Dispatch of Volunteer Responders to Out-of-Hospital Cardiac Arrests

Wolf creek XVII part 4: Amplifying lay-rescuer response

Introduction

Amplifying lay-rescuer response is a key priority to increase survival from out-of-hospital cardiac arrest (OHCA). We describe the current state of lay-rescuer response, how we envision the future, and the gaps, barriers, and research priorities that will amplify response to OHCA.

Methods

'Amplifying Lay-Rescuer Response' was one of six focus topics for the Wolf Creek XVII Conference held on June 14-17, 2023, in Ann Arbor, Michigan, USA. Conference invitees included international thought leaders and scientists in the field of cardiac arrest resuscitation from academia and industry. Participants submitted via online survey knowledge gaps, barriers to translation and research priorities for each focus topic. Expert panels used the survey results and their own perspectives and insights to create and present a preliminary unranked list for each category that was debated, revised and ranked by all attendees to identify the top 5 for each category.

Results

The top five knowledge gaps as ranked by the panel, reflected a recognition of the need to better understand the psycho-social aspects of lay response. The top five barriers to translation reflected issues at the individual, community, societal, structural, and governmental levels. The top five research priorities were focused on understanding the social/psychological and emotional barriers to action, finding the most effective/cost-effective strategies to educate lay persons and implement community life-saving interventions, evaluation of new technological solutions and how to enhance the role of dispatch working with lay-rescuers.

Conclusion

Future research in lay rescuer response should incorporate technology innovations, understand the "humanity" of the situation, leverage implementation science and systems thinking to save lives. This will require the field of resuscitation to engage with scholars outside our traditional ranks and to be open to new ways of thinking about old problems.

Improving survival after cardiac arrest in Europe: The synergetic effect of rescue chain strategies

Sudden cardiac arrest is a global problem and is considered the third leading cause of death in industrialized countries. Patient survival rates after out-of-hospital cardiac arrest (OHCA) vary significantly between countries and continents. In particular, the 2021 European Resuscitation Council (ERC) Resuscitation Guidelines place a special focus on the chain of survival of patients after OHCA. As a complex, interconnected approach, the focus is on: Raising awareness for cardiac arrest and lay resuscitation, school children's education in resuscitation "KIDS SAVE LIVES", first responder systems - technologies to engage the community, telephone-assisted resuscitation (telephone-CPR; T-CPR) by dispatchers, and cardiac arrest centers (CAC) for further treatment in specialized hospitals. The Systems Saving Lives approach is a comprehensive strategy that emphasizes the interconnectedness of all links in the chain of survival following an OHCA, with a particular focus on the relationship between the community and emergency medical services (EMS). This system-level approach emphasizes the importance of the connection between all those involved in the chain of survival. It has a high potential to improve overall survival after OHCA. Therefore, it is recommended that these strategies be promoted and expanded in all countries.

Volunteer Responder Interventions in Out-of-Hospital Cardiac Arrest in Urban, Suburban, and Rural Areas

BACKGROUND

Patients with out-of-hospital cardiac arrest (OHCA) in rural areas experience longer emergency response times and have lower survival rates compared with patients in urban areas. Volunteer responders might improve care and outcomes for patients with OHCA specifically in rural areas. Therefore, we investigated volunteer responder interventions based on the degree of urbanization.

METHODS AND RESULTS

We included 1310 OHCAs from 3 different regions in Denmark where volunteer responders had arrived at the OHCA location. The location was classified as urban, suburban, or rural according to the Eurostat Degree of Urbanization Tool. A logistic regression model was used to examine associations between the degree of urbanization and volunteer responder arrival before emergency medical services, cardiopulmonary resuscitation, or defibrillation. We found the odds for volunteer responder arrival before emergency medical services more than doubled in rural areas (odds ratio [OR], 2.60 [95% CI, 1.91-3.53]) and suburban areas (OR, 2.05 [95% CI, 1.56-2.69]) compared with urban areas. In OHCA cases where volunteer responders arrived first, odds for bystander cardiopulmonary resuscitation was tripled in rural areas (OR, 3.83 [95% CI, 1.64-8.93]) and doubled in suburban areas (OR, 2.27 [95% CI, 1.17-4.41]) compared with urban areas. Bystander defibrillation was more common in suburban areas (OR, 1.53 [95% CI, 1.02-2.31]), where almost 1 out of 4 patients received bystander defibrillation, compared with urban areas.

CONCLUSIONS

Volunteer responders are significantly more likely to arrive before emergency medical services in rural and suburban areas than in urban areas. Patients with OHCA received more cardiopulmonary resuscitation in rural and suburban areas and more defibrillation in suburban areas than in urban areas.

[Prehospital resuscitation : Current status, results and strategies for improvement in Germany]

Out-of-hospital cardiac arrest (OHCA) is one of the most frequent causes of death in Europe and is associated with a dismal prognosis. The annual incidence in Germany is approximately 100-120 per 100,000 inhabitants (ca. 80,000-100,000 cases). With the use of cardiopulmonary resuscitation (CPR) about 40% of patients have a return of spontaneous circulation (ROSC); however, after OHCA only 15% of patients survive for 30 days and less than 10% survive with no or only minor neurological deficits. Data from the German Resuscitation Register demonstrate that there was no change in the results over the last 15 years, despite all medical innovations, higher rates of coronary interventions, higher use of mechanical support systems and improvement in intensive care treatment. A high proportion of patients with OHCA have a cardiac or coronary cause. As shown by the data from the German Cardiac Arrest Register (G-CAR) an early coronary angiography is often carried out after CPR in Germany; however, in randomized clinical studies an immediate coronary angiography in patients with non-ST segment elevation in the electrocardiogram (ECG) was not associated with an improvement in the prognosis. In large randomized studies the use of mechanical CPR systems and the implantation of mechanical circulatory support devices after OHCA also did not lead to a reduction in mortality. The most important impact factor for the success of CPR is the time interval between collapse and start of CPR, if possible also by bystander resuscitation. Therefore, the focus of efforts for improving CPR should be on increasing the rate of patients with early CPR. Experiences from Denmark and The Netherlands indicate that this can be successful by education and training of the general population, telephone resuscitation and apps for alerting lay persons.

Automated external defibrillators and the link to first responder systems

PURPOSE OF REVIEW

Automated external defibrillators are a very effective treatment to convert ventricular fibrillation (VF) in out-of-hospital cardiac arrest. The purpose of this paper is to review recent publications related to automated external defibrillators (AEDs).

RECENT FINDINGS

Much of the recent research focus on ways to utilize publicly available AEDs included in different national/regional registers. More and more research present positive associations between engaging volunteers to increase the use of AEDs. There are only a few recent studies focusing on professional first responders such as fire fighters/police with mixed results. The use of unmanned aerial vehicles (drones) lacks clinical data and is therefore difficult to evaluate. On-site use of AED shows high survival rates but suffers from low incidence of out-of-hospital cardiac arrest (OHCA).

SUMMARY

The use of public AEDs in OHCA are still low. Systems focusing on engaging volunteers in the cardiac arrest response have shown to be associated with higher AED usage. Dispatching drones equipped with AEDs is promising, but research lacks clinical data. On-site defibrillation is associated with high survival rates but is not available for most cardiac arrests.

Predictive Dispatch of Volunteer First Responders: Algorithm Development and Validation

BACKGROUND

Smartphone-based emergency response apps are increasingly being used to identify and dispatch volunteer first responders (VFRs) to medical emergencies to provide faster first aid, which is associated with better prognoses. Volunteers' availability and willingness to respond are uncertain, leading in recent studies to response rates of 17% to 47%. Dispatch algorithms that select volunteers based on their estimated time of arrival (ETA) without considering the likelihood of response may be suboptimal due to a large percentage of alerts wasted on VFRs with shorter ETA but a low likelihood of response, resulting in delays until a volunteer who will actually respond can be dispatched.

OBJECTIVE

This study aims to improve the decision-making process of human emergency medical services dispatchers and autonomous dispatch algorithms by presenting a novel approach for predicting whether a VFR will respond to or ignore a given alert.

METHODS

We developed and compared 4 analytical models to predict VFRs' response behaviors based on emergency event characteristics, volunteers' demographic data and previous experience, and condition-specific parameters. We tested these 4 models using 4 different algorithms applied on actual demographic and response data from a 12-month study of 112 VFRs who received 993 alerts to respond to 188 opioid overdose emergencies. Model 4 used an additional dynamically updated synthetic dichotomous variable, frequent responder, which reflects the responder's previous behavior.

RESULTS

The highest accuracy (260/329, 79.1%) of prediction that a VFR will ignore an alert was achieved by 2 models that used events data, VFRs' demographic data, and their previous response experience, with slightly better overall accuracy (248/329, 75.4%) for model 4, which used the frequent responder indicator. Another model that used events data and VFRs' previous experience but did not use demographic data provided a high-accuracy prediction (277/329, 84.2%) of ignored alerts but a low-accuracy prediction (153/329, 46.5%) of responded alerts. The accuracy of the model that used events data only was unacceptably low. The J48 decision tree algorithm provided the best accuracy.

CONCLUSIONS

VFR dispatch has evolved in the last decades, thanks to technological advances and a better understanding of VFR management. The dispatch of substitute responders is a common approach in VFR systems. Predicting the response behavior of candidate responders in advance of dispatch can allow any VFR system to choose the best possible response candidates based not only on ETA but also on the probability of actual response. The integration of the probability to respond into the dispatch algorithm constitutes a new generation of individual dispatch, making this one of the first studies to harness the power of predictive analytics for VFR dispatch. Our findings can help VFR network administrators in their continual efforts to improve the response times of their networks and to save lives.