For extremity wounds in which direct pressure has been tried and has failed to control the bleeding, consider a tourniquet. Until recently, using tourniquets for prehospital hemorrhage control has been discouraged, however data from studying combat survival for trauma victims indicates that early use of tourniquets before the patient bleeds into shock increases survival by almost a factor of 10. It is now recommended that EMTs carry tourniquets and apply them in the prehospital setting when extremity bleeding cannot be controlled with direct pressure.
The most common type of commerical tourniquet used in the field is a Combat Application Tourniquet (CAT) which consists of an adjustable strap, a tightening rod, called the windlass rod, clips for retaining the rod once tightened, and a strap to retain the rod in the clips.
To apply a Combat Application Tourniquet (CAT):
- DO NOT remove the gauze pads over the wound
- Place the tourniquet on the limb a minimum of 2" above the level of the bleeding (never over a joint) and fasten to itself tightly enough that 3 fingers cannot be slipped between the tourniquet and the limb.
- Use the windlass rod and twist to tighten until the bleeding stops and the distal pulse disappears. This should not take more than 3 turns, however it is critical that you apply the tourniquet with the aim of stopping the bleeding, not just slowing it down.
- Clip the windlass rod in place, and restrain with the strap.
- Write the time of application down on the tourniquet and record in the patient care report
- If bleeding has not been controlled with adequate tightening of the tourniquet, consider applying a second tourniquet next to the first.
- Transport immediately. When it has had a tourniquet applied, the limb has a limited amount of time to survive and needs to reach definitive care quickly.
Complications. The most prevalent and serious complication of a tourniquet that has been poorly applied or left on for an extended period is Compartment syndrome. When circulation is interrupted for a prolonged period it leads to tissue swelling and cellular rupture. This swelling creates increased pressure on the blood vessels, muscle, and nerves inside a sheath of non-compliant fascia within the extremity (the "compartment"). The increasing pressure can become a run away cycle even after circulation is restored as more swelling makes the perfusion worse which increases the ischemia and swelling. If this process is not corrected, it can lead to permanent damage and possible amputation of the affected area.
There is an outdated practice of periodically loosening a tourniquet to allow circulation to enter back into the limb. This has not been shown to have clinical benefit, and is not recommended.
If a commercial (CAT) tourniquet is not available, use an improvised tourniquet. One of the more common improvised tourniquets is triangular bandage folded into a cravat, using a wooden or plastic device as a windlass to tighten it. Utilize all of the above parameters when tightening the tourniquet, documentation, etc.
Minimizing the time to definitive care is the most effective way to avoid complications from tourniquets.