A 35-year-old man in haemorrhagic shock following abdominal trauma receives massive transfusion. After 8 units of packed red blood cells, 8 units of fresh frozen plasma, and 1 unit of apheresis platelets, his ionised calcium is 0.85 mmol/L. What is the most likely cause and treatment?
- A Dilutional hypocalcaemia — treat with calcium gluconate IV
- B Citrate toxicity causing hypocalcaemia — treat with calcium chloride or calcium gluconate IV ✓
- C Hypomagnesaemia — treat with magnesium sulphate
- D Massive transfusion-related haemolysis — treat with forced diuresis
Correct answer: B. Citrate toxicity causing hypocalcaemia — treat with calcium chloride or calcium gluconate IV
Explanation
Blood products are anticoagulated with citrate, which chelates ionised calcium. During rapid massive transfusion, the liver cannot metabolise citrate fast enough, causing citrate accumulation and hypocalcaemia. Ionised hypocalcaemia causes myocardial depression, coagulopathy, and vasodilation. Treatment is IV calcium chloride (10 mL of 10% CaCl2 per 4 units of blood products) or calcium gluconate. This is a well-recognised complication of massive transfusion protocols and should be monitored and corrected proactively.
Reference: Bailey & Love's Short Practice of Surgery, 27th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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