Tourniquet
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A tourniquet is a tightly tied band applied around a body part (an arm or a leg) in an attempt to stop severe traumatic bleeding. Severe bleeding means the loss of more than 1,000 ml (1 liter) of blood. This flow of blood can soak a paper or cloth hankerchief in a few seconds. In such a situation, the bleeding will cause the death of the casualty in seconds to minutes.
Other methods that should be applied first and in conjunction, if possible, include:
- direct pressure
- elevation of the limb or wound above the heart
- the use of a pressure point to slow the artery above the injury
- blood-clotting agents or bandages
Even in cases of amputation, most bleeding can be controlled through these alternative methods. The rare exception is when a limb is shattered by massive trauma or when a major blood vessel is torn along its length. Even in these cases, the use of a pressure point above the wound (i.e. proximal to the wound), or application by a doctor of an hemostat, to clamp the blood vessel above the tear is strongly preferred.
The use of tourniquets is taught to emergency medical technicians including combat lifesavers, and as a part of military first aid in basic training. It is also part of the French basic first aid courses (for bystanders).
A tourniquet is a last resort method of bleeding control.
Tourniquets are also used during some orthopedic surgeries to allow the surgeon to work in a bloodless field. When used this way the duration of application and pressure of the tourniquet are carefully monitored. Under these well controlled conditions complications from the tourniquet are rare.
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Risks of a tourniquet
As the tourniquet stops the perfusion of the limb, the resulting anoxia can cause the death of the limb, forcing the later surgical amputation of the limb just below the level the tourniquet is applied. This is likely to occur when the tourniquet stays in place several hours. In any event, once a tourniquet has been applied, advanced medical care from a doctor or hospital will be required to salvage the limb if not save the life of the patient.
The status of the tourniquet varies widely according to the country. This situation can be illustrated by the opposite philosophies applied in the United States and in France.
In any case, the first aider/rescue should act according to the local conditions (laws, rescue organisation and philosophy).
In the United States
The decision to employ a tourniquet should be made by a paramedic or preferably a doctor if at all possible. But when severe external bleeding cannot be controlled by other means, a tourniquet may be the only way for a first-aider to save the casualty. (A medical professional would use a hemostat or resort to field surgery.)
The first aid instruction no longer teaches the use of the tourniquet for the following reasons:
- the effectiveness of direct pressure, elevation and pressure points (controlling severe bleeding in up to 90% of cases as estimated by US medical sources)
- the vastly increased difficulty of reattaching an amputated limb when a tourniquet has been applied to the victim
- unnecessary use by poorly trained bystanders
- the unavoidable risks to both limb and life even when properly employed
- the rare nature of injuries that require tourniquets, which typically occur in unusual settings such as working with agricultural or industrial machinery and the battlefield
The use of a tourniquet by a layperson in countries where it is considered outside the scope of practice of first aid may result in civil lawsuits and/or criminal charges, especially if the application was later found to have been unnecessary.
In France
In France, the tourniquet is taught to the general public, in the first level of first aid course (Attestation de formation aux premiers secours, 10 hours without any prerequisite). The French emergency medical service (Samu) considers that the rhabdomyolysis (destruction of the muscle cells due to the anoxia) is not likely to endanger the limb before six hours, i.e. the casualty receives advanced medical cares by a physician (either a medical prehospital team or at the emergency room of a hospital) long before the risk occurs.
The act is thus considered as proportional to the risk (death by blood loss), and the first aider/rescuer is not likely to be condemened in case the limb is lost (although the legal risk is not totally absent): this loss would be attributed to the wound and not to the saving act. Especially, the tourniquet is considered as an alternative to avoid infection by contact with the blood of the casualty when the first aider has no protecting device (e.g. plastic bag, piece of cloth etc.).
When to use a tourniquet
A tourniquet should be applied only when other methods were tried and failed to stop life-threatening bleeding.
A tourniquet could be used if a single first-aider is holding a pressure point and is forced by exigent circumstances to abandon the casualty to save lives (for example, to call for help or perform triage). However, this practice is not sanctioned in some countries, including the United States.
Tourniquets are not used to treat snakebite; a constrictive band intended to slow the spread of poison through the lymphatic system in a snakebite victim should be fairly loose compared to a tourniquet.
How to make a tourniquet
To properly apply a tourniquet, a strap, preferably a large and non-elastic strap such as a necktie, belt, sling or scarf, is tightened around the limb, between the wound and the heart. Rubber tubing is more difficult to tighten properly and generally should only be used by paramedics or medical teams.
If a suitable strap is not available, any improvised material long enough can be used. This is particularly important in the case of a severed femoral artery. Life-saving tourniquets have been fashioned from fabric, duct tape, elastic, rope, string, twine, and even wire. The less suitable the material, the more likely that amputation will later result.
If at all possible, apply the tourniquet as low as possible above the injury. If later amputation is required, the placement of the tourniquet will demarcate the line of amputation, which can unnecessarily cripple a person by depriving them of a joint (knee or elbow) which could have been otherwise saved.
French sources recommend that a tourniquet be applied above the elbow for an arm wound and above the knee for a leg wound. This is said to be because the forearm and the calf have two bones; the artery can slide between these bones, and the tourniquet will be inefficient.
The tourniquet is usually tied with a slipknot. You can also wrap the strap around the limb and tie tightly; a stick is wound underneath the tubing and twisted until the strap is tightened so that the bleeding is stopped, the stick is tied in its present position with additional tubing or bandages. The name "tourniquet" is derived from this stick, which means "turning stand" in French.
A tourniquet must not be tightened more tightly than is required to stop the bleeding. This is to minimize the tissue damage inflicted by the tourniquet. If a tourniquet is used, immediately mark the letter "T" on the victim's forehead with a marker, pen, or dirt; if possible write the date and 24-hour time the tourniquet was applied (example: "8/7 2215"). When transferring the patient to another person's care, be certain that receiving medical personnel know that a tourniquet has been applied. This is imperative to identify the patient for priority medical care which may save limb or life.
Once a tourniquet is done
Never loosen a tourniquet in the field: while the tourniquet maintaints the blood in the rest of the body, the limb is poorly oxygenated (anoxia), so the muscles controlling the blood vessels are relaxed (vasodilatation). If the tourniquet is released, the blood will flow through these wide opened vessels; the blood pressure will drop, causing an hypovolemic shock, or worse making the cardiac pumping inefficient.
Additionally, after several minutes, toxins will begin to build up in the dead tissue below the tourniquet (rhabdomyolysis). These toxins can swiftly kill if introduced into the body's bloodstream. Some sources have in the past recommended periodic loosening of a tourniquet (no less often than every eight to ten minutes) in the attempt to prevent this build-up. However, the risks of this procedure include reopening the life-threatening wound as well as accumulated toxins in the blood, and it is best left to battlefield medical providers and medical professionals.
In wilderness first aid, it is imperative that any person with a tourniquet be evacuated to advanced medical care as soon as reasonably possible. Immediate MEDEVAC is indicated if the limb is to be salvaged. If the limb is lost, MEDEVAC is indicated if transport will be delayed more than twenty-four hours.
In triage, a person with a tourniquet should be considered "I" for immediate in the START protocol and at least "Yellow" or higher in other protocols.fr:garrot pt:Garrote