Hemorrhage is excessive bleeding that may pose a health risk because of the volume of blood lost or the location of the bleeding. It can have a wide range of causes, from a ruptured arteriovenous malformation in the brain to a severe injury in a car accident. When a patient has a hemorrhage, care providers need to locate and stop the bleeding, address complications, and keep the patient stable. Some blood loss can be fatal because of the sheer volume of the loss.
Care providers can use a number of scales to classify bleeding by severity. Some systems span one through five classes, while others have only four. In a five class scale, the classification runs from the lowest class, one, with about 7% of blood volume lost, to the highest, five, where the patient has lost 40% or more of her blood volume. Generally, a mild hemorrhage involves loss of less than 15% of the blood volume. Losses of 15% to 30% or 30% to 40% are more serious, while 40% or higher are a major cause for concern.
One potential complication is hypovolemic shock, where a patient goes into shock because of the sheer volume of blood loss and can start to experience organ damage and eventual failure of bodily organs. With internal bleeding, blood can pool and create bruising or generate pressure on organs that can cause them to malfunction. In the brain, this is a particular cause for concern, as there is limited room for pressure in the skull and the blood may cause brain damage. The patient's blood loss also damages brain cells that won't get enough blood, and he can be at risk for serious complications.
Patients can hemorrhage because of serious injuries near major blood vessels, rupture of fragile blood vessels, or slow bleeds that are not identified early because the symptoms may be subtle. In any case where a patient appears to have internal injuries, the doctor may want to perform an evaluation to check for internal bleeding. Head injuries in particular are closely watched for signs of bleeding because the margin of error is not very forgiving.
First aid for hemorrhage in the field includes applying pressure to stop the bleeding if the source can be located and this is feasible. The patient's airway and breathing should also be carefully monitored. Hypovolemic shock may lead to shallow respiration, and rescue breathing could become necessary. It is also inadvisable to move the patient or to remove any embedded foreign objects, as this could put him at risk of new injuries.