In an 18-year-old female in shock after a motor vehicle collision who is receiving rapid transfusions, the most likely cause of the described scenario is:

In an 18-year-old female in shock after a motor vehicle collision who is receiving rapid transfusions, the most likely cause of the described scenario is:

• A. Citrate toxicity
• B. Hyperkalemia
• C. Hemolytic transfusion reaction
• D. Cardiac tamponade

Answer: (A)

Rapid transfusion brings a large amount of citrate into the circulation. Citrate is used as an anticoagulant in stored blood and, if given fast enough, can overwhelm the body’s ability to metabolize it. Citrate binds ionized calcium, causing acute hypocalcemia. Calcium is essential for maintaining myocardial contractility and vascular tone, so when calcium levels drop, cardiac performance and vascular resistance decline, leading to hypotension and shock. This mechanism directly links the transfusion process to the patient’s shock state. In this scenario, the link between rapid transfusion and a calcium-chelating agent explains the sudden hemodynamic collapse better than other possibilities. Hyperkalemia from stored blood can occur with transfusion but tends to cause specific cardiac electrical changes rather than the immediate shock picture driven by hypocalcemia. Hemolytic transfusion reaction usually presents with fever, pain, and hemoglobinuria, not the rapid development of shock from low calcium. Cardiac tamponade would be a traumatic injury finding with distinct signs like jugular venous distension and muffled heart sounds, not the transfusion-related mechanism described.

Rapid transfusion brings a large amount of citrate into the circulation. Citrate is used as an anticoagulant in stored blood and, if given fast enough, can overwhelm the body’s ability to metabolize it. Citrate binds ionized calcium, causing acute hypocalcemia. Calcium is essential for maintaining myocardial contractility and vascular tone, so when calcium levels drop, cardiac performance and vascular resistance decline, leading to hypotension and shock. This mechanism directly links the transfusion process to the patient’s shock state.

In this scenario, the link between rapid transfusion and a calcium-chelating agent explains the sudden hemodynamic collapse better than other possibilities. Hyperkalemia from stored blood can occur with transfusion but tends to cause specific cardiac electrical changes rather than the immediate shock picture driven by hypocalcemia. Hemolytic transfusion reaction usually presents with fever, pain, and hemoglobinuria, not the rapid development of shock from low calcium. Cardiac tamponade would be a traumatic injury finding with distinct signs like jugular venous distension and muffled heart sounds, not the transfusion-related mechanism described.