TOURNIQUET

If used at the wrong time and by inexperienced hands, a tourniquet can do more harms than good. But it can halt severe blood loss from a limb in an emergency

A tourniquet is essentially a bandage which, when placed around a limb and tightened, cuts off the blood supply to part of the limb beyond it. It does this by arteries. Its use in medicine goes back for thousands of years, but it is probably true to say that it is not employed as much today as it was even 50 years ago.

It has two main purposes. First, in an emergency it can be used to stop major bleeding from a limb. Second, it can be used during operations providing a blood-free area for the surgeon to work on.

The correct application of a tourniquet can, in some circumstances, be life saving, but it should be stressed that incorrect use can lead to a worsening of the situation, and even to permanent damage to the limb. Normally, it is best to stop bleeding from a limb with firm pressure over the bleeding area.

DANGERS

A tourniquet can possibly be dangerous in several ways. For instance, if it is applied too tightly or round part of the limb insufficiently covered with muscle, this could lead to nerves being damaged. Also, leaving the tourniquet on for too long may cause serious damage and ultimately tissues can die because they are deprived of blood.

Also, paradoxically, if the tourniquet is not tight enough, there may be an increase in the amount of bleeding. What happens here is that if the tourniquet is tight enough to block the veins, where blood is at a very low pressure, but not tight enough to block the arteries, where blood is at high pressure the blood is still able get into the limb, along the arteries but cannot return via the veins. If there is a cut is a large vein the bleeding will increase, owing to the increase in pressure in the veins from blood that cannot return.

Finally, during the period a tourniquet is in place, the blood vessels can increase in diameter in a response to the lack of oxygenated blood in the limb. On release of the tourniquet, these vessels can bleed freely, actually giving worse bleeding than before.

Because of all these dangers a tourniquet should not be used to control bleeding should not be used to control bleeding unless it is absolutely essential.

USE OF TOURNIQUETS

Before taking the drastic measure of applying a tourniquet, there are certain things that can be tried to stop the bleeding. The first thing to do is to elevate the limb. This cause the blood to be pumped against the force of gravity, and if the bleeding is at the end of the limb is may stop at once. Second, firm pressure on the bleeding area may stop the bleeding. In an emergency, a clean handkerchief or a towel will quite suitable.

If you are faced with bleeding you must keep up the pressure for at least five minutes. Only if this and elevation of the limb fail to stop or keep the bleeding to a reasonable level should the use of tourniquet be considered. Tourniquets can be mad and used in the following way. A bandage or a handkerchief or scarf is tied loosely around the limb, over a muscular part, and then tightened. The tourniquet should feel really quite tight, and there should be an obvious lessening in the amount of bleeding within about half a minute.

If the patient cannot be taken to a hospital straightaway, the tourniquet should be released completely every 20 minutes or so, to prevent damage to the limb caused by blood starvation.

TOURNIQUETS IN SURGERY

Tourniquets are also used in planned operations to enable the surgeon to operate without blood interfering with what he is doing. Typically tourniquets are used during operations on joints, such as cartilage and tendon operations.

The limb is emptied of blood by winding a special rubber bandage tightly around the limb from the end of the limb, towards the body, gradually squeezing out the blood without losing any. Then a special tourniquets is placed around the upper part of the limb. The tourniquet consists of a hollow rubber tube which can be inflated to the desired pressure with a pump. The rubber bandage is removed and the operation is then performed.