, apply, but do not tighten, a second tourniquet above the first. If bleeding starts as you loosen the first tourniquet and it breaks upon re-tightening, a back-up is already in place.
- Step 2. Before loosening the tourniquet, remove the initial wound dressing, clear the wound of all debris, and consider applying a gauze or hemostatic dressing and pressure bandage.
- Step 3. Slowly loosen the tourniquet to evaluate the status of the bleeding. If bleeding is present and you cannot control it, retighten the tourniquet.