This study provides a comprehensive quantitative and qualitative overview of changed proceedings in CPR across the whole chain of survival due to the COVID-19 pandemic in the Freiburg region. Quantitative data according to Utstein style from the prehospital and hospital admission phase shows only a moderate impact on bystander CPR rates, EMS response times and transportation rate after OHCA has been documented during the COVID-19 pandemic. Qualitative evaluation further reveals profound changes in the whole rescue system.
Major findings in this current investigation are longer mean EMS response times during the pandemic period. While our data do not provide a full explanation, longer turnover times per vehicle and case due to increased hygiene measures as well as staffing issues might have contributed to this observation, leading to less availability of ambulances and thus longer distances and travel times per unit. However, this remains speculative and warrants further investigation. Baldi et al. described a prolongation of 3 min in EMS arrival time, which they, at least in part, attributed to a higher case-load [8]. In two systematic reviews, prolonged EMS response times were consistent findings across several studies [16, 17].
Furthermore, there is a tendency towards lower rate of shockable rhythms and lower rates of ROSC during the pandemic period. This is also in line with the increased severity of “pre-existing conditions” (PEC) documented in the pandemic period, comparable with the recently published experience from Northern Italy and Paris [8, 9], as well as an increase in suspected non-cardiac causes of arrest.
The EMS documentation of „pre-existing conditions “(PEC) originally refers to comorbid and functional status with impact on independent living as the discriminator. However, it leaves room for a subjective evaluation by the emergency physician, based on the available information on scene. Hence, it does not sharply discriminate between chronic diagnoses and immediate peri-arrest illness and acute deterioration. More critical conditions at the time of cardiac arrest might have accounted for the shift to document worse PEC values characterizing the status preceding the event. Currently, this cannot be strengthened by additional data, and has to be speculated on.
In the literature, progressive deterioration of chronic conditions as well as delays in seeking medical attention and visits to the emergency department for acute, new-onset conditions such as acute coronary syndromes or severe infections have been described [18,19,20,21,22,23].
Beyond that, the data suggests a change in EMS decision making on scene during the pandemic period with less patients affected by OHCA were transported to hospital and more CPR attempts were terminated on scene (Fig. 4). Worse pre-existing conditions may have played a role in supporting these terminations of resuscitation efforts.
Also, the fear of EMS personnel of self-infection due to CPR during transportation might have contributed to this finding, but this was not examined. The odds of a favorable outcome may have further been decreased by the general changes in the rescue system described herein.
A key factor of favorable neurologic survival following OHCA is bystander CPR [24]. Before the pandemic, intensive efforts have been undertaken to improve the corresponding rates in Germany. Public campaigns and events, as well as the start of an app-based alarm system resulting in increased interest of the local and regional media in cardiac arrest, first aid, and related themes, supported this need in the Freiburg region in July 2018 leading to an increase in bystander CPR from 42.1 to 57% within 1 year. Although statistically not significant, the dynamic of the bystander CPR rate is remarkable regarding its drop back to 33% in 2020 after withholding the smartphone-based activation of first responders from March 18th due to public health and safety concerns. The bystander CPR rate of 2020 resembles the rates of 2016 through 2018 before the start of the app-based alarm system (Fig. 2). Another important driver of improvement in bystander-CPR rates, i.e. Kids Save Lives programs, has been paused together with the lock-down of schools. As these are struggling to return to normal routine, resuming CPR teaching activities poses further challenges on the system. A group of authors has therefore suggested a “Renewed Kids Save Lives campaign” to further increase awareness and fight sudden cardiac death in the era of COVID-19″ [25].
Furthermore, the possible impact of the pandemic on the behavior in OHCA of the public, i.e. patients, relatives, bystanders with their willingness to help and to call for help, has also to be taken into account. We observed a significant drop in bystander CPR rates during the pandemic, when the OHCA was directly witnessed (Fig. 3). This is again in line with findings in several studies, as summarized in the reviews by Lim [16] and Scquizzato [17]. A multinational, social media-based public survey by Grunau and coworkers confirmed fear of infection as a major obstacle to commence bystander CPR, among others [26]. It adds to the known barriers to perform CPR, such as fear of causing harm, or low confidence in own skills. Perceptions and possible fears regarding bystander CPR should be analyzed further in order to define suitable programs to inform the public during pandemic waves, and to undertake measures to preserve or improve these rates. Grunau et al’s results suggest that provision of protective gear has the potential to increase willingness to help. Further emphasizing compression-only CPR, or modifing the Basic Life Support algorithm by omitting the listen and feel-component of checks for breathing are further examples. Some national councils have included covering mouth and nose with tissues or face covers while performing CPR in their COVID-19 recommendations [11, 27]. Notably, our findings are in contrast to what we expected: In case of observed OHCA, the observers are often relatives or friends. We would expect these persons (probably knowing whether the relative is healthy or might suffer from COVID-19) are ready to help even under pandemic conditions. As very few people used to be around public places, we expected that the bystander CPR rate in all OHCA cases (including the non-observed OHCA cases) would have dropped, which it did not.
The app-based alarm system was reactivated on May 26th, 2020 following the provision of protective gear for all registered rescuers. With the reduction of infection numbers following the general lock-down, it is planned to stepwise resume all additional resuscitation services. However, processes will still need to be adjusted to evolving evidence around infection risk through resuscitation measures. Hereby precautions for staff safety are a prerequisite. As all voluntary actions in the provision of CPR depend on the willingness and competence to help, perceptions and fears in the public need to be addressed with impactful educational measures. Although our data does not show a significant impact on survival, the overall survival after OHCA in 2020 halved compared to the same time periods in 2016 through 2019.
Public training in basic life support is another important pillar to enhance rates and quality of bystander CPR. The classic training formats had to be discontinued during the pandemic. Alternative digital formats with online parts and blended learning concepts should be further developed, adjusted to local needs and made easily accessible to the public, as a complement to reduced BLS training capacity. In their COVID-19 guidelines, the ERC therefore underlines the growing importance of “distance learning, self-directed learning, augmented and virtual learning” [10]. Birkun demonstrated a motivating effect of distance learning via a massive open online course regarding willingness to provide CPR, and a considerable increase in course registrations for this online course format [28]. Ali and colleagues systematically reviewed different CPR training strategies, including online-only-delivery, a feasible fallback-option when face-to-face training is not possible [29]. Virtual reality CPR training applications are increasingly being developed and made publicly available, facilitating low-budget-high-fidelity virtual training at home. Some of them have been designed in cooperation with national resuscitation councils, such as “Lifesaver VR” (Resuscitation Council UK, in English) [30], “TK-RescueMeVR” (German Resuscitation Council, in German) [31] or VR CPR (Italian Resuscitation Council) [32, 33]. While public institutions and healthcare authorities are struggling with more immediate effects of the pandemic and the disease itself, stakeholders in resuscitation care should be aware of all details and collateral effects on any part of the rescue system. Lay persons should be informed about infection risk when performing BLS and about measures to reduce the risk. Furthermore, it is very important to inform people about current recommendations (BLS under COVID conditions) to avoid that patients suffering from OHCA do not receive adequate measures. In line with ILCOR Consensus on Science and Treatment Recommendations (CoSTR) on improvement of system performance, we therefore took into account clinical outcome data, as well as system level variables [34] and qualitative information to inform dealing with the current pandemic wave, and foster preparedness for future pandemics with regard to cardiac arrest care.
Limitations of our study
Cases of OHCA where no CPR was attempted were not included in this study. It is therefore possible that the incidence of OHCA was higher and survival lower. EMS dispatchers were instructed to investigate regarding symptoms of COVID-19. The impact of a warning category being assigned to a call on the process times was not analyzed. The COVID infection status of OHCA patients, if not reported by proxies or confirmed by laboratory testing in hospital was not automatically available at the time of arrest, nor retrospectively in all cases due to legal data protection limiting exchange between public health service and EMS. Ambulance process times of 2016 were not available and therefore not included in this study. Neurologic recovery is an important outcome in resuscitation studies. However our study was mainly focused on the prehospital period including hospital admission. Further data sources and outcome information are being prepared for future analyses.
Generalizability
The generalizability of our study is limited due to the two-tiered, physician based nature of our rescue system. Regarding transport times, results from our urban area might be different from more rural areas. The additional services such as smartphone activated rescuers and eCPR are not available in other systems, so bystander CPR rates as well as transport with ongoing CPR might differ. Although relevantly affected, our area did not suffer from most severe strain as oher regions did, where caseload might be more pronounced. Thus, with higher or lower COVID-19 incidence or SARS-CoV-2 infection rates in other pandemic waves, or differently affected regions, outcomes and quantitative system level characteristics may vary. Therefore, muti-regional, national and international publications and review thereof are needed to achieve a more granular picture of pandemic related changes to resusciation systems worldwide, understand systematic phenomena and identify potential intervention targets.
