Hemorrhage can result from a number of causes including trauma, medical conditions, or medications that affect the coagulation pathway. In the context of trauma, loss of circulating blood volume from hemorrhage is the most common cause of shock. Hemorrhagic shock is a common and frequently treatable cause of death in injured patients and is second only to traumatic brain injury as the leading cause of death from trauma. Timely recognition, appropriate resources, and appropriate responses are critical for preventing death.
Obtain rapid control of external hemorrhage.
Control compressible and extremity bleeding with direct pressure.
Recognize serious occult bleeding.
Strive to mitigate the lethal triad of trauma (hypothermia, acidosis, and coagulopathy).
Initiate rapid conveyance to an appropriate lead trauma hospital.
Assessment and stabilization should follow the CABCDE pattern:
Disability (neurologic status)
The Advanced Trauma Life Support (ATLS) manual produced by the American College of Surgeons describes four classes of hemorrhage to emphasize the early signs of the shock state. Clinicians should note that significant drops in blood pressure are generally not manifested until Class III hemorrhage develops and up to 30% of a patient's blood volume can be lost before this occurs.
Class I hemorrhage involves a blood volume loss of up to 15%. The heart rate is minimally elevated or normal and there is no change in blood pressure, pulse pressure, or respiratory rate.
Class II hemorrhage occurs when there is a 15-30% blood volume loss and is manifested clinically as tachycardia (heart rate of 100-120 beats/minute), tachypnea (respiratory rate of 20-24 breaths/minute), and a decreased pulse pressure. Systolic blood pressure (SBP) changes may be minimal, if at all. The skin may be cool and clammy, and capillary refill may be delayed. This can be considered moderate hemorrhage.
Class III hemorrhage involves a 30-40% blood volume loss, resulting in a significant drop in blood pressure and changes in mental status. Any hypotension (SBP < 90 mmHg) or a drop in blood pressure greater than 20-30% of the measurement at initial presentation is cause for concern. While diminished anxiety or pain may contribute to such a drop, the clinician must assume it is due to hemorrhage until proven otherwise. Heart rate (≥ 120 beats/minute and thready) and respiratory rate are markedly elevated, while urine output is diminished. Capillary refill is delayed. Both class III and class IV should be considered severe hemorrhage.
Class IV hemorrhage involves > 40% blood volume loss leading to significant depression in blood pressure and mental status. Most patients in Class IV shock are hypotensive (SBP < 90 mmHg). Pulse pressure is narrowed (≤ 25 mmHg) and tachycardia is marked (> 120 beats/minute). Urine output is minimal or absent. The skin is cold and pale, and capillary refill is delayed.