A tourniquet should be applied to a wound only by trained medical personnel, because if applied too long this may cut off all the blood supply to the area and lead to gangrene. Also, do not give the casualty food or drink, which might delay surgery. Advise the casualty to keep still, because this encourages the formation of clots; sudden movements may dislodge these so that bleeding starts again.

Internal bleeding

It is important to try and recognize the symptoms of internal bleeding, but any casualty who has suffered severe injuries should be suspected of having internal bleeding. Their skin may feel cold and clammy and the pulse may be weak but rapid. They may feel faint or have symptoms of shock. When internal bleeding is associated with a fracture, there may be swelling and tenderness. First aid treatment is to get the casualty to rest, to try to reduce bleeding, and to

Severe bleeding, in which one litre of blood or more is lost may be life-threatening, because there are only five litres or so of blood in the adult body, and much less in children. External bleeding, in which blood escapes from the body, is usually obvious; but internal bleeding, when blood escapes from the circulation but not from the body, is more difficult to detect. Depending on which kind of blood vessel is injured bleeding may be: . arterial (bright red in colour, fast-flowing and sometimes spurting out in rhythm with the heartbeat) . venous (darker red in colour, and if a large enough vessel has been injured, welling up continuously from the wound) . capillary (blood oozes from the wound, as in minor cuts) Clotting

If the blood did not clot, a person would die from even the smallest wound. In this process platelets collect in the blood vessel that has been injured. This causes chemicals to be released that react with clotting factors in plasma to form, in a complicated chain reaction, long threads of fibrin. The fibrin threads seal the site of the wound by criss-crossing each other to create a type of net that holds platelets and blood cells together, and squeazes liquid out of the area. A solid plug is thus formed that prevents the escape of further blood. This is, however, only a temporary measure; the platelets continue to arrive at the side and secrete chemicals until a true clot is established.

External bleeding

Minor cuts and grazes can be cleaned and dressed at home, but someone who has a deep cut or who has lost a lot of blood should be sent to hospital: blood replacement by transfusion may be necessary. Severe bleeding may distract you in an emergency, so always check first that the casualty is breathing and that the heart is still beating. When assessing the amount of blood lost it helps to picture a ‘spilt’ amount of another fluid, such as from a bottle of milk. Even if the casualty is conscious, it is better to treat him or her lying down, because this conserves the blood in the area of the major organs, especially the brain. If the bleeding is from a limb, this should be raised, but do not attempt this if you think the limb might be fractured. When treating the wound, use a clean gauze dressing and apply pressure to the wound to stop the bleeding, pressing the edges together in the case of a cut. If a clean dressing is not immediately available, use your hands initially and improvize a dressing out of any clean material. If blood seeps through, put further dressings on top, secured in place, but not too tightly, with a bandage. If bleeding from a limb persists in spite of these measures, try applying indirect pressure over the specific pressure points.

Arrange for him or her to reach hospital as soon as possible.

Internal bleeding may be indicated if the injured person vomits or coughs up blood. Brown blood resembling coffee grounds is partly digested and probably results from a bleeding stomach ulcer. Red foamy blood results from injuries to the lungs, possibly fractured ribs. Casualties with chest or lung injuries should be transferred to hospital in a sitting position, leaning over towards the injured side, so that the uninjured lung does not start to collect blood too.


These are commonly caused by a knock to the nose or blowing it over-vigorously. Someone with a nosebleed should be advised to sit forward, breathing through the mouth and pinching the nostrils together firmly between the fingers for at least ten minutes. At the end of that time, pressure on the nose should be slowly released; if bleeding continues, the nose should be held pinched for another ten minutes. When bleeding has stopped, the person should be advised not to blow his or her nose for several hours and not to strain or stoop because this may cause bleeding to start again. If the nosebleed does not cease after two or three attempts at stopping it, consult a doctor.