A tourniquet can be defined as a constricting or compressing device used to control arterial and venous blood flow to a portion of an extremity for a period of time. Pressure is applied circumferentially around a portion of a limb at a desired location; this pressure is transferred to the walls of blood vessels, causing them to become temporarily occluded or restricted. In surgical settings, a tourniquet is used to occlude arterial blood flow following exsanguination to produce a relatively bloodless operative field and to minimize blood loss. In emergency settings, a tourniquet is used stop traumatic bleeding such that medical care can be provided in time before the injured person bleeds out. In rehabilitation settings, a tourniquet is used to restrict arterial blood flow at a consistent and safe pressure for short periods of time during low intensity exercise to more rapidly increase muscle size and strength.
Select an appropriate material. If you have a well-designed medical tourniquet at your disposal then that's great, but in most emergency situations you'll have to improvise. In the absence of a specially designed tourniquet, choose something that is strong and pliable (although not too stretchy), but long enough to tie around the injured limb.Good choices would be a necktie, bandana, leather belt, straps from knapsack or handbag, cotton shirt or long stocking.
Apply the tourniquet between the heart and injury. Place your tourniquet around the injured limb, between the open wound and the heart (or proximal to the wound) — the purpose is to cut off the strong blood flow within arteries leaving the heart, not the more superficial veins returning blood back to the heart. More specifically, place your tourniquet about two to four inches away from the edge of the wound. Don't place it directly over the wound because the arteries upstream from the injury will still drain into and out from the open wound.
Tourniquet cuffs can be cylindrical or contour in shape. Cylindrical tourniquet cuffs are designed to fit optimally on cylindrically shaped limbs. However, human limbs may be conically-shaped (i.e. tapered), particularly in extremely muscular or obese individuals. Applying a cylindrical cuff on a tapered limb can result in poor fit, sliding of the cuff distally on the limb during the procedure, and inability to achieve a bloodless field at normal pressures.
The Amphibious Tourniquet is the only wearable, and marine environment specific tourniquet for water sports and maritime professionals. It comes equipped with a stainless steel ratcheting buckle which works in tandem with a ladder strap system as its means of mechanical advantage.