From the Guidelines
Hypocalcemia during mass transfusion should be monitored and corrected promptly with calcium chloride to maintain ionized calcium levels within the normal range, as recommended by the European guideline on management of major bleeding and coagulopathy following trauma: sixth edition 1. Hypocalcemia during mass transfusion occurs when large volumes of citrated blood products are rapidly administered to a patient, causing a decrease in ionized calcium levels. Citrate, used as an anticoagulant in stored blood products, binds to calcium and temporarily reduces the amount of physiologically active calcium in the bloodstream. This typically becomes clinically significant when transfusion rates exceed 50 mL/kg/hour or when more than one blood volume is replaced within 24 hours.
Key Points to Consider
- To prevent and treat transfusion-associated hypocalcemia, calcium supplementation should be administered, typically as calcium chloride 10 mg/kg IV (or calcium gluconate 30 mg/kg IV) when signs of hypocalcemia appear or prophylactically during massive transfusion protocols.
- Calcium chloride is preferred in emergency situations as it provides three times more elemental calcium than calcium gluconate, as noted in the European guideline 1.
- Monitoring of ionized calcium levels is essential during massive transfusions, with a target of maintaining levels above 1.0 mmol/L, as recommended by the European guideline 1.
- Patients with liver dysfunction are at higher risk for hypocalcemia during mass transfusion because the liver is responsible for metabolizing citrate, so more aggressive calcium replacement may be needed in these cases, as discussed in the European guideline 1.
Symptoms and Risks
- Symptoms of hypocalcemia include tetany, muscle cramps, paresthesias, QT prolongation, hypotension, and cardiac arrhythmias, which can be life-threatening if not promptly addressed.
- Low calcium concentrations at admission are associated with platelet activation, aggregation, decreased clot strength, blood transfusions, and increased mortality, as noted in the European guideline 1.
Recommendation
The administration of calcium chloride to correct hypocalcemia is recommended, as stated in the European guideline on management of major bleeding and coagulopathy following trauma: sixth edition 1.
From the Research
Hypocalcemia during Mass Transfusion
- Hypocalcemia is a common complication during massive transfusion, occurring in 97% of patients, with 71% experiencing severe hypocalcemia 2.
- The condition is caused by the chelation of calcium by citrate in blood products, leading to a decrease in ionized calcium levels 2.
- Severe hypocalcemia (ionized calcium < 0.90 mmol/L) is associated with higher mortality rates, with 49% of patients experiencing severe hypocalcemia dying, compared to 24% of those with non-severe hypocalcemia 2.
Calcium Replacement Strategies
- A study found that an empiric calcium replacement strategy of 1 gram of calcium chloride per liter of citrated bank blood transfused, in 200 mg/200 mL increments, resulted in successful maintenance of ionized calcium during massive transfusion 3.
- Another study suggested that calcium gluconate infusion at a rate of 1.6 g/h can stabilize plasma ionized calcium levels and prevent hypocalcemic reactions during therapeutic plasma exchange 4.
- Implementation of a calcium replacement protocol during massive transfusion in trauma patients was found to reduce the incidence of hypocalcemia from 95.2% to 63% 5.
Monitoring and Supplementation Guidelines
- Severe hypocalcemia commonly occurs during massive transfusion protocols, with 59.1% of patients experiencing severe hypocalcemia 6.
- The prevalence of hypocalcemia increases with the volume of blood products transfused, with 83.3% of patients receiving 13 or more units of packed red blood cells experiencing hypocalcemia 6.
- Standardized protocols for recognition and management of severe hypocalcemia during massive transfusions may improve outcomes, with regular monitoring of ionized calcium levels and administration of calcium supplementation as needed 6.