Anti-arrhythmic Drugs and Cardiac Arrest

OVERVIEW

While the listed drugs have theoretical benefits in selected situations, no medication has been shown to improve long-term survival in humans after cardiac arrest. Priorities are defibrillation, oxygenation and ventilation together with external cardiac compression.

ANZCOR

PRIORITIES IN CARDIAC ARREST

• BLS
• ALS
• Early defibrillation
• High-quality, uninterrupted external cardiac compressions (30:2 – adults, 15:1 – children)
• Treatment of reversible causes (H’s and T’s)

RATIONALE AND EVIDENCE

Rationale

• anti-arrhythmic drugs may be used to cardiovert from VT/VF to a perfusing rhythm either directly or by facilitating electrical cardioversion
• anti-arrhythmic drugs may be used to prevent the recurrence of VT/VF following defibrillation

Evidence

Taken from the ILCOR CoSTR webpage:

• ILCOR suggest the use of amiodarone or lidocaine in adults with shock refractory ventricular fibrillation/pulseless ventricular tachycardia (VF/pVT) (weak recommendation, low quality evidence).
• ILCOR suggest against the routine use of magnesium in adults with shock refractory VF/pVT (weak recommendation, very low-quality evidence).
• In making a weak recommendation, ILCOR considered the reported increase in the important but short-term outcome of ROSC of both amiodarone (Kudenchuk 1999 871) or lidocaine (Kudenchuk 2016 1711) with no evidence of improved or worse longer-term outcomes ranked as critical: survival or good neurological survival to hospital discharge.

Anti-arrhythmic drugs

AMIODARONE

• Indication: Shock-resistant VF and pulseless VT
• Dose:
  • Adults: 300mg IV/IO for initial dose, consider 150mg as repeat dose, and then infusion of 15mg/kg over 24 hours
  • Paeds: 5mg/kg IV/IO [max 300mg]
• Frequency: Between the 3^rd and 4^th shock, consider further dose
• MoA: Class III antiarrhythmic with effects on sodium, potassium and calcium channels
• Adverse effects: Hypotension, bradycardia, heart block, tissue necrosis in extravasation
• Contraindications: Rare to have contraindications in cardiac arrest — caution with WPW (case report of spontaneous VF, however, if using for VF or VT, may as well crack on) or patients with 2^nd or 3^rd degree heart block (get ready to pace)
• Administration advice: Must be administered in 5% dextrose, otherwise will precipitate in saline, remember to also administer flush with 5% dextrose

LIGNOCAINE (LIDOCAINE)

• Indication: For shock refractory and/or amiodarone refractory VT/VF
• Dose:
  • Adults:
    • 1mg/kg bolus IV/IO, addition bolus of 0.5mg/kg may be administered IV/IO, 2-3x dose via ETT.
    • Infusion: 1-4mg/min do not commence prior to ROSC.
  • Paeds:
    • 1mg/kg IV/IO. 2-3x the dose via ETT.
• Frequency: Bolus initial dose, consider a second dose after 5 mins, and can consider infusion in refractory VT
• MoA: Class IB antiarrhythmic, sodium channel blocker
• Adverse effects: Neurological effects such as slurred speech, altered consciousness, muscle twitching and seizures; cardiovascular such as hypotension, bradycardia, heart block, asystole
• Contraindications: Relative in heart failure and liver failure
• Administration advice:
  • Most commonly recommended infusion: 1-4mg/min after ROSC for up to 24 hours (use the lowest possible rate that controls the arrhythmia)
  • One way to administer such an infusion:
    • 4mg/min for 1 hour, then 2mg/min for 1 hour, then 1mg/min for 22 hours
    • If using 1% lignocaine: 24mL/hour (240mg/hour) for 1 hour, then 12mL/hour (120mg/hour), then 6mL/hour (60mg/hour)
  • Lignocaine 1% = 10mg/mL
    • Commonly presented in 5mL ampoules = 50mg in 5mL
  • Lignocaine 2% = 20mg/mL
    • Commonly presented in 5mL ampoules = 100mg in 5mL
  • Avoid administration in the same cannula with sodium bicarbonate

MAGNESIUM

• Indication: Torsades de pointes, digoxin toxicity, VF/pulseless VT, documented hypokalaemia or hypomagnesaemia
• Dose:
  • Adults: Boluses of 5mmol IV/IO (5mmol = 1.2g of Magnesium sulphate)
  • Paeds: Boluses of 0.1-0.2mmol/kg IV/IO
• Frequency: May repeat bolus once. Adults: followed by infusion of 20mmol over 1-4 hours. Paeds: followed by infusion of 0.3mmol/kg over 4 hours.
• MoA: Essential electrolyte for membrane stability, and essential cofactor in enzyme systems
• Adverse effects: Muscle weakness and respiratory failure
• Administration advice:
  • Administer boluses over 1-2mins
  • 2.47g = 10mmol of magnesium sulphate heptahydrate
    • 1mmol = 0.247g
    • 1g = 4mmol / 2g = 8mmol / 4g = 16mmol / 6g = 24mmol
  • Incompatible with: Calcium chloride, sodium bicarbonate, potassium phosphate

SODIUM BICARBONATE

• Indication: Hyperkalaemia, metabolic acidosis, TCA overdose, protracted cardiac arrest
• Dose:
  • Adults: 1mmol/kg IV/IO
  • Paeds: 0.5-1mmol/kg IV/IO
• Frequency: As guided by blood gases.
• MoA: It is an alkalising solution that combines with hydrogen ions to form a weak carbonic acid –> breaks down to CO₂ and H₂O
• Adverse effects: Metabolic alkalosis, hypokalaemia, hyperosmolality (secondary to sodium load), intracellular acidosis may develop (as CO2 shifts intracellularly)
• Contraindications: Hypokalaemia
• Administration advice:
  • Give over 1-2mins
  • ANZCOR recommends NOT to give routine sodium bicarbonate in paediatric arrests unless for hyperkalaemia or TCA overdose
  • Requires good ventilation to blow off CO2 produced from same (as able)
  • May inactivate adrenaline or calcium if administered in the same IV line, may also precipitate and result in loss of a precious IV line during the arrest.
  • The 8.4% bottles of sodium bicarbonate provide 1mmol/mL of sodium and bicarbonate
  • To quickly prepare an isotonic preparation; dilute 150mmol of sodium bicarbonate (150mL of the 8.4% stuff) into 850mL of 5% dextrose (remove 150mL prior, otherwise you won’t fit the 150mL in)
  • Sodium bicarbonate is not compatible with a number of medications nor Hartmann’s fluid (anything that contains calcium or magnesium salts)

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References and Links

OTHER RELEVANT PAGES

• LITFL — Drugs for Cardiac Arrest
• Deranged Physiology — Anti-arrhythmic Drugs in Cardiac Arrest

JOURNAL ARTICLES / WEB PAGES

• Boyd T, Brady W. The “Code Drugs in Cardiac Arrest”–the use of cardioactive medications in cardiac arrest resuscitation. Am J Emerg Med. 2012 Jun;30(5):811-8. doi: 10.1016/j.ajem.2011.04.009. Epub 2011 Jun 12. Review. PubMed PMID: 21665413.
• Collinsworth, K., Kalman, S., & Harrison, D. (1974). The Clinical Pharmacology of Lidocaine as an Antiarrhythymic Drug. Circulation, 50(6), 1217-1230. doi: 10.1161/01.cir.50.6.1217 [Free Full Text]
• Lee SW. Drugs in resuscitation: an update. Singapore Med J. 2011 Aug;52(8):596-602. Review. PubMed PMID: 21879219. [Free Full Text]
• Lidocaine CV, Lidopen (lidocaine) dosing, indications, interactions, adverse effects, and more. (2022). Retrieved 13 August 2022, from https://reference.medscape.com/drug/lidocaine-cv-lidopen-342302
• Ong ME, Pellis T, Link MS. The use of antiarrhythmic drugs for adult cardiac arrest: a systematic review. Resuscitation. 2011 Jun;82(6):665-70. doi: 10.1016/j.resuscitation.2011.02.033. Epub 2011 Mar 27. Review. PubMed PMID: 21444143.
• Olasveengen TM, Sunde K, Brunborg C, Thowsen J, Steen PA, Wik L. Intravenous drug administration during out-of-hospital cardiac arrest: a randomized trial. JAMA. 2009 Nov 25;302(20):2222-9. doi: 10.1001/jama.2009.1729. PubMed PMID: 19934423.
• Resus.org.au. 2016. ANZCOR Guideline 11.5 – Medications in Adult Cardiac Arrest. [online] Available at: <https://resus.org.au/download/section_11/anzcor-guideline-11-5-medications-august-16.pdf> [Accessed 13 August 2022].
• Resus.org.au. 2021. ANZCOR Guideline 12.2 – Paediatric Advanced Life. [online] Available at: <https://resus.org.au/download/section_12/anzcor-guideline-12-2-paediatric-advanced-life-support-pals-nov-2021.pdf> [Accessed 13 August 2022].
• Soar J, Donnino MW, Andersen LW, Berg KM, Böttiger BW, Callaway CW, Deakin CD, Drennan I, Neumar RW, Nicholson TC, O’Neil BJ, Paiva EF, Parr MJ, Reynolds JC, Ristagno G, Sandroni C, Wang TL, Welsford M, Nolan JP, Morley PT. Antiarrhythmic Drugs for Cardiac Arrest in Adults and Children Consensus on Science and Treatment Recommendations [Internet] Brussels, Belgium: International Liaison Committee on Resuscitation (ILCOR) Advanced Life Support Task Force, 2018 May 30. Available from: http://ilcor.org [Free webpage access here]

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