Tourniquet
bleeding or uncontrolled hemorrhage.
Severe bleeding means: the 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 a few minutes.
Risks of a tourniquet
As the tourniquet stops the perfusion of the limb, the resulting anoxia causes the death of the limb and can lead to the amputation of the limb just below the level the tourniquet is applied. This usually happens when the tourniquet stays in place several hours, which is not likely to happen in a city of a country which has an efficient pre-hospital medical service (the rescue team arrives few minutes after the call). However, this situation must be kept in mind, especially in case of an accident in wilderness. This is "losing a limb to save a life" and is a decision that should be made by a paramedic or preferably a doctor if at all possible. But when the bleeding cannot be controlled by any other mean (direct pressure or distant pressure point), it is the only way to save the casualty.
Some first aid instruction no longer teaches the use of the tourniquet because of the consequences.
When to use a tourniquet
A tourniquet should be applied:
- when the other methods were tried and were not efficient, or
- when you are holding a pressure point and must leave, either to call for help (you are the only bystander and have no cell phone) or to deal with other casualties.
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.
Even in cases of amputation, most bleeding can be controlled through direct pressure, elevation (above the heart) and the use of pressure points. The rare exception is when a limb is shattered by massive trauma or a major blood vessel is torn along its length. Even in these cases, the use of a distant pressure point, or of an hemostat, to clamp the vessel above the tear is strongly preferred.
How to make a tourniquet
To properly apply a tourniquet, a strap, preferably a large and non-elastic strap such as a necktie or a scarf, is tightened around the limb, between the wound and the heart:
- for an arm wound: above the elbow;
- for a leg wound: above the knee.
(The forearm and the calf have two bones; the artery can slide between these bones, and the tourniquet will be inefficient). This usually performed with a 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 a few tens of minutes, toxins are likely to have built up in the dead tissue below the tourniquet (rhabdomyolysis).
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).
In wilderness first aid, it is imperative that any person with a tourniquet be evacuated to advanced medical care as soon as reasonably possible; 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.
