title: Increase in pre-shock pause caused by drug administration before defibrillation: an observational, full-scale simulation study.
abstract: BACKGROUND
  The importance of circulation during cardiopulmonary resuscitation has led to efforts to decrease time without chest compressions ("no-flow time"). The no-flow time from the interruption of chest compressions until defibrillation is referred to as the "pre-shock pause". A shorter pre-shock pause increases the chance of successful defibrillation. It is unclear whether drug administration affects the length of the pre-shock pause. Our study compares pre-shock pause with and without drug administration in a full-scale simulation.
  
  
  METHODS
  This was an observational study in an ambulance including 72 junior physicians and a cardiac arrest scenario. Data were extracted by reviewing video recordings of the resuscitation. Sequences including defibrillation and/or drug administration were identified and assigned to one out of four categories: Defibrillation only (DC-only) and drug administration just prior to defibrillation (Drug+DC) for which the pre-shock pause was calculated, and drug administration alone (Drug-only) for which pre-drug time was calculated.
  
  
  RESULTS
  DC-only sequences were identified in 68/72 simulations, Drug+DC in 24/72, and Drug-only in 33/72. Median pre-shock pauses were 18s (DC-only) and 32 (Drug+DC), and median pre-drug pause 6. The variation between pauses was statistically significant (p<<0.001). DC-only and Drug+DC sequences was found in 22/72 simulations. A statistically significant difference of 8s was found between the median pre-shock pauses: 17s (DC-only) and 25 (Drug+DC) (p<<0.001). For un-paired observations, the pre-shock pause increased with 78% and for paired observations 47%.
  
  
  CONCLUSIONS
  Drug administration prior to defibrillation was associated with significant increases in pre-shock pauses in this full-scale simulation study.
authors.affiliation: Centre for Medical Education, Faculty of Health Sciences, University of Aarhus, Aarhus N, Denmark. cbh@medu.au.dk
authors.forename: Christian Bjerre
authors.initials: CB
authors.lastname: Høyer
authors.forename: Erika F
authors.initials: EF
authors.lastname: Christensen
authors.forename: Berit
authors.initials: B
authors.lastname: Eika
mesh_terms: D054058:Acute Coronary Syndrome / Q000150:complications / Q000628:therapy; D016887:Cardiopulmonary Resuscitation / Q000379:methods*; D002316:Cardiotonic Agents / Q000008:administration & dosage*; D003198:Computer Simulation; D003326:Coronary Circulation; D004334:Drug Administration Schedule; D004554:Electric Countershock; D006323:Heart Arrest / Q000209:etiology / Q000503:physiopathology* / Q000628:therapy*; D006336:Heart Massage; D006801:Humans; D007275:Injections, Intravenous; D008348:Manikins; D013997:Time Factors; D014693:Ventricular Fibrillation / Q000209:etiology / Q000628:therapy; D014743:Videotape Recording
chemical_list: D002316:Cardiotonic Agents