A trauma patient receives 15 units of packed red blood cells emergently. The core temperature drops to 33.5°C. What is the direct effect of hypothermia on coagulation that contributes to the lethal triad in trauma?

• A Hypothermia causes platelet sequestration in the liver
• B Hypothermia impairs platelet function and enzymatic coagulation cascade ✓
• C Hypothermia increases fibrinolysis
• D Hypothermia destroys circulating fibrinogen

Explanation

Hypothermia (below 34°C) directly impairs both platelet function and the enzymatic activity of coagulation factors, worsening hemorrhage. This is part of the lethal triad of hypothermia, acidosis, and coagulopathy in trauma. Standard coagulation tests (PT/INR, aPTT) are performed at 37°C and do not reflect in vivo hypothermic coagulopathy. Active warming with forced air warmers, warm fluids, and increased ambient temperature is essential in massive transfusion.

Reference: ATLS Advanced Trauma Life Support, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.