The following text should not be construed as an admission of knowledge in the prior art. Furthermore, citation or identification of any document in this application is not an admission that such document is available as prior art to the present invention, or that any reference forms a part of the common general knowledge in the art.
Loss of blood is a major cause of death in emergency situations in which the injured person is alone or medical assistance is not immediately available. The use of a tourniquet to stop blood loss from an injured arm or leg is a well-known technique for preventing death in these situations. In general, for emergency use where the victim is alone, the victim must be able to apply the tourniquet to his or her own arm or leg and occlude blood flow using only one hand.
Tourniquets of the prior art generate inward radial compression on the limb by being put into high levels of circumferential tension when wrapped around the limb. As the pressure on the limb increases, the friction between the strap and the limb also increases, causing the underlying soft tissue to move with the strap as it is drawn tight. This tends to draw soft tissues underlying the strap into the ratchet or buckle device, pinching the soft tissue and creating a region of very high localized pressure which will cause unnecessary injury. This effect may also create high shearing stresses in the underlying soft tissues, increasing the probability of nerve and tissue injury. Friction between the strap and the limb may also create regions of low pressure by preventing tension from being distributed evenly in the strap around the entire limb circumference, and as a result, arterial blood may still flow through these low pressure regions although overall strap tension is very high. In general, the application of uneven or non-uniform application of pressure around the limb leads to the need for unnecessarily high overall tourniquet pressures to reliably and predictably stop arterial blood flow, and this need for unnecessarily high pressure increases the probability of a range of unnecessary injuries to nerves, muscles and the limb.
The use of a tourniquet in many emergency situations, including many recreational activities, such as hiking, rock climbing and camping, imposes a weight restriction on the tourniquet. Simply stated, if a tourniquet is too bulky or has an excessive weight, the potential user, such as a hiker, will not pack and carry the tourniquet with them. Therefore, there is a need of a relatively small and light-weight tourniquet that can be easily packed and carried, and subsequently used at remote locations, if necessary.
Accordingly, there is a need for an emergency, light-weight tourniquet that provides improved radial pressure to the wounded limb, thereby restricting blood flow to the limb. Furthermore, there is a need for such a tourniquet that can be applied by the victim using one hand.