Sodium citrate binds calcium and is used as an anticoagulant in blood products. Infusion of a large amount of blood products containing citrate can result in transient hypocalcemia.



(1) hypocalcemia: usually mild, but the patient may develop muscle spasms and facial grimacing; in severe cases patients may have laryngeal spasm, convulsions, cardiac arrhythmias, and respiratory arrest.

(2) metabolic alkalosis


Factors worsening the effects:

(1) shock

(2) hypothermia


Patients at risk:

(1) neonates and small infants undergoing exchange transfusions

(2) following massive transfusion of FFP, whole blood or platelets, with infusion rates exceeding 100 mL per minute

(3) patients with severe liver disease receiving blood products

(4) occasionally during apheresis procedures



(1) Most patients respond well to simply slowing or discontinuing the product infusion.

(2) Patients with severe symptoms may require intravenous calcium infusion.

(2a) Use the ionized calcium level as the guide for replacement. Total calcium levels will also measure calcium bound to circulating citrate.

(2b) Proceed slowly to minimize the risk of giving too much calcium, resulting in hypercalcemia and consequent ventricular arrhythmias.

(2c) Do not infuse the calcium through the transfusion line.

(2d) Do not add the calcium to blood product bags.


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