Tourniquet Use

Part of First Aid

A tourniquet is a last-resort device that completely cuts off blood flow to a limb to prevent death from uncontrollable arterial bleeding. Modern combat medicine has proven that early tourniquet use saves lives with far fewer complications than previously believed.

When to Use a Tourniquet

A tourniquet is appropriate when — and only when — direct pressure, wound packing, and pressure bandages have failed to control life-threatening limb bleeding. Specifically:

• Arterial bleeding from an arm or leg that doesn’t stop with 10 minutes of firm direct pressure
• Amputations — partial or complete loss of a limb
• Multiple casualties — you need to stop one person’s bleeding fast so you can help others
• You can’t reach the wound — crushed limb under debris, wound in a location where direct pressure is impossible
• Mass hemorrhage — blood is pooling on the ground, soaking through dressings rapidly, and the person shows signs of shock

Tourniquets Are for Limbs Only

Never apply a tourniquet to the neck, torso, or head. Tourniquets work by compressing an artery against a bone — this is only possible on arms and legs. For junctional bleeding (groin, armpit, neck), use wound packing and direct pressure.

The Old Myths vs. Reality

For decades, first aid training taught that tourniquets cause automatic limb loss and should be avoided at all costs. Military data from Iraq and Afghanistan proved this wrong:

Myth	Reality
Tourniquets always cause amputation	Limbs survive 6+ hours of tourniquet time in most cases
Only use as absolute last resort	Early application saves more lives than delayed use
Loosen every 15-20 minutes	Never loosen in the field — this causes dangerous reperfusion and resumed bleeding
They cause permanent nerve damage	Temporary numbness is common; permanent damage is rare with proper application

The modern consensus is clear: if someone is bleeding to death from a limb wound and direct pressure isn’t working, apply a tourniquet immediately. The risk of limb complications is real but small. The risk of death from hemorrhage is immediate and certain.

Improvised Tourniquet Construction

Commercial tourniquets (CAT, SOF-T, SWAT-T) are the gold standard. If you find any in abandoned vehicles, military gear, or first aid kits, take them — they’re worth their weight in gold. But in a post-collapse world, you’ll likely need to improvise.

Materials Needed

1. Band: A strip of strong material at least 1.5 inches (4 cm) wide. Wider is better — narrow materials (rope, wire, paracord) cut into tissue and cause unnecessary damage without improving effectiveness.

   Good options:

   • Folded triangular bandage or cravat

   • Torn strip of shirt or pants (fold to double thickness)

   • Belt (only if wide and flexible — stiff leather belts are hard to tighten enough)

   • Scarf or headband

   • Strap from a backpack

   Never Use Thin Materials

   Wire, paracord, shoestring, zip ties, and other narrow materials crush tissue, damage nerves, and may not even occlude the artery effectively. Always use something at least 1.5 inches (4 cm) wide. If your material is narrow, fold it over itself until it’s wide enough.

2. Windlass: A rigid stick, rod, or tool used to twist the band tighter. Roughly 6-8 inches (15-20 cm) long, strong enough not to break under twisting force.

   Good options:

   • Sturdy stick, roughly thumb thickness
   • Screwdriver or wrench
   • Tent stake
   • Folded metal strip
   • Thick marker or pen (less ideal — may break)

3. Securing mechanism: Something to hold the windlass in place after tightening — a second strip of cloth, tape, or the tail end of the tourniquet band itself.

Assembly

1. Fold or roll your band material to roughly 1.5-2 inches (4-5 cm) width.
2. Make it long enough to wrap around the limb at least twice, with enough extra to tie a knot.
3. Have your windlass and securing strip ready before you start.

Application Procedure

Placement

Apply the tourniquet 2-3 inches (5-7 cm) above the wound — between the wound and the heart. Never place it directly over a wound, over a joint (elbow or knee), or below the wound.

If you can’t tell exactly where the bleeding is coming from (common with blood-soaked clothing), place the tourniquet high and tight — as high on the limb as possible:

• Upper arm, near the armpit
• Upper thigh, near the groin

This is the military standard and eliminates the risk of placing it too low.

Step-by-Step

1. Wrap the band around the limb twice. Tie a simple overhand knot (half-knot), keeping it tight against the skin. Don’t go over clothing if you can avoid it — tourniquets slip on fabric.

2. Place the windlass on top of the knot. Tie a second overhand knot over the windlass, locking it in place. You now have a square knot with the windlass trapped in the center.

3. Twist the windlass to tighten. Rotate the stick like winding a clock. Each turn dramatically increases compression. The band will tighten around the limb, compressing tissue and collapsing the artery against the bone.

4. Keep twisting until bleeding stops. This is the critical endpoint — not until it’s “pretty tight,” but until you cannot see any more blood flowing from the wound. For large limbs (thighs), this requires significant force. Don’t stop short.

5. Secure the windlass so it can’t unwind. Tie the loose ends of the band around the windlass, or use a separate strip of cloth. Tape it if available. The windlass must not slip — even a quarter-turn of loosening can restart arterial flow.

6. Note the time. Write “TK” and the time on the patient’s forehead, chest, or the tourniquet itself with any available marker, charcoal, or blood. If nothing to write with, remember the time. This is critical information for anyone providing further care.

Verification

After applying, check:

• Bleeding has stopped — look at the wound, not just the bandage
• No pulse below the tourniquet — check the radial pulse (wrist) for arm tourniquets, or the dorsalis pedis (top of foot) for leg tourniquets. If you can still feel a pulse, the tourniquet isn’t tight enough. Tighten further.
• The windlass is secured and cannot unwind

Common Mistakes

Mistake	Consequence	Fix
Not tight enough	Occludes veins but not arteries — increases bleeding	Tighten until bleeding stops AND distal pulse disappears
Too narrow a band	Tissue damage, pain, incomplete occlusion	Use material at least 1.5 inches (4 cm) wide
Placed over a joint	Cannot compress artery against bone at the joint	Move above (closer to torso) the joint
Placed too low	Bleeding continues from vessels above the tourniquet	When in doubt, go high and tight
Loosening to “check”	Restarts hemorrhage, washes out clots	Never loosen once applied in the field
Not securing the windlass	Windlass unwinds, tourniquet loosens	Tie, tape, or strap the windlass firmly

Duration and Limb Viability

A properly applied tourniquet can remain in place for up to 6 hours before the risk of irreversible limb damage becomes significant. In practice:

• Under 2 hours: Almost no risk of permanent damage. Temporary numbness and tingling are normal.
• 2-6 hours: Increasing risk of nerve and muscle damage, but limb survival is still likely.
• Over 6 hours: Significant risk of irreversible damage. Amputation may become necessary even if the limb is reperfused.

In a survival setting, leave the tourniquet on until you have:

• A controlled environment where you can manage re-bleeding
• Clean dressings and wound packing ready
• The ability to apply direct pressure immediately if bleeding restarts

Converting a tourniquet back to direct pressure should only be done by someone who understands the risks and has the resources to manage them. In the field with ongoing danger or transport, leave it on.

Two-Tourniquet Rule

If one tourniquet doesn’t stop the bleeding — especially on the thigh, which has a large muscle mass — apply a second tourniquet directly above the first. Two tourniquets side by side distribute force over a wider area and are more likely to occlude the femoral artery in a muscular leg.

After Application

Once the tourniquet is on and bleeding is controlled:

1. Treat for shock — lay flat, elevate legs (unless leg is the injury), keep warm
2. Splint the limb if possible — immobilization reduces pain and further tissue damage
3. Do not cover the tourniquet — it needs to be visible to anyone providing further care
4. Monitor — check every 15-30 minutes that the windlass hasn’t slipped and bleeding hasn’t restarted
5. Give water if the person is conscious, alert, and has no abdominal injuries — they need fluid to compensate for blood loss
6. Pain management — tourniquet pain is intense. Reassure the patient. Distraction helps. If any analgesics are available, use them.

Key Takeaways

• Apply a tourniquet when direct pressure and wound packing fail to stop life-threatening limb bleeding — do not hesitate
• Use material at least 1.5 inches (4 cm) wide with a rigid windlass; avoid wire, cord, or narrow straps
• Place it 2-3 inches above the wound (or high and tight if wound location is unclear) — never over a joint
• Tighten until bleeding stops and you cannot feel a distal pulse — undertightening is the most common error
• Never loosen in the field — note the application time and leave it for qualified care to remove