Smartphone alerting systems for rescuers in case of an out of hospital cardiac arrest have been established and are being scientifically evaluated in many countries. To sufficiently achieve their main goal, i.e. reduce No-Flow time until professional help arrives, the number of volunteers registered and willing to respond is of utmost importance.
We do not yet have evidence about the density of responders needed to reach cardiac arrest locations in a reasonable time, i.e. less than 4–5 minutes. As most systems activate rescuers within a very small radius [10] – typically less than 1,000 meters – a high number of volunteers is necessary to achieve this objective. The SAS in southern Denmark region had response times of 4:46 minutes (median) with 0.6 volunteers per km2 [11].
However, this is a very rural area and the commitment of the first responders is probably very high. In Stockholm, a first responder density of 0.28–0.39 per km2 was associated with first responders arriving prior to the ambulance in 25% of the cases [12]. Both systems include lay rescuers. In the Freiburg RDL system, according to legal issues, only volunteers with at least 48 hours training in emergency medicine skills are registered. With regards to the possibly achievable number of volunteers, we rated this as disadvantage.
Under pandemic conditions, the achievement of the abovementioned goal, is endangered. Lay people may tend not to start BLS due to a risk of infection, which reduces bystander CPR rates. Although the COVID guidelines suggest compression-only resuscitation for lay rescuers [9], these guidelines are typically not known to lay rescuers.
Several studies have addressed this issue, demonstrating an increased incidence of OHCA and at the same time a severe impact on the chain of survival [7, 8]. Reduced willingness to help has been considered one of the most important factors on the side of the community response. Smartphone alerting systems activating more qualified volunteers may fill this void and help save more lives. First responders working as healthcare professionals in ambulance services or in the hospital are trained in BLS as well as hygiene and they know how to safely treat infectious patients. Even those volunteers in our system who have the lowest possible qualification, very basic emergency medicine technicians, are trained to wear PPE when treating casualties. This was a strong advantage when planning to restart the system during pandemic conditions.
Whilst some systems remained inactive or restarted with the recommendation to merely wear a mouth and nose protection, other systems provide PPE to their volunteers. FFP-2 or FFP-3 masks can easily be carried. However, according to the COVID guidelines, these masks alone do not meet the minimum hygiene recommendations, nor do they have providers feel safe. Mackler and colleagues performed a survey investigating the willingness of paramedics to remain on duty if they had to care for patients with smallpox [13]. Only 4% of the respondents would stay on duty if they had no protective gear and no vaccine was available, but 39% would be ready to care for the infectious patients if protective gear was available. The mortality rate of COVID-19 is much lower than smallpox, but it is assumed that providing adequate PPE would increase the number of volunteers answering calls. Based on data from their EMS and health services, Sayre and coworkers estimated how in their area, the risk of a fatal SARS-CoV-2-infection for an unprotected lay rescuer would be 1:10,000 bystander CPR events, while 300:10,000 OHCA patients could be saved with bystander CPR [14].
We had expected that the rate of alarms with at least one first responder accepting the call would decrease after the restart of the system under pandemic conditions. Even if the volunteers felt safe with their PPE, we expected that they would not have the backpack with PPE with them permanently, therefore rejecting the alarm. The results of our survey showed that the readiness of the first responders to answer calls after being equipped with PPE is slightly but significantly lower than before the pandemic, but it is still much higher than without PPE. The number of volunteers who registered as first responders remained unchanged after the restart of the system, and the response rate of first responders after the restart is even slightly higher than before the lockdown. This may not only be due to a higher readiness, but also due to the increasing number of registered volunteers.
In Germany, neither the country/ federal state nor the health insurances cover the costs of first responder systems. Thus, it is a challenge to find funding for additional costs like PPE. The most expensive part of the personal equipment is the bag and mask. As the bag is further used by the ambulance paramedics when they arrive at the scene, an agreement was made with the EMS to replace the used bag/mask of the first responders. Thus, the responder is ready for the next call and RDL must only replace the less expensive other parts of the set.
In summary, weighing the safety of BLS providers, including trained volunteers, against the additional lives that can be saved from sudden cardiac arrest by immediate bystander CPR is a major challenge in the current pandemic. It will remain an individual decision on an institutional level, for how long, with which precautions and at which risk the single components of the rescue system can be maintained.
Continuing to send unprotected volunteers in our SAS was not an option during the first peak of the COVID19-wave. Therefore we consider the provision of PPE the key factor for the early restart of the RDL system. This notion is not only confirmed by the stable numbers of registered volunteers and high response rates, but also by the replies to our survey. These clearly indicate that the willingness to help is preserved even under pandemic conditions, when PPE, or a vaccine in the near future, are provided, while it dramatically drops when protective gear is not available.
The community’s engagement in terms of crowdfunding the PPE as well as further volunteer registration and alarm acceptance was surprisingly intense and encouraging.
This, and the subsequent early restart of the system became an important intervention to fill the serious void in the chain of survival caused by reduced bystander CPR rates.
Although it is unclear whether systems in other regions and countries experience similar support, RDL can therefore only encourage our colleagues to request private or crowdfunding for their first responder systems, respectively, and aim for provision of protective gear to responders.