APPENDIX A: Drugs used during the treatment of cardiac arrest.

The effective management of cardiac arrest involves timely administration of drugs alongside high-quality CPR and defibrillation. This section details the key drugs used in resuscitation, their indications, doses, and mechanisms of action.

 Adrenaline (Epinephrine)

Role in Cardiac Arrest

• A critical vasopressor that increases coronary and cerebral perfusion pressure during CPR.
• Enhances myocardial contractility and promotes the return of spontaneous circulation (ROSC).

Indications & Administration

• Given for shockable (VF/pVT) and non-shockable (asystole/PEA) cardiac arrests.
• Dose: 1 mg IV/IO every 3-5 minutes during cardiac arrest.
• First dose timing:
  • After the third shock for shockable rhythms (VF/pVT).
  • Immediately after vascular access for non-shockable rhythms (asystole/PEA).
• Adverse Effects: Can cause hypertension, tachycardia, and arrhythmias post-ROSC.

 Amiodarone

Role in Cardiac Arrest

• A class III antiarrhythmic that stabilises cardiac membranes by blocking potassium channels.
• Used to terminate shock-resistant ventricular fibrillation (VF) and pulseless ventricular tachycardia (pVT).

Indications & Administration

• Dose: 300 mg IV/IO after the third shock for persistent VF/pVT.
• A repeat dose of 150 mg may be given if VF/pVT persists.
• Always followed by a flush to ensure drug delivery.
• Contraindications: Avoid in cases of severe bradycardia, heart block, or hypotension.

 Lidocaine (Alternative to Amiodarone)

Role in Cardiac Arrest

• A sodium channel blocker used as an alternative to amiodarone for VF/pVT refractory to defibrillation.
• It reduces myocardial excitability and suppresses ectopic ventricular activity.

Indications & Administration

• Dose: 1 mg/kg IV/IO, followed by further doses up to 3 mg/kg if needed.
• Do NOT use lidocaine if amiodarone has already been administered.
• Adverse effects: Can cause neurological toxicity, including seizures and altered consciousness in overdose.

 Magnesium Sulphate

Role in Cardiac Arrest

• Primarily used for Torsades de Pointes (polymorphic VT associated with QT prolongation).
• Helps in cases of hypomagnesaemia, which can lead to arrhythmias.

Indications & Administration

• Dose: 2 g IV/IO over 1-2 minutes for Torsades de Pointes or suspected hypomagnesaemia.
• Adverse effects: High doses may cause hypotension, respiratory depression, and cardiac arrest.

 Calcium Chloride

Role in Cardiac Arrest

• Used in specific cases, including hyperkalaemia, hypocalcaemia, and calcium channel blocker overdose.
• Helps restore cardiac excitability and contractility.

Indications & Administration

• Dose: 10 mL of 10% calcium chloride IV/IO for severe hyperkalaemia or overdose.
• Not routinely given in cardiac arrest unless indicated.
• Adverse effects: Can cause tissue necrosis if extravasation occurs.

 Sodium Bicarbonate

Role in Cardiac Arrest

• Buffering agent used to correct severe metabolic acidosis.
• Only considered in prolonged resuscitation efforts or specific cases.

Indications & Administration

• Dose: 50 mmol IV/IO slow push, repeated as necessary.
• Used for hyperkalaemia, tricyclic antidepressant overdose, or prolonged cardiac arrest with severe acidosis.
• Routine use is NOT recommended due to risks of worsening intracellular acidosis.

 Naloxone (Opioid Reversal)

Role in Cardiac Arrest

• Used to reverse opioid-induced respiratory depression in suspected opioid overdose.
• Not a primary drug for cardiac arrest unless opioid toxicity is suspected.

Indications & Administration

• Dose: 0.4–2 mg IV/IO every 2-3 minutes as needed (max 10 mg).
• Considered in cardiac arrest due to suspected opioid toxicity.

 Summary Table: Drug Use in Cardiac Arrest

Key Takeaways

✔ Drugs are secondary to high-quality CPR and defibrillation in cardiac arrest.
✔ Adrenaline is the most critical drug, but timing matters—give early in non-shockable rhythms and after the third shock in shockable rhythms.
✔ Antiarrhythmic drugs (amiodarone or lidocaine) should be used selectively.
✔ Reversible causes (e.g., hyperkalaemia, opioid overdose, metabolic acidosis) guide additional drug therapy.
✔ Routine administration of sodium bicarbonate and calcium is NOT recommended unless specifically indicated.