Which set of findings constitutes the lethal triad in trauma?

• A. Hypothermia, Coagulopathy, Acidosis
• B. Hypoxia, Pain, Anemia
• C. Hyperthermia, Hypertension, Alkalosis
• D. Hypoglycemia, Infection, Dehydration

Answer: (A)

The lethal triad in trauma is hypothermia, coagulopathy, and acidosis. Each of these worsens the others, creating a vicious cycle that drives ongoing bleeding and poor outcomes. Hypothermia slows enzymatic reactions and impairs platelet function, making clot formation less effective. Coagulopathy means the body's ability to clot is diminished, so bleeding continues and tissue hypoperfusion worsens. Acidosis, from poor perfusion and anaerobic metabolism, further impairs coagulation pathways and platelet function, and it can also depress cardiac performance. In a bleeding trauma patient, you often see these three together: heat is lost or diluted during resuscitation, the patient bleeds and loses clotting factors, and poor perfusion pushes lactic acid up, reinforcing the cycle.

The other sets don’t fit this pattern because they don’t capture the self-perpetuating interaction that makes the trauma lethal triad particularly dangerous. Understanding this triad helps explain why rapid hemorrhage control, preserving body temperature, and balanced resuscitation are crucial to interrupt the cycle.