A tourniquet is a device designed to apply circumferential pressure to an arm or leg to completely stop the flow of arterial blood to that limb. The purpose of applying this extreme pressure is to halt life-threatening hemorrhage that would otherwise result in rapid death from blood loss. This measure is a last resort, reserved only for extreme emergencies where conventional methods of bleeding control have failed or are impossible to sustain. A properly applied tourniquet creates a temporary state of ischemia, or lack of blood flow, which buys precious time until professional medical help can be reached.
When to Use a Tourniquet
The decision to use a tourniquet must be based on the severity of the bleeding, not the size of the injury. A tourniquet should only be considered for severe, life-threatening external bleeding that cannot be controlled by applying firm, direct pressure to the wound. This kind of bleeding is often characterized by blood spurting rhythmically or flowing profusely, soaking through dressings almost immediately.
Tourniquets are exclusively for injuries on the extremities (arms or legs) and are never used on the head, neck, or torso. Scenarios that necessitate immediate application include traumatic amputations or mass casualty events where multiple victims require rapid intervention and resources are limited. In these situations, controlling massive hemorrhage takes precedence over the risks associated with cutting off blood supply.
Selecting Suitable Improvised Materials
A functional improvised tourniquet requires two fundamental components: a constricting band and a windlass. The constricting band wraps around the limb and applies the pressure necessary to occlude blood flow. To prevent the material from cutting into the skin and causing tissue damage, the band must be at least 1.5 to 2 inches wide (approximately 4 to 5 centimeters).
Suitable materials for the band should be strong and pliable but not overly stretchy. Materials that are too narrow, such as thin rope, wire, or shoelaces, must be avoided completely, as they can cause severe nerve and soft tissue damage without effectively stopping arterial flow.
Constricting Band Materials
- A wide belt
- A scarf
- A triangular bandage
- A piece of cloth ripped from a shirt or trouser leg
The second component, the windlass, is a rigid object used to twist the band, multiplying the tightening force. It must be durable enough to withstand significant torsional pressure without snapping or bending. Good examples include a sturdy stick or wooden dowel, a metal rod, or the handle of a tool that is at least 4 to 6 inches long. The selection of a strong windlass is necessary to ensure the improvised device can apply the pressure needed to save a life.
Thin or brittle items like standard pens or pencils should not be used, as they are likely to break when the necessary force is applied. Failure of a windlass during application can result in a loss of pressure.
Detailed Steps for Application
The correct application of a makeshift tourniquet begins with proper placement on the limb. The band should be positioned high and tight on the extremity, 2 to 3 inches above the wound site, but never directly over a joint, fracture, or the wound itself. If the injury is near a joint, the device should be placed above the joint, closer to the torso, to ensure effective compression.
After placing the band around the limb, wrap it tightly and tie the ends together using the first half of a square knot. This initial knot secures the band in place, creating a loop that is as tight as possible by hand. The windlass device is then positioned directly over the center of this half-knot.
The second half of the square knot is tied over the windlass, trapping the rigid object against the band. Once secured, the windlass is twisted in one direction to begin tightening the tourniquet. This twisting action increases the circumferential pressure on the limb, compressing the arteries beneath the muscle.
The windlass must be twisted continuously until the massive, life-threatening bleeding completely stops, which is the only reliable indicator of success. This twisting will be extremely painful for the casualty, but it is necessary to achieve full arterial occlusion. Once the bleeding has ceased, the windlass must be secured firmly so that it cannot untwist or unravel, typically by tying the remaining tails of the band around the ends of the windlass.
The improvised device must be checked to ensure no pulse can be felt below the application point, confirming that blood flow has been fully stopped. If bleeding continues or a pulse is present, the windlass must be twisted further, or a second tourniquet should be applied higher up on the limb. The goal is to completely occlude the deeper, high-pressure arteries, which requires significant force.
Critical Safety Considerations
The application of any tourniquet, especially an improvised one, carries severe risks due to the prolonged lack of blood flow (ischemia). This lack of oxygenated blood can lead to nerve damage, muscle death, and potential loss of the limb if the duration of application is excessive. The goal is to limit the time the limb is without blood flow, ideally to less than two hours, before medical professionals can intervene.
Once the tourniquet is applied and the bleeding is controlled, it must never be loosened or removed by an untrained individual. Only trained medical personnel should perform this action. Releasing the pressure can cause a sudden rush of toxic blood back into the body, known as reperfusion injury, or cause the casualty to bleed to death quickly if the underlying injury is not addressed.
A critical step after application is to document the exact time the tourniquet was applied. This time stamp is vital information for the receiving medical team to assess the risk of tissue damage. The application time should be written clearly on the patient, often on the forehead or on a piece of tape secured to the device.
The makeshift tourniquet must remain visible to all responding personnel and should not be covered by clothing or blankets. Seeking immediate professional medical attention is necessary, as the tourniquet is a temporary measure designed only to keep the patient alive until advanced care is available.