|
A tourniquet is a constricting or compressing device, specifically a bandage, used to control venous and arterial circulation to an extremity for a period of time. Pressure is applied circumferentially upon the skin and underlying tissues of a limb; this pressure is transferred to the walls of vessels, causing them to become temporarily occluded. It is generally used as a tool for a medical professional in applications such as cannulation or to stem the flow of traumatic bleeding, especially by military medics. The tourniquet is usually applied when the patient is in a life-threatening state as a result of continuous bleeding. A primitive tourniquet can be made from a stick and a rope (or leather belt). The rope is made into a loop that fits over the damaged limb and the stick is inserted through the loop. The loop is tightened by twisting the stick. This primitive device stems the flow of blood but side-effects such as tissue damage and nerve damage may occur. In modern medicine, pre-assembled devices have been developed. They avoid side-effects of the traditional rope-and-stick tourniquets and can be faster or easier to apply. Some modern tourniquets can be applied, in theory, with one hand. == History == During Alexander the Great’s military campaigns in the fourth century BC, tourniquets were used to stanch the bleeding of wounded soldiers. Romans used them to control bleeding, especially during amputations. These tourniquets were narrow straps made of bronze, using only leather for comfort. In 1718, French surgeon Jean Louis Petit developed a screw device for occluding blood flow in surgical sites. Before this invention, the ''tourniquet'' was a simple garrot, tightened by twisting a rod (thus its name ''tourniquet'', from ''tourner'' = to turn). Joseph Lister is credited for being the first to use a tourniquet device to create a bloodless surgical field in 1864. He also recommended exsanguinations prior to tourniquet application by limb elevation. In 1873, Friedrich von Esmarch developed a rubber bandage that would both control bleeding and exsanguinate. This device is known as Esmarch's bandage for surgical haemostasis or Eschmarch's Tourniquet. At the time this device was superior to Petit’s device as there were no screws to loosen or cloth to tear. In 1881, Richard von Volkmann showed that limb paralysis can occur from the use of the Esmarch tourniquet. In 1904, Harvey Cushing created a pneumatic tourniquet. This type of tourniquet compressed the underlying blood vessels using a compressed gas source to inflate a cylindrical bladder. This was superior to the Esmarch tourniquet in two ways: (1) the tourniquet could be applied and removed quickly; and (2) this method of limb occlusion decreased the incidence of nerve paralysis. August Bier used two tourniquets for administering segmental anesthesia in 1908. In this procedure circulation is isolated in a limb and the limb is then infused intravenously. In 1963 Hamilton E. Holmes reintroduced Bier’s method as a single tourniquet technique. Today, the two-tourniquet technique is used frequently and is called intravenous regional anesthesia (IVRA). It is also commonly referred to as Bier block, or Bier’s method. In the early 1980s microprocessor-controlled tourniquets were invented by James McEwen, a biomedical engineer in Vancouver, Canada. The first US patent for an electronic tourniquet system was awarded to Dr. McEwen in 1984 and to date he has been awarded many more US and foreign patents for tourniquet improvements. The use of automatic tourniquet systems has significantly improved tourniquet safety. Modern automatic tourniquets are self-calibrating and self-contained. These new tourniquet devices also provide a variety of safety features that are not possible in older mechanical tourniquets.〔 In the 2000s, silicon ring tourniquet, or elastic ring tourniquet, which was developed by Dr. Noam Gavriely, a professor of medicine and former emergency physician. The tourniquet consists of an elastic ring made of silicone, stockinet, and pull straps made from ribbon that are used to roll the device onto the limb. The silicone ring tourniquet exsanguinates the blood from the limb while the device is being rolled on, and then occludes the limb once the desired occlusion location is reached. Unlike the historical mechanical tourniquets, the device reduces the risk of nerve paralysis. The surgical tourniquet version of the device is completely sterile, and provides improved surgical accessibility due to its narrow profile that results in a larger surgical field. It has been found to be a safe alternative method for most orthopedic limb procedures, but it does not completely replace the use of contemporary tourniquet devices. More recently the silicone ring tourniquet has been used in the fields of emergency medicine and vascular procedures.〔 After World War II, the US military reduced use of the tourniquet because the time between application and reaching medical attention was so long that the damage from stopped circulation was worse than that from blood loss. Since the beginning of the 21st century, US authorities have resuscitated its use in both military and non-military situations because treatment delays have been dramatically reduced. The Virginia State Police and police departments in Dallas, Philadelphia and other major cities provide tourniquets and other advanced bandages. In Afghanistan and Iraq, only 2 percent of soldiers with severe bleeding died compared with 7 percent in the Vietnam War, in part because of the combination of tourniquets and rapid access to doctors. In civilian use, emerging practices include transporting tourniquetted patients even before emergency responders arrive and including tourniquets with defibrillators for emergency use. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Tourniquet」の詳細全文を読む スポンサード リンク
|