The Combat Application Tourniquet (CAT) Gen 7 is the most widely issued tourniquet in the US military and one of several approved by the Committee on Tactical Combat Casualty Care. If you carry one, you need to be able to apply it correctly under stress, in the dark, with one hand, while someone is shooting at you. That's not an exaggeration. That's the training standard.
Here's how to apply it correctly, the mistakes that get people killed, and how to practice until it's automatic.
When to apply
A tourniquet goes on any life-threatening extremity hemorrhage. That means bright red arterial spurting, dark steady venous flow that won't stop with pressure, or any amputation. If you're in Care Under Fire and someone has a significant extremity bleed, the tourniquet goes on immediately. You're not doing wound assessment while rounds are coming in. Tourniquet, move to cover, reassess later.
In Tactical Field Care, you have time to evaluate. A tourniquet might not be necessary for every bleed. But the threshold for application should be low. You can always convert a tourniquet later. You can't un-bleed someone.
Deliberate application (TFC)
- Expose the wound. Cut away clothing if needed.
- Place the tourniquet 2-3 inches above the wound. Not on a joint.
- Route the band through the buckle. Pull ALL slack out first. This is the number one error. If there's slack in the band, the windlass won't generate enough pressure to occlude the artery.
- Twist the windlass until bleeding stops AND you can't feel a distal pulse. Both criteria must be met. Bleeding stopped but pulse still present means venous occlusion only. The artery is still flowing and the limb is now congesting.
- Lock the windlass into the clip.
- Secure the tail strap over the windlass.
- Mark the time on the tourniquet AND on the casualty's forehead with a marker.
Hasty application (CUF)
Under fire, you go high and tight. As proximal as possible on the extremity, over the uniform. No time to expose, no time to measure 2-3 inches. Slap it on, crank the windlass until the bleeding stops, lock it, and move. You'll convert to a deliberate application when you're in cover.
One-handed self-application
You need to be able to tourniquet your own arm or leg with one hand. This is a perishable skill that requires regular practice.
For your arm: pre-stage the tourniquet on your upper arm with the band routed through the buckle but loose. Pull the tail with your teeth to tighten. Twist the windlass against your body or a hard surface. Lock with your working hand.
For your leg: place high on the thigh, route the band, pull slack with both hands if possible, or use your body weight and the ground to help seat the tourniquet. Twist the windlass and lock.
Practice this monthly. Time yourself. You should be able to self-apply in under 30 seconds.
Common mistakes
Leaving slack in the band is the biggest one. If you didn't pull the slack before twisting, the tourniquet will feel tight but won't occlude the artery. The casualty continues to bleed and you think you've fixed it.
Placing over a joint. The tourniquet can't compress effectively over the knee or elbow. Go above or below.
Not twisting enough. If there's still a distal pulse, keep twisting. Add a second tourniquet proximal and touching the first if one tourniquet at maximum tightness doesn't stop the bleeding.
Removing in the field. Never remove a tourniquet in the field. Conversion (loosening while maintaining hemostatic backup) is done only when all criteria are met: tactical situation permits monitoring, tourniquet has been on less than 6 hours, and the casualty is not in shock.
Practice tools
We built tourniquet application training into medeor.app with quizzes that test placement, timing, and decision-making. The app also has grade sheets tied to the actual TCCC evaluation standards so you can practice to the test. Free, works on your phone, no account needed.
Get a training tourniquet and a buddy. Practice weekly until you can apply it blindfolded. That's not a figure of speech. Medics practice blindfolded because nighttime casualties are real and your headlamp might be the thing that gets you shot.