title: Improved survival after out-of-hospital cardiac arrest is associated with an increase in proportion of emergency crew--witnessed cases and bystander cardiopulmonary resuscitation.
abstract: BACKGROUND
  Out-of-hospital cardiac arrest (OHCA) is a major public health problem. We sought to describe changes in 1-month survival after OHCA in patients given cardiopulmonary resuscitation (CPR) during the last 14 years in Sweden.
  
  
  RESULTS
  All patients experiencing OHCA in whom CPR was attempted between 1992 and 2005 and who were reported to the Swedish Cardiac Arrest Register were included in the study. In all, 38,646 patients were included in this survey. The proportion of patients who were admitted alive to a hospital increased from 15.3% in 1992 to 21.7% in 2005 (P for trend <0.0001). The corresponding values for patients being alive after 1 month were 4.8% and 7.3%, respectively (P for trend <0.0001). The increase in 1-month survival was particularly evident among patients found with a shockable rhythm (increase from 12.7% in 1992 to 22.3% in 2005; P for trend <0.0001). The corresponding figures for patients found with a nonshockable rhythm were 1.2% in 1992 and 2.3% in 2005 (P for trend=0.044). Factors that potentially contributed to the improved survival rate were an increase in emergency medical crew-witnessed cases from 9% in 1992 to 15% in 2005 (P for trend <0.0001) and, to a lesser degree, an increase in bystander CPR from 31% in 1992 to 50% in 2005 (P for trend <0.0001). After adjustment for potential risk factors, the increase in survival remained significant.
  
  
  CONCLUSIONS
  We found a significant increase in survival after OHCA in Sweden over the last 14 years. The increase was particularly marked among patients found with a shockable rhythm and was associated with an increase in the proportion of crew-witnessed cases and, to a lesser degree, an increase in the performance of bystander CPR.
authors.affiliation: Department of Cardiology, South Hospital, Karolinska Institute, SE-118 83 Stockholm, Sweden. jacob.hollenberg@sodersjukhuset.se
authors.forename: Jacob
authors.initials: J
authors.lastname: Hollenberg
authors.forename: Johan
authors.initials: J
authors.lastname: Herlitz
authors.forename: Jonny
authors.initials: J
authors.lastname: Lindqvist
authors.forename: Gabriel
authors.initials: G
authors.lastname: Riva
authors.forename: Katarina
authors.initials: K
authors.lastname: Bohm
authors.forename: Mårten
authors.initials: M
authors.lastname: Rosenqvist
authors.forename: Leif
authors.initials: L
authors.lastname: Svensson
mesh_terms: D000368:Aged; D016887:Cardiopulmonary Resuscitation / Q000401:mortality* / Q000706:statistics & numerical data / Q000639:trends*; D004634:Emergency Medical Technicians; D005260:Female; D006323:Heart Arrest / Q000401:mortality / Q000628:therapy*; D006801:Humans; D008297:Male; D015996:Survival Rate; D013548:Sweden; D016896:Treatment Outcome