How to Apply a Tourniquet & Run the MARCH Sequence
The single most survivable battlefield death is the one where someone bleeds out from a limb with a tourniquet sitting in their pouch. This is the buddy-aid version of Tactical Combat Casualty Care — how to get a CAT on high and tight, why you write the time on it, and how the MARCH sequence keeps you working the right problem first. Learn it before you need it, because you will not have time to learn it when you do.
This page is a plain-English study aid built from public Tactical Combat Casualty Care doctrine. It is not a substitute for hands-on, instructor-led TCCC certification. Tourniquets, chest seals, airways, and wound packing are skills you have to put your hands on under a qualified instructor — reading about them is not the same as being able to do them under stress. In a real emergency, call 911 / your medical channel and get a trained provider. Learn this material; do not let a webpage be your only training.
When a tourniquet is the answer
A tourniquet is for life-threatening bleeding from an arm or a leg — bright red blood that is spurting, pooling, or soaking through faster than you can control it, or an amputation. When the choice is between saving the limb and saving the life, you save the life. Modern TCCC doctrine put the limb tourniquet back at the front of the line precisely because decades of data showed how many people died from bleeding that a tourniquet stops in seconds.
Under effective fire, the only medicine that matters is fire superiority and a tourniquet high on the limb — everything else waits until you and the casualty are behind cover. Off the limbs — neck, armpit, groin, torso — a tourniquet will not work; those wounds get hemostatic gauze packed hard into the wound and direct pressure.
The MARCH sequence
MARCH is the TCCC assessment order — you work it top to bottom because it treats the things that kill fastest, first. Preventable battlefield death is overwhelmingly extremity hemorrhage, tension pneumothorax, and airway obstruction, in that order. MARCH puts them in your hands in the sequence that saves the most people.
Life-threatening bleeding kills faster than anything else on the battlefield. Find the pump, stop the pump. For a bleeding limb, a tourniquet goes on first and it goes on now. Junctional and truncal wounds get packed with hemostatic gauze and hard direct pressure.
A casualty who can talk has an airway. An unconscious casualty without an airway obstruction is managed by positioning — a head-tilt/chin-lift or jaw-thrust, then the recovery position. TCCC providers use a nasopharyngeal airway; that is a trained skill, not a bystander move.
Look for penetrating chest trauma and labored breathing. An open ("sucking") chest wound gets a vented chest seal. Watch for tension pneumothorax — a progressively harder time breathing after a chest wound — which is treated with needle decompression by a trained provider.
Now reassess every tourniquet and dressing — is the bleeding actually stopped? Consider converting to a wound-packed pressure dressing only if trained and the situation allows. Assess for shock: pale, cool, clammy, altered. IV/IO fluids and blood products are provider-level care.
A bleeding casualty gets cold fast, and cold blood does not clot. Get them off the ground, cut wet clothing away, and wrap them — a casualty blanket or anything dry. Protect the head: assume a spinal injury on any blast or fall, and keep monitoring level of consciousness.
Where it goes: high and tight
Two to three inches above the wound on a single bone segment — never over a joint. If the wound is a mess of blood you cannot assess, or you are still under fire, go as high on the limb toward the torso as the tourniquet will sit. You can always move it down later once the casualty is safe; you cannot un-bleed them.
Applying a CAT, step by step
The Combat Application Tourniquet is the CoTCCC-recommended windlass tourniquet you will most likely carry. The SOF-T Wide works the same way with a metal windlass. On yourself, one-handed application is a trained skill — practice it on your strong and weak side both.
- 1Get the tourniquet on the limb
Route the injured limb through the loop of the tourniquet, or wrap the self-adhering band around the limb and re-thread the buckle. Under fire, a limb tourniquet is applied high and tight over the uniform — you are not looking for the wound, you are stopping the bleed.
- 2Place it high and tight
Position the tourniquet 2–3 inches above the wound, never over a joint. If you cannot see the wound or there is a lot of blood, go high and tight — as high on the limb toward the torso as you can. Two tourniquets side by side may be needed for a large leg.
- 3Pull the band tight, then windlass
Pull the free running end of the band as tight as you physically can before you touch the windlass — most of the pressure comes from the initial pull, not the rod. Then twist the windlass rod until the bright red bleeding stops and the distal pulse is gone.
- 4Lock and secure the windlass
Lock the windlass rod into the clip. Secure it with the strap so it cannot unwind. A tourniquet that loosens on the ride to the aid station is a tourniquet that failed. If bleeding continues, tighten further or apply a second tourniquet just above the first.
- 5Write the time
Mark the time of application — on the tourniquet's time strip, on the casualty's skin, or on the casualty card. Not the time of injury, the time the tourniquet went on. The surgical team downrange needs that number to manage the limb. No pen? Use blood, dirt, anything.
- 6Reassess and do not loosen it
Confirm the bleeding is stopped and check for a distal pulse — there should be none. Do not periodically loosen a tourniquet to "let blood back in" — that is an old myth that kills people. Once it is on and effective, it stays on until a provider decides otherwise.
Mark the time of application — not the time of injury — on the tourniquet, the casualty's skin, or the casualty card. The surgical team uses that clock to decide how to manage the limb. A tourniquet with a "T" and a time on it is doing its whole job. One with no time makes everyone downstream guess.
The mistakes that get people killed
This is the deadliest mistake. A tourniquet that is tight enough to stop the veins from draining but not tight enough to stop the arteries makes the bleeding worse — blood pumps in and cannot get out. If it hurts and it is still bleeding, it is not tight enough. Crank it down or add a second one.
A tourniquet with no time on it forces the surgical team to assume the worst-case clock. Two seconds with a marker changes how they manage the limb. Write it every single time.
People bleed out in minutes. The decision to apply a tourniquet is not a close call when a limb is spurting — it is the whole ballgame. Modern doctrine is clear: put it on early, put it on tight, sort out the details later. Hesitation is the injury that kills.
A tourniquet placed over the knee or elbow cannot compress the artery against bone. Go 2–3 inches above the wound on a single bone segment, or high and tight toward the torso if you cannot see the wound.
The IFAK basics
Your Individual First Aid Kit is built to treat you — a buddy uses your kit on you, not theirs. Know where every item lives, keep the tourniquet somewhere either hand can reach it, and check it. A kit you have never opened is a kit you cannot use in the dark. The core load-out, aligned to the CoTCCC recommendations:
- At least one limb tourniquet (CAT or SOF-T Wide) — carried where either hand can reach it, not buried in a pouch
- Hemostatic gauze (Combat Gauze / chitosan) for wound packing
- A pressure/emergency trauma dressing (the "Israeli" bandage)
- A vented chest seal (two, ideally — entry and exit)
- A nasopharyngeal airway with lubricant (for trained providers)
- Gloves, a marker or casualty card, and trauma shears
Want the honest breakdown of what actually belongs in a kit — and what the vendors oversell? See the Gear Locker: IFAK.
Key Takeaways
- Life-threatening limb bleeding gets a tourniquet first — high and tight, 2–3 inches above the wound, never over a joint.
- Most of the pressure comes from pulling the band tight before you touch the windlass. Twist until the bright red bleeding stops and the distal pulse is gone.
- A tourniquet too loose is worse than none — it becomes a venous tourniquet and bleeds faster. If it hurts and still bleeds, it is not tight enough.
- Write the time of application on the tourniquet — every time. It changes how the surgical team manages the limb.
- Once it is on and effective, it stays on. Do not periodically loosen it. Hesitation and loosening are what kill.
- Work the problem in order: MARCH — Massive hemorrhage, Airway, Respiration, Circulation, Hypothermia/Head.
- This is a study aid, not certification. Put your hands on the skills under a qualified TCCC instructor.
Sources
- Committee on Tactical Combat Casualty Care (CoTCCC), Joint Trauma System — TCCC Guidelines for Medical Personnel and TCCC Skill Cards (MARCH sequence; limb tourniquet, high and tight; write the time of application).
- U.S. Army — TC 4-02.1, First Aid (Training Circular): tourniquet application, wound packing, and casualty assessment.
- Ranger Medic Handbook, 75th Ranger Regiment (Tactical Trauma Protocols): the MARCH assessment and TCCC casualty management.
- Committee on Tactical Combat Casualty Care — recommended devices list (CAT and SOF-T Wide limb tourniquets; hemostatic gauze; vented chest seals).
Doctrine is periodically revised by the CoTCCC. Verify against the current published TCCC guidelines and your unit's medical guidance before relying on any procedure. This page is educational and does not replace hands-on TCCC certification.