Refers to loss of 20% of total blood volume.
Surgery is the most common cause.
Procedures associated with major blood loss include liver transplantation, cardiovascular procedures, hepatic resections, orthopedic procedures and spine surgery.
Trauma can be associated with major blood loss and can contribute to deaths in approximately 30% of traumatic related deaths.
Orthostatic hypotension implies at least a 15% loss of blood volume and suggests a severe bleeding episode.