Written by Amanda Mathews
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In this secondary analysis of the ALPS trial (Amiodarone, Lidocaine, or Placebo Study), researchers found that early administration of amiodarone (within 8 minutes) is associated with greater functional survival in OHCA with initial shockable rhythm when compared to placebo.
Why does this matter?
Cardiac arrest due to a shockable arrhythmia (VF and pulseless VT) is a presentation commonly encountered by EM providers. We want to improve functional neurologic outcomes. A recent study found lidocaine may be better than amiodarone for in-hospital cardiac arrest. The original ALPS trial did not find a functional survival benefit for lidocaine and amiodarone overall but did identify a benefit in the subset of patients with bystander and EMS witnessed arrest. These researchers wanted to determine if this benefit was due to earlier time to antiarrhythmic administration.
Amio early?
The ALPS trial enrolled patients >18 years old with non-traumatic shock refractory OHCA. 10 sites and 55 EMS agencies were included in the study. The intervention being studied was the administration of amiodarone, lidocaine, or placebo. The original study enrolled 3026 patients; this secondary analysis included the 2802 patients who did not get ROSC prior to study drug administration. The time cutoff of 8 minutes from EMS arrival to drug administration was determined based on power analysis to detect a 10% difference in survival to discharge.
One-third of patients received the study drug within the determined cutoff of 8 minutes. In this “early group,” amiodarone when compared to placebo resulted in higher survival to admission (62.0% vs. 48.5%, p=0.001), survival to discharge (37.1% vs. 28.0%, p=0.021), and functional survival (31.6% vs. 23.3%, p=0.029). Early and late lidocaine administration and late amiodarone administration (>8 minutes after EMS arrival) did not show any statistically significant differences when compared to placebo. The researchers applied a number of other secondary analyses; the most relevant finding was that administration of amiodarone with epinephrine showed higher survival to discharge (32.2% vs. 23.5%, p=0.038) and functional survival (27.0% vs. 19.2%, p=0.046) compared to placebo.
Amiodarone is already in the ACLS algorithm and is used by many providers in shockable cardiac arrests. Based on this analysis, I will consider asking for amiodarone early in my next resuscitation.
Editor’s note: Following the standard ACLS pathway, if the first shock is delivered within 4 minutes then amiodarone is called for in the algorithm before 8 minutes. So, “early” amiodarone is less early than it is on time. ~Nick Zelt
Source
Survival by Time-to-Administration of Amiodarone, Lidocaine, or Placebo in Shock-Refractory Out-of-Hospital Cardiac Arrest. Acad Emerg Med. 2023 Mar 4. doi: 10.1111/acem.14716. Epub ahead of print.
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