Pathophysiology

Haemorrhage
Must be recognized and managed aggressively to reduce the severity and duration of shock and avoid death and/or multiple organ failure

Pathophysiology
Haemorrhage leads to a state of hypovolaemic shock.
The combination of tissue trauma and hypovolemic shock leads to the development of an endogenous coagulopathy called acute traumatic coagulopathy (ATC).
Ongoing bleeding with fluid and red blood cells resuscitation leads to a dilution of a coagulation factors which worsen the coagulopathy.
Acidosis induced by hypo perfused state leads to decrease function of coagulation proteases resulting in coagulopathy.
Under perfused muscle is unable to generate heat cause hypothermia and further haemorrhage.
So, every effort must therefore be made to rapidly identify and stop haemorrhage and to avoid or limit physiological exhaustion from coagulopathy, acidosis and hypothermia.
Definitions
Revealed and concealed haemorrhage
Revealed haemorrhage is obvious external haemorrhage (open arterial wound, massive hematemesis from a duodenal ulcer)
Concealed haemorrhage is contained within the body cavity and must be suspected, actively investigated and controlled.
In trauma, haemorrhage may be concealed within the chest, abdomen, pelvis, retroperitonium or in the limbs (vascular injury, long bone fractures)
Non traumatic conceled haemorrhage such as occult gastrointestinal bleeding or rupture aortic aneurysm