Guidelines for Intravenous Calcium Replacement in Severe Hypocalcemia

Definition and Monitoring

Severe hypocalcemia is defined as total or albumin-corrected calcium <7.5 mg/dL (<1.87 mmol/L) or ionized calcium <0.9 mmol/L, according to the Kidney International and Critical Care guidelines 1, 2
Ionized calcium levels should be monitored and maintained within the normal range (1.1-1.3 mmol/L) in all patients with severe hypocalcemia, as recommended by the Critical Care guideline 1, 3

Calcium chloride is the preferred agent for IV calcium replacement in severe hypocalcemia, containing 270 mg of elemental calcium per 10 mL of 10% solution, as stated in the Critical Care guideline 1
Calcium chloride is particularly preferable in patients with liver dysfunction, where decreased citrate metabolism results in slower release of ionized calcium, according to the Critical Care guideline 1

Hypocalcemia is common during massive transfusion due to citrate-mediated chelation of calcium, with each unit of packed red blood cells or fresh frozen plasma containing approximately 3g of citrate that chelates calcium, as noted in the Critical Care guideline 1
In hemorrhagic shock with massive transfusion, liver function is often impaired due to hypoperfusion, resulting in decreased citrate metabolism and worsening hypocalcemia, according to the Critical Care guideline 1

In patients with CKD, hypocalcemia is common and may require correction, particularly when severe, as stated in the Kidney International guideline 2, 4
Correction of hypocalcemia is now considered reasonable in patients with CKD, given the well-understood risks of severe hypocalcemia, according to the Kidney International guideline 2, 4

Watch for signs of cardiac dysrhythmias, which are associated with ionized calcium levels below 0.8 mmol/L, as recommended by the Critical Care guideline 1

Avoid overcorrection which can result in iatrogenic hypercalcemia, renal calculi, and renal failure, as warned by the Genetics in Medicine guideline 5