Bleeding is the escape of blood from blood vessels. It takes place when there is a break in arteries, veins, or capillaries (tiny blood vessels). Breaks may be caused by injury or by tissue damage resulting from cancer, an ulcer, or infections.
Kinds of bleeding.
Blood from an artery spurts from a wound due to the great pressure it is under. Bleeding from a vein, where there is less pressure, flows steadily. Blood from capillaries leaks out slowly.
Bleeding may be external, on the outside of the body, or internal, on the inside. When the skin breaks and bleeds it is called a laceration. In an injury that does not break the skin, blood seeps from injured blood vessels into the surrounding flesh, forming a bruise. Internal bleeding is caused by disease or injury and may occur slowly or rapidly. Severe bleeding is called a hemorrhage, and may occur internally or externally.
Effects of bleeding.
Minor bleeding from cuts or bruises normally does not cause a problem. However, when a loss of blood occurs that is greater than the amount of new blood produced by the bone marrow, a weakened condition called anemia develops. Bleeding within the skull produces pressure on the brain that can injure brain tissue, sometimes resulting in loss of brain function. In some circumstances, bleeding into other internal organs may cause organ damage or failure.
The sudden loss of a large quantity of blood causes a drop in blood pressure, resulting in a dangerous condition called shock. Shock may be the only apparent symptom of internal hemorrhaging. Too great a loss of blood will result in death.
How bleeding is stopped.
Bleeding is usually controlled by the formation of a clot within a broken blood vessel. The clot seals the vessel and prevents the flow of blood. A clot on the skin surface is a scab. Coagulation, the blood-clotting process, is one of the body’s vital protective functions. Some people have blood that does not clot normally. These individuals tend to bleed heavily from even a slight injury. Hemophilia, a hereditary disease, is one of several conditions in which excessive bleeding occurs.
First aid for bleeding.
First aid for bleeding consists of applying pressure on the wound. Pressure applied by a sterile gauze bandage held firmly on the wound usually stops the flow of blood. Small vessels near the surface of the skin may be compressed on the side of the wound from which the blood is flowing.
If direct pressure fails to stop the bleeding, it may be necessary to press on the artery above the bleeding point. Places where an artery lies over a bone and may be easily compressed are called pressure points. The two most common ones are in the upper arm and at the top of the thigh where it meets the abdomen. Both direct pressure on the wound and pressure to an artery should be maintained until medical help arrives.
Nosebleed may be stopped by pressing the nostrils together, or by applying cold, wet compresses to the nose. If these methods are not effective, a physician should be called.
