cardioprotector
Intravenous calcium is a rapidly acting membrane-stabilizing agent, primarily used for its cardioprotective effects in severe hyperkalaemia, rather than lowering serum potassium.
agents
| Agent | Concentration | Elemental Calcium | Key Difference |
|---|---|---|---|
| Calcium Gluconate | 10% solution (100 mg/mL) | 90 mg/10 mL | Peripheral line safe. Less irritating. |
| Calcium Chloride | 10% solution (100 mg/mL) | 270 mg/10 mL | Central line preferred (vesicant). 3x more potent. |
indications & dosing
1. hyperkalaemia (cardiac arrest or ecg changes)
- Role: Stabilizes cardiac myocyte membrane potential (reverses effect on resting membrane potential), preventing arrhythmias. Does NOT lower serum potassium.
- Dose:
- Calcium Gluconate: 10–20 mL of 10% solution IV over 2–5 minutes. Repeat every 5–10 minutes as needed for ECG changes.
- Calcium Chloride: 5–10 mL of 10% solution IV over 2–5 minutes. Use if central access available or if unresponsive to gluconate.
- Monitor: ECG for resolution of wide QRS, peaked T waves.
2. symptomatic hypocalcaemia
- Symptoms: Tetany, carpopedal spasm, seizures, QT prolongation.
- Dose:
- Calcium Gluconate: 10–20 mL of 10% solution IV over 10–20 minutes. Follow with continuous infusion if needed (e.g., 100 mL of 10% gluconate in 1L D5W/NS over 12-24h).
- Note: Calcium Chloride is generally avoided for non-emergency hypocalcemia due to extravasation risk.
3. calcium channel blocker overdose
- Mechanism: Overcomes competitive blockade at the L-type calcium channels.
- Dose: Often requires larger, repeated boluses (e.g., 20 mL of 10% Calcium Gluconate every 5 mins) and continuous infusions, guided by haemodynamics.
adverse effects
- Bradycardia / Hypotension: If pushed too rapidly, especially with Calcium Chloride.
- Extravasation: Calcium Chloride is highly irritating and can cause tissue necrosis if extravasated (central line preferred).
- Precipitation: Do not mix with bicarbonate-containing solutions (e.g., Sodium Bicarbonate, Lactated Ringer’s) as it will precipitate Calcium Carbonate.
- Hypercalcaemia: If administered excessively.
clinical pearls
- Always have a central line if using Calcium Chloride in non-arrest situations.
- Monitor ECG continuously during rapid administration.
- Calcium is a temporary measure in hyperkalaemia; always address the underlying cause (shift K+ into cells, eliminate K+ from body).