I'm not a doctor - but you really want to check out some books on critical-care and emergency nursing.
EMTs and ER staff refer to the 'Golden Hour' The time you have to stop blood loss and stabilize the patient. In the event of massive blood loss - first get the blood pressure up by giving IV fluid (Blood transfusions are NOT given in the field). Then make sure enough oxygen is getting to the brain.
Symptoms will include low body temperature, weakness, confusion, unconsciousness.
Once the Golden hour is past - shock will be irreversable and the patient dies, not immediately, but the organ damage is too great for recovery.
