title: A multicenter prospective randomized study comparing the efficacy of escalating higher biphasic versus low biphasic energy defibrillations in patients presenting with cardiac arrest in the in-hospital environment.
abstract: BACKGROUND
  Biphasic defibrillation has been practiced worldwide for >15 years. Yet, consensus does not exist on the best energy levels for optimal outcomes when used in patients with ventricular fibrillation (VF)/pulseless ventricular tachycardia (VT).
  
  
  METHODS
  This prospective, randomized, controlled trial of 235 adult cardiac arrest patients with VF/VT was conducted in the emergency and cardiology departments. One group received low-energy (LE) shocks at 150-150-150 J and the other escalating higher-energy (HE) shocks at 200-300-360 J. If return of spontaneous circulation (ROSC) was not achieved by the third shock, LE patients crossed over to the HE arm and HE patients continued at 360 J. Primary end point was ROSC. Secondary end points were 24-hour, 7-day, and 30-day survival.
  
  
  RESULTS
  Both groups were comparable for age, sex, cardiac risk factors, and duration of collapse and VF/VT. Of the 118 patients randomized to the LE group, 48 crossed over to the HE protocol, 24 for persistent VF, and 24 for recurrent VF. First-shock termination rates for HE and LE patients were 66.67% and 64.41%, respectively (P=0.78, confidence interval: 0.65-1.89). First-shock ROSC rates were 25.64% and 29.66%, respectively (P=0.56, confidence interval: 0.46-1.45). The 24-hour, 7-day, and 30-day survival rates were 85.71%, 74.29%, and 62.86% for first-shock ROSC LE patients and 70.00%, 50.00%, and 46.67% for first-shock ROSC HE patients, respectively. Conversion rates for further shocks at 200 J and 300 J were low, but increased to 38.95% at 360 J.
  
  
  CONCLUSIONS
  First-shock termination and ROSC rates were not significantly different between LE and HE biphasic defibrillation for cardiac arrest patients. Patients responded best at 150/200 J and at 360 J energy levels. For patients with VF/pulseless VT, consideration is needed to escalate quickly to HE shocks at 360 J if not successfully defibrillated with 150 or 200 J initially.
authors.affiliation: Department of Emergency Medicine, Singapore General Hospital.
authors.forename: Venkataraman
authors.initials: V
authors.lastname: Anantharaman
authors.affiliation: Department of Emergency Medicine, Tan Tock Seng Hospital.
authors.forename: Seow Yian
authors.initials: SY
authors.lastname: Tay
authors.affiliation: Emergency Medicine Department, National University Hospital.
authors.forename: Peter George
authors.initials: PG
authors.lastname: Manning
authors.affiliation: Department of Emergency Medicine, Singapore General Hospital.
authors.forename: Swee Han
authors.initials: SH
authors.lastname: Lim
authors.affiliation: Department of Cardiology, National Heart Centre.
authors.forename: Terrance Siang Jin
authors.initials: TS
authors.lastname: Chua
authors.affiliation: Accident and Emergency Department, Changi General Hospital, Singapore.
authors.forename: Mohan
authors.initials: M
authors.lastname: Tiru
authors.affiliation: Department of Emergency Medicine, Singapore General Hospital.
authors.forename: Rabind Antony
authors.initials: RA
authors.lastname: Charles
authors.affiliation: Department of Emergency Medicine, Singapore General Hospital.
authors.forename: Vidya
authors.initials: V
authors.lastname: Sudarshan
keywords: cardiopulmonary resuscitation; defibrillation; high-energy; low-energy; sudden cardiac arrest