When is calcium infusion indicated?

Indications for Calcium Infusion

Calcium infusion is primarily indicated for acute symptomatic hypocalcemia, calcium channel blocker toxicity, hyperkalemia, hypermagnesemia, and as part of management in specific toxic exposures. 1, 2

Specific Indications

Hypocalcemia

• Acute symptomatic hypocalcemia (ionized calcium <0.75 mmol/L) presenting with tetany, neuromuscular irritability, paresthesias, muscle cramps, laryngospasm, seizures, or cardiac dysfunction 3
• Post-thyroid or parathyroid surgery hypocalcemia 3
• Critically ill trauma patients with moderate to severe hypocalcemia (ionized calcium <1 mmol/L) 4
• Early neonatal hypocalcemia due to interruption of placental transfer and relative immaturity of hormonal control 5

Toxicology Emergencies

• Calcium channel blocker toxicity with hemodynamic instability (bradycardia, hypotension, ECG changes) refractory to other treatments 5
• Beta-blocker overdose with shock refractory to other measures 5
• Hypermagnesemia with cardiotoxicity or cardiac arrest 5
• Hyperkalemia with cardiac manifestations 5

Administration Guidelines

• For calcium channel blocker toxicity: Infuse 20 mg/kg (0.2 mL/kg) of 10% calcium chloride intravenously over 5-10 minutes; if beneficial, follow with an infusion of 20-50 mg/kg per hour 5
• For beta-blocker overdose: Administer 0.3 mEq/kg of calcium (0.6 mL/kg of 10% calcium gluconate or 0.2 mL/kg of 10% calcium chloride) IV over 5-10 minutes, followed by an infusion of 0.3 mEq/kg per hour 5
• For acute hypocalcemia: IV calcium in the form of 100-200 mg of elemental calcium, with subsequent therapy depending on the underlying cause 3
• For critically ill trauma patients with hypocalcemia: Infusion of 4g calcium gluconate at a rate of 1g/hour has shown efficacy 4

Important Considerations

Route of Administration

• Calcium chloride is preferably administered via a central venous catheter due to risk of severe tissue injury if extravasation occurs 5
• If no central venous access is available, calcium gluconate should be used through a secure peripheral IV 5
• Calcium chloride provides more rapid increase in ionized calcium than calcium gluconate and is preferred for critically ill patients 5

Monitoring

• Monitor serum ionized calcium concentration to prevent hypercalcemia 5
• Monitor heart rate during administration; stop injection if symptomatic bradycardia occurs 5
• For continuous infusions, titrate to adequate hemodynamic response 5
• Avoid severe hypercalcemia (ionized calcium levels greater than twice the upper limits of normal) 5

Precautions

• Do not mix calcium with sodium bicarbonate or vasoactive amines 5
• Use caution when infusing into a peripheral IV due to risk of infiltration and tissue injury 5
• For cardiac arrest associated with hyperkalemia or hypermagnesemia, calcium chloride (10%) 5-10 mL OR calcium gluconate (10%) 15-30 mL IV over 2-5 minutes may be considered 5

Special Populations

• In neonates, calcium infusion may be used for prevention and treatment of early neonatal hypocalcemia 5
• In pediatric patients with calcium channel blocker toxicity, calcium infusion is recommended as part of the treatment protocol 5
• During massive transfusion, calcium should be administered if ionized calcium levels are low or if ECG changes suggest hypocalcemia 5

Remember that while calcium infusion can be life-saving in appropriate situations, it should be administered with careful monitoring due to potential adverse effects including hypercalcemia, tissue damage from extravasation, and cardiac dysrhythmias 5, 3, 6.