Applying a tourniquet can help slow or limit excessive bleeding in an emergency. It typically involves wrapping material around the source of bleeding and applying pressure to stop or slow bleeding.

It is important to know how to use tourniquets properly, as there are several mistakes people can make that may make the tourniquet less effective, or that cause damage to nerves and blood vessels.

A medical professional may also apply a tourniquet before basic medical procedures, such as drawing blood or placing an IV line, or to reduce blood flow during surgery.

In this article, we will explain when to apply a tourniquet, how to apply one, and how to make a tourniquet from everyday items. We will also look at common mistakes to avoid and what to do if a tourniquet does not help.

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People can use tourniquets in emergency situations to help slow or stop excessive bleeding. They work by putting pressure on blood vessels, limiting how much blood can pass through them.

Use a tourniquet if pressure from the hands or bandages does not significantly slow or stop excessive bleeding. People should also use a tourniquet if a person has:

  • lost a lot of blood
  • spurting or pulsating blood
  • a deep or large wound
  • multiple sources of bleeding or wounds
  • lost consciousness while bleeding

Avoid using tourniquets, or use them with caution, if the person has:

If a bystander is applying a tourniquet and does not know if a person has these conditions, or cannot find out because they are unconscious, they should use a tourniquet anyway if no other means of stopping bleeding are working.

Typically, people use tourniquets on arms or legs. In extreme cases, it may be appropriate to apply a tourniquet around the torso. A person can apply a tourniquet whether a person is conscious or unconscious.

Before applying a tourniquet in an emergency, it is important to dial 911. People who are bleeding enough to warrant a tourniquet need immediate medical attention.

It may also be necessary to:

  • get the person to safety
  • help them sit or lie down
  • put something soft under their head
  • remove dangerous objects from the immediate area

In emergency situations, the best type of tourniquet to use is a one with a windlass. A windlass is a winch-like rod that helps tighten the tourniquet.

Most medical tourniquets with windlasses consist of flattened fabric or plastic strapping with a clasp or buckle, a windlass, and a clip to hold the windlass.

The American College of Surgeons provides the following demonstration of how to use a tourniquet:

According to the Stop the Bleed (STB) initiative, there are seven basic steps to follow when applying a windlass tourniquet.

Step 1

Find the source of bleeding. Look where most of the blood is and try to follow it to the source. If this is difficult, try asking the person where they feel the most pain, or whether they feel a pulsating, tingling, or numb sensation anywhere.

Step 2

Expose the source of bleeding by tearing away or removing clothing. If there are multiple sources of bleeding, work on the most significant source first.

After exposing the area, apply pressure as firmly as possible to the bleed, or just above it, using a clean cloth or gauze. If neither of these items are available, apply pressure using a hand, knee, elbow, or whatever is accessible.

If it is not possible to expose the source of the bleeding, apply pressure over the top of the obstruction as best as possible.

Monitor the wound to assess whether the bleeding has slowed or stopped. If the dressing or cloth becomes soaked in blood, or bleeding does not slow down or stop, apply the tourniquet.

Step 3

Wrap the tourniquet around the impacted limb 2–3 inches (5–7.6 centimeters) above the source of bleeding. Make sure the tourniquet is around a part of the limb that is between the source of bleeding and the heart.

For example, if the wound is on the forearm, apply the tourniquet to the upper arm.

If it is not possible to expose the wound, wrap the tourniquet over the top of the clothing. If clothing or other items bunch up when trying to wrap the tourniquet around them, flatten them out as much as possible.

Step 4

If someone is alert and conscious, tell them that the following step may be very painful.

Clip the two ends of the tourniquet together using the buckle or clasp, then pull firmly on the end of the strapping to the right of the clasp or buckle.

For instructions on using an improvised tourniquet, see the following section.

Step 5

Twist the windlass on the tourniquet gently to the right to further tighten the tourniquet. Turn the windlass until the bleeding stops.

Step 6

Once the bleeding substantially slows or stops, secure the windlass by attaching it to the windlass clip on the tourniquet. If the tourniquet has a velcro strap, wrap it around the windlass to further secure it.

Step 7

Take note of the time by writing on the tourniquet itself, or by recording it on a phone or device. A person may wish to use a timer to keep track of how long the tourniquet is on for.

Continue monitoring the bleeding. When the emergency services arrive, let them know how long the tourniquet has been in place.

If a person does not have a medical tourniquet, they can make one from everyday items. However, it is important to note people should only do this as a last resort.

First, a person needs something they can wrap around the skin, such as:

  • a long sock
  • tights, pantyhose, or stockings
  • a piece of torn fabric or long rags
  • a scarf or neck tie
  • a hand or tea towel
  • exercise or resistance bands
  • wide plastic tubing
  • an elastic bandage
  • a head wrap or bandana

The material should be at least 1.5 inches (3.8 cm) wide, wherever possible. Do not use a belt, unless there are no other options available.

Wrap the item around a limb a few inches above the source of bleeding and tie a strong knot. To make a homemade tourniquet more effective, make an improvised windlass by placing a rod-like item in the tourniquet knot and twisting it.

Items that can function as a makeshift windlass include:

  • car jack handles
  • strong sticks
  • a closed pocket knife
  • carabiners
  • broom handles
  • large closed scissors

Once the tourniquet is tight enough, secure the makeshift windlass by twisting a rubber band, hair tie, key ring, or piece of fabric around it so it remains in place.

Applying a tourniquet incorrectly can make the tourniquet less effective, or even cause nerve or blood vessel damage. Avoid:

  • placing the tourniquet in an area not between the source of bleeding and the heart
  • placing the tourniquet around a joint, such as an elbow, wrist, knee, ankle, or shoulder
  • placing the tourniquet on top of the source of bleeding, or too close to it
  • using a tourniquet that is too thin, such as a necktie, cables, zip ties, or thin tubing
  • making the tourniquet too tight, which can damage nerves and blood vessels or completely stop blood flow to a large portion of the limb
  • applying a tourniquet to an area covered by thick clothing or other materials

If the tourniquet does not slow or stop the bleeding, try to get emergency help. Call 911 if a person has not already done so, or if possible, ask a bystander to find a medical professional nearby.

Try elevating a wounded limb above the level of the heart. Try to keep the person conscious and stay with them until emergency services arrive.

Once medical professionals are present, provide as many details as possible about the situation, such as:

  • when the injury occurred or when bleeding began
  • how long the bleeding has been going on
  • the cause of the injury or bleeding
  • the location or extent of additional wounds or injuries
  • when someone applied the tourniquet and the effect it had
  • how much blood someone has lost

In an emergency, a tourniquet can help reduce or stop excessive bleeding. A doctor or nurse may also use a tourniquet during procedures, such as drawing blood or inserting an IV line.

Always call 911 first if a person has excessive bleeding. Then, apply pressure to try and stop the bleeding, using a tourniquet if this does not slow bleeding down.

Stay with the person until an ambulance comes, or help them get to emergency help if an ambulance is not available.