CPR Seattle Blog

Learn more about Safety, CPR and First Aid

Tourniquets: Should you use one in an emergency?

The First Aid classes at CPR Seattle addresses the use of tourniquets in cases of severe bleeding that pressure alone cannot stop.

We also indicate that the use of a tourniquet by untrained rescuers can easily result in more harm than good. The use of tourniquets has a bit of a spotty history, in that there are many opinions as to their efficacy, some using no more than anecdotal evidence. We’ll take a look at the related issues in this post, but keep one overriding fact in mind – you should never try to use a tourniquet to control severe bleeding until after first attempting targeted direct pressure. Most bleeding can be stopped very well by this method alone, even bleeding that is coming from a large vein or artery. Given enough time, the bleeding will usually stop. Uncontrolled bleeding is one of the most preventable causes of death, so there may indeed be occasions where proper use of a tourniquet can save the life of a bleeding victim.

Problems related to tourniquet use cover a wide range. Issues include:

  • Applying too loosely. This can causing bleeding to worsen, as the return or venous blood is blocked but arterial blood continues to pass by the tourniquet.
  • Releasing it too soon, causing severe bleeding to resume. Not only can the bleeding result in death, but the returning blood flow can also damage compressed blood vessels.
  • Leaving it on too long, causing neurovascular damage and tissue death. Generally, permanent nerve, muscle and blood vessel damage can occur after about two hours.
  • Placing it too far away from the wound, or on the wrong type of wound (i.e. wounds at a joint)
  • Fabricating a tourniquet from an inappropriate material. Parachute cord can cut into the skin, blood pressure cuffs can loosen. Tourniquets should be 1” to 2” wide. The wider the tourniquet, the more pressure will be required. Commercially available tourniquets such as the CAT (Combat Application Tourniquet, pictured above) are recommended over one improvised out of found materials.
  • Periodic loosening (due to pain or concerns about blood flow to vital organs), which leads to the victim slowly bleeding to death.
  • Applying it to a victim with low blood pressure (i.e., someone receiving CPR or in shock) can lead to increased bleeding if the victim is subsequently resuscitated, as the tourniquet pressure that was effective earlier is now insufficient for the higher re-established blood pressure.

We’ve looked at things not to do with a tourniquet, but if one is in fact necessary, principles to remember when applying a tourniquet include:

  • The tourniquet must completely stop arterial (e.g. moving away from the heart) blood flow.
  • Larger limbs require maintaining more pressure.
  • As tourniquet width increases, required pressure increases (the material will also tend to bend in the middle, moving pressure towards the center and away from the edges).
  • Place a tourniquet approximately two inches from the wound if able. Repositioning may be necessary if the chosen location proves to be ineffective. Make sure it is applied upstream; i.e. between the wound and the heart.
  • Apply with as much direct skin contact as possible to reduce chances of the clothing causing the tourniquet to slip.
  • Record the time of application for EMS; write it on the limb itself or in close proximity.
  • If EMS is significantly delayed, cooling the limb with ice/cold packs (or exposing it to a cold environment) may help reduce tissue damage.

Professional healthcare providers will go through intensive training in order to learn how and when to use a tourniquet effectively.

Even then, dangers are still present. For the lay rescuer, remember: always apply targeted, direct external pressure as the first line of care for bleeding. Only when this fails should a tourniquet be applied. Loss of life due to bleeding outweighs loss of limb due to complications with tourniquet use. For information derived from a 2016 survey of EMS agencies, see this article posted at the Journal of Emergency Medical Services website.


Published on November 4, 2013