Internal bleeding, often more serious than external bleeding, is usually the result of Crush injuries, Fractures, or a burst peptic ulcer. Blood lost internally can pool in connected tissues and cause a build-up of pressure on vial organs, a haemorrhage inside the skull, for example, can lead to compression of the brain (see Head injuries). Both internal and external bleeding can reduce blood pressure and cause Shock.
Internal bleeding should be suspected if the person has pale, clammy skin, and a rapid, feeble pulse. (Note that the pulse may be slow if bleeding inside the skull has occurred.) Breathing may become shallow, with air hunger (yawning), restlessness, and thirst. Coughing or vomiting blood is another sign. There may also be pain and swelling at the site of bleeding, or bruising under the skin.
First, encourage the person to rest quietly with legs raised, unless recourse there is a chest injury, in which case he or she should sit propped up. Dial 911 and keep the person warm until help arrives. There is nothing else you can do, unless you have special training.