Calcium Chloride

Essential Electrolyte - An increase in myocardial contractility elevates cardiac output, whereas a decrease in peripheral vascular resistance is linked to a reduced heart rate. Calcium is essential for these cardiovascular functions, playing a vital role in the contraction of cardiac, smooth, and skeletal muscles. It is also crucial for maintaining the functional integrity of the nervous, muscular, and skeletal systems, as well as for cell membrane and capillary permeability. Additionally, calcium is important for renal function, respiration, and blood clotting.

Serum Monitoring - Target ionized calcium 1.1–1.35 mmol/L or total serum calcium 8.5–10.0 mg/dL. Recheck after each dose in critically ill or rapidly changing patients.

Avoid Rapid Injection - this can cause arrhythmias, hypotension, or hypertension.

Extravasation Risk - Use the IV route only; extravasation can cause necrosis or sloughing. Treat with 1% procaine hydrochloride and hyaluronidase if extravasation occurs.

Hypercalcemia -  More dangerous than hypocalcemia.  Monitor serum calcium levels and ECG to prevent complications like arrhythmias, coma, or sudden death. Signs include shortened QT interval, bradycardia, nausea, and altered mentation. Manage with saline infusion and IV furosemide.

Acidifying Effects - Avoid in cases of concurrent acidosis and hypocalcemia.

Transfusion Monitoring - Administer calcium during rapid transfusions of citrated blood (>2ml/kg/min) to prevent hypocalcemia.  Hypocalcemia can also be caused by large volumes of colloid solutions.

Extravasation Risk - IV route only. Central venous access is strongly preferred to minimize extravasation risk and phlebitis. Extravasation causes tissue necrosis or sloughing. If extravasation occurs, treat with 1% procaine hydrochloride and hyaluronidase.

Acidifying Effects - Avoid concurrent use in patients with existing acidosis and hypocalcemia; calcium chloride has mild acidifying properties that may worsen the metabolic picture.

Drug Interactions - Calcium potentiates the toxic effects of digoxin — avoid in digitalis toxicity due to risk of fatal arrhythmias. Do not mix calcium chloride with solutions containing carbonates, phosphates, or sulfates; precipitation will occur.

Transfusion Protocol - In massive transfusion (>2 mL/kg/min of citrated blood), administer calcium prophylactically — citrate chelates ionized calcium and can precipitate acute hypocalcemia, cardiac depression, and coagulopathy.

Absolute - Hypercalcemia, digitalis toxicity (risk of fatal arrhythmias)

Relative - Concurrent acidosis with hypocalcemia (acidifying effect may worsen status)

Caution - Patients on digoxin (even without frank toxicity). Rapid transfusion scenarios — titrate dose carefully. Parenteral admixtures containing carbonates, phosphates, or sulfates. Renal Impairment (increases hypercalcemia risk because there's reduced excretion).

Adults - IV 500-1000 mg; Administer no faster than 1.0 mL/min (2%–10% solution)

Peds: IV 10-25 mg/kg; Give over 5-10 minutes (2% - 10% solution)

Maintain serum calcium 8.5 - 10.0 mg/dL

Contraindicated

Primary Role - Calcium acts as a second messenger in cell signaling; regulates neurotransmitter release; stabilizes cell membranes; essential for enzyme activity and bone remodeling via hydroxyapatite formation.

Muscle Contraction - Triggers actin-myosin cross-bridge cycling in cardiac, smooth, and skeletal muscle via calcium-calmodulin and troponin C pathways.

Cardiovascular - Positive inotrope; Increases myocardial contractility and cardiac output; modulates peripheral vascular resistance.

Neurological - Required for action potential propagation and stabilization of excitable membranes; tightly regulated by PTH, calcitonin, and vitamin D.

Not metabolized

GI and renal pathways

No direct reversal; In cases of hypercalcemia, effects can be managed through aggressive IV normal saline hydration and IV diuretics (e.g., furosemide). Avoid thiazide diuretics — they reduce renal calcium excretion and will worsen hypercalcemia

Ionized calcium is the physiologically active fraction. Hypoalbuminemia will lower total serum calcium but may spare ionized levels — measure ionized calcium directly when clinically relevant.

Calcium Chloride vs. Calcium Gluconate - Calcium chloride provides ~3× more elemental calcium per gram than calcium gluconate (272 mg vs. 93 mg per gram) and is the preferred agent in hemodynamic emergencies.