A tourniquet is a device designed to completely constrict blood flow within a limb, a measure used to stop life-threatening hemorrhage that cannot be controlled by direct pressure alone. This application is not a primary first aid step but a temporary, last-resort solution intended to prevent a person from bleeding to death until professional medical help is available. Properly applied, a tourniquet compresses the arteries against the bone, stopping the arterial flow of blood to the injured extremity. Although the procedure carries risks to the limb, the immediate goal is to save the life of the person experiencing massive blood loss.
Deciding When Tourniquet Use is Necessary
The decision to apply a tourniquet must be made quickly and is reserved for situations involving massive, uncontrollable bleeding from an arm or a leg. This kind of hemorrhage is typically characterized by blood spurting rapidly from a wound or pooling quickly on the ground, indicating a major artery has been compromised. If the bleeding is too severe, if the limb is partially or fully amputated, or if the scene is unsafe, a tourniquet becomes necessary.
The immediate risk of death from hemorrhagic shock outweighs the potential risk of damage to the limb from the tourniquet itself. If a person has lost enough blood to enter shock or is bleeding out in a matter of minutes, a tourniquet is the appropriate intervention. This device is not for minor cuts or moderate bleeding; its application is justified only by the presence of a truly life-threatening bleed.
Selecting Materials for Improvised Construction
An improvised tourniquet requires two distinct components: a broad constricting band and a rigid windlass mechanism. The constricting band must be made of material that is at least 1.5 to 2 inches wide. Using materials like thin rope, wire, or cord is strongly discouraged because they concentrate the pressure into a narrow area, which is less likely to stop arterial flow and far more likely to cause severe nerve and tissue damage. Good options include a folded triangular bandage, a wide piece of cloth torn from clothing, or a scarf.
This object must be rigid, sturdy, and long enough to be twisted without breaking under significant strain, ideally between four to six inches in length. Suitable items include a strong stick, a metal rod, a closed pocket knife, or a heavy-duty pen. Avoid materials that are brittle or too thin, such as small twigs or standard pencils, as they will snap when the necessary torque is applied.
Step-by-Step Application Technique
Place the constricting band high and tight on the injured limb, positioning it two to three inches above the wound. Avoid placing the tourniquet directly on a joint, such as the elbow or knee, as the underlying bone structure will prevent effective compression of the artery. The band should be wrapped tightly around the limb and secured with a simple overhand knot.
The rigid windlass object is placed directly on top of this initial knot, and a second half-knot is tied over the windlass to secure it firmly against the band. The tourniquet is then tightened by twisting the windlass rod in one direction, which rapidly increases the circumferential pressure on the limb.
Continue twisting until the massive bleeding completely stops; this typically requires significant force and will cause considerable pain to the injured person, which is an expected and necessary sign that the tourniquet is working. Once the flow of blood has ceased, the windlass must be secured immediately to prevent it from unwinding. This is accomplished by using the remaining ends of the constricting band or a second piece of material to tie the windlass rod to the limb, locking it in its tightened position.
Immediate Post-Application Care and Critical Warnings
The time the tourniquet was applied must be noted clearly on the person or on the tourniquet itself. Prolonged application beyond two hours increases the risk of nerve damage and other complications. A tourniquet must be tightened enough to stop all arterial blood flow, not just the venous return; insufficient pressure can actually worsen bleeding by preventing deoxygenated blood from returning to the body while the artery continues to pump blood into the limb.
It must never be loosened or removed by a layperson. Only trained medical personnel should make this decision upon arrival, as removing a tourniquet prematurely can cause the person to rapidly bleed out or suffer reperfusion injury. Tourniquets are strictly for limbs and must never be applied to the neck, torso, or head. The immediate priority becomes transporting the person to definitive medical care as quickly as possible.