A tourniquet is a medical device designed to constrict blood flow to an extremity, making it a lifesaving tool for controlling severe, life-threatening hemorrhage in an arm or a leg. This device, often a strap with a tightening mechanism, works by applying circumferential pressure to the limb until the flow of blood is completely stopped. Its sole purpose in an emergency setting is to prevent a person from bleeding to death from uncontrolled blood loss.
The Critical Rule of Placement
A fundamental rule in hemorrhage control is that a tourniquet must always be placed above the wound, meaning closer to the center of the body or the torso. Placing it below the injury would allow the artery to continue pumping blood out of the wound site, making the device ineffective. The physiological reason for this placement is to compress the main artery supplying blood to the injured area, cutting off the source of the flow.
Proper placement is generally two to three inches above the bleeding site, positioning it on a single long bone section of the limb, such as the upper arm or the thigh. Avoid placing the tourniquet directly over a joint, like the elbow or the knee, because the arteries are less compressible in these areas, which can reduce the device’s effectiveness. If the wound is very close to the torso, apply it “high and tight” in the armpit or groin crease to ensure the most proximal compression possible.
Identifying Life-Threatening Bleeding
The decision to use a tourniquet is reserved for life-threatening extremity hemorrhage, as it is a powerful tool with potential risks, and should not be used for minor bleeding. The initial and preferred method for controlling external bleeding is always direct pressure, but a tourniquet becomes necessary when this fails or is impractical.
Life-threatening bleeding is characterized by several signs. These include blood that is spurting or pumping out of the wound, indicating arterial involvement, or blood that is pooling rapidly on the ground. Another indicator is clothing or bandages that quickly become soaked with blood and cannot be controlled with firm and sustained direct pressure. Tourniquets are also immediately appropriate for wounds involving a partial or complete amputation of a limb.
Applying the Tourniquet: A Step-by-Step Guide
The correct application of a commercial tourniquet is paramount to its success in stopping blood flow. First, the device should be placed directly on the skin, if possible, or over a thin layer of clothing, and positioned two to three inches above the wound. The strap is then pulled through the buckle or clip and tightened as much as possible to remove all slack around the limb.
Once the strap is snug, the windlass rod is engaged and twisted rapidly. This twisting action applies the necessary circumferential pressure to occlude the underlying artery. The windlass must be turned continuously until the bleeding completely stops and the distal pulse is no longer detectable.
The windlass is then secured into its locking clip or cradle to prevent it from unwinding and losing tension. This process will be painful for the injured person, but the pain is necessary to achieve the pressure required to stop the hemorrhage. If the first tourniquet fails to stop the bleeding, a second one should be applied immediately above the first one and tightened until the flow ceases.
Post-Application Care and Monitoring
After a tourniquet has been successfully applied, several immediate steps are required while waiting for professional medical assistance. The most important administrative step is to clearly mark the time of application on the tourniquet itself or, if not possible, directly on the patient’s forehead or a piece of tape affixed to the patient. This time stamp is crucial information for medical staff, as it helps them manage the risk of tissue damage from prolonged lack of blood flow, known as ischemia.
The tourniquet must be left exposed and visible, not covered by blankets or clothing, so that the medical team can easily identify its presence and status upon arrival. Once a tourniquet is applied and is effective, it must never be loosened or removed by a layperson. Doing so can cause the patient to rapidly bleed out again or potentially release harmful metabolic byproducts into the general circulation. The patient requires immediate transport to a hospital for definitive care, as tourniquets are only a temporary measure until surgical intervention is possible.