Out of hospital cardiac arrest with shock-refractory ventricular tachycardia (VT) or fibrillation (VF) carries a severe prognosis. Despite their frequent use and guideline inclusion in this scenario, evidence that amiodarone or lidocaine improve survival is lacking. In this large multicenter randomized controlled double-blind trial, 3026 adult patients with spontaneously occurring out-of-hospital cardiac arrest and shock-refractory VT or VF were randomized by paramedics to treatment with amiodarone (974), lidocaine (993) or saline placebo (1059), along with standard care. After presentation to the hospital, patients received open-label drugs, emergent angiography, and cooling as clinically indicated. The primary outcome was survival to discharge with secondary outcomes including neurological and functional status in survivors. Mean time to paramedic arrival and study drug administration were 8 and 19 minutes respectively. There was no significant survival difference between the three groups (24.4%, 23.7%, and 21.0% respectively), nor differences in important neurologic outcomes. Treatment with amiodarone did result in shorter CPR times and fewer shocks but also had a higher rate of subsequent cardiac pacing. In the sub-group of patients with a witnessed arrest, both amiodarone and lidocaine significantly improved survival (27.7% vs. 27.8% vs. 22.7%) and this effect was even more apparent when the arrest was witnessed by the paramedic crew (absolute risk reduction of 21.9%), though the trial was not sufficiently powered for these secondary analyses.
Neither amiodarone nor lidocaine improved survival or neurologic status in patients with refractory VT or VF out-of-hospital arrest. It is possible that select populations with better opportunities for survival may realize benefits from these drugs not apparent in the broader, more moribund cohort, but this will need to be tested in an adequately powered study.
Kudenchuk PJ, Brown SP, Daya M, Rea T, Nichol G, Morrison LJ, Leroux B, Vaillancourt C, Wittwer L, Callaway CW, Christenson J, Egan D, Ornato JP, Weisfeldt ML, Stiell IG, Idris AH, Aufderheide TP, Dunford JV, Colella MR, Vilke GM, Brienza AM, Desvigne-Nickens P, Gray PC, Gray R, Seals N, Straight R, Dorian P; Resuscitation Outcomes Consortium Investigators. Amiodarone, Lidocaine, or Placebo in Out-of-Hospital Cardiac Arrest. N Engl J Med. 2016 Aug 25;375(8):802-3.
Hussain Contractor and James M. McCabe