A tourniquet is a medical device designed to apply circumferential pressure to a limb to completely restrict blood flow. Its purpose is to stop massive, life-threatening hemorrhage that cannot be controlled by applying direct pressure alone. Tourniquets are necessary in time-sensitive situations where rapid blood loss from an arm or leg threatens survival. While proper use can prevent death, incorrect application may fail to stop the bleeding or cause unnecessary harm, making precise placement and technique essential.
Identifying the Correct Placement Zone
The location for applying a tourniquet is determined by balancing speed and precision, using the principle of placing the device between the wound and the heart. In high-stress situations where a wound cannot be immediately identified, the “High and Tight” rule is prioritized. This involves placing the tourniquet as far up the injured limb as possible, right against the armpit or groin. Applying the tourniquet high ensures the device is proximal to the injury, covering potential damage to major arteries higher up the limb than the visible wound.
When conditions allow for a more thorough assessment, placement should be more targeted. The tourniquet should be placed approximately two to three inches above the source of the bleeding. This precise placement minimizes the amount of healthy tissue deprived of blood flow, reducing the risk of nerve or muscle damage. However, the device must never be placed directly over a joint, such as the elbow or knee, because the underlying bone structure prevents the necessary compression of blood vessels.
If the injury is located extremely close to the torso, the “High and Tight” placement remains the most effective option for controlling hemorrhage. Although direct application to the skin is preferred, temporary placement over thin clothing is acceptable if immediate action is required. When the source of bleeding is clearly identified, the tourniquet should be placed two to three inches above the wound. When in doubt about the injury’s exact location or severity, placing the tourniquet higher on the limb is the safer choice to ensure blood flow is fully cut off.
Critical Application Steps for Effectiveness
Selecting the correct placement zone is only the first step; the mechanics of tightening the device determine its effectiveness. The strap must first be pulled tight to remove all slack, ensuring the tourniquet is snug against the limb. After securing the buckle, the windlass—a rod on the device—is engaged to apply the required pressure. The windlass must be twisted repeatedly until the massive bleeding completely stops.
Stopping the visible bleeding is the primary indication of a successful application. A secondary confirmation of effectiveness is the absence of a pulse below the tourniquet, known as the distal pulse. Once the bleeding has ceased, the windlass rod must be secured in place using the clip or strap to prevent it from unwinding. Because the device works by fully occluding blood flow, the application process will cause severe pain. The pressure must remain sufficient to stop arterial blood flow until professional medical care can take over.
Post-Application Safety and Information Transfer
Once a tourniquet has been effectively applied and the bleeding is controlled, the immediate next step is to document the time of application. This time must be noted clearly on the tourniquet strap itself or on the patient, such as on the forehead, using a permanent marker. Recording the time is important because extended periods of restricted blood flow can lead to tissue damage due to a lack of oxygen. The goal is to limit the time the tourniquet is inflated to less than two hours when possible. Modern guidelines recognize that life preservation outweighs the risk of tissue damage.
Once the tourniquet is applied and effective, it must never be loosened or removed. Removing the device prematurely can cause a sudden, massive return of blood flow, leading to shock or a recurrence of life-threatening bleeding. Care of the patient should be transferred to Emergency Medical Services (EMS) as quickly as possible. Communicating the time the tourniquet was applied provides responding medical professionals with the information needed to manage the patient’s subsequent care.