Blood Products in the Field
Prehospital blood product administration is one of the most significant advances in trauma care in recent years. Traditionally limited to hospital settings, blood transfusion is now being performed by EMS agencies across the country, particularly for patients with severe hemorrhage where crystalloid fluids alone cannot maintain adequate perfusion. The evidence supporting early transfusion in trauma continues to grow.
Why Crystalloid Alone Is Not Enough
For decades, EMS protocols for hemorrhagic shock relied on large-volume crystalloid infusion (normal saline or lactated Ringer's). However, crystalloid does not carry oxygen, does not contain clotting factors, and can dilute the patient's remaining blood components (hemodilution), worsening coagulopathy. Massive crystalloid resuscitation is associated with tissue edema, hypothermia, and the "lethal triad" of coagulopathy, acidosis, and hypothermia that drives mortality in severe trauma.
Blood products address these limitations by restoring oxygen-carrying capacity, providing clotting factors, and maintaining oncotic pressure without the dilutional effects of crystalloid.
Types of Prehospital Blood Products
- Whole blood: Contains red cells, plasma, platelets, and clotting factors in their natural ratios. Increasingly favored for prehospital use due to simplicity and physiological advantages.
- Packed red blood cells (PRBCs): Provide oxygen-carrying capacity. Used when whole blood is not available.
- Plasma (thawed or liquid): Provides clotting factors and volume expansion. Some agencies carry plasma alone or in combination with PRBCs.
- Freeze-dried plasma: Does not require refrigeration, has a long shelf life, and is reconstituted with sterile water in the field. Increasingly used by military and civilian EMS agencies.
Practical Considerations
Blood products require cold storage, blood type compatibility considerations (most prehospital programs use type O low-titer whole blood or O-negative PRBCs), transfusion reaction monitoring, and waste management for expired products. EMS agencies that carry blood must establish partnerships with blood banks, develop storage and tracking protocols, and train providers in transfusion procedures and complication recognition.
For the NREMT exam, understand the rationale for blood product administration in severe hemorrhage and the limitations of crystalloid-only resuscitation. Know the signs of transfusion reactions including fever, urticaria, hypotension, and dyspnea.