Abstract and Introduction
Abstract
Aims To describe out-of-hospital cardiac arrest (OHCA) in Sweden from a long-term perspective in terms of changes in outcome and circumstances at resuscitation.
Methods and results All cases of OHCA (n = 59 926) reported to the Swedish Cardiac Arrest Register from 1992 to 2011 were included. The number of cases reported (n/100 000 person-years) increased from 27 (1992) to 52 (2011). Crew-witnessed cases, cardiopulmonary resuscitation prior to the arrival of the emergency medical service (EMS), and EMS response time increased (P < 0.0001). There was a decrease in the delay from collapse to calling for the EMS in all patients and from collapse to defibrillation among patients found in ventricular fibrillation (P < 0.0001). The proportion of patients found in ventricular fibrillation decreased from 35 to 25% (P < 0.0001). Thirty-day survival increased from 4.8 (1992) to 10.7% (2011) (P < 0.0001), particularly among patients found in a shockable rhythm and patients with return of spontaneous circulation (ROSC) at hospital admission. Among patients hospitalized with ROSC in 2008–2011, 41% underwent therapeutic hypothermia and 28% underwent percutaneous coronary intervention. Among 30-day survivors in 2008–2011, 94% had a cerebral performance category score of 1 or 2 at discharge from hospital and the results were even better if patients were found in a shockable rhythm.
Conclusion From a long-term perspective, 30-day survival after OHCA in Sweden more than doubled. The increase in survival was most marked among patients found in a shockable rhythm and those hospitalized with ROSC. There were improvements in all four links in the chain of survival, which might explain the improved outcome.
Introduction
The reported incidence of treated out-of-hospital cardiac arrest (OHCA) has varied over time between countries and also among counties. In Europe, the reported incidence of treated OHCA has varied between17 and 53 per 100 000 person-years. Recent experience from Sweden suggests some under-reporting on the incidence of OHCA. Furthermore, survival after OHCA has generally been reported to be low, but there has been variability between reports. Nevertheless, in previous studies, there has been an increase in survival over time, regardless of the initial rhythm and witnessed status among patients with OHCA in whom resuscitation was attempted.
At present, there are a number of large registries, such as the Resuscitation Outcomes Consortium (ROC), the Cardiac Arrest Registry to Enhance Survival (CARES), the Victorian Ambulance Cardiac Arrest Register (VACAR), the European Cardiac Arrest Register (EuReCa), and the Swedish Cardiac Arrest Register (SCAR). However, it is possible to argue about whether they are comparable in terms of validity. These registries gather the data prospectively. The number of cases in which information is missing when it comes to important clinical variables, as well as the inclusion and exclusion criteria for participation, will determine the comparability of the registries. To document and present OHCA data in a comparable way, the Utstein template is recommended. An additional factor is that there are also different medical records in the emergency medical service (EMS) systems which will influence the structure of recording and the opportunity to report OHCA data.
The aim of this study is to describe OHCA in Sweden from a long-term perspective in terms of changes in outcome, circumstances at resuscitation, and validity based on the information gathered from the SCAR.