A tourniquet is a crucial device designed to stop life-threatening external bleeding, particularly from limbs. Its primary purpose is to control severe blood loss that could lead to shock or death. While a life-saving tool, its effectiveness depends significantly on correct, accurate placement. This article explores the general principles and specific anatomical considerations for proper tourniquet placement.
Core Principles of Placement
Effective tourniquet application relies on fundamental principles. The “high and tight” guideline means placing the tourniquet as high on the limb as possible, close to the torso. This ensures it is above all major blood vessels supplying the limb, even if the wound location is unclear or in a high-stress environment.
For optimal compression, apply a tourniquet directly to the skin whenever possible. Applying it over thick clothing reduces effectiveness and may allow it to slip. If clothing obstructs the area, cut or remove it to expose the skin beneath.
The tourniquet must always be positioned proximal to the bleeding site, meaning closer to the body’s core and between the wound and the heart. This strategic placement ensures blood flow through the main artery supplying the injured area is cut off. If time permits and the wound is visible, placing the tourniquet two to three inches above the injury is also recommended.
Historically, tourniquets were thought most effective when applied over a single bone, where arteries could be compressed. However, modern understanding indicates well-designed tourniquets effectively occlude blood flow in two-bone compartments. Placing it as low (distal) on the limb as possible while still above the wound can reduce tissue deprived of blood flow, potentially leading to better outcomes.
Specific Locations for Application
Precise anatomical placement is essential for a tourniquet to function as intended and prevent further injury. For upper extremity injuries, apply the tourniquet to the upper arm, as high as possible near the armpit. This allows for effective compression of the brachial artery, which supplies blood to the lower arm.
For lower extremity bleeding, place the tourniquet on the upper thigh, as high as possible, close to the groin. This targets the femoral artery, the major vessel supplying the leg. If the wound is clearly visible and time allows, placing the tourniquet two to three inches above the injury site, while avoiding joints, is also an acceptable method to minimize tissue damage.
Never place a tourniquet directly over a joint, such as the elbow, knee, wrist, ankle, shoulder, or hip. Joints contain dense bone structures and irregular surfaces that prevent effective arterial compression, rendering the tourniquet ineffective. Placing it over a joint can also increase the risk of nerve damage.
Tourniquets are designed for use on limbs (arms and legs) and should not be applied to other body parts. Attempting to apply a tourniquet to the torso, neck, or head is ineffective for controlling bleeding and can cause severe, life-threatening harm due to complex anatomy and vital organs.
Avoiding Common Placement Errors
Incorrect tourniquet placement can significantly reduce effectiveness or cause additional harm. One frequent error is applying the tourniquet over thick layers of clothing. Fabric prevents sufficient direct pressure on the limb, allowing it to slip or providing inadequate compression to stop arterial blood flow.
Another mistake involves placing the tourniquet directly over a joint. Joints cannot provide the solid surface needed for proper arterial compression, and such placement risks nerve damage. The tourniquet should always be positioned on a muscular part of the limb, above the joint if the injury is below it.
Applying the tourniquet too loosely is a serious error that can worsen bleeding. A loose tourniquet might occlude veins, which carry blood back to the heart, but fail to stop higher-pressure arterial flow. This can lead to blood pooling in the limb below the tourniquet and increased blood loss. The tourniquet must be tightened until bleeding completely stops.
Placing the tourniquet too low, or distal to the actual wound, is also ineffective. If an artery is severely injured, it can retract higher into the limb, meaning a tourniquet placed too close to the visible wound might not be above the point of arterial retraction. The tourniquet must be proximal to the injury to cut off the blood supply effectively. Before application, expose the limb by removing or cutting clothing to precisely identify the bleeding source and ensure direct skin contact for optimal placement.