Combat Application Tourniquet System (CATS)

The Combat Application Tourniquet System (CATS) is a one-handed tourniquet that completely occludes arterial and venous blood flow of an extremity in the event of a traumatic wound with significant hemorrhage (Figure 1). The CATS uses a windlass system with a free-moving internal band to provide circumferential pressure to the extremity. Once it is tightened and the bleeding has stopped, the windlass is locked in place. A hook-and-loop strap is then applied to secure the windlass during casualty evacuation. The combat application tourniquet (CAT) — also known as the one-hand tourniquet — differs from traditional tourniquets because it can be put on by the soldier with one hand and does not require the use of sticks for tightening.

Figure 1. CATS one-handed tourniquet; photo courtesy of Phil Durango, LLC (Golden, Colorado)

Tourniquet use in Operation Iraqi Freedom has been lifesaving for combat casualties. The CAT has been the most effective field tourniquet, both in laboratory testing and clinical experience. Improvised tourniquets are less effective and are only recommended when no scientifically designed tourniquets are available, as evidenced in the casualty data. Prehospital tourniquet use has improved survival 23%, relative to emergency department use, and use before shock onset has improved survival 90% relative to use after shock onset. The rates of complications (eg, compartment syndrome) have been low.

Despite the policy of encouragement of tourniquet use for limb bleeding, in 1 year 10 patients arrived dead at a Baghdad combat support hospital (CSH) with isolated limb exsanguinations. Use before extrication and transportation is recommended. For limbs of greater girth and tourniquets of lesser width, side-by-side use of additional tourniquets improved effectiveness if one tourniquet was not effective. Historically, there was only one first-aid device, the Thomas splint, that improved survival for limb-injured patients. Now there are data from Operation Iraqi Freedom that show that tourniquets also save lives.

– John F. Kragh, MD, COL , MC, US Army

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