First-response treatment after out-of-hospital cardiac arrest: a survey of current practices across 29 countries in Europe

Background In Europe, survival rates after out-of-hospital cardiac arrest (OHCA) vary widely. Presence/absence and differences in implementation of systems dispatching First Responders (FR) in order to arrive before Emergency Medical Services (EMS) may contribute to this variation. A comprehensive overview of the different types of FR-systems used across Europe is lacking. Methods A mixed-method survey and information retrieved from national resuscitation councils and national EMS services were used as a basis for an inventory. The survey was sent to 51 OHCA experts across 29 European countries. Results Forty-seven (92%) OHCA experts from 29 countries responded to the survey. More than half of European countries had at least one region with a FR-system. Four categories of FR types were identified: (1) firefighters (professional/voluntary); (2) police officers; (3) citizen-responders; (4) others including off-duty EMS personnel (nurses, medical doctors), taxi drivers. Three main roles for FRs were identified: (a) complementary to EMS; (b) part of EMS; (c) instead of EMS. A wide variation in FR-systems was observed, both between and within countries. Conclusions Policies relating to FRs are commonly implemented on a regional level, leading to a wide variation in FR-systems between and within countries. Future research should focus on identifying the FR-systems that most strongly influence survival. The large variation in local circumstances across regions suggests that it is unlikely that there will be a ‘one-size fits all’ FR-system for Europe, but examining the role of FRs in the Chain of Survival is likely to become an increasingly important aspect of OHCA research.


Introduction
Out-of-hospital cardiac arrest (OHCA) is lethal within minutes of collapse if left untreated, and the majority of OHCA patients die before hospital admission [1,2]. If early cardiopulmonary resuscitation (CPR) is provided, survival rate increases [3,4]. In particular, presence of shockable rhythm is an important determinant of survival, and OHCA patients who are found with a shockable initial rhythm are more likely to survive if they are defibrillated with an automated external defibrillator (AED) [5]. However, many OHCA patients are not found in a shockable rhythm due to prolonged emergency medical services (EMS) response times, particularly in residential areas where most OHCAs occur [6][7][8]. When CPR is started quickly after collapse, the length of time that a shockable rhythm persists may be extended [9], thus prolonging the opportunity for successful defibrillation. Identifying and implementing systems that increase the likelihood of immediate CPR provision and rapid defibrillation are vital to improving survival. The deployment of First Responders (FRs) is one method that has been developed in order to meet this challenge.
FR-systems have been implemented differently across Europe. Some countries have expanded the traditional EMS response with dispatch of CPR trained firefighters and police officers equipped with AEDs. Research has shown that the introduction of these types of dispatched FRs led to shorter response times [10], and increased 30 day survival [11,12]. Dispatch of trained citizen-FRs may also be successful in reducing response time [13], time to initiation of CPR [14,15], time to defibrillation [16], and overall survival [17].
Survival rates after OHCA vary widely between regions across Europe [2] and the presence or absence of FRsystems, and differences in their implementation, may contribute to this variation. For instance, FRs may be less effective when they are inefficiently deployed and/or time from collapse to initiation of CPR is prolonged when the technology used for FR dispatch is suboptimal [15]. In addition, differences in FR skill sets may contribute, e.g., level of resuscitation training, available equipment, and experience in coping with emergency situations.
Survival rates after OHCA may increase across Europe if FR-systems are optimized. Similarly, optimization efforts may benefit from past experiences in FR implementation across Europe. However, to date, no comprehensive inventory of the different types of dispatched FR-systems used across Europe exists. Additionally, while the most recent European Resuscitation Guidelines emphasise the importance of community response in saving lives [18], the extent to which establishment of FR-systems has been adopted as national policy across Europe is unknown. Therefore, the aim of this paper is to create an inventory of dispatched FR-systems across Europe, and to determine whether countries have a national policy regarding FRsystems. This will serve as a basis to highlight key differences in order to ultimately optimise FR-systems across Europe.

Design and set up
This research was conducted as part of the ESCAPE-NET project that aims to discover the causes and best treatments of OHCA [19]. A mixed-method survey was combined with information retrieved from national resuscitation councils and national EMS services as a basis for an inventory.

Survey and information gathering
The content of the survey was determined after several meetings with an expert panel, consisting of five experts in the field of OHCA (three cardiologists, one EMSconsultant and one intensive care nurse; initials: IT, RK, AT, FS, and MR) in Europe. The survey was built by Dutch researchers and finalised after a pilot carried out by Amsterdam Resuscitation Studies (ARREST) [20] researchers.
The survey was sent to 51 OHCA professionals across 29 European countries between August and November 2018 (Additional file 1: Supplementary 1a). An OHCA professional was defined as a European Resuscitation Council (ERC) or ESCAPE-NET member with a long working experience (≥5 years) in the field of OHCA and, in particular, in prehospital resuscitation strategies. OHCA professionals were recruited during the ESCAPE-NET [19] and EuReCa [2] sessions at the ERC Congress in Bologna, 2018 (additional file 1: Supplementary 1a). Informed consent for using the contact details of the participants was sought and provided. A second attempt was made to get non-responding survey participants to take part within three weeks. All survey results were validated with the respondents before results were finalised.
In addition, data on national policies regarding FRs was sought from national resuscitation councils (or national EMS services where no council existed). If no response from a national council was received within three weeks, other national experts in the field of OHCA were consulted. Similar to the survey respondents, national experts had a long working experience (≥5 years) in the field of OHCA and were identified using the ERC or ESCAPE-NET network. Where possible, answers from survey respondents and national resuscitation councils were cross checked.

Definitions
For the purposes of this study, EMS and FRs were defined as follows:

Emergency medical services (EMS)
Emergency Medical Services included on-duty emergency medical personnel who were dispatched by a dispatch centre to provide acute medical care and to transport the patient to a hospital equipped to provide acute care.

First responder (FR)
First Responders were defined as all individuals who were dispatched by a dispatch centre to attend OHCA events and initiate early CPR. FRs potentially included firefighters and police officers (traditional FRs) [21,22], off-duty EMS staff and citizen-responders. An extensive description of EMS and FRs is provided in Additional file 1: Supplementary 1b.

FR-system
The availability of dispatched FRs was determined for each country and/or region. A FR-system was defined as nationwide when it covered ≥50% of the country. The FR-system was described and characteristics were assessed (by examining each individual type of FR, as part of the FR-system). Characteristics included: recruitment and activation methods, role on scene, equipment, CPR training and frequency of training, registration, feedback, financial support, and emotional support. An extensive description of all characteristics is provided in Additional file 1: Supplementary 1c.

Results
The response rate to the survey was 92% (47/51); information was obtained from 29 countries. For the specific questions on national policy, the response rate from national resuscitation councils was 62% (16/26; in 26 of the 29 studied countries, a national resuscitation council existed). This rate increased to 77% (20/26) after consulting other experts.
The survey identified three main roles for FRs in the event of OHCA: 1) Complementary to the statutory EMS response; 2) Part of the statutory EMS response; 3) Instead of EMS.
More than half (19 of 29) of European countries or regions thereof had FR-systems (Fig. 2a). Such FR-systems were implemented nationwide in 16 countries, and regionally in 3 countries. In 14 countries, the FR-systems acted complementary to the statutory EMS response, while in one country FRs were part of the EMS response (France), and in another, FRs substituted the EMS (remote areas in Iceland). In 10 of 29 countries there was no dispatched FR-system (Fig. 2b).

Variation in first responder-systems nationally and regionally
Variation in the type of FR-systems was observed both between and within countries. FR-systems with one FR type existed nationwide in 8 countries and regionally in 9 countries. FR-systems with two FR types existed regionally in eight countries. FR-systems including three or four FR types existed nationwide in 6 countries and regionally in 2 countries (Fig. 2a, Additional file 1: Supplementary 2).

Characteristics of first responder-systems
Next, we analysed the characteristics of the FR types in more detail. Tables 1, 2 and 3 list the characteristics of firefighters, citizen-responders and police officers; Additional file 1: Table S1 lists the characteristics of the "other FRs". A summarised description is provided below. Response characteristics: availability and alerts Different methods were used to alert FRs. For firefighters and police officers, a standard communication system is often used. A smaller proportion of regions used a dedicated mobile phone alert (Tables 1 and 3). Citizen-responders are dispatched using a dedicated mobile phone alert in all but one region (in which only the standard communication system is used). While firefighters and police officers tend to be available on a 24/7 basis, this is not the case for all FR types (Table 2).
In several countries, there is an age threshold to be dispatched as a citizen-responder (e.g., ≥16 or ≥ 18 years). Also, in a few countries there is no dispatch of citizen-responders to children (e.g., < 8 years).

Equipment
In every country and region, FRs either carry an AED, or are directed by the dispatch centre to the nearest publicly accessible AED. Safety jackets, pocket masks, mobile phones, and rescuer kits are generally part of the equipment.

Training and registration
In most European regions, CPR training is required and checked before FRs can be dispatched, except for citizenresponders in Denmark (in two regions: Capital region and Central region) and Hungary. The frequency of mandatory CPR training differed between countries, particularly for citizen-responders (varying from monthly training to none). In Italy, untrained citizens are by law not allowed to use an AED, but can perform CPR.
Citizen-responders are most commonly registered in online databases such as HartslagNu (the Netherlands), MOMENTUM (Switzerland), O2 SOS (Czech Republic), DAE respondER (Italy). In some countries, including Ireland and Scotland, registration is managed by the       If citizen-responders are considered to be implemented in the total country, differences in density and characteristics, from city to city, may exist Abbreviations: as in Table 1 a The respondent specifically indicated that APP usage is not universal and (major) differences   If police officers are considered to be implemented in the total country, differences in density and characteristics, from city to city, may exist Abbreviations: as in Table 1 Oving et al. ambulance service on an EMS-owned database. Several countries (Denmark: region Zealand and Southern Denmark, Czech Republic, Ireland and Switzerland) require absence of a criminal record (or of a criminal conviction of significance) in order to be able to register as a citizen-responder.

National and regional policies
Policies relating to the implementation of FR-systems are described on national or regional level, or both ( Table 4). National policies may apply to the total FRsystem or may be limited to one FR type only (Additional file 1: Table S2).

Future implementations of FR-systems in Europe
As shown in Fig. 2b, some countries did not dispatch FRs to attend an OHCA at the time of the survey. Respondents from Bosnia-Herzegovina, Croatia, Cyprus, Estonia, Greece, France, Iceland, and Serbia were not aware of plans to introduce FR-systems to their countries in the short term. Specific reasons for this are described in Additional file 1: Table S2, and include: (1) implementation of FRs is not a subject of interest or not considered as a priority; (2) there is a lack of a legal background definition for FRs, and (3) there are some local unmapped AEDs, but the location of these AEDs is not available to the dispatch centre. At the time of our survey, in Malta, government and non-governmental organisations were negotiating to implement a FR-system. In Spain, at least two regional EMS-systems were recruiting citizens to respond to OHCA. In Italy, there were indications that the Province of Pavia would begin implementing FR-systems within a few months (Additional file 1: Table S2).

Key findings
Our study shows the variety of FR-systems that have developed in Europe to expedite provision of good quality CPR and defibrillation in case of an OHCA. These FRsystems have either been implemented nationwide or regionally, and development is primarily influenced by local initiatives, circumstances and opportunities. Policies regarding FRs are commonly implemented on a regional level, even if a national policy exists. This has resulted in a wide variety of FR-systems both between and within countries. Even in countries that do not have FR-systems in place, local and national initiatives to implement FR-systems are being developed.

The need for FR-systems
The evidence for the benefits of early defibrillation are clear, therefore it may be suggested that increasing the number of AEDs available should be sufficient to improve OHCA survival. However, an increased number of AEDs alone is unlikely to improve survival in a costeffective manner, as demonstrated by an Irish Health Technology Assessment which calculated that an investment of €105 million in AED purchase would yieldat bestan additional 10 lives saved per year [23]. Rather, the strategic deployment of AEDs by CPR-competent FRs may be an important link in the Chain of Survival [12,16,17], as acknowledged in the most recent European Resuscitation Guidelines [18].
We observed that, even in countries with a national FR-policy, the organisation of FR-systems is often managed by regional EMS. The design of FR-systems is thus commonly influenced by local circumstances and by what is available. For instance, in Slovenia, a FR-system with voluntary firefighters was chosen because of the extensive network of volunteer fire brigades across all villages. Although there is interest from police officers to be part of this FR-system, the network of police patrols in Slovenia is less dense than that of fire fighters and, therefore, police are not included in the FR-system.

Important aspects of FR-systems
It is unlikely that a "one size fits all" FR-system in Europe can be implemented. However, by combining results from this study with previous studies, some important aspects of FR-systems have been identified.
First, FR type and number of dispatched FR types within one FR-system may be important. In our study, firefighters featured highly as FR types and previous research has demonstrated their role in OHCA-survival [11,12,24,25]. FR-systems involving police officers and/ or dispatched citizen-responders are very promising, but more research is needed [14,26,27]. In certain regions, multiple FR types in one FR-system exist. So far, only limited evidence towards the effectiveness of having multiple FR-types is available. A study performed in the Netherlands by Zijlstra and colleagues showed that, while the contribution of citizen-responders was limited by the strong involvement of other FRs and their competing contribution to OHCA care, it was estimated that, without the citizen-responders, 7.3% of patients would not have received a first shock within 6 min [16]. Also, in Sweden, a study comparing additional dispatch of CPR trained firefighters and police officers equipped with AEDs to a control group where only EMS was dispatched showed that dispatching these two FRs was associated with a significant increase in 30-day survival [27]. However, more research is needed.
Second, the method of alerting FRs matters. Our results showed that firefighter and police FRs are commonly alerted by their own standard dispatch system, and previous evidence highlighted the benefit of direct communication between the EMS and firefighter and Czech Republic National and regional There is a national policy related to professional FRs (firefighters/police officers). This policy is very general (e.g. CPR training requirement). All 14 regional EMS organizations in the country have been using professional FRs to some extent. They differ a little across the areas to optimise the best strategy per region. Only 1 EMS has also introduced a mobile app for alerting FRs, incl. Both off-duty EMS personnel and citizen FRs. Citizen FRs need to have a valid BLS/AED course certificate.
Denmark National and regional Denmark has a strategy of engaging the community in saving lives after OHCA and succeeded in tripling the bystander rate and the survival after OHCA within the last 15 years. New programs dispatching citizen-responders through a smart phone application has been implemented within the last few years. The government of Denmark supports the 10 steps of increasing survival after OHCA defined by the Global Resuscitation Alliance, GRA: https://www.globalresuscitationalliance.org/wp-content/pdf/acting_on_the_call.pdf and has a national "Resuscitation Academy" program working to implement the 10 steps in the five Danish regional EMS organizations. Denmark also has some experience including professional fire fighters and police at OHCA already and expects to strengthen this collaboration within the next years.
Ireland National and regional The National Ambulance Service has a history of FR involvement which predates the 2000s. General practitioners have been acting as FRs in selected parts of the country since the early 1990s. The first formal recommendation to support the development of first responders appears in the following national document which was produced by our Department of Health: "Reducing the Risk: A Strategic Approach. Report of the Task Force on Sudden Cardiac Death (2006)". The National Ambulance Service has policy and procedure documents to support first responder involvement in cardiac arrest response. Ireland is in the process of developing a national OHCA strategy, which will include further specific recommendations to further the development of first response in Ireland.

Italy
Regional Law in Italy: Citizen trained in BLS are allowed to start CPR and to use an AED; citizens not trained can start CPR and use an AED accordingly to the law that regulates the "state of necessity" in emergency situations. The law in Italy for FRs and untrained lay people is a barrier to diffusion of bystander intervention. Some regions in Italy (Region of Emilia Romagna) implemented FRs. FRs will become more common in Italy in other regions (e.g., Province of Pavia).
Luxembourg Regional Since July 1, 2018 Luxembourg is completely reorganised in only one EMS organisation for the country. Luxembourg has a FR system working in 56 out of 102 municipalities. This service is provided exclusively by volunteer firefighters because they are "in the system" and thus quite easily reachable. There are different modalities according to local circumstances. Either the FR get to the scene by their own means (when they have the equipment in their car) or they meet at the fire station to get their equipment before going to the scene. In Luxembourg, for the moment, there are only firefighters acting as "organized" FRs. Police is more reluctant to participate and there is no citizen-responder system. There is a mandatory training in CPR for school children since 2017 and the Luxembourg Resuscitation Council strives to train as many as possible persons in elementary CPR (hands-only) on a voluntary basis.
Netherlands National and regional In the Netherlands, a national policy regarding citizen-responders was published, whereas the requirements for firefighters and police officers are described on regional level only. Regarding the implementation of AEDs and citizen-responders, the first policy was written in 2002. The reason to involve no citizen-responders in the capital Amsterdam is the proximity of police officers and firefighters (always shorter than 6 min to OHCA victim).
Norway National and regional police FRs [28,29]. A mobile phone alert is often used to alert citizen-responders, but only a few regions use a mobile phone alert to alert other FR types (i.e., firefighters and police officers). In a study carried out in Switzerland, all FR types (firefighters, police, citizenresponders) were alerted by either an app or textmessage system (both considered as a mobile phone alert) [15]. The app-system, when compared to a textmessage system, was found to be highly efficient in the deployment of FRs, significantly reducing the time to initiation of CPR and increasing survival rates [15]. Third, our study showed that the response capabilities of FRs should be considered. In the Czech Republic, firefighters were dispatched only in rare cases because they share locations with the EMS. Another example regarding response capabilities includes: in several countries there is no dispatch to children < 8 years by citizenresponders. Although this applies to a minority of the OHCA population, it should be taken into account. Also, the distinction between volunteer and professional FRs may have an impact on FR engagement and response. Another example includes Slovenia where the local EMS determines the need for FRs, and requests local volunteer firefighters to become FRs. As this strategy depends on local firefighter interest, there are still areas in Slovenia without FRs.
Fourth, our study showed that frequent CPR training is a feature of most FR-systems, as would be expected. Previous research has highlighted the superiority of off-duty medical professionals over laypersons [30] and more recent studies have shown the positive impact of trained citizenresponders on neurological outcomes [31]. Some regions allow citizen-responders to register as FRs without validating CPR-training (e.g., Denmark: Capital region and Central region), whereas CPR training is mandatory in two other regions in Denmark (Region Zealand and Region Southern Denmark). However, in the two regions where CPR training is not mandatory, CPR training is strongly recommended. Also, in Denmark, large-scale population-based CPR training is common, and the positive impact of populationbased CPR training has most recently been demonstrated by Kobayashi and colleagues in Japan [32]. Finally, improved survival after implementation of FR-systems is unlikely to occur unless all links in the Chain of Survival are working. Hence, improvements in bystander-CPR should receive high priority.

Future implementation of FR-systems
We hypothesise that the general tendency in Europe towards more widespread implementation of FR-systems will increase OHCA survival rates. At present, FRimplementation may not be a priority for every country and difficulties in the legal definition of FRs may contribute to this. However, lack of national policies may not be an impediment to local development. For instance, in Greece, small local initiatives already exist in the absence of a national policy. In Croatia, local initiatives are developed, including nurses on motorbikes and CPR-trained firefighters and police officers equipped with AEDs. However, these initiatives are not currently connected to the EMS to be dispatched and this may limit their rapid response. In other countries and regions, while there is interest, local AEDs are not registered; this may also delay implementation of an effective FR-system. These developments highlight that FRsystems are strongly driven by local initiative and local capabilities. The need to allow flexibility in how FRsystems are implemented locally is likely to be an important consideration in ensuring the sustainability of FR-systems into the future.

Strengths and limitations
To the best of our knowledge, this study provides the most comprehensive overview of first response in Europe to date. While heterogeneity in FR-systems is a key finding, common themes have been identified that provide a basis for understanding the development of FRsystems at a European level. It is acknowledged that a Table 4 Analysis of national policies relating to First Responders, per country (Continued)

Country
Implementation: National or Regional Short description of policy England National and regional In England, ambulance trusts are responsible for local implementation, but there is an overarching Governance Framework.

Sweden
Regional based Strategies or policies recommending establishment or the development of FRs in Sweden is lacking. Policies are regional.
Switzerland Regional based In Switzerland all health issues (except the management of epidemics and disasters) are left to the cantons. It follows that with 26 cantons, there are 26 different health laws. Since the FR network is still considered ancillary to the EMS, there is no health law that takes this into account. This is the reason why there are so many different approaches (even inside the cantons). Only a few cantons have created a structure for the purpose of uniformly managing the FRs. Leading position and pioneer is Canton Ticino (https://www.ticinocuore.ch/en). The Swiss Resuscitation Council is working on a national strategy against OHCA.
convenience sampling method was used to recruit respondents, but the sample was drawn from participants in well-established European networks that have an active interest in OHCA. A limitation of this study is that, in countries/regions considered as being covered by a specific FR-system, it was not feasible to estimate the density of FRs (and differences, from city to city, may exist). Also, it was not possible to relate different FR-systems to differences in survival rates. However, this study has highlighted a unique element of the Chain of Survival which should be considered in any further studies of OHCA epidemiology.
When a FR-system is being developed, it is important to analyse response times in order to confirm that the system actually contributes to early CPR and early defibrillation, using measured effects. Only then in the long run, the cost and effort of maintaining such a FR-system will remain accepted in the community.

Conclusions
At present, more than half of European countries dispatch FRs after a suspected OHCA. Policies relating to FRs are mostly managed by local EMS, leading to a wide variation between and within countries. Even in countries that do not have existing FR-systems, many have local initiatives and future plans for FR-system implementation. The willingness of people to volunteer their time and skills to provide a first response to OHCA has led to the development of a variety of national and local solutions, and has created a new paradigm within the Chain of Survival that needs to be researched and evaluated more extensively. Areas for future research include: identifying the most effective methods of FR dispatch; identifying FR-systems that most strongly influence survival; assessing the effect of adding a FR type in an existing FR-system; and understanding what motivates a volunteer to become a FR and what sustains that motivation. The diverse findings of our study reflect the diversity in circumstances across various European regions and suggest that it is unlikely that there will be a 'one size fits all' FR-system across Europe. Rather, an overall European policy that advises on the critical requirements for effective FR may be of benefit.
Additional file 1. Respondents and survey definitions.