To Amio Or Not To Amio...That is the Question!

To Amio Or Not To Amio…That is the Question!

Case:

62 year old man calls 911 for chest pain. While pulling into the ambulance bay, he goes into pulseless ventricular tachycardia (pVT). EMS has initiated CPR and delivered one shock prior to arrival in the critical care room. At the next scheduled rhythm check, he remains in pVT. Epinephrine is given, and CPR is continued. The pharmacist asks, “would you like me to draw up a dose of amiodarone?”

Clinical Question:

Should amiodarone be administered for patients in cardiac arrest with shock-refractory ventricular fibrillation or tachycardia (VF/VT)?

Summary of Evidence

• Current Advanced Cardiac Life Support (ACLS) guidelines say to “consider” amiodarone for shock-refractory VF/VT.(1)

• This recommendation is based on a physiologic rationale – that antiarrhythmic drugs, which decrease automaticity, may help to organize deranged electrical conduction in the heart.

• Two randomized controlled trials conducted in the early 2000s demonstrated short-term survival benefit for amiodarone in this setting. Both studies showed increased rates of return of spontaneous circulation (ROSC) and survival to hospital admission among patients treated with amiodarone compared to the control groups. (2-3)

• Neither of these studies demonstrated any benefit of amiodarone for longer-term outcomes.

• A randomized trial conducted in 2016 found no benefit of amiodarone for survival to hospital discharge or favorable neurologic outcomes.(4)

• A 2016 meta-analysis concluded that amiodarone offers short-term benefit, but does not impact long-term survival outcomes.(5)

Recommendations

• It is probably reasonable to give amiodarone in most shock-refractory VF/VT arrests.

• Amiodarone has never been found to be harmful, and it has been shown to improve the likelihood of ROSC.

• ROSC is an absolute prerequisite to longer-term survival, and there may be individual cases in which amiodarone provides benefit, even though this is not demonstrable at the population level.

• Caution should be exercised in patients who have little chance of meaningful neurologic recovery, as there is some risk of amiodarone leading to futile interventions. These include patients with prolonged/unwitnessed arrest, lack of immediate CPR, or other poor prognostic signs.

References

1. Neumar RW, Shuster M, Callaway CW, et al. Part 1: Executive summary: 2015 American Heart Association guidelines update for cardiopulmonary resuscitation and emergency cardiovascular care. Circulation. 2015;132(18 Suppl 2):S315-67.

2. Kudenchuk PJ, Cobb LA, Copass MK, et al. Amiodarone for resuscitation after out-of-hospital cardiac arrest due to ventricular fibrillation. N Engl J Med. 1999;341(12):871-878.

3. Dorian P, Cass D, Schwartz B, Cooper R, Gelaznikas R, Barr A. Amiodarone as compared with lidocaine for shock-resistant ventricular fibrillation. N Engl J Med. 2002;346(12):884-890.

4. Kudenchuk PJ et al. Amiodarone, Lidocaine, or Placebo in Out-of-Hospital Cardiac Arrest. N Engl J Med. 2016;374:1711-22.

5. Laina A, Karlis G, Liakos A, Georgiopoulos G, Oikonomou D, Kouskouni E, Chalkias A, Xanthos T. Amiodarone and cardiac arrest: Systematic review and meta-analysis. Int J Cardiol. 2016;221:780-8.