A tourniquet is an emergency device designed to manage severe, life-threatening external bleeding on an arm or leg. Its purpose is to apply concentrated pressure around a limb to stop massive blood loss that cannot be controlled by direct pressure alone. The device is a wide band with a mechanism to achieve and maintain extreme tightness, making it an indispensable tool for immediate hemorrhage control. This rapid intervention is frequently the difference between survival and the onset of hypovolemic shock, a condition where the body loses too much blood to function.
Purpose and Mechanism of Action
The purpose of a tourniquet is to control catastrophic hemorrhage. In a trauma scenario, a tourniquet is used when direct pressure to the wound is ineffective, impractical, or when multiple victims require immediate attention. The mechanism of action involves applying circumferential pressure to the limb, which compresses the underlying arteries and veins against the bone.
The goal is complete arterial occlusion, meaning the pressure must be high enough to collapse the arteries and halt blood flow distal to the tourniquet’s placement. If the device is applied too loosely, it may only block venous return while allowing arterial flow to continue, potentially increasing blood loss. Stopping all blood flow to the injured area prevents the person from bleeding out while awaiting definitive medical care. This action buys precious time, which is the primary factor in surviving massive trauma.
Essential Steps for Proper Application
The first step in applying a tourniquet is to place it high and tight on the injured limb, approximately two to three inches above the wound, but never directly over a joint. While bare skin is preferable, it can be applied over clothing, provided the device is not placed over bulky objects in pockets. The band should be pulled as tightly as possible before securing the strap buckle.
Once the strap is tightened, the mechanical windlass rod must be twisted until the bleeding completely stops. This twisting action increases the circumferential pressure until the arterial flow is occluded, which is the clear sign of a successful application. Securing the windlass rod into its locking clip or mechanism is the final step, ensuring the pressure is maintained and the device cannot accidentally loosen. Proper application is painful because of the high pressure required to compress the arteries, but this pain is necessary to save a life.
Commercial Versus Improvised Devices
Purpose-built commercial tourniquets are significantly more effective and reliable than improvised alternatives. These manufactured devices feature a wide band and a durable windlass system specifically engineered to generate and sustain the high pressure needed for arterial occlusion. Studies have shown that commercial tourniquets have a much higher success rate in achieving complete hemorrhage control, especially when applied by untrained personnel.
Improvised devices, which might include materials like belts, strips of cloth, or thin ropes, often lack the necessary width and tensile strength to apply sufficient, uniform pressure across the limb. While an improvised device using a wide material and a sturdy windlass stick can sometimes be effective, non-windlass improvised tourniquets fail to stop bleeding in a high percentage of cases. Improvised methods should only be considered as a last resort when a commercial device is absolutely unavailable, as the risk of partial occlusion leading to increased blood loss is high.
Critical Safety and Post-Application Care
Once a tourniquet has been properly applied and bleeding has stopped, several critical safety steps must be followed to maximize the chances of a positive outcome. The exact time the tourniquet was applied must be immediately noted, often by writing the time directly onto the device or the patient’s forehead with a marker. This time stamp is mandatory medical information, as it helps determine the likelihood of tissue damage caused by prolonged lack of blood flow, known as ischemia.
The tourniquet must never be covered by clothing or blankets, as it needs to remain visible to all incoming medical personnel. Once tightened, the tourniquet must not be loosened or removed by the person who applied it, as only trained medical professionals should perform this action under controlled circumstances. The patient requires immediate transport to a facility for definitive medical care, since a limb can sustain damage to nerves and muscle tissue if blood flow is restricted for too long. While the risk of losing the limb exists with prolonged use, the immediate application of a tourniquet prioritizes saving the person’s life over the potential loss of the limb.