Cardiac Arrest Medicines

Drugs in cardiac arrest are secondary to high-quality chest compressions, early defibrillation for shockable rhythms, airway and oxygenation, and treatment of reversible causes. Drugs are given intravenously or intraosseously, and access must not interrupt compressions.

Rhythm. Shockable rhythms (ventricular fibrillation, pulseless ventricular tachycardia) are treated with shocks first. Non-shockable rhythms (asystole, pulseless electrical activity) need adrenaline as soon as access is available.

Reversible causes. Hypoxia, hypovolaemia, hypo- or hyperkalaemia and other metabolic causes, hypothermia, tension pneumothorax, tamponade, toxins, and thrombosis (coronary or pulmonary).

Not advised routinely. Vasopressin, corticosteroids, atropine, and sodium bicarbonate without a specific indication.

All rhythms. Adrenaline.

Shockable rhythm. Amiodarone after the third shock, with lidocaine as an alternative if amiodarone is not available.

Specific causes.

• Hyperkalaemia, hypocalcaemia, calcium channel blocker toxicity: calcium chloride.

• Hyperkalaemia, tricyclic antidepressant overdose, severe acidosis: sodium bicarbonate.

• Torsades de pointes: magnesium sulphate.

• Suspected massive pulmonary embolism: thrombolysis.

• Local anaesthetic toxicity: lipid emulsion.

• Anaphylaxis: adrenaline, and fluid.

• Opioid respiratory arrest: naloxone.

Special groups.

• Children: weight-based doses, with the first priority being ventilation.

• Pregnancy: left uterine displacement and early perimortem delivery by 4 to 5 minutes. Magnesium toxicity is reversed with calcium.

• Hypothermia: withhold adrenaline until the temperature is over 30 degrees Celsius, and continue the resuscitation.

• East Africa: where defibrillators are scarce, prioritise early compressions and check dilutions carefully, because 1 mg/mL and 1 in 10,000 adrenaline are confused.

• Adrenaline: 1 mg intravenously or intraosseously every 3 to 5 minutes. After the third shock in shockable rhythms, and as soon as possible in non-shockable rhythms. Children 10 micrograms/kg (0.1 mL/kg of 1 in 10,000).

• Amiodarone: 300 mg intravenously after the third shock, then 150 mg after the fifth. Children 5 mg/kg.

• Lidocaine: 1 to 1.5 mg/kg intravenously, then 0.5 to 0.75 mg/kg if needed.

• Calcium chloride 10 percent: 10 mL intravenously.

• Sodium bicarbonate: 8.4 percent 50 mL (50 mmol) intravenously.

• Magnesium sulphate: 2 g (8 mmol) intravenously over 10 to 15 minutes.

• Alteplase: 50 mg intravenous bolus for suspected pulmonary embolism, repeated once after 15 minutes if needed, with continued compressions for 60 to 90 minutes.

• Lipid emulsion 20 percent: 1.5 mL/kg bolus, then 15 mL/kg/h.

• Naloxone: 0.4 to 2 mg intravenously or intramuscularly.

Monitoring. Rhythm check every 2 minutes, end-tidal carbon dioxide (a sudden rise suggests return of circulation), glucose, potassium, blood gases and point-of-care ultrasound for causes.

Stop rules. Stop resuscitation when the team judges that return of circulation will not occur, taking account of the cause, rhythm, duration, end-tidal carbon dioxide and prior wishes.

Referral and escalation. Call senior and critical care help at the start. For refractory ventricular fibrillation or arrest from a reversible cause, consider extracorporeal support where available. Move straight to post-resuscitation care when circulation returns.

Common errors. Interrupting compressions to gain access, wrong adrenaline dilution, delaying adrenaline in non-shockable rhythms, and missing reversible causes.