NATURAL BODY REACTIONS TO BLEEDING
The body has natural mechanisms that act to control bleeding.
a. Contraction. If a blood vessel is severed, the end of the vessel may
contract and decrease the size of the opening through which blood can escape the
vessel. This contraction is temporary and full bleeding will occur when the vessel
relaxes. Contraction can often lead to a false impression of the severity of the wound.
During care under fire, aggressive use of tourniquets is needed to ensure that, as the
body starts to relax, the patient does not bleed out.
b. Clotting. The body's primary defense against blood loss is clotting. When
a blood vessel is damaged or cut, platelets (thrombocytes) in the blood attach
themselves to the damaged part of the blood vessel and begin plugging the opening.
Fibrinogen in the blood changes to fibrin and reinforces the platelets. An insoluble clot
forms that plugs the torn or cut blood vessel until the vessel is repaired. If the blood
vessel is large and the damage is severe, a clot may not form in time to stop the
c. Immobilization. The body may also react to damage by immobilizing the
injured part. The casualty with an injured leg may fall or lie down and remain still. The
muscles become more rigid to decrease pain and the casualty will tend to avoid
moving the injured body part. This natural splinting reaction helps to reduce blood loss
by restricting activity of the body part. The more active the body part, the greater the
blood flow in the injured part.
COMMONLY USED TERMS
a. Signs and Symptoms. A sign is something the medic can detect, such as
seeing a bruise, hearing noises during breathing, or measuring vital signs. A symptom
is a complaint voiced by the casualty that the medic cannot directly observe, such as
pain in the casualty's back or a headache.
b. Dressing. The term dressing refers to the material that is placed directly on
top of the open wound. The dressing absorbs some of the blood and helps a clot to
form. The clot, if successful, plugs the opening in the blood vessel and stops the
bleeding. The dressing also protects the wound from additional contamination and
injury. A dressing can be applied to any open wound.
c. Bandage. A bandage is the material used to hold (secure) the dressing in
place so the dressing will not slip and destroy the clot that is forming. In addition to
keeping the dressing in place, the pressure applied by the bandage also helps to
compress the injured blood vessel and, thereby, reduce bleeding. The ends of the
bandage are called the tails.