There may be a clinical benefit to administering amiodarone or lidocaine to patients with nonshockable-turned-shockable out-of-hospital cardiac arrest, researchers reported in Circulation.
For the ALPS study, as Cardiology Today previously reported, researchers randomly assigned patients with nontraumatic out-of-hospital cardiac arrest, vascular access and ventricular fibrillation/ventricular tachycardia (VF/VT) to amiodarone, lidocaine or placebo from paramedics. In a cohort of 3,026 patients with initial VF/VT, survival to hospital discharge was slightly higher for those assigned amiodarone or lidocaine than those assigned placebo, but the difference was more prominent in those who experienced a witnessed cardiac arrest.
For the current analysis, a cohort of 1,063 patients from the study with initial nonshockable-turned-shockable rhythms were evaluated.
Baseline characteristics across the three arms were balanced, but the placebo group had fewer men and was less likely to receive bystander CPR.
Compared with those assigned placebo, those assigned amiodarone or lidocaine needed fewer shocks, required fewer supplemental doses of the study drug and needed fewer ancillary antiarrhythmic drugs (P < .05 for all). Peter J. Kudenchuk, MD, from the department of medicine, division of cardiology, University of Washington, Seattle, and colleagues wrote.
Survival to hospital discharge was 4.1% in those assigned amiodarone, 3.1% in those assigned lidocaine and 1.9% in those assigned placebo (P = .24), according to the researchers.
There was no interaction between study drug assignment and discharge survival based on initiating rhythm (asystole, pulseless electric activity or VF/VT), they wrote.
Survival rates were consistently higher across subgroups with amiodarone or lidocaine vs. placebo, although no group reached statistical significance, according to the researchers.
Adjusted absolute difference in survival for amiodarone vs. placebo was 2.3% (95% CI, –0.3 to 4.8), whereas adjusted absolute difference in survival for lidocaine vs. placebo was 1.2% (95% CI, –1.1 to 3.6), Kudenchuk and colleagues wrote.
More than half of survivors were functionally independent or needed only minimal assistance, and rates of drug-related adverse effects were low, according to the researchers.
“Outcome from nonshockable-turned-shockable [out-of-hospital cardiac arrest] is poor but not invariably fatal,” the researchers wrote. “The findings may signal a clinical benefit from amiodarone or lidocaine when shock-refractory VF/VT arises at any time or from any [out-of-hospital cardiac arrest] rhythm along the course of resuscitation, and invites further investigation.” – by Erik Swain
The study drugs were provided for free by Baxter Healthcare. The authors report no relevant financial disclosures.