Blood Loss
Blood Loss
Blood carries oxygen from the lungs to the tissues around the body, and then takes waste carbon dioxide back to the lungs for expiration.
The amount of blood in the body depends on the size of the person; roughly 500ml for every 7kg in weight. For a child, blood loss of just 200ml can be life threatening.
When the body looses blood it tries to compensate by making some changes. Blood flow is directed to major organs and away from peripheries like the skin. The heart beats faster to maintain blood pressure.
Anyone losing more than 10% of their blood will need to be treated for shock; the body cannot compensate blood loss greater than one-third so immediate action is required for someone suffering heavy bleeding.
As blood loss increases, levels of consciousness will begin to drop and cyanosis (blue tinges to lips and skin) may be present. Breathing and pulse will be rapid. At 40% blood loss, the casualty will be unresponsive with severe cyanosis and cold and clammy skin, at this point the situation will be life threatening.
Types of bleeding
Arterial
Bleeding from the arteries becomes life threatening very quickly. The blood will spurt and looks bright red as it contains oxygen.
Venous
Blood will flow from a vein like a thick liquid. The colour will be a dark red as it is no longer carrying oxygen.
Capillary
Bleeding from the capillaries, which happens in all wounds, is more easily controlled as blood usually trickles from the wound.
