Termination of resuscitation in out-of-hospital cardiac arrest in women and men: An ESCAPE-NET project.

AIM: Women have less favorable resuscitation characteristics than men. We investigated whether the Advanced Life Support Termination of Resuscitation rule (ALS-TOR) performs equally in women and men. Additionally, we studied whether adding or removing criteria from the ALS-TOR improved classification into survivors and non-survivors. METHODS: We analyzed 6,931 female and 14,548 male out-of-hospital cardiac arrest (OHCA) patients from Dutch and Swedish registries, and validated in 10,772 female and 21,808 male Danish OHCA patients. Performance measures were calculated for ALS-TOR in relation to 30-day survival. Recursive partitioning analysis was performed with the ALS-TOR criteria, as well as age, comorbidities, and additional resuscitation characteristics (e.g. initial rhythm, OHCA location). Finally, we explored if we could reduce the number of ALS-TOR criteria without loss of prognostic value. RESULTS: The ALS-TOR had a specificity and positive predictive value (PPV) of ≥99% in both women and men (e.g. PPV 99.9 in men). Classification by recursive partitioning analysis showed a high sensitivity but a PPV below 99%, thereby exceeding the acceptable miss rate of 1%. A combination of no return of spontaneous circulation (ROSC) before transport to the hospital and unwitnessed OHCA resulted in nearly equal specificity and PPV, higher sensitivity, and a lower transport rate to the hospital than the ALS-TOR. CONCLUSION: For both women and men, the ALS-TOR has high specificity and low miss rate for predicting 30-day OHCA survival. We could not improve the classification with additional characteristics. Employing a simplified version may decrease the number of futile transports to the hospital.

Characteristics and motivational factors for joining a lay responder system dispatch to out-of-hospital cardiac arrests.

BACKGROUND: There has been in increase in the use of systems for organizing lay responders for suspected out-of-hospital cardiac arrests (OHCAs) dispatch using smartphone-based technology. The purpose is to increase survival rates; however, such systems are dependent on people's commitment to becoming a lay responder. Knowledge about the characteristics of such volunteers and their motivational factors is lacking. Therefore, we explored characteristics and quantified the underlying motivational factors for joining a smartphone-based cardiopulmonary resuscitation (CPR) lay responder system. METHODS: In this descriptive cross-sectional study, 800 consecutively recruited lay responders in a smartphone-based mobile positioning first-responder system (SMS-lifesavers) were surveyed. Data on characteristics and motivational factors were collected, the latter through a modified version of the validated survey "Volunteer Motivation Inventory" (VMI). The statements in the VMI, ranked on a Likert scale (1-5), corresponded to(a) intrinsic (an inner belief of doing good for others) or (b) extrinsic (earning some kind of reward from the act) motivational factors. RESULTS: A total of 461 participants were included in the final analysis. Among respondents, 59% were women, 48% between 25 and 39 years of age, 37% worked within health care, and 66% had undergone post-secondary school. The most common way (44%) to learn about the lay responder system was from a CPR instructor. A majority (77%) had undergone CPR training at their workplace. In terms of motivation, where higher scores reflect greater importance to the participant, intrinsic factors scored highest, represented by the category values (mean 3.97) followed by extrinsic categories reciprocity (mean 3.88) and self-esteem (mean 3.22). CONCLUSION: This study indicates that motivation to join a first responder system mainly depends on intrinsic factors, i.e. an inner belief of doing good, but there are also extrinsic factors, such as earning some kind of reward from the act, to consider. Focusing information campaigns on intrinsic factors may be the most important factor for successful recruitment. When implementing a smartphone-based lay responder system, CPR instructors, as a main information source to potential lay responders, as well as the workplace, are crucial for successful recruitment.

National coverage of out-of-hospital cardiac arrests using automated external defibrillator-equipped drones - A geographical information system analysis.

BACKGROUND: Early defibrillation is essential for increasing the chance of survival in out-of-hospital-cardiac-arrest (OHCA). Automated external defibrillator (AED)-equipped drones have a substantial potential to shorten times to defibrillation in OHCA patients. However, optimal locations for drone deployment are unknown. Our aims were to find areas of high incidence of OHCA on a national level for placement of AED-drones, and to quantify the number of drones needed to reach 50, 80, 90 and 100% of the target population within eight minutes. METHODS: This is a retrospective observational study of OHCAs reported to the Swedish Registry for Cardiopulmonary Resuscitation between 2010-2018. Spatial analyses of optimal drone placement were performed using geographical information system (GIS)-analyses covering high-incidence areas (>100 OHCAs in 2010-2018) and response times. RESULTS: 39,246 OHCAs were included. To reach all OHCAs in high-incidence areas with AEDs delivered by drone or ambulance within eight minutes, 61 drone systems would be needed, resulting in overall OHCA coverage of 58.2%, and median timesaving of 05:01 (min:sec) [IQR 03:22-06:19]. To reach 50% of the historically reported OHCAs in <8 min, 21 drone systems would be needed; for 80%, 366; for 90%, 784, and for 100%, 2408. CONCLUSIONS: At a national level, GIS-analyses can identify high incidence areas of OHCA and serve as tools to quantify the need of AED-equipped drones. Use of only a small number of drone systems can increase national coverage of OHCA substantially. Prospective real-life studies are needed to evaluate theoretically optimized suggestions for drone placement.

Incidence and characteristics of drowning in Sweden during a 15-year period.

AIM: Drowning is a global health problem and deeper knowledge about the extent and causes is of utmost importance for implementing preventative actions. The aim of this study was to describe the incidence and characteristics of drowning in Sweden over time, including both non-fatal and fatal cases. METHODS: All cases identified as drowning (ICD-10 coding) at a national level in Sweden between 2003-2017 were collected. Three sources of data from the Swedish National Board of Health and Welfare were extracted via the Cause of Death Register and the National Patient Register. RESULTS: Over 15 years, a total of 6609 cases occurred, resulting in an annual incidence of 4.66 per 100 000. The median age was 49 years (IQR 23-67) and 67% were males. Non-fatal drownings represented 51% (n = 3363), with an overall non-fatal to fatal ratio of 1:1, this being 8:1 for children (0-17 years of age). Non-fatal cases were more often female (36% vs. 30%; p < 0.001), younger 30 (IQR 10-56) vs. 60 (IQR: 45-72) (p < 0.001) and of unintentional nature (81% vs. 55%; p < 0.001). The overall incidence decreased over time from 5.6 to 4.1 per 100 000 (p < 0.001). The highest rate of 30-day survival was found in females 0-17 years (94%, 95% CI 91.1-95.5) and the lowest in males >66 years (28.7%, 95% CI 26.2-31.2). Although the incidence in children 0-4 years increased from 7.4 to 8.1 per 100 000 (p < 0.001), they demonstrated the highest non-fatal to fatal ratio (13:1). CONCLUSION: Drowning is declining but remains a consistent and underestimated public-health problem. Non-fatal drowning cases represent about half of the burden and characteristics differ from fatal drowning cases, being younger, more often female and of unintentional nature.

The use of drones and a machine-learning model for recognition of simulated drowning victims-A feasibility study.

BACKGROUND: Submersion time is a strong predictor for death in drowning, already 10 min after submersion, survival is poor. Traditional search efforts are time-consuming and demand a large number of rescuers and resources. We aim to investigate the feasibility and effectiveness of using drones combined with an online machine learning (ML) model for automated recognition of simulated drowning victims. METHODS: This feasibility study used photos taken by a drone hovering at 40 m altitude over an estimated 3000 m2 surf area with individuals simulating drowning. Photos from 2 ocean beaches in the south of Sweden were used to (a) train an online ML model (b) test the model for recognition of a drowning victim. RESULTS: The model was tested for recognition on n = 100 photos with one victim and n = 100 photos with no victims. In drone photos containing one victim (n = 100) the ML model sensitivity for drowning victim recognition was 91% (95%CI 84.9%-96.2%) with a median probability score that the finding was human of 66% (IQR 52-71). In photos with no victim (n = 100) the ML model specificity was 90% (95%CI: 83.9%-95.6%). False positives were present in 17.5% of all n = 200 photos but could all be ruled out manually as false objects. CONCLUSIONS: The use of a drone and a ML model was feasible and showed satisfying effectiveness in identifying a submerged static human simulating drowning in open water and favorable environmental conditions. The ML algorithm and methodology should be further optimized, again tested and validated in a real-life clinical study.

Drone delivery of an automated external defibrillator - a mixed method simulation study of bystander experience.

BACKGROUND: Out-of-hospital cardiac arrest (OHCA) affects some 275,000 individuals in Europe each year. Time from collapse to defibrillation is essential for survival. As emergency medical services (EMS) response times in Sweden have increased, novel methods are needed to facilitate early treatment. Unmanned aerial vehicles (i.e. drones) have potential to deliver automated external defibrillators (AED). The aim of this simulation study was to explore bystanders' experience of a simulated OHCA-situation where a drone delivers an AED and how the situation is affected by having one or two bystanders onsite. METHODS: This explorative simulation study used a mixed methodology describing bystanders' experiences of retrieving an AED delivered by a drone in simulated OHCA situations. Totally eight participants were divided in two groups of bystanders a) alone or b) in pairs and performed CPR on a manikin for 5 minutes after which an AED was delivered by a drone at 50 m from the location. Qualitative data from observations, interviews of participants and video recordings were analysed using content analysis alongside descriptive data on time delays during bystander interaction. RESULTS: Three categories of bystander experiences emerged: 1) technique and preparedness, 2) support through conversation with the dispatcher, and 3) aid and decision-making. The main finding was that retrieval of an AED as delivered by a drone was experienced as safe and feasible for bystanders. None of the participants hesitated to retrieve the AED; instead they experienced it positive, helpful and felt relief upon AED-drone arrival and were able to retrieve and attach the AED to a manikin. Interacting with the AED-drone was perceived as less difficult than performing CPR or handling their own mobile phone during T-CPR. Single bystander simulation introduced a significant hands-off interval when retrieving the AED, a period lasting 94 s (range 75 s-110 s) with one participant compared to 0 s with two participants. CONCLUSION: The study shows that it made good sense for bystanders to interact with a drone in this simulated suspected OHCA. Bystanders experienced delivery of AED as safe and feasible. This has potential implications, and further studies on bystanders' experiences in real cases of OHCA in which a drone delivers an AED are therefore necessary.

Potential organ donors after Out-of-Hospital Cardiac Arrest during a ten-year period in Stockholm, Sweden.

BACKGROUND: Donation after brain death (DBD) is current praxis in Sweden. Circulatory death is far more common. Donation from patients suffering Out-of-Hospital Cardiac Arrest (OHCA) may have the potential to increase the organ-donor pool. The aim of this study was to describe the potential donor pool and its characteristics if uncontrolled donation after circulatory death (uDCD) were to be implemented in the metropolitan area of Stockholm, Sweden. METHODS: A retrospective analysis was made using data from the Swedish Register for cardiopulmonary resuscitation (SRCR) between 2006 and 2015. Evaluation of potential organ donors was made using selection criteria from five previously published protocols concerning uDCD. RESULTS: When applying different criteria from each of the five studied protocols in a total of 9,793 cases of OHCA, between 7.5% (n=732) and 1.5% (n=150) of the patients were found to be potential candidates for uDCD. The median age of the sampled uDCD candidates in each protocol was between 48 and 57 years. Male donors were found in 67-76% of all cases. CONCLUSION: Although not taking important real-life limitations into account, our results indicate that implementation of a uDCD programme may substantially increase the number of potential organ donors in Stockholm.

Experiences and outcome from the implementation of a national Swedish automated external defibrillator registry.

BACKGROUND: Early cardiopulmonary resuscitation (CPR) and defibrillation with an Automated External Defibrillator (AED) increase survival from out-of-hospital cardiac arrest (OHCA). Although international guidelines recommend the use of AED registries to increase AED use, little is known about implementation. The aim of this paper is to describe the development of a national AED registry, to analyse the coverage and barriers to register AEDs. METHODS: The Swedish AED Registry (SAEDREG) was initiated in 2009 with the purpose of gathering the data of all public AEDs in Sweden. Data on all AEDs between 2013 and 2016 were included in the study. Additionally, data of non-registered AEDs was collected in one region using a survey to AED owners focusing on AED functionality. RESULTS: The number of AEDs doubled between 2013-2016. A total of 6703 AEDs (30%) were removed due to unavailability of validation. At the end of 2016, AEDs were most frequently registered in offices and workplaces, 45% (n = 7241) followed by shops, 7% (n = 1200). In the Gotland region, 218 AEDs, 57% (n = 124) were registered in the SAEDREG. Of n = 94 Non-registered AED functionality was high, the main reason not to register was unawareness of the SAEDREG, 74.5%. Of those aware of the register but not having registered, 25% stated "hard to register" as cause. CONCLUSIONS: A national AED registry may gather information of AEDs on a national level. Although numbers have doubled between 2013-2016 in Sweden, a large proportion is still non-registered. More awareness of the registry and easier registration process is needed. General AED functionality seems high regardless of registered or non-registered AEDs. A key area for future research may be to use AED-registers to ascertain effectiveness of AED programs in terms of actual patient outcome.

The challenges and possibilities of public access defibrillation.

Out-of-hospital cardiac arrest (OHCA) is a major health problem that affects approximately four hundred and thousand patients annually in the United States alone. It is a major challenge for the emergency medical system as decreased survival rates are directly proportional to the time delay from collapse to defibrillation. Historically, defibrillation has only been performed by physicians and in-hospital. With the development of automated external defibrillators (AEDs), rapid defibrillation by nonmedical professionals and subsequently by trained or untrained lay bystanders has become possible. Much hope has been put to the concept of Public Access Defibrillation with a massive dissemination of public available AEDs throughout most Western countries. Accordingly, current guidelines recommend that AEDs should be deployed in places with a high likelihood of OHCA. Despite these efforts, AED use is in most settings anecdotal with little effect on overall OHCA survival. The major reasons for low use of public AEDs are that most OHCAs take place outside high incidence sites of cardiac arrest and that most OHCAs take place in residential settings, currently defined as not suitable for Public Access Defibrillation. However, the use of new technology for identification and recruitment of lay bystanders and nearby AEDs to the scene of the cardiac arrest as well as new methods for strategic AED placement redefines and challenges the current concept and definitions of Public Access Defibrillation. Existing evidence of Public Access Defibrillation and knowledge gaps and future directions to improve outcomes for OHCA are discussed. In addition, a new definition of the different levels of Public Access Defibrillation is offered as well as new strategies for increasing AED use in the society.

Drones may be used to save lives in out of hospital cardiac arrest due to drowning.

BACKGROUND: Drowning leading to out-of-hospital cardiac arrest (OHCA) and death is a major public health concern. Submersion with duration of less than 10min is associated with favorable neurological outcome and nearby bystanders play a considerable role in rescue and resuscitation. Drones can provide a visual overview of an accident scene, their potential as lifesaving tools in drowning has not been evaluated. AIM: The aim of this simulation study was to evaluate the efficiency of a drone for providing earlier location of a submerged possible drowning victim in comparison with standard procedure. METHOD: This randomized simulation study used a submerged manikin placed in a shallow (<2m) 100×100-m area at Tylösand beach, Sweden. A search party of 14 surf-lifeguards (control) was compared to a drone transmitting video to a tablet (intervention). Time from start to contact with the manikin was the primary endpoint. RESULTS: Twenty searches were performed in total, 10 for each group. The median time from start to contact with the manikin was 4:34min (IQR 2:56-7:48) for the search party (control) and 0:47min (IQR 0:38-0:58) for the drone-system (intervention) respectively (p<0.001). The median time saved by using the drone was 3:38min (IQR 2:02-6:38). CONCLUSION: A drone transmitting live video to a tablet is feasible, time saving in comparison to traditional search parties and may be used for providing earlier location of submerged victims at a beach. Drone search can possibly contribute to earlier onset of CPR in drowning victims.

Medical versus non medical etiology in out-of-hospital cardiac arrest-Changes in outcome in relation to the revised Utstein template.

INTRODUCTION: The Utstein-style recommendations for reporting etiology and outcome in out-of-hospital cardiac arrest (OHCA) from 2004 have recently been revised. Among other etiologies a medical category is now introduced, replacing the cardiac category from Utstein template 2004. AIM: The aim of this study is to describe characteristics and temporal trends from reporting OHCA etiology according to the revised Utstein template 2014 in regards to patient characteristics and 30-day survival rates. METHODS: This registry study is based on consecutive OHCA cases reported from the Emergency medical services (EMS) to the Swedish Registry of Cardiopulmonary Resuscitation (SRCR) 1992-2014. Characteristics, including a presumed cardiac etiology in Utstein template 2004, were transcribed to a medical etiology in Utstein template 2014. RESULTS: Of a total of n=70,846 cases, 92% were categorized as having a medical etiology and 8% as having a non-medical cause. Using the new classifications, the 30-day survival rate has significantly increased over a 20-year period from 4.7% to 11.0% in the medical group and from 3% to 9.9% in the non-medical group (p≤0.001). Trauma was the most common cause in OHCA of a non-medical etiology (26%) with a 30-day survival rate of 3.4% whilst drowning and drug overdose had the highest survival rates (14% and 10% respectively). CONCLUSION: Based on Utstein 2014 categories of etiology, overall survival after OHCA with a medical etiology has more than doubled in a 20-year period and tripled for non-medical cases. Patients with a medical etiology found in a shockable rhythm have the highest chance of survival. There is great variability in characteristics among non-medical cases.

Unmanned aerial vehicles (drones) in out-of-hospital-cardiac-arrest.

BACKGROUND: The use of an automated external defibrillator (AED) prior to EMS arrival can increase 30-day survival in out-of-hospital cardiac arrest (OHCA) significantly. Drones or unmanned aerial vehicles (UAV) can fly with high velocity and potentially transport devices such as AEDs to the site of OHCAs. The aim of this explorative study was to investigate the feasibility of a drone system in decreasing response time and delivering an AED. METHODS: Data of Global Positioning System (GPS) coordinates from historical OHCA in Stockholm County was used in a model using a Geographic Information System (GIS) to find suitable placements and visualize response times for the use of an AED equipped drone. Two different geographical models, urban and rural, were calculated using a multi-criteria evaluation (MCE) model. Test-flights with an AED were performed on these locations in rural areas. RESULTS: In total, based on 3,165 retrospective OHCAs in Stockholm County between 2006-2013, twenty locations were identified for the potential placement of a drone. In a GIS-simulated model of urban OHCA, the drone arrived before EMS in 32 % of cases, and the mean amount of time saved was 1.5 min. In rural OHCA the drone arrived before EMS in 93 % of cases with a mean amount of time saved of 19 min. In these rural locations during (n = 13) test flights, latch-release of the AED from low altitude (3-4 m) or landing the drone on flat ground were the safest ways to deliver an AED to the bystander and were superior to parachute release. DISCUSSION: The difference in response time for EMS between urban and rural areas is substantial, as is the possible amount of time saved using this UAV-system. However, yet another technical device needs to fit into the chain of survival. We know nothing of how productive or even counterproductive this system might be in clinical reality. CONCLUSIONS: To use drones in rural areas to deliver an AED in OHCA may be safe and feasible. Suitable placement of drone systems can be designed by using GIS models. The use of an AED equipped drone may have the potential to reduce time to defibrillation in OHCA.

An evaluation of post-resuscitation care as a possible explanation of a difference in survival after out-of-hospital cardiac arrest.

BACKGROUND: A recently published study has shown that survival after out-of-hospital cardiac arrest (OHCA) in Göteborg is almost three times higher than in Stockholm. The aim of this study was to investigate whether in-hospital factors were associated with outcome in terms of survival. METHODS: All patients suffering from OHCA in Stockholm and Göteborg between January 1, 2000 and June 30, 2002 were included. The two groups were compared with reference to patient characteristics, medical history, pre-hospital and hospital course (including in-hospital investigations and interventions) and mortality. All medical charts from patients admitted alive to the different hospitals were studied. Data from the Swedish National Register of Deaths regarding long-term survival were analysed. Pre-hospital data were collected from the Swedish Ambulance Cardiac Arrest Register. RESULTS: In all, 1542 OHCA in Stockholm and 546 in Göteborg were registered during the 30-month study period. In Göteborg, 28% (153 patients) were admitted alive to the two major hospitals whereas in Stockholm 16% (253 patients) were admitted alive to the seven major hospitals (p<0.0001). On admission to the emergency rooms, a larger proportion of patients in Stockholm was unconscious (p=0.006), received assisted breathing (p=0.008) and ongoing CPR (p=0.0002). Patient demography, medical history, in-hospital investigations and interventions and in-hospital mortality (78% in Göteborg, 80% in Stockholm) did not differ between the two groups. Various pre-hospital time intervals were significantly longer in Stockholm than in Göteborg. Total survival to discharge after OHCA was 3.3% in Stockholm and 6.1% in Göteborg (p=0.01). CONCLUSION: An almost 2-fold difference in survival after OHCA between Stockholm and Göteborg appears to be associated with pre-hospital factors only (predominantly in form of prolonged intervals in Stockholm), rather than with in-hospital factors or patient characteristics.