A tourniquet is a constricting or compressing device 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.
In 1718 French surgeon
Jean Louis Petitdeveloped a screw device for occluding blood flow in surgical sites. He named this device after the French verb “tourner” (to turn), “tourniquet” as it is commonly known today. This would not have been possible without the prior work of William Harvey, an English surgeon who traced the human circulation in 1628. Joseph Listeris 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 Esmarchdeveloped a rubber bandage that would both control bleeding and exsanguinate. This device is known as "Esmarch's bandage for surgical haemostasis" or "Esmarch'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 Volkmannshowed that limb paralysis can occur from the use of the Esmarch tourniquet.
Harvey Cushingcreated 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 Bierused 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. Holmesreintroduced Bier’s method as a single tourniquet technique. Today, the two-tourniquet technique is used frequently and is called intra-venous 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.Fact|date=July 2008
There are two types of tourniquets: surgical tourniquets and emergency tourniquets. Surgical tourniquets are frequently used in orthopedic surgery while emergency tourniquets are limited to emergency situations to control blood loss.
Surgical tourniquets prevent blood flow to a limb and enable surgeons to work in a bloodless operative field. This allows surgical procedures to be performed with improved precision, safety and speed. Tourniquets are widely used in orthopedic and plastic surgery, as well as in intravenous regional anesthesia (
Bier blockanesthesia) where they serve the additional function of preventing local anesthetic in the limb from entering general circulation.
Emergency tourniquets are used in emergency bleeding control to prevent severe blood loss from limb trauma. Emergency tourniquets are generally used as a last resort, especially in civilian applications, for all blood flow below the application of an emergency tourniquet is stopped, and can subsequently kill the tissue, leading to eventual loss of the limb below application. [cite web|url=http://www.cdc.gov/nasd/docs/d000701-d000800/d000799/d000799.html|last=Cyr|first=Dawna L|coauthors=Johnson, Steven B|title=Basic First Aid|publisher=The University of Maine|date=September 2006|accessdate=2008-02-25] [cite journal |author=Ruterbusch, VL; Swiergosz, MJ; Montgomery, LD; Hopper, KW; Gerth, WA |title=ONR/MARCORSYSCOM Evaluation of Self-Applied Tourniquets for Combat Applications |journal=US Naval Experimental Diving Unit Technical Report |volume=NEDU-TR-05-15 |date=2005 |url=http://archive.rubicon-foundation.org/3476 |accessdate=2008-07-22 ] [cite journal |author=Hill, JP; Montgomery, LD; Hopper, KW; Roy, LA |title=Evaluation of Self-Applied Tourniquets for Combat Applications, Second Phase. |journal=US Naval Experimental Diving Unit Technical Report |volume=NEDU-TR-07-07 |date=2007 |url=http://archive.rubicon-foundation.org/6870 |accessdate=2008-07-22 ]
However, use of tourniquets is widespread in military applications, and have the potential to save lives during major limb trauma. Analysis has shown that in cases of major limb trauma, there is no apparent link between tourniquet application and morbidity of the limb. [cite journal |author=Kragh JF, Walters TJ, Baer DG, Fox CJ, Wade CE, Salinas J, Holcomb, JB |title=Practical use of emergency tourniquets to stop bleeding in major limb trauma |journal=J Trauma |volume=64 |issue=2 Suppl |pages=S38–49; discussion S49–50 |year=2008 |month=February |pmid=18376170 |doi=10.1097/TA.0b013e31816086b1 |url=http://meta.wkhealth.com/pt/pt-core/template-journal/lwwgateway/media/landingpage.htm?an=00005373-200802001-00008 |accessdate=2008-08-20]
In recent years there have been significant advancements in tourniquets. These advancements have vastly improved tourniquet safety.
Limb occlusion pressure
Limb occlusion pressure (LOP) is the minimum tourniquet pressure required to occlude blood flow to a specific patient's limb at a specific time and accounts for a patient’s limb and vessel characteristics, and the type and fit of the cuff. LOP can be determined by gradually increasing tourniquet pressure until distal arterial pulses cease, as indicated by a device sensing blood flow, such as a Doppler
stethoscope. Studies have shown that cuff pressure based on LOP measured immediately prior to surgery is generally lower than commonly used cuff pressures and is sufficient to maintain a satisfactory surgical field [McEwen JA, Inkpen KB, Younger A. “Thigh tourniquet safety: Limb occlusion pressure measurement and a wide contoured cuff allow lower cuff pressure.” Surg Tech. 2002; 34:8-18.] .
Automatic tourniquet systems are capable of providing safety features that are not possible in older mechanical tourniquets. These systems can monitor the cuff inflation time as well as regulate the cuff pressure to a known pressure throughout the surgical procedure. Some microprocessor controlled tourniquets are capable of calculating LOP in about 30 seconds. [http://www.zimmer.com/z/ctl/op/global/action/1/id/9371/template/MP/prcat/M8/prod/y Zimmer] Automatic Tourniquet Systems] This assists the operating room staff in deciding what the tourniquet pressure should be set at on a per-patient basis.
Contoured and wide cuffs
Studies have shown that tourniquet cuff pressure can be substantially reduced by using wide, contoured cuffs. [Pedowitz RA, Gershuni DH, Botte MJ, et al. “The use of lower tourniquet inflation pressures in extremity surgery facilitated by curved and wide tourniquets and an integrated cuff inflation system.” Clin Orthop Relat Res. 1993; 287:237-244.] A wider and contoured cuff has more contact with the limb's surface area and disperses the cuff's force. This concept is emerging from the surgical field into the emergency field with wider emergency tourniquets.
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tourniquet — [ turnikɛ ] n. m. • 1669; t. de fortif. 1575; de tourner 1 ♦ Appareil formé d une croix tournant autour d un pivot, placé à l entrée d un chemin ou d un édifice afin de livrer passage aux personnes chacune à son tour. Passer dans un tourniquet.… … Encyclopédie Universelle
Tourniquet — «Tourniquet» Сингл Marilyn Manson из альбома Antichrist Superstar Выпущен … Википедия
tourniquet — Tourniquet. s. m. Machine composée de deux pieces de bois ou de fer croisées, qui tourne sur un pivot, qu on met devant des portes ou des barrieres, pour empescher qu il n y puisse passer plus d un homme à la fois. Il faut passer par le… … Dictionnaire de l'Académie française
Tourniquet — (franz., spr. turnikä, Turnikett, Aderpresse), chirurg. Instrument zum Zusammenpressen von Arterien, um Verblutung bei Verletzungen, bei Operationen u. zu verhüten. Dasselbe besteht (s. Abbildung) in einem Polster (Pelotte), das oberhalb der… … Meyers Großes Konversations-Lexikon
tourniquet — 1690s, from Fr. tourniquet surgical tourniquet, also turnstile, dim. of torner to turn, from O.Fr. tourner, torner (see TURN (Cf. turn)) … Etymology dictionary
Tourniquet — [turnike̱; aus gleichbed. frz. tourniquet] s; s, s: Aderpresse, schlingenförmiges Instrument zum Abklemmen von Blutgefäßen … Das Wörterbuch medizinischer Fachausdrücke
Tourniquet — Tour ni*quet, n. [F., fr. tourner to turn.] (Surg.) An instrument for arresting hemorrhage. It consists essentially of a pad or compress upon which pressure is made by a band which is tightened by a screw or other means. [1913 Webster] … The Collaborative International Dictionary of English
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Tourniquet — (frz., spr. turnikeh), Aderpresse, durch einen Gurt befestigtes Polster zum Zusammenpressen von Arterien, um bei Amputationen Blutung zu verhüten; meist ersetzt durch die künstliche Blutleere (s. Amputation); auch s.v.w. Drehgefach (s.d. nebst… … Kleines Konversations-Lexikon