title: Wide variation in cardiopulmonary resuscitation interruption intervals among commercially available automated external defibrillators may affect survival despite high defibrillation efficacy.
abstract: OBJECTIVE
  Recent studies have associated interruptions of cardiopulmonary resuscitation imposed by automated external defibrillators (AEDs) with poor resuscitation outcome. In particular, the "hands-off" interval between precordial compressions and subsequent defibrillation shock has been implicated. We sought to determine the range of variation among current-generation AEDs with respect to this characteristic.
  
  
  METHODS
  Seven AEDs from six manufacturers were characterized via stopwatch and arrhythmia simulator with respect to the imposed hands-off interval. All AEDs were equipped with new batteries, and measurements were repeated five times for each AED.
  
  
  RESULTS
  A wide variation in the hands-off interval between precordial compressions and shock delivery was observed, ranging from 5.2 to 28.4 secs, with only one AED achieving an interruption of <10 secs. Laboratory and clinical data suggest that this range of variation could be responsible for a more than two-fold variation in patient resuscitation success, an effect that far exceeds any defibrillation efficacy differences that may hypothetically exist.
  
  
  CONCLUSIONS
  In addition to defibrillation waveform and dose, researchers should consider the hands-off cardiopulmonary resuscitation interruption interval between cardiopulmonary resuscitation and subsequent defibrillation shock to be an important covariate of outcome in resuscitation studies. Defibrillator design should minimize this interval to avoid potential adverse consequences on patient survival.
authors.affiliation: Philips Medical Systems, Seattle, WA, USA.
authors.forename: David
authors.initials: D
authors.lastname: Snyder
authors.forename: Carl
authors.initials: C
authors.lastname: Morgan
mesh_terms: D016887:Cardiopulmonary Resuscitation; D004554:Electric Countershock / Q000295:instrumentation*; D004867:Equipment Design; D006323:Heart Arrest / Q000628:therapy*; D006801:Humans; D016896:Treatment Outcome