Bleeding is the loss of blood from the body. Children are put more in danger by bleeding as they have less blood to lose. The average adult human will be in medical danger after 2 liters (2 quarts) and could die of hypovolemic shock if more blood is lost.
There are four types of bleedings:
- minor traumatic bleedings: these are little and superficial wounds; the loss of blood is nat dangerous and the bleeding will stop spontaneously; the main risk is the infection;
- severe traumatic bleeding: 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;
- externalised bleeding: the blood flow through a natural orifice, such as the nose, the ears, the mouth (spitting and vomitting blood), the vagina (except for the natural mensturation), the uretra and the anus; the blood come from the interior of the body and reveals a hidden trauma or a disease;
- internal bleeding: the blood flows inside the body; it cannot be seen, but can be suspected by shock symptoms.
First aid
Severe traumatic bleeding
A major technique of first aid is to control bleeding through direct pressure with the hand (possibly protected by a plastic bag, a glove or a piece of stuff); it can be replaced when necessary by the application of a bandage over the wound.
When the direct pressure is not possible (e.g. there is a foreign body inside the wound, or a broken bone comes outside, or the wound is too large for the hand), then it is possible to compress the artery against a bone, between the wound and the heart (see Pressure point).
In extreme cases of an injured limb, a tourniquet may be used. If the medical care are delayd (after a few hours), the injured limb must generally be amputated afterwards, just below the level the tourniquet is applied; this is "losing a limb to save a life". This risk is very low in the urban environment of a developped country (the delay before a rescue team arrives is a few minutes after the call), but must be taken into account in wilderness or in countries that do not have organised prehospital medical services. Some first aid instruction no longer teaches the use of the tourniquet because the risk may be greater than the benefit; some other consider that saving a life is above the rest.
Externalised bleeding
The only minor situation is a spontaneous nose bleeding, or a nose bleeding caused by a slight trauma (such as a child putting his finger in the nose). Just sit down, blow through the bleeding nostril to evcuate the forming clot, and press the nostrilm with a finger, the head bowed downwards, during ten minutes. Consult a doctor when the bleeding does not stop or starts again.
Any other situation must be considered as an emergency: place the person in a comfortable situation (lying or seated), call for help and follow the instructions.
Internal bleeding
This will appear like a feeling of sickness; the interior of the lips are white, the person is thirsty (do not give anything to drink!); the pulse is fast (120 or more) and difficult to feel.
These symptoms are not specific to an internal bleeding, but are always a medical emergency. Lay the person down, and call for help.
Risk of blood contamination
Concerning the direct exposure of the first-aider's skin to the blood: the skin is watertight, so if the skin is not wounded (skin disease or very recent wound), there is no risk of contamination by a disease of the casualty. Before any further activity (especially eating, drinking, touching the eyes, the mouth or the nose), the hand must be carefully and softly washed with clear water, then bathed five minutes in diluted bleach (sodium hypochlorite).
However, to avoid any risk, it is highly recommended to protect the hands, e.g. by a plastic bag or a cloth, before pressing the wound. If there is nothing to protect the hands (well an accident might happen happen on a nude beach), watch your hand to be sure they are not wounded, or use a distant compression of the artery (pressure point with your hand if you know the anatomic references, or a tourniquet).
In case of blood exposure, even on safe skin, the first-aider should go to the emergency service, where an anti-retroviral therapy will be started just in case.
Medical care
Blood lost by bleeding can be replaced by blood transfusion. The human body also generates blood at a rate of about 2 quarts (2 liters) per week.
The practise of causing bleeding intentionally to remove excess or "bad" blood from a person's body is called bloodletting or phlebotomy.