Survival After Out-of-Hospital Cardiac Arrest in Relation to Age and Early Identification of Patients with Minimal Chance of Long-Term Survival

BACKGROUND: -Survival following out-of-hospital cardiac arrest (OHCA) has increased during the last decade in Denmark. We aimed to study the impact of age on changes in survival and whether it was possible to identify patients with minimal chance of 30-day survival.

METHODS AND RESULTS: -Using data from the nationwide Danish Cardiac Arrest Registry (2001─2011), we identified 21,480 patients ≥18 years old with a presumed cardiac-caused OHCA for which resuscitation was attempted. Patients were divided into three pre-selected age-groups: "working-age-patients" aged 18-65 years (33.7%); "early-senior-patients" aged 66-80 years (41.5%); and "late-senior-patients" aged >80 years (24.8%). Characteristics in working-age-patients, early-senior-patients, and late-senior-patients: witnessed arrest 53.8%, 51.1%, and 52.1%; bystander CPR 44.7%, 30.3%, and 23.4%; and pre-hospital shock from a defibrillator 54.7%, 45.0% and 33.8%, all p<0.05. Between 2001 and 2011, return of spontaneous circulation (ROSC) upon hospital arrival increased: working-age-patients from 12.1% to 34.6%; early-senior-patients 6.4% to 21.5%; and late-senior-patients 4.0% to 15.0%, all p<0.001. Furthermore, 30-day survival increased: working-age-patients 5.8% to 22.0%, p<0.001; and early-senior-patients 2.7% to 8.4%, p<0.001; while late-senior-patients only experienced a minor increase 1.5% to 2.0%, p=0.01. Overall, three out of 9499 patients, achieved 30-day survival if they met two criteria: had not achieved ROSC upon hospital arrival; and had not received a pre-hospital shock from a defibrillator.

CONCLUSIONS: -All age groups experienced a large temporal increase in survival on hospital arrival, but the increase in 30-day survival was most prominent in the young. Using only two criteria, it was possible to identify patients with minimal chance of 30-day survival.