Among patients who survive after out-of-hospital cardiac arrest (OHCA), a large proportion are recruited from cases witnessed by the Emergency Medical Service (EMS), since the conditions for success are most optimal in this subset.
To evaluate outcome after EMS-witnessed OHCA in a 20-year perspective in Sweden, with the emphasis on changes over time and factors of importance.
All patients included in the Swedish Cardiac Arrest Register from 1990 to 2009 were included.
There were 48,349 patients and 13.5% of them were EMS witnessed. There was a successive increase in EMS-witnessed OHCA from 8.5% in 1992 to 16.9% in 2009 (p for trend