Cardiac arrest outside and inside hospital from a 30 year perspective in the Municipality of Gothenburg

Abstract

Aims: 1:To describe the epidemiology of both out-of-hospital cardiac arrest (OHCA) and in-hospital cardiac arrest (IHCA) in the Municipality of Gothenburg. 2:To describe the differences and similarities in cardiac arrest inside and outside hospital. 3:To describe the eventual change in outcome following the implementation of mechanical chest compression in the emergency medical service. Method: Consecutive OHCA cases in the Municipality of Gothenburg between 1980 and 2009 to which the emergency medical service responded were followed up to hospital discharge and at 1-month after the event for survival and neurological outcome according to the Utstein guidelines. Consecutive IHCA cases at Sahlgrenska university hospital between 1994 and 2006 to which the rescue team was called were followed up to discharge and at one month after the event for survival and neurological outcome according to the Utstein guidelines. We used the Swedish Cardiac Arrest Register for comparison. Results: In the time period 1980 - 1999 there were 5270 resuscitation attempts in relation to OHCA of which 3871 were regarded as being of cardiac aetiology. The delay to defibrillation was short (8 minutes median) and 27 percent of the witnessed OHCAs and 12 percent of the unwitnessed OHCAs received bystander-CPR. In all, 8.8% survived to discharge. In the Utstein ”golden standard” (bystander-witnessed cardiac arrest of cardiac aetiology found in ventricular fibrillation), 20 % were discharged from hospital. In the time period 1994 – 2002, the rescue team at Sahlgrenska University hospital was called 1570 times. In 71% of the cases, the patient had suffered a cardiac arrest. If the patients found in ventricular fibrillation were defibrillated within three minutes, survival to discharge was 63% if the IHCA occurred on a ward with ECG-monitoring capacity and 72% if the IHCA occurred on a ward without ECG-monitoring capacity. Of IHCAs between 1994 and 2001 (n=833) 37 per cent survived to hospital discharge, and 86 percent of them were alive one year later. The survival after IHCA was three times higher compared with OHCA for shockable rhythms and seven times higher for non-shockable rhythms. Between 1992 and 2009, curve for the survival after OHCA had a U shape, with the highest survival at the beginning and at the end. During the last decade, there was an increase in survival which was associated in terms of time with an increase in the use of mechanical chest compression. However, other factors of importance for survival, such as bystander CPR and post-resuscitation care, also changed. Conclusion: If patients with ventricular fibrillation are defibrillated within three minutes after collapse, the majority will survive. There are changes in survival after OHCA in Gothenburg over time with improvement and deterioration. The mechanisms behind these changes are not entirely understood, but a delay to start of treatment and post-resuscitation care are most probably important. Survival after IHCA is much higher than after OHCA, but this is not solely explained by a short time to the delivery of treatment.