Out-of-hospital cardiac arrest affects approximately 300 000 individuals in North America annually, with an incidence of treated out-of-hospital cardiac arrest of approximately 56 per 100 000 person-years.^1,2 In Denmark, the corresponding incidence has previously been calculated to be 62 per 100 000 person-years, with approximately 3500 treated annually.³ Despite efforts to improve prognosis, survival remains low, with aggregated survival-to-discharge rates less than 8%.^1,4,5 In many cases, time from recognition of cardiac arrest to the arrival of emergency medical services (EMS) is long,⁵ leaving bystanders in a critical position to potentially influence patient prognosis through intervention before EMS arrival.^5-7 However, only a minority of cardiac arrests receive bystander cardiopulmonary resuscitation (CPR).^1,5,8

Remote ischaemic conditioning with transient ischaemia and reperfusion applied to the arm has been shown to reduce myocardial infarct size in patients with ST-elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PPCI). We investigated whether remote ischaemic conditioning could reduce the incidence of cardiac death and hospitalisation for heart failure at 12 months. We did an international investigator-initiated, prospective, single-blind, randomised controlled trial (CONDI-2/ERIC-PPCI) at 33 centres across the UK, Denmark, Spain, and Serbia. Patients (age >18 years) with suspected STEMI and who were eligible for PPCI were randomly allocated (1:1, stratified by centre with a permuted block method) to receive standard treatment (including a sham simulated remote ischaemic conditioning intervention at UK sites only) or remote ischaemic conditioning treatment (intermittent ischaemia and reperfusion applied to the arm through four cycles of 5-min inflation and 5-min deflation of an automated cuff device) before PPCI. Investigators responsible for data collection and outcome assessment were masked to treatment allocation. The primary combined endpoint was cardiac death or hospitalisation for heart failure at 12 months in the intention-to-treat population. This trial is registered with ClinicalTrials.gov (NCT02342522) and is completed. Between Nov 6, 2013, and March 31, 2018, 5401 patients were randomly allocated to either the control group (n=2701) or the remote ischaemic conditioning group (n=2700). After exclusion of patients upon hospital arrival or loss to follow-up, 2569 patients in the control group and 2546 in the intervention group were included in the intention-to-treat analysis. At 12 months post-PPCI, the Kaplan-Meier-estimated frequencies of cardiac death or hospitalisation for heart failure (the primary endpoint) were 220 (8·6%) patients in the control group and 239 (9·4%) in the remote ischaemic conditioning group (hazard ratio 1·10 [95% CI 0·91-1·32], p=0·32 for intervention versus control). No important unexpected adverse events or side effects of remote ischaemic conditioning were observed. Remote ischaemic conditioning does not improve clinical outcomes (cardiac death or hospitalisation for heart failure) at 12 months in patients with STEMI undergoing PPCI. British Heart Foundation, University College London Hospitals/University College London Biomedical Research Centre, Danish Innovation Foundation, Novo Nordisk Foundation, TrygFonden.

The emergency medical healthcare system outside hospital varies greatly across the globe - even within the western world. Within the last ten years, the demand for emergency medical service systems has increased, and the Danish emergency medical service system has undergone major changes. Therefore, we aimed to provide an updated description of the current Danish prehospital medical healthcare system. Since 2007, Denmark has been divided into five regions each responsible for health services, including the prehospital services. Each region may contract their own ambulance service providers. The Danish emergency medical services in general include ambulances, rapid response vehicles, mobile emergency care units and helicopter emergency medical services. All calls to the national emergency number, 1-1-2, are answered by the police, or the Copenhagen fire brigade, and since 2011 forwarded to an Emergency Medical Coordination Centre when the call relates to medical issues. At the Emergency Medical Coordination Centre, healthcare personnel assess the situation guided by the Danish Index for Emergency Care and determine the level of urgency of the situation, while technical personnel dispatch the appropriate medical emergency vehicles. In Denmark, all healthcare services, including emergency medical services are publicly funded and free of charge. In addition to emergency calls, other medical services are available for less urgent health problems around the clock. Prehospital personnel have since 2015 utilized a nationwide electronic prehospital medical record. The use of this prehospital medical record combined with Denmark’s extensive registries, linkable by the unique civil registration number, enables new and unique possibilities to do high quality prehospital research, with complete patient follow-up.

A criteria-based nationwide Emergency Medical Dispatch (EMD) system was recently implemented in Denmark. We described the system and studied its ability to triage patients according to the severity of their condition by analysing hospital admission and case-fatality risks.

Background—: Data on long-term function of out-of-hospital cardiac arrest survivors are sparse. We examined return to work as a proxy of preserved function without major neurologic deficits in survivors. Methods and Results—: In Denmark, out-of-hospital cardiac arrests have been systematically reported to the Danish Cardiac Arrest Register since 2001. During 2001–2011, we identified 4354 patients employed before arrest among 12 332 working-age patients (18–65 years), of whom 796 survived to day 30. Among 796 survivors (median age, 53 years [quartile 1–3, 46–59 years]; 81.5% men), 610 (76.6%) returned to work in a median time of 4 months [quartile 1–3, 1–19 months], with a median time of 3 years spent back at work. A total of 74.6% (N=455) remained employed without using sick leave during the first 6 months after returning to work. This latter proportion of survivors returning to work increased over time (66.1% in 2001–2005 versus 78.1% in 2006–2011; P =0.002). In multivariable Cox regression analysis, factors associated with return to work with ≥6 months of sustainable employment were as follows: (1) arrest during 2006–2011 versus 2001–2005, hazard ratio (HR), 1.38 (95% CI, 1.05–1.82); (2) male sex, HR, 1.48 (95% CI, 1.06–2.07); (3) age of 18 to 49 versus 50 to 65 years, HR, 1.32 (95% CI, 1.02–1.68); (4) bystander-witnessed arrest, HR, 1.79 (95% CI, 1.17–2.76); and (5) bystander cardiopulmonary resuscitation, HR, 1.38 (95% CI, 1.02–1.87). Conclusions—: Of 30-day survivors employed before arrest, 76.6% returned to work. The percentage of survivors returning to work increased significantly, along with improved survival during 2001–2011, suggesting an increase in the proportion of survivors with preserved function over time.

Background—: Survival after out-of-hospital cardiac arrest 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 out-of-hospital cardiac arrest for which resuscitation was attempted. Patients were divided into 3 preselected age-groups: working-age patients 18 to 65 years of age (33.7%), early senior patients 66 to 80 years of age (41.5%), and late senior patients >80 years of age (24.8%). Characteristics in working-age patients, early senior patients, and late senior patients were as follows: witnessed arrest in 53.8%, 51.1%, and 52.1%; bystander cardiopulmonary resuscitation in 44.7%, 30.3%, and 23.4%; and prehospital shock from a defibrillator in 54.7%, 45.0%, and 33.8% (all P <0.05). Between 2001 and 2011, return of spontaneous circulation on hospital arrival increased: working-age patients, from 12.1% to 34.6%; early senior patients, from 6.4% to 21.5%; and late senior patients, from 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), whereas late senior patients experienced only a minor increase (1.5% to 2.0%; P =0.01). Overall, 3 of 9499 patients achieved 30-day survival if they met 2 criteria: had not achieved return of spontaneous circulation on hospital arrival and had not received a prehospital 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. With the use of only 2 criteria, it was possible to identify patients with a minimal chance of 30-day survival.