Emergency tourniquet

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Improvised tourniquet on an accidentally severed finger Improvised tourniquet.jpg
Improvised tourniquet on an accidentally severed finger

Emergency tourniquets are cuff-like devices designed to stop severe traumatic bleeding before or during transport to a care facility. They are wrapped around the limb, proximal to the site of trauma, and tightened until all blood vessels underneath are occluded. The design and construction of emergency tourniquets allows quick application by first aid responders or the injured persons themselves. [1] Correct use of tourniquet devices has been shown to save lives under austere conditions with comparatively low risk of injury. In field trials, prompt application of emergency tourniquets before the patient goes into shock are associated with higher survival rates than any other scenario where tourniquets were used later or not at all. [2] [3]

Contents

Tourniquet design

Emergency Tourniquet Devices
Tourniquet.jpeg
Windlass tourniquet
EMT Emergency & Military Tourniquet.jpg
Pneumatic tourniquet

Existing guidelines call for the use of improvised "rope-and-stick" tourniquets as a last resort to stop severe bleeding. However, purpose-made tourniquet devices that are well designed can provide greatly increased safety and efficacy. [2] [4] Variability in performance has been shown to exist between various designs and application methods. [5] [6]

Mechanical advantage

Mechanisms that confer sufficient mechanical advantage are essential for applying adequate pressure to stop bleeding, particularly on the lower extremities. Pressures that occlude venous but not arterial flow can exacerbate hemorrhage and cause damage to healthy tissue. [1]

Mechanical characteristics of emergency tourniquet devices

TourniquetStrap width (cm) [1] Mechanism [1] Note [1]
SAM XT Tourniquet3.7 Windlass and Buckle Buckle sets with correct force; windlass finishes pressure
Combat Application Tourniquet (CAT)3.8 Windlass Stick and strap inside outer sleeve
Emergency & Military Tourniquet (EMT)9.1 Pneumatic Hand pump and inflatable bladder
K2 Tactical Tourniquet (K2)3.8 Clamp Modified wood clamp
Smart Tactical Application Tourniquet (S.T.A.T.)2.5 Ratchet Strap with ratcheting mechanism
Last Resort Tourniquet (LRT)5.1 Ratchet Strap with ratcheting mechanism
London Bridge Tourniquet (LBT)2.4 Ratchet Strap with ratcheting mechanism
Mechanical Advantage Tourniquet (MAT)3.8 Block and tackle Pulleys on outer frame
One-Handed Tourniquet (OHT)2.8ElasticParallel bungee cords and clamp
Self-Applied Tourniquet System (SATS)3.8 cam Cantilever system
Special Operations Forces Tactical Tourniquet (SOFTT)3.7 Windlass Stick and strap
Glia tourniquetVariable Windlass Stick and strap

Most commercial tourniquets cost in the range from $30-$50 (USD). Results from laboratory and field testing suggest that windlass and pneumatic mechanisms are effective where other systems fail due to excessive pain, slipping, inadequate force, or mechanical failure. [1]

Pressure gradients

Pressure underneath a tourniquet cuff is not evenly distributed, with the highest pressures localized around the cuff center line and decreasing to zero near the cuff edges. [7] A high rate of change of pressure across the cuff width, or a high cuff pressure gradient, is a leading cause of nerve and muscle injury from tourniquet use. [7] Tourniquets with wider straps or cuffs, especially those with pneumatic actuation in contrast to mechanical force, distribute pressure more evenly and produce lower pressure gradients. [7] They are therefore more likely to stop bleeding and less likely to cause damage to underlying tissue, in addition to being significantly less painful than tourniquets with narrow straps and bands. [4] [8] Over pressure protection in certain emergency tourniquets also help to prevent excessive force from damaging the limb. [1]

Risks

Emergency tourniquet being applied in simulated combat. Military devices are designed for rugged environments. Tourniquet application.jpg
Emergency tourniquet being applied in simulated combat. Military devices are designed for rugged environments.

Possible risks of complications—morbidity—related to emergency tourniquet use include

Emergency care services implementing routine tourniquet use, especially in the civilian setting, should exercise caution and ensure that training is adequate for optimal results. [3] However, given proper precautions, the occurrence of complications due to tourniquet use is quite rare. [9] Designed tourniquet devices are routinely tightened over healthy limbs during training with no ill effects, and recent evidence from combat hospitals in Iraq suggests that morbidity rates are low when users adhere to standard best practices. Since no better alternatives exist for users to self-apply with only basic training, the benefit of tourniquet use far outweighs the risks. [2] [3] [9]

Safe tourniquet practice involves:

1. Careful placement of tourniquet proximal to all sites of hemorrhage.

2. Limiting tourniquet time to less than two hours, if possible.

3. Minimizing excessive applied pressure beyond the point of complete blood flow cessation. [2] [9]

Current developments

Tourniquet application on the lower arm during training. Device user knowledge greatly increases survival rate and minimizes complications. US Navy 100505-N-8377A-039 Quartermaster 2nd Class Caleb Murray works with two members of the Royal Brunei Navy Support Squadron, demonstrating the proper use of a tourniquet.jpg
Tourniquet application on the lower arm during training. Device user knowledge greatly increases survival rate and minimizes complications.

Field experience

Latest field trials suggest that wider straps are more effective and less painful than tourniquets with thinner straps. The concept of limb occlusion pressure is also gaining prominence over the misconception that greater applied force results in greater effectiveness. In addition, studies of failed cases indicate that the correct devices should be coupled with training that facilitates realistic expectations and correct user actions. [4] The Stop The Bleed educational initiative provides knowledge aimed at the greater public on when to use a tourniquet and the correct user actions. [10]

Emerging needs

Despite the success of widespread tourniquet deployment to limit combat casualties, many preventable deaths from hemorrhage occur where conventional tourniquet use is inappropriate. The need exists for controlling junctional bleeding, especially in the pelvic area. [11] In 2012, the Combat Ready Clamp (CRoC) was selected by the U.S. Army Institute of Surgical Research (USAISR) for that purpose. [12] Another emerging need is more refined training regimes and doctrine based on scientific evidence, which can ensure that future tourniquet practice and policies are in line with the most current body of knowledge. [11]

See also

Related Research Articles

<span class="mw-page-title-main">Bleeding</span> Loss of blood escaping from the circulatory system

Bleeding, hemorrhage, haemorrhage or blood loss is blood escaping from the circulatory system from damaged blood vessels. Bleeding can occur internally, or externally either through a natural opening such as the mouth, nose, ear, urethra, vagina or anus, or through a puncture in the skin. Hypovolemia is a massive decrease in blood volume, and death by excessive loss of blood is referred to as exsanguination. Typically, a healthy person can endure a loss of 10–15% of the total blood volume without serious medical difficulties. The stopping or controlling of bleeding is called hemostasis and is an important part of both first aid and surgery.

Bleeding time is a medical test done on someone to assess their platelets function. It involves making a patient bleed, then timing how long it takes for them to stop bleeding using a stopwatch or other suitable devices.

<span class="mw-page-title-main">Compartment syndrome</span> Condition in which increased pressure results in insufficient blood supply

Compartment syndrome is a condition in which increased pressure within one of the body's anatomical compartments results in insufficient blood supply to tissue within that space. There are two main types: acute and chronic. Compartments of the leg or arm are most commonly involved.

<span class="mw-page-title-main">Battlefield medicine</span> Treatment of wounded combatants and non-combatants in or near an area of combat

Battlefield medicine, also called field surgery and later combat casualty care, is the treatment of wounded combatants and non-combatants in or near an area of combat. Civilian medicine has been greatly advanced by procedures that were first developed to treat the wounds inflicted during combat. With the advent of advanced procedures and medical technology, even polytrauma can be survivable in modern wars. Battlefield medicine is a category of military medicine.

<span class="mw-page-title-main">Thrombolysis</span> Breakdown (lysis) of blood clots formed in blood vessels, using medication

Thrombolysis, also called fibrinolytic therapy, is the breakdown (lysis) of blood clots formed in blood vessels, using medication. It is used in ST elevation myocardial infarction, stroke, and in cases of severe venous thromboembolism.

<span class="mw-page-title-main">Internal bleeding</span> Medical condition

Internal bleeding is a loss of blood from a blood vessel that collects inside the body, and is not usually visible from the outside. It can be a serious medical emergency but the extent of severity depends on bleeding rate and location of the bleeding. Severe internal bleeding into the chest, abdomen, pelvis, or thighs can cause hemorrhagic shock or death if proper medical treatment is not received quickly. Internal bleeding is a medical emergency and should be treated immediately by medical professionals.

<span class="mw-page-title-main">Major trauma</span> Injury that could cause prolonged disability or death

Major trauma is any injury that has the potential to cause prolonged disability or death. There are many causes of major trauma, blunt and penetrating, including falls, motor vehicle collisions, stabbing wounds, and gunshot wounds. Depending on the severity of injury, quickness of management, and transportation to an appropriate medical facility may be necessary to prevent loss of life or limb. The initial assessment is critical, and involves a physical evaluation and also may include the use of imaging tools to determine the types of injuries accurately and to formulate a course of treatment.

<span class="mw-page-title-main">Spinal board</span> Device used in pre-hospital trauma care

A spinal board, is a patient handling device used primarily in pre-hospital trauma care. It is designed to provide rigid support during movement of a person with suspected spinal or limb injuries. They are most commonly used by ambulance staff, as well as lifeguards and ski patrollers. Historically, backboards were also used in an attempt to "improve the posture" of young people, especially girls.

<span class="mw-page-title-main">Intracerebral hemorrhage</span> Type of intracranial bleeding that occurs within the brain tissue itself

Intracerebral hemorrhage (ICH), also known as hemorrhagic stroke, is a sudden bleeding into the tissues of the brain, into its ventricles, or into both. An ICH is a type of bleeding within the skull and one kind of stroke. Symptoms can vary dramatically depending on the severity, acuity, and location (anatomically) but can include headache, one-sided weakness, numbness, tingling, or paralysis, speech problems, vision or hearing problems, memory loss, attention problems, coordination problems, balance problems, dizziness or lightheadedness or vertigo, nausea/vomiting, seizures, decreased level of consciousness or total loss of consciousness, neck stiffness, and fever.

A traction splint most commonly refers to a splinting device that uses straps attaching over the pelvis or hip as an anchor, a metal rod(s) to mimic normal bone stability and limb length, and a mechanical device to apply traction to the limb.

<span class="mw-page-title-main">Pelvic fracture</span> Broken bone in nonacetabular portions of pelvis

A pelvic fracture is a break of the bony structure of the pelvis. This includes any break of the sacrum, hip bones, or tailbone. Symptoms include pain, particularly with movement. Complications may include internal bleeding, injury to the bladder, or vaginal trauma.

<span class="mw-page-title-main">Tourniquet</span> Medical device

A tourniquet is a device that is used to apply pressure to a limb or extremity in order to stop the flow of blood. It may be used in emergencies, in surgery, or in post-operative rehabilitation.

<span class="mw-page-title-main">Emergency bleeding control</span> Procedures to rapidly limit dangerous levels of bleeding

Emergency bleeding control describes actions that control bleeding from a patient who has suffered a traumatic injury or who has a medical condition that has caused bleeding. Many bleeding control techniques are taught as part of first aid throughout the world, though some more advanced techniques such as tourniquets, are often taught as being reserved for use by health professionals, or as an absolute last resort, to mitigate associated risks, such as potential loss of limbs. To manage bleeding effectively, it is important to be able to readily identify types of wounds and types of bleeding.

<span class="mw-page-title-main">Equipment of an American combat medic</span>

Combat medics of the United States military may put themselves at greater risk than many other roles on the battlefield. In recent conflicts, the enemies faced by a professional army may not have respect for the laws of war and may actively target combat medics for the significant value they have in keeping the unit combat-effective. Since the non-combatant status granted to medics may not always be respected, modern combat medics carry weapons for personal defense and in most Western armies are virtually indistinguishable from regular infantrymen.

<span class="mw-page-title-main">Intravenous regional anesthesia</span>

Intravenous regional anesthesia (IVRA) or Bier's block anesthesia is an anesthetic technique on the body's extremities where a local anesthetic is injected intravenously and isolated from circulation in a target area. The technique usually involves exsanguination of the target region, which forces blood out of the extremity, followed by the application of pneumatic tourniquets to safely stop blood flow. The anesthetic agent is intravenously introduced into the limb and allowed to diffuse into the surrounding tissue while tourniquets retain the agent within the desired area.

<span class="mw-page-title-main">QuikClot</span> Medical dressing applied to stop bleeding

QuikClot is a brand of hemostatic wound dressing that contains an agent that promotes blood clotting. The brand is owned by Teleflex. It is primarily used by militaries and law enforcement to treat hemorrhaging from trauma.

<span class="mw-page-title-main">Tactical Combat Casualty Care</span> United States military guidelines for prehospital trauma care

Tactical Combat Casualty Care are the United States military guidelines for trauma life support in prehospital combat medicine, designed to reduce preventable deaths while maintaining operation success. The TCCC guidelines are routinely updated and published by the Committee on Tactical Combat Casualty Care (CoTCCC), which is part of the Defense Committees on Trauma (DCoT) division of the Defense Health Agency (DHA). TCCC was designed in the 1990s for the Special Operations Command medical community. Originally a joint Naval Special Warfare Command and Special Operations Medical Research & Development initiative, CoTCCC developed combat-appropriate and evidence-based trauma care based on injury patterns of previous conflicts. The original TCCC corpus was published in a Military Medicine supplement in 1996. TCCC has since become a Department of Defense (DoD) course, conducted by National Association of Emergency Medical Technicians.

Endovascular and hybrid trauma and bleeding management is a new and rapidly evolving concept within medical healthcare and endovascular resuscitation. It involves early multidisciplinary evaluation and management of hemodynamically unstable patients with traumatic injuries as well as being a bridge to definitive treatment. It has recently been shown that the EVTM concept may also be applied to non-traumatic hemodynamically unstable patients.

<span class="mw-page-title-main">Resuscitative endovascular balloon occlusion of the aorta</span> Temporary procedure to support blood pressure and stem blood loss

Resuscitative endovascular balloon occlusion of the aorta (REBOA) is a minimally invasive procedure performed during resuscitation of critically injured trauma patients. Originally developed as a less invasive alternative to emergency thoracotomy with aortic cross clamping, REBOA is performed to gain rapid control of non-compressible truncal or junctional hemorrhage. REBOA is performed first by achieving access to the common femoral artery (CFA) and advancing a catheter within the aorta. Upon successful catheter placement, an occluding balloon may be inflated either within the descending thoracic aorta (Zone 1) or infrarenal abdominal aorta (Zone 3). REBOA stanches downstream hemorrhage and improves cardiac index, cerebral perfusion, and coronary perfusion. Although REBOA does not eliminate the need for definitive hemorrhage control, it may serve as a temporizing measure during initial resuscitation. Despite the benefits of REBOA, there are significant local and systemic ischemic risks. Establishing standardized REBOA procedural indications and mitigating the risk of ischemic injury are topics of ongoing investigation. Although this technique has been successfully deployed in adult patients, it has not yet been studied in children.

<span class="mw-page-title-main">Pelvic binder</span> Device used to compress the pelvis

A pelvic binder is a device used to compress the pelvis in people with a pelvic fracture in an effort to stop bleeding.

References

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  12. "New truncal tourniquet ready for battle use".