title: Who survives from out-of-hospital pulseless electrical activity?
abstract: OBJECTIVE
  To study factors associated with short-term and long-term survival after out-of-hospital cardiac arrest presenting with pulseless electrical activity (PEA).
  
  
  METHODS
  This was a retrospective observational study. All out-of-hospital cardiac arrests in Helsinki, Finland during 1 January 1997-31 December 2005 were prospectively registered in the cardiac arrest database. Of 3291 arrests 984 had PEA as the first registered rhythm.
  
  
  RESULTS
  The use of adrenaline was the only factor associated with long-term survival, by increasing mortality. Increasing delay to the return of spontaneous circulation (ROSC) was the only factor associated with survival among patients that survived to admission, also by increasing mortality. There were no survivors that were discharged in overall performance category (OPC) 1-2 after a bystander-witnessed arrest (excluding cases of hypothermia and/or near-drowning) with first responding unit (FRU)-delay over 14 min, or that were resuscitated for more than 20 min. There were no survivors who were discharged in OPC 1-2 after an unwitnessed arrest with the duration of advanced life support (ALS) exceeding 5.5 min.
  
  
  CONCLUSIONS
  The use of adrenaline during resuscitation was the only significant factor which was found to decrease the long-term survival. Among admitted patients, short delay to ROSC was the only factor associated with increased survival. Bystander-CPR and delays to the arrival of the FRU or to the initiation of ALS were not associated with survival. Therefore, it seems difficult to increase survival rates of PEA by improving the chain of survival. More effort should be put to education of the public to call for an ambulance before the cardiac arrest occurs.
authors.affiliation: Helsinki Emergency Medical Services (EMS), Department of Anaesthesiology and Intensive Care Medicine, Helsinki University Central Hospital, P.O. Box 112, FIN-00099 Helsingin Kaupunki, Finland. Taneli.vayrynen@hus.fi
authors.forename: Taneli
authors.initials: T
authors.lastname: Väyrynen
authors.forename: Markku
authors.initials: M
authors.lastname: Kuisma
authors.forename: Teuvo
authors.initials: T
authors.lastname: Määttä
authors.forename: James
authors.initials: J
authors.lastname: Boyd
mesh_terms: D000368:Aged; D004562:Electrocardiography; D004632:Emergency Medical Services; D005260:Female; D005387:Finland / Q000453:epidemiology; D005500:Follow-Up Studies; D006323:Heart Arrest / Q000401:mortality* / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D010045:Outpatients; D012189:Retrospective Studies; D015996:Survival Rate; D013997:Time Factors; D014505:Urban Population