A tourniquet is a device designed to apply pressure to a limb, stopping severe blood loss. It controls life-threatening bleeding from an arm or leg when direct pressure is insufficient or impractical. A tourniquet serves as a temporary, life-saving measure in emergencies.
Principles of Effective Tourniquet Use
An effective tourniquet requires two main components: a constricting band and a windlass mechanism. The constricting band wraps around the limb, applying circumferential pressure. For effective arterial occlusion and to minimize tissue damage, this band should be at least 1.5 to 2 inches wide, ideally 3 inches or more. Narrower materials like shoelaces or wire can cause nerve damage and may not stop bleeding.
The band material should be strong and non-elastic to maintain consistent pressure once tightened. The windlass is a rigid object used to twist and tighten the band, generating the pressure needed to occlude arterial blood flow. Without a windlass, applying enough force to stop arterial bleeding is difficult, risking increased blood loss if only venous flow is restricted.
Common Improvised Materials
When a commercial tourniquet is unavailable, everyday items can be adapted. For the constricting band, suitable materials include a strong scarf, a triangular bandage folded into a wide strip, a sturdy belt, or thick cloth torn from a shirt or towel. These items are generally wide enough and strong enough to apply broad, firm pressure. A belt can be used as the band, but its buckle is often insufficient for tightening, requiring a separate windlass.
For the windlass, a rigid object that will not break under pressure is needed. Examples include a sturdy stick, a metal pen, a chopstick, a small wrench, or a broom handle. Select a windlass robust enough to withstand the twisting force needed for arterial occlusion. After tightening, a secondary material like another piece of cloth or tape is needed to secure the windlass and prevent unwinding.
Application Techniques for Improvised Tourniquets
Applying an improvised tourniquet correctly is crucial for effectiveness. First, expose the wound by removing or cutting clothing to identify the bleeding source. Next, place the improvised band 2 to 3 inches above the wound, between the wound and the heart. Avoid placing the tourniquet directly on a joint, such as the elbow or knee, as this can cause nerve or blood vessel damage and may not stop bleeding.
Wrap the material tightly around the limb and tie a half-knot. Place the windlass object on top of this half-knot and tie a second half-knot over it to secure the windlass. Begin twisting the windlass until bleeding stops completely. This twisting will be painful for the injured person, but it is necessary to achieve adequate pressure. Once bleeding stops, secure the windlass in place to prevent loosening, often by tying the remaining ends of the band around the windlass or using tape. Finally, note the time the tourniquet was applied, as this information is important for medical professionals.
Critical Safety Considerations
A tourniquet should only be used for severe, life-threatening bleeding from an arm or leg that direct pressure cannot control. It is a measure of last resort when other methods fail or are impractical. While tourniquets save lives, improper or prolonged application carries risks.
Potential complications include nerve damage, muscle injury, and tissue damage due to lack of blood flow, ranging from temporary to permanent. Research suggests tourniquets can remain in place for up to two hours with minimal increased risk of permanent damage. However, prolonged application beyond this timeframe, especially 4 to 6 hours, increases the likelihood of severe complications, including potential limb loss. Once applied, a tourniquet should never be loosened or removed by an untrained individual, as this can lead to further blood loss and reperfusion injury. Immediate medical attention should always be sought once a tourniquet has been applied.