To-urniquet or Not To-urniquet?

Is there a question?

Well - yes.

Use of tourniquets to control bleeding on the battlefield dates from the late 17th century, but the principle of applying an improvised windlass above a wound to constrict blood flow and stop otherwise-controllable hemorrhage has almost certainly been around as long as warfare itself.  As early as World War 1, tourniquet use was being called into question because of resultant complications, and came in and out of favour throughout the 20th century.  In recent years, more rigorous research again questioned their usefulness - not only because simple manual pressure and pressure dressings are actually quite effective methods to control even catastrophic hemorrhage, but also because of the risks of tissue death and deterioration caused by occluding blood flow to a limb.

However, it looks like its time for another turn of the wheel.  As evidence continues to accumulate, former tourniquet detractors are coming around to its use as a fast, effective life-saving tool.  We're going to do a quick overview of some of the risks involved with tourniquet use - because you should never apply a medical technique if you don't know the risks - and then see how they balance out against potential rewards in an austere environment.

What does a tourniquet do?

The purpose of a tourniquet is to apply sufficient pressure to a limb that arterial blood flow below the tourniquet will be completely occluded, or blocked.  This has the effect of stopping even the strongest or most pervasive bleeds, but it also starves the tissues of the limb of the oxygen and nutrients it needs to survive.

Types of Tourniquet

Commercial tourniquets include the CAT and the SOF-TT tourniquets.  The CAT is used by paramedics in British Columbia.  It has the advantage of being a little lighter and a little smaller, but the plastic construction isn't as durable.  The SOF-TT is a military-grade tool.  The metal construction is really reliable, but its bulky, and heavy for the weight-conscious packer.

Special Operations Forces Tactical Tourniquet

Combat Action Tourniquet

Tourniquets can also be improvised.  One method is to form a spanish windlass above a wide cloth bandage.  These may require a bit of padding under the knot, but otherwise work perfectly well.

How to Tie a Wide Bandage Tourniquet

Risks and Concerns with Tourniquet Application

The concerns of using a tourniquet involve a combination of ischemia to the limb itself, and a return of toxins to the rest of the body if the tourniquet is released prematurely.  Those issues include:

  • Permanent damage to muscle, blood vessels, nerves and skin can occur within 2 hours.  It has been traditionally believed that this damage will be complete - resulting in amputation - in 6 hours or less.  This, as it turns out, is not true - or at least does not apply equally to everyone.
  • Increased bleeding if the tourniquet is not tight enough.  This happens when the tourniquet is tight enough to occlude venous return, but not so tight as to stop arterial flow into the limb.  The result is increased local blood pressure, which speeds up the bleeding instead of stopping it.
  • A properly applied tourniquet is extremely painful.  This leads to inadequate tightening - with the risks previously described.
  • Reperfusion injury refers to the return of toxins released from dying muscle cells to the heart and other vital organs.  In sufficient quantities, these can cause cardiac arrest or severe kidney damage.
  • Tourniquets have often been used in situations when they are not necessary.  In a study of pre-hospital tourniquet use in the UK, as many as 47% of tourniquets were unnecessarily applied.  When one considers the many risks of their use, this high number of unnecessary tourniquets seems alarming.  However, particularly in an austere environment, your ability to control the bleed is not your only consideration.

Rewards of Tourniquet Use

On the other hand, tourniquets save lives.

  • A properly applied tourniquet provides a secure and reliable hemorrhage control.  This is particularly the case in catastrophic hemhorrage in austere environments, where the importance of hypothermia treatment in trauma requires the responder to apply bulky insulating layers to all of their patients.  Pressure dressings and soaker bandages might become dislodged, or allow continued slow bleeding that can go undetected under all those layers.
  • Tourniquets are fast - application of manual pressure followed by pressure dressings to control severe bleeds might take 10 minutes or more.  The application of a tourniquet will quickly allow the wilderness first aid practitioner to move on to other treatments, including critical hypothermia prevention.
  • Accumulated evidence shows that the deterioration caused by ischemia below the tourniquet isn't as irreversible as we once believed.  There is one case of a soldier in Afghanistan who wore a properly applied tourniquet for over 14 hours, with full recovery of the limb.  Of course, that individual would have enjoyed the holy trinity of health, youth, and fitness - but it does give more time than previously believed.

The Bottom Line

Tourniquets are no longer last resort treatments, especially in wilderness settings.  I recommend you carry a commercial tourniquet, or be very familiar with how to construct an improvised one (a tightened belt won't do - TV is bad!) and do not hesitate to apply it if:

  • You have any doubt as to your ability to control a bleed.
  • Hypothermia prevention will be delayed by other hemorrhage control.
  • Other serious injuries, or life-threatening conditions need your attention. 
  • The area is hazardous, and the patient has to be moved quickly.

Some other considerations in tourniquet use include:

  • Tourniquets work best over single bones - upper arm or upper leg.  Applying a tourniquet over the radius and ulna of the lower arm, or the tibia and fibula of the lower leg, can allow the artery to slip into a hollow between the bones, preventing effective hemhorrage control.
  • Always record the time the tourniquet was applied.  Write it in black marker either on the commercial tourniquet or above the wound.
  • Leave the limb with the tourniquet outside your hypothermia package. It doesn't need to be heated, and the cold will slow tissue death. (Also, every tourniqueted limb increases core body temperature by 1 -2 degrees C.)
  • DO NOT REMOVE THE TOURNIQUET!  This should only be done by medical professionals in a hospital environment.  You place your patient at grave risk if you remove the tourniquet yourself.
  • When you hand your patient off to the next level of care - Search & Rescue, paramedics, or hospital staff - make sure they are aware of the tourniquet and the circumstances surrounding its application.

Stay safe out there!

Kieran

Kieran Hartle

Coast Wilderness Medical Training, 704-1960 Alberni Street, Vancouver, BC