APPENDIX B: Drugs used in the peri arrest period

 Key Drugs Used in the Peri-Arrest Period

1. Adenosine

• Indications: Paroxysmal supraventricular tachycardia (SVT) with re-entrant circuits (AVNRT, AVRT).
• Dose:
  • 6 mg IV bolus, followed by 12 mg IV if unsuccessful (up to two additional doses).
• Mechanism: Blocks AV nodal conduction, causing temporary asystole before normal sinus rhythm resumes.
• Side Effects: Flushing, nausea, chest discomfort, dizziness—typically transient.
• Administration: Rapid IV push, followed by saline flush to ensure rapid circulation.

2. Adrenaline (Epinephrine)

• Indications:
  • Second-line treatment for cardiogenic shock.
  • Bradycardia (alternative to external pacing if atropine fails).
  • Anaphylaxis (first-line treatment).
• Dose:
  • Bradycardia: 2–10 mcg/min IV infusion.
  • Cardiogenic shock: 0.05–1 mcg/kg/min IV.
  • Anaphylaxis: 0.5 mg IM, repeated every 5 minutes if necessary.
• Mechanism: Potent vasoconstrictor and inotrope that increases heart rate, blood pressure, and cardiac output.
• Caution: May cause hypertension, arrhythmias, and increased myocardial oxygen demand.

3. Amiodarone

• Indications:
  • Haemodynamically stable ventricular tachycardia (VT).
  • Polymorphic VT and wide-complex tachycardias.
  • Atrial fibrillation (AF) with rapid ventricular response.
• Dose:
  • 300 mg IV over 10–60 minutes, followed by 900 mg over 24 hours if needed.
• Mechanism: Antiarrhythmic affecting sodium, potassium, and calcium channels, prolonging the refractory period.
• Side Effects: Hypotension, bradycardia, phlebitis (if given peripherally).
• Administration: Preferably via central line due to risk of thrombophlebitis.

4. Aspirin

• Indication: Acute coronary syndromes (ACS).
• Dose: 300 mg orally, crushed or chewed as soon as possible.
• Mechanism: Inhibits platelet aggregation, reducing clot formation.
• Benefit: Improves survival and reduces cardiovascular mortality in ACS.

5. Atropine

• Indications:
  • Bradycardia (sinus, atrial, nodal, AV block) with haemodynamic instability.
• Dose:
  • 500 mcg IV, repeated every 3-5 minutes (maximum 3 mg).
• Mechanism: Blocks parasympathetic (vagal) stimulation, increasing heart rate.
• Side Effects: Dry mouth, urinary retention, blurred vision, acute confusion (especially in elderly patients).
• Caution: Not beneficial in asystole or PEA.

6. Beta-Blockers (Atenolol, Metoprolol, Propranolol, Esmolol)

• Indications:
  • Narrow-complex tachycardias (SVT, atrial fibrillation/flutter).
  • Hypertension and rate control in atrial arrhythmias.
• Doses:
  • Atenolol: 5 mg IV over 5 minutes, repeat after 10 minutes if needed.
  • Metoprolol: 2–5 mg IV at 5-min intervals (max 15 mg).
  • Propranolol: 100 mcg/kg IV in three doses at 2–3 min intervals.
  • Esmolol: 500 mcg/kg IV over 1 minute, then 50–200 mcg/kg/min infusion.
• Caution: Avoid in hypotension, heart failure, and bradycardia.

7. Sodium Bicarbonate

• Indications:
  • Hyperkalaemia.
  • Tricyclic antidepressant overdose.
• Dose: 50 mmol IV, repeat as necessary based on blood gas analysis.
• Mechanism: Buffers metabolic acidosis but can cause paradoxical intracellular acidosis.
• Caution:
  • Routine use in cardiac arrest is NOT recommended.
  • Should NOT be mixed with calcium solutions due to precipitation risk.

8. Digoxin

• Indication: Atrial fibrillation with fast ventricular response.
• Dose: 500 mcg IV over 30 minutes.
• Mechanism: Increases vagal tone, reducing AV conduction and slowing heart rate.
• Caution: Risk of toxicity (arrhythmias, GI symptoms, visual disturbances).

9. Magnesium Sulphate

• Indications:
  • Polymorphic VT (torsades de pointes).
  • Digoxin toxicity.
  • Correction of hypomagnesaemia.
• Dose:
  • 2 g IV over 10 minutes, may be repeated once.
• Mechanism: Stabilises cardiac membranes and reduces arrhythmias.

10. Nitrates (GTN, Isosorbide Dinitrate)

• Indications:
  • Angina, myocardial infarction (MI), left ventricular failure.
• Dose:
  • GTN sublingual: 300–400 mcg tablet or spray.
  • GTN IV infusion: 10–200 mcg/min.
  • Isosorbide dinitrate IV: 2–10 mg/hr.
• Mechanism: Vasodilation (primarily venous), reducing cardiac workload and oxygen demand.
• Caution: Avoid in hypotension (SBP < 90 mmHg).

 Important Considerations for Peri-Arrest Drug Use

✔ Drugs should only be given by trained clinicians familiar with their indications and side effects.
✔ Flushing IV drugs with saline prevents pooling in the IV line.
✔ Beta-blockers and digoxin should be used cautiously in haemodynamically unstable patients.
✔ Sodium bicarbonate is NOT for routine use—only in specific toxic/metabolic conditions.
✔ Nitrates are contraindicated in hypotension due to vasodilation effects.
✔ Fibrinolytics (e.g., Alteplase, Tenecteplase) should only be used in suspected PE arrests.

 Summary of Key Peri-Arrest Drugs in ALS

 Adenosine → First-line for SVT, given rapid IV push.
 Adrenaline → Used for bradycardia, anaphylaxis, cardiogenic shock.
 Amiodarone → Antiarrhythmic for VT and AF with RVR, stabilises cardiac conduction.
 Aspirin → Antiplatelet for ACS, reduces mortality.
 Atropine → For bradycardia, increases heart rate by blocking vagal activity.
 Beta-Blockers → For SVT and atrial arrhythmias, but not in hypotension or bradycardia.
 Sodium Bicarbonate → Used only in hyperkalaemia and tricyclic overdose.
 Magnesium → First-line for torsades de pointes.
 Nitrates → Reduce angina symptoms, but avoid in hypotension.