In the Field
Coagulopathy is the technical term for blood that is not clotting the way it should. In trauma, it can be caused by the injury itself, by the body's response to massive bleeding, or by medications the patient was taking before they were ever hurt. The practical consequence is the same: bleeding that should stop does not, and the patient dies from a wound that should have been survivable. Knowing whether your patient is coagulopathic, and why, drives the choice between hemostatic agents and the urgency of evacuation.
Common Mistake
Assuming all trauma patients have normal clotting function when many older patients are on anticoagulants and most severely injured patients develop trauma-induced coagulopathy quickly.
Technical Detail
Coagulopathy is impaired blood clotting. The body's normal response to vascular injury (vasoconstriction, platelet plug formation, and the cascade of clotting factors that produces a stable fibrin clot) is disrupted, and bleeding continues longer than it should.
Causes in trauma medicine. Several distinct causes produce coagulopathy in trauma patients:
Trauma-induced coagulopathy (TIC). A specific syndrome that develops in severely injured patients, driven by tissue injury, shock, and inflammation. Occurs in 25 to 35 percent of major trauma patients on arrival at definitive care, often before any fluid resuscitation has occurred. Develops rapidly and worsens outcomes substantially.
Dilutional coagulopathy. Caused by aggressive crystalloid fluid resuscitation that dilutes the patient's clotting factors. One of the major reasons modern trauma resuscitation has shifted toward permissive hypotension and away from large-volume crystalloid administration.
Consumption coagulopathy. Massive ongoing hemorrhage uses up clotting factors faster than the body can produce them. The remaining factors are insufficient to form effective clots.
Hypothermia-induced coagulopathy. Reduced core body temperature impairs the function of clotting factors and platelets. One of the limbs of the Lethal Triad.
Acidosis-induced coagulopathy. Acidic blood reduces the function of clotting factor enzymes. Another limb of the Lethal Triad.
Hypocalcemia-induced coagulopathy. Calcium is required at multiple steps in the clotting cascade. The fourth limb of the Lethal Diamond.
Pre-existing medication coagulopathy. Patients on warfarin, direct oral anticoagulants (DOACs such as rivaroxaban, apixaban, dabigatran), antiplatelet medications (aspirin, clopidogrel), or with bleeding disorders (hemophilia, von Willebrand disease) arrive at the trauma scene already coagulopathic. The aging population in many civilian trauma settings means a significant percentage of casualties are on anticoagulants.
Field implications. The presence or likelihood of coagulopathy affects several decisions:
Hemostatic agent selection. Chitosan-based agents (Celox, ChitoGauze, ChitoSAM) work independently of the clotting cascade and remain effective in coagulopathic patients. Kaolin-based agents (Combat Gauze) require functional clotting factors and may be less effective in severely coagulopathic patients. See the Chitosan and Kaolin entries.
Urgency of evacuation. A coagulopathic patient is bleeding faster than a non-coagulopathic patient with the same wound. Evacuation timelines should reflect this.
Fluid resuscitation philosophy. Avoiding aggressive crystalloid administration prevents dilutional coagulopathy from developing during resuscitation.
Hypothermia prevention. Active warming preserves clotting function and prevents the hypothermia-coagulopathy spiral.
TXA administration. Tranexamic acid stabilizes formed clots and reduces fibrinolysis. CoTCCC and many civilian trauma protocols call for TXA administration within three hours of injury for patients with significant hemorrhage.
Calcium administration. As recognized in the Lethal Diamond model, calcium administration during massive transfusion supports coagulation function.
Field history-taking. When operationally feasible, asking about anticoagulant medications and bleeding history is valuable. A patient on warfarin or a DOAC requires more aggressive intervention and more urgent evacuation than the same wound in an otherwise healthy patient.
