Tourniquet Application — Step by Step

Uncontrolled limb haemorrhage is the leading cause of preventable death in both military and civilian trauma. The tourniquet — once feared as a limb-threatening device of last resort — is now recognised as the single most effective intervention for stopping arterial bleeding from an extremity. Modern trauma protocols and mass-casualty response programmes worldwide, including the Stop the Bleed initiative, train bystanders to apply tourniquets because lives can be saved in the minutes before emergency services arrive.

Fear of causing harm by applying a tourniquet is understandable. The evidence, however, is clear: the risk of not applying a tourniquet when arterial bleeding is present is death. The risk of applying a tourniquet correctly for a few hours is minimal.

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When to Use a Tourniquet

A tourniquet is the correct intervention for limb bleeding that:

• Cannot be controlled by direct pressure — continuous firm direct pressure for at least 3 minutes has not stopped bleeding
• Is arterial in nature — bright red blood spurting in pulses, or rapid bleeding that soaks through dressings quickly
• Involves a traumatic amputation — partial or complete loss of a limb at any level above the wrist or ankle
• Results from blast or explosion injury — multiple simultaneous wounds, no time for individual assessment of each

Situation	Tourniquet Indicated?
Arterial bleeding from limb, direct pressure failed	Yes — immediately
Traumatic amputation of arm or leg	Yes — immediately
Blast injury with multiple limb wounds	Yes — apply to all affected limbs
Venous bleeding controlled by pressure	No — continue direct pressure
Bleeding from neck, groin, or armpit	No — tourniquet cannot be placed here; use wound packing
Impaled object in limb with minimal bleeding	No — stabilise object, do not remove

⚠️ Do not delay tourniquet application waiting to try direct pressure if bleeding is obviously arterial — spurting blood from a limb requires a tourniquet, not gauze.

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Tourniquet Types — In Order of Preference

1. Combat Application Tourniquet (CAT) — Generation 7

The CAT is the most widely used and validated commercial tourniquet globally. It uses a windlass (a rotating rod) to apply continuous tightening pressure. A self-locking clip prevents the windlass from unwinding. It can be applied with one hand, making it suitable for self-application.

2. SOFTT-W (Special Operations Forces Tactical Tourniquet Wide)

Slightly wider strap (38 mm vs 38 mm CAT) with a metal windlass. Some providers prefer the metal construction for durability. Slightly more complex one-handed application than the CAT.

3. RATS (Rapid Application Tourniquet System)

A stretchy rubber tourniquet — very fast to apply, especially self-application, but requires more wraps on larger limbs and the pressure distribution is narrower.

4. Improvised Tourniquet

Used only when no commercial tourniquet is available. A last resort with significantly higher failure rate and more tissue damage.

Improvised materials (in order of suitability):

• Triangular bandage (from a first-aid kit) — fold to 4–5 cm width
• Necktie, belt, or webbing belt (cut to flat ribbon)
• Clothing strips (minimum 4 cm wide — anything narrower cuts without stopping flow)

Never use wire, rope, cord, or anything less than 4 cm wide — these will cause severe tissue damage and nerve injury while failing to stop arterial flow.

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Application Technique — Commercial Tourniquet (CAT)

Preparation

1. Identify the wound site — confirm limb bleeding that requires a tourniquet
2. Expose the limb if possible — cut clothing away if time permits
3. Position the tourniquet 5–7.5 cm (2–3 inches) above the wound, on the proximal side (between the wound and the heart)
4. Never place over a joint — place on the upper arm or upper thigh only, not at the elbow or knee

Application Steps

1. Slide the limb through the loop (or wrap around the limb if already trapped)
2. Pull the free end of the strap through the buckle and pull tight — the initial strap tension should be firm
3. Twist the windlass — turn the rod repeatedly until the bleeding stops. The patient will feel significant pressure. Continue tightening until bleeding ceases — do not stop because the patient reports pain
4. Lock the windlass — secure the rod in the clip or velcro keeper so it cannot unwind
5. Check bleeding — confirm the wound has stopped bleeding by direct observation
6. Note the time — write the time of application with a permanent marker directly on the tourniquet strap and, if possible, on the patient's forehead with a large "T" and the time

If Bleeding Does Not Stop

• Tighten the windlass further — insufficient tension is the most common reason for tourniquet failure
• If tightening fully and bleeding continues, apply a second tourniquet proximal to (above) the first, as close as possible to the first

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One-Handed Self-Application

Arterial bleeding from a forearm or lower leg may require self-application. The CAT is designed for this.

1. Pre-position the tourniquet on your arm or leg before it is needed if you anticipate wounding (training exercise, tactical situation)
2. Thread the limb through the loop and pull the strap across the velcro backing
3. Tighten the strap by pulling the free end with your teeth or by anchoring against a surface
4. Twist the windlass — this is possible single-handed; anchor the tourniquet against your body if needed
5. Apply until pain forces you to stop — then add one more turn if still bleeding

Practice is essential. Self-application under stress with a bleeding hand or arm is extremely difficult without prior rehearsal.

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Time Stamping — Critical Step

The reason for time-stamping every tourniquet application is that prolonged application (generally beyond 2 hours) can cause nerve and tissue injury, and in rare cases, limb loss — primarily due to ischaemia. Emergency medical personnel need to know exactly when the tourniquet was applied to manage this risk.

Always write:

• The letter "T" on the patient's forehead (so it is visible to any provider even if clothing is removed)
• The time of application
• Use a permanent marker — blood and water will wash off pen ink

Never remove a tourniquet in the pre-hospital environment unless a medical professional explicitly instructs you to. Removing a tourniquet can cause sudden haemorrhage and shock.

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Junctional Haemorrhage — Where Tourniquets Cannot Be Applied

Bleeding from the groin (femoral vessels), axilla (brachial/axillary vessels), or the base of the neck cannot be addressed with a limb tourniquet. These wounds require different techniques:

• Wound packing with haemostatic gauze — pack the wound cavity, hold firm pressure for 3 minutes
• Junctional tourniquets — specialist devices like the SAM Junctional Tourniquet (SAM-JT) or JETT can apply pressure to the inguinal ligament region; these require training
• Improvised axillary compression — deep packing and chest bandaging for armpit wounds

The groin is particularly challenging — the femoral artery can bleed fatally within 3–5 minutes of complete transaction. A fist or knuckles pressed into the inguinal crease can provide temporary compression while wound packing is prepared.

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What to Tell Emergency Services

When handing a patient with a tourniquet to paramedics or at hospital:

1. Where the tourniquet is applied
2. The time it was applied (written on the patient — confirm verbally)
3. Whether it controlled bleeding completely
4. How many tourniquets were applied
5. Any relevant mechanism of injury

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Quick Reference

Step	Detail
When to apply	Arterial limb bleeding, amputation, blast injury
Placement	5–7.5 cm (2–3 inches) above wound, not over joint
Tighten until	Bleeding STOPS — not just reduces
If bleeding persists	Second tourniquet above the first
Time stamp	Write "T + time" on tourniquet strap and patient's forehead
Improvised minimum width	4 cm (1.6 inches) — narrower causes damage without stopping flow
Never apply to	Neck, chest, abdomen — tourniquet is for limbs only
Remove in field	Never — leave for medical professionals
Self-application	Possible with CAT — practice before you need it
Max time before ischaemia risk	2 hours (but never remove in field — hospital will manage)

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Building a Trauma Response Habit

Having a tourniquet is only useful if it is immediately accessible. Commercial tourniquets kept at the bottom of a bag are useless in the first 90 seconds of an arterial bleed. Consider:

• Mounting a CAT in a visible, accessible location in your vehicle
• Attaching one to your first-aid kit in a clearly marked external pocket
• Wearing one pre-positioned on your person if working in high-risk environments
• Knowing where your workplace first-aid cabinet's tourniquet is before an incident occurs

Stop the Bleed training courses (typically 2 hours) teach tourniquet use, wound packing, and direct pressure in a single hands-on session. They are available in most countries and are free or very low cost.