Survival in Out-of-Hospital Cardiac Arrest After Standard Cardiopulmonary Resuscitation or Chest Compressions Only Before Arrival of Emergency Medical Services: Nationwide Study During Three Guideline Periods

BACKGROUND

In out-of-hospital cardiac arrest, chest compression-only cardiopulmonary resuscitation (CO-CPR) has emerged as an alternative to standard CPR (S-CPR), using both chest compressions and rescue breaths. Since 2010, CPR guidelines recommend CO-CPR for both untrained bystanders and trained bystanders unwilling to perform rescue breaths. The aim of this study was to describe changes in the rate and type of CPR performed before the arrival of emergency medical services (EMS) during 3 consecutive guideline periods in correlation to 30-day survival.

METHODS

All bystander-witnessed out-of-hospital cardiac arrests reported to the Swedish register for cardiopulmonary resuscitation in 2000 to 2017 were included. Nonwitnessed, EMS-witnessed, and rescue breath-only CPR cases were excluded. Patients were categorized as receivers of no CPR (NO-CPR), S-CPR, or CO-CPR before EMS arrival. Guideline periods 2000 to 2005, 2006 to 2010, and 2011 to 2017 were used for comparisons over time. The primary outcome was 30-day survival.

RESULTS

A total of 30 445 patients were included. The proportions of patients receiving CPR before EMS arrival changed from 40.8% in the first time period to 58.8% in the second period, and to 68.2% in the last period. S-CPR changed from 35.4% to 44.8% to 38.1%, and CO-CPR changed from 5.4% to 14.0% to 30.1%, respectively. Thirty-day survival changed from 3.9% to 6.0% to 7.1% in the NO-CPR group, from 9.4% to 12.5% to 16.2% in the S-CPR group, and from 8.0% to 11.5% to 14.3% in the CO-CPR group. For all time periods combined, the adjusted odds ratio for 30-day survival was 2.6 (95% CI, 2.4-2.9) for S-CPR and 2.0 (95% CI, 1.8-2.3) for CO-CPR, in comparison with NO-CPR. S-CPR was superior to CO-CPR (adjusted odds ratio, 1.2; 95% CI, 1.1-1.4).

CONCLUSIONS

In this nationwide study of out-of-hospital cardiac arrest during 3 periods of different CPR guidelines, there was an almost a 2-fold higher rate of CPR before EMS arrival and a concomitant 6-fold higher rate of CO-CPR over time. Any type of CPR was associated with doubled survival rates in comparison with NO-CPR. These findings support continuous endorsement of CO-CPR as an option in future CPR guidelines because it is associated with higher CPR rates and overall survival in out-of-hospital cardiac arrest.

Urban environment shortens telomere length in nestling great tits, Parus major

Urban environments are expanding rapidly, and with urbanization come both challenges and opportunities for wildlife. Challenges include combating the anthropogenic disturbances such as light, noise and air pollution and lower availability of natural food sources. The benefits are many, including the availability of anthropogenic food sources, breeding boxes and warmer temperatures. Thus, depending on the context, urbanization can have both positive and negative effects on fitness related traits. It is well known that early-life conditions can have lifelong implications on fitness; little is however known about development in urban environments. We reciprocally cross-fostered urban and rural nestling great tits (Parus major L.) to study how growing up in an urban versus rural habitat affected telomere length (TL)-a suggested biomarker of longevity. We show, for the first time, that growing up in an urban environment significantly shortens TL, independently of natal origin (i.e. urban or rural). This implies that the urban environment imposes a challenge to developing birds, with potentially irreversible effects on lifespan.

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.

Cross-cultural variation in women's preferences for cues to sex- and stress-hormones in the male face

Women in the UK prefer the faces of men with low levels of the stress hormone cortisol, and the relationship is moderated by the sex hormone testosterone. In a Latvian sample, however, women's preferences were not affected by cortisol, and the interaction with testosterone differed from that of the UK. To further explore cross-cultural variation in preferences for facial cues to sex- and stress-hormones, we tested the preferences of women from 13 countries for facial composites constructed to differ in combinations of the hormones. We found significant relationships between a measure of societal development (the United Nations human development index 2011) and preferences for cues to testosterone in the face, and the interaction between preferences for cues to testosterone and cortisol. We also found a significant relationship between preferences for cues to testosterone and a societal-level measure of parasite stress. We conclude that societal-level ecological factors influence the relative value of traits revealed by combinations of sex- and stress-hormones.

Candidate genes for colour and vision exhibit signals of selection across the pied flycatcher (Ficedula hypoleuca) breeding range

The role of natural selection in shaping adaptive trait differentiation in natural populations has long been recognized. Determining its molecular basis, however, remains a challenge. Here, we search for signals of selection in candidate genes for colour and its perception in a passerine bird. Pied flycatcher plumage varies geographically in both its structural and pigment-based properties. Both characteristics appear to be shaped by selection. A single-locus outlier test revealed 2 of 14 loci to show significantly elevated signals of divergence. The first of these, the follistatin gene, is expressed in the developing feather bud and is found in pathways with genes that determine the structure of feathers and may thus be important in generating variation in structural colouration. The second is a gene potentially underlying the ability to detect this variation: SWS1 opsin. These two loci were most differentiated in two Spanish pied flycatcher populations, which are also among the populations that have the highest UV reflectance. The follistatin and SWS1 opsin genes thus provide strong candidates for future investigations on the molecular basis of adaptively significant traits and their co-evolution.

Automated external defibrillators delivered by drones to patients with suspected out-of-hospital cardiac arrest

AIMS 

Early defibrillation is critical for the chance of survival in out-of-hospital cardiac arrest (OHCA). Drones, used to deliver automated external defibrillators (AEDs), may shorten time to defibrillation, but this has never been evaluated in real-life emergencies. The aim of this study was to investigate the feasibility of AED delivery by drones in real-life cases of OHCA.

METHODS AND RESULTS 

In this prospective clinical trial, three AED-equipped drones were placed within controlled airspace in Sweden, covering approximately 80 000 inhabitants (125 km2). Drones were integrated in the emergency medical services for automated deployment in beyond-visual-line-of-sight flights: (i) test flights from 1 June to 30 September 2020 and (ii) consecutive real-life suspected OHCAs. Primary outcome was the proportion of successful AED deliveries when drones were dispatched in cases of suspected OHCA. Among secondary outcomes was the proportion of cases where AED drones arrived prior to ambulance and time benefit vs. ambulance. Totally, 14 cases were eligible for dispatch during the study period in which AED drones took off in 12 alerts to suspected OHCA, with a median distance to location of 3.1 km [interquartile range (IQR) 2.8-3.4). AED delivery was feasible within 9 m (IQR 7.5-10.5) from the location and successful in 11 alerts (92%). AED drones arrived prior to ambulances in 64%, with a median time benefit of 01:52 min (IQR 01:35-04:54) when drone arrived first. In an additional 61 test flights, the AED delivery success rate was 90% (55/61).

CONCLUSION 

In this pilot study, we have shown that AEDs can be carried by drones to real-life cases of OHCA with a successful AED delivery rate of 92%. There was a time benefit as compared to emergency medical services in cases where the drone arrived first. However, further improvements are needed to increase dispatch rate and time benefits.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov Identifier: NCT04415398.

Computational design of mechanically coupled axle-rotor protein assemblies

Natural molecular machines contain protein components that undergo motion relative to each other. Designing such mechanically constrained nanoscale protein architectures with internal degrees of freedom is an outstanding challenge for computational protein design. Here we explore the de novo construction of protein machinery from designed axle and rotor components with internal cyclic or dihedral symmetry. We find that the axle-rotor systems assemble in vitro and in vivo as designed. Using cryo-electron microscopy, we find that these systems populate conformationally variable relative orientations reflecting the symmetry of the coupled components and the computationally designed interface energy landscape. These mechanical systems with internal degrees of freedom are a step toward the design of genetically encodable nanomachines.

Sympatric divergence and clinal variation in multiple coloration traits of Ficedula flycatchers

Geographic variation in phenotypes plays a key role in fundamental evolutionary processes such as local adaptation, population differentiation and speciation, but the selective forces behind it are rarely known. We found support for the hypothesis that geographic variation in plumage traits of the pied flycatcher Ficedula hypoleuca is explained by character displacement with the collared flycatcher Ficedula albicollis in the contact zone. The plumage traits of the pied flycatcher differed strongly from the more conspicuous collared flycatcher in a sympatric area but increased in conspicuousness with increasing distance to there. Phenotypic differentiation (PST ) was higher than that in neutral genetic markers (FST ), and the effect of geographic distance remained when statistically controlling for neutral genetic differentiation. This suggests that a cline created by character displacement and gene flow explains phenotypic variation across the distribution of this species. The different plumage traits of the pied flycatcher are strongly to moderately correlated, indicating that they evolve non-independently from each other. The flycatchers provide an example of plumage patterns diverging in two species that differ in several aspects of appearance. The divergence in sympatry and convergence in allopatry in these birds provide a possibility to study the evolutionary mechanisms behind the highly divergent avian plumage patterns.

Effect of mobile application-based versus DVD-based CPR training on students' practical CPR skills and willingness to act: a cluster randomised study

OBJECTIVES

The aim was to compare students' practical cardiopulmonary resuscitation (CPR) skills and willingness to perform bystander CPR, after a 30 min mobile application (app)-based versus a 50 min DVD-based training.

SETTINGS

Seventh grade students in two Swedish municipalities.

DESIGN

A cluster randomised trial. The classes were randomised to receive app-based or DVD-based training. Willingness to act and practical CPR skills were assessed, directly after training and at 6 months, by using a questionnaire and a PC Skill Reporting System. Data on CPR skills were registered in a modified version of the Cardiff test, where scores were given in 12 different categories, adding up to a total score of 12-48 points. Training and measurements were performed from December 2013 to October 2014.

PARTICIPANTS

63 classes or 1232 seventh grade students (13-year-old) were included in the study.

PRIMARY AND SECONDARY OUTCOME MEASURES

Primary end point was the total score of the modified Cardiff test. The individual variables of the test and self-reported willingness to make a life-saving intervention were secondary end points.

RESULTS

The DVD-based group was superior to the app-based group in CPR skills; a total score of 36 (33-38) vs 33 (30-36) directly after training (p<0.001) and 33 (30-36) and 31 (28-34) at 6 months (p<0.001), respectively. At 6 months, the DVD group performed significantly better in 8 out of 12 CPR skill components. Both groups improved compression depth from baseline to follow-up. If a friend suffered cardiac arrest, 78% (DVD) versus 75% (app) would do compressions and ventilations, whereas only 31% (DVD) versus 32% (app) would perform standard CPR if the victim was a stranger.

CONCLUSIONS

At 6 months follow-up, the 50 min DVD-based group showed superior CPR skills compared with the 30 min app-based group. The groups did not differ in regard to willingness to make a life-saving effort.

Increased survival from out-of-hospital cardiac arrest when off duty medically educated personnel perform CPR compared with laymen

BACKGROUND

Bystander cardiopulmonary resuscitation (CPR) has been proved to save lives; however, whether survival is affected by the training level of the bystander is not fully described.

AIM

To describe if the training level of laymen and medically educated bystanders affect 30-day survival in out-of-hospital cardiac arrests (OHCA).

METHODS

This observational study included all witnessed and treated cases of bystander CPR reported to the Swedish Registry of Cardiopulmonary Resuscitation between 2010 and 2014. Bystander CPR was divided into two categories: (a) lay-byCPR (non-medically educated) and (b) med-byCPR (off duty medically educated personnel).

RESULTS

During 2010-2014, 24,643 patients were reported to the OHCA registry, of which 6850 received lay-byCPR and 1444 med-byCPR; 16,349 crew-witnessed and non-witnessed cases and those with missing information were excluded from the analysis. The median interval from collapse to call for emergency medical services was 2min in both groups (p=0.97) and 2min from collapse to start of CPR for lay-byCPR versus 1min for med-byCPR (p<0.0001). There were no significant differences in CPR methods used; 64.3% (lay-byCPR) and 65.7% (med-byCPR) applied compressions and ventilation, respectively (p=0.33). The 30-day survival was 14.7% for lay-byCPR and 17.2% for the med-byCPR group (p=0.02). The odds ratio adjusted for potential confounders regarding survival (med-byCPR versus lay-byCPR) was 1.34 (95% confidence interval, 1.11-1.62; p=0.002).

CONCLUSIONS

In cases of OHCA, medically educated bystanders initiated CPR earlier and an increased 30-day survival was found compared with laymen bystanders. These results support the need to improve the education programme for laypeople.

Developmental profile of patients with maple syrup urine disease

The progress of nine maple syrup urine disease patients (eight classical, one possible variant) was reviewed to look for similarities in developmental patterns. A consistent developmental profile of stronger Verbal than Performance IQ and lower than familially expected IQ was seen. Younger age at diagnosis was associated with a milder neonatal course. Those who were asymptomatic or suffered mild complications in the newborn period have higher IQs than children experiencing moderate or severe complications. Children with asymptomatic or mild neonatal course also required less special education services. Overall, a picture of ubiquitous motor, visual-analytic and learning deficits is seen.

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.

Effect of Smartphone Dispatch of Volunteer Responders on Automated External Defibrillators and Out-of-Hospital Cardiac Arrests: The SAMBA Randomized Clinical Trial

Importance

Smartphone dispatch of volunteer responders to nearby out-of-hospital cardiac arrests (OHCAs) has emerged in several emergency medical services, but no randomized clinical trials have evaluated the effect on bystander use of automated external defibrillators (AEDs).

Objective

To evaluate if bystander AED use could be increased by smartphone-aided dispatch of lay volunteer responders with instructions to collect nearby AEDs compared with instructions to go directly to patients with OHCAs to start cardiopulmonary resuscitation (CPR).

Design, Setting, and Participants

This randomized clinical trial assessed a system for smartphone dispatch of volunteer responders to individuals experiencing OHCAs that was triggered at emergency dispatch centers in response to suspected OHCAs and randomized 1:1. The study was conducted in 2 main Swedish regions: Stockholm and Västra Götaland between December 2018 and January 2020. At study start, there were 3123 AEDs in Stockholm and 3195 in Västra Götaland and 24 493 volunteer responders in Stockholm and 19 117 in Västra Götaland. All OHCAs in which the volunteer responder system was activated by dispatchers were included. Excluded were patients with no OHCAs, those with OHCAs not treated by the emergency medical services, and those with OHCAs witnessed by the emergency medical services.

Interventions

Volunteer responders were alerted through the volunteer responder system smartphone application and received map-aided instructions to retrieve nearest available public AEDs on their way to the OHCAs. The control arm included volunteer responders who were instructed to go directly to the OHCAs to perform CPR.

Main Outcomes and Measures

Overall bystander AED attachment, including those attached by volunteer responders and lay volunteers who did not use the smartphone application.

Results

Volunteer responders were activated for 947 patients with OHCAs. Of those, 461 were randomized to the intervention group (median [IQR] age of patients, 73 [61-81] years; 295 male patients [65.3%]) and 486 were randomized to the control group (median [IQR] age of patients, 73 [63-82] years; 312 male patients [65.3%]). Primary outcome of AED attachment occurred in 61 patients (13.2%) in the intervention arm vs 46 patients (9.5%) in the control arm (difference, 3.8% [95% CI, -0.3% to 7.9%]; P = .08). The majority of AEDs were attached by lay volunteers who were not using the smartphone application (37 in intervention arm, 28 in control). There were no significant differences in secondary outcomes. Among the volunteer responders using the application, crossover was 11% and compliance to instructions was 31%. Volunteer responders attached 38% (41 of 107) of all AEDs and provided 45% (16 of 36) of all defibrillations and 43% (293 of 666) of all CPR.

Conclusions and Relevance

In this study, smartphone dispatch of volunteer responders to OHCAs to retrieve nearby AEDs vs instructions to directly perform CPR did not significantly increase volunteer AED use. High baseline AED attachement rate and crossover may explain why the difference was not significant.

Trial Registration

ClinicalTrials.gov Identifier: NCT02992873.

The effect of a national web course "Help-Brain-Heart" as a supplemental learning tool before CPR training: a cluster randomised trial

BACKGROUND

The effectiveness of cardiopulmonary resuscitation (CPR) learning methods is unclear. Our aim was to evaluate whether a web course before CPR training, teaching the importance of recognition of symptoms of stroke and acute myocardial infarction (AMI) and a healthy lifestyle, could influence not only theoretical knowledge but also practical CPR skills or willingness to act in a cardiac arrest situation.

METHODS

Classes with 13-year-old students were randomised to CPR training only (control) or a web course plus CPR training (intervention). Data were collected (practical test and a questionnaire) directly after training and at 6 months. CPR skills were evaluated using a modified Cardiff test (12-48 points). Knowledge on stroke symptoms (0-7 points), AMI symptoms (0-9 points) and lifestyle factors (0-6 points), and willingness to act were assessed by the questionnaire. The primary endpoint was CPR skills at 6 months. CPR skills directly after training, willingness to act and theoretical knowledge were secondary endpoints. Training and measurements were performed from December 2013 to October 2014.

RESULTS

Four hundred and thirty-two students were included in the analysis of practical skills and self-reported confidence. The mean score for CPR skills was 34 points after training (control, standard deviation [SD] 4.4; intervention, SD 4.0; not significant [NS]); and 32 points at 6 months for controls (SD 3.9) and 33 points for intervention (SD 4.2; NS). At 6 months, 73% (control) versus 80% (intervention; P = 0.05) stated they would do compressions and ventilation if a friend had a cardiac arrest, whereas 31% versus 34% (NS) would perform both if the victim was a stranger. One thousand, two hundred and thirty-two students were included in the analysis of theoretical knowledge; the mean scores at 6 months for the control and intervention groups were 2.8 (SD 1.6) and 3.2 (SD 1.4) points (P < 0.001) for stroke symptoms, 2.6 (SD 2.0) and 2.9 (SD 1.9) points (P = 0.008) for AMI symptoms and 3.2 (SD 1.2) and 3.4 (SD 1.0) points (P < 0.001) for lifestyle factors, respectively.

DISCUSSION

Use of online learning platforms is a fast growing technology that increases the flexibility of learning in terms of location, time and is available before and after practical training.

CONCLUSIONS

A web course before CPR training did not influence practical CPR skills or willingness to act, but improved the students' theoretical knowledge of AMI, stroke and lifestyle factors.

Are first responders first? The rally to the suspected out-of-hospital cardiac arrest

BACKGROUND

Time is the crucial factor in the "chain of survival" treatment concept for out-of-hospital cardiac arrest (OHCA). We aimed to measure different response time intervals by comparing emergency medical system (EMS), fire fighters and smartphone aided volunteer responders.

METHODS

In two large Swedish regions, volunteer responders were timed from the alert until they arrived at the scene of the suspected OHCA. The first arriving volunteer responders who tried to fetch an automated external defibrillator (AED-responder) and who ran to perform bystander cardiopulmonary resuscitation (CPR-responder) were compared to both the first arriving EMS and fire fighters. Three-time intervals were measured, from call to dispatch, the unit response time (from dispatch to arrival) and the total response time.

RESULTS

During 22 months, 2631 suspected OHCAs were included. The median time from call to dispatch was in minutes 1.8 (95% CI = 1.7-1.8) for EMS, 2.9 (95% CI = 2.8-3.0) for fire-fighters and 3.0 (95% CI = 2.9-3.1) for volunteer responders. The median unit response time was 8.3 (95% CI = 8.1-8.5) for EMS, 6.8 (95% CI = 6.7-6.9) for fire fighters and 6.0 (95% CI = 5.7-6.2) for AED-responders and 4.6 (95% CI = 4.5-4.8) for CPR-responders. The total response time was 10.4 (95% CI = 10.1-10.6) for EMS, 10.2 (95% CI = 9.9-10.4) for fire fighters, 9.6 (95% CI = 9.1-9.8) for AED-responders and 8.2 (95% CI = 8.0-8.3) for CPR-responders.

CONCLUSION

First arriving volunteer responders had the shortest unit response time when compared to both fire fighters and EMS, however this advantage was reduced by delays introduced at the dispatch center. Earlier automatic dispatch should be considered in further studies.

Direct evidence concerning the 'major role' of fluoride dentifrices in the caries decline. A 6-year analytical cohort study

The role of fluoride (F) dentifrices in caries decline was investigated by assessing the effect of variation in their use on caries scores among teenagers. The material comprised 211 subjects aged about 11 years at base line and 18 years at the last examination. Pairs of posterior bitewing radiographs were assessed by one examiner. Information concerning dental health behavior was collected by questionnaire and about treatment received from dental records. A reversal of the traditional DFS gender difference occurred during teenage years. Multivariate regression analyses showed an inverse relationship between variation in F dentifrice use and current decay (D1S) at age 18 years (P < 0.04) and with caries incidence per year (D1FS) during the whole observation period (P < 0.02). Total explained variance in 6-year deltaD1FS scores was 29.8%, of which variation in toothbrushing behavior contributed 1.8 percentage points. While confirming the multifactorial nature of dental caries, these results also provided quantitative evidence for the role of variation in F dentifrice use in caries incidence and decline.

Effect of two additional interventions, test and reflection, added to standard cardiopulmonary resuscitation training on seventh grade students' practical skills and willingness to act: a cluster randomised trial

OBJECTIVES

The aim of this research is to investigate if two additional interventions, test and reflection, after standard cardiopulmonary resuscitation (CPR) training facilitate learning by comparing 13-year-old students' practical skills and willingness to act.

SETTINGS

Seventh grade students in council schools of two municipalities in south-east Sweden.

DESIGN

School classes were randomised to CPR training only (O), CPR training with a practical test including feedback (T) or CPR training with reflection and a practical test including feedback (RT). Measures of practical skills and willingness to act in a potential life-threatening situation were studied directly after training and at 6 months using a digital reporting system and a survey. A modified Cardiff test was used to register the practical skills, where scores in each of 12 items resulted in a total score of 12-48 points. The study was conducted in accordance with current European Resuscitation Council guidelines during December 2013 to October 2014.

PARTICIPANTS

29 classes for a total of 587 seventh grade students were included in the study.

PRIMARY AND SECONDARY OUTCOME MEASURES

The total score of the modified Cardiff test at 6 months was the primary outcome. Secondary outcomes were the total score directly after training, the 12 individual items of the modified Cardiff test and willingness to act.

RESULTS

At 6 months, the T and O groups scored 32 (3.9) and 30 (4.0) points, respectively (p<0.001), while the RT group scored 32 (4.2) points (not significant when compared with T). There were no significant differences in willingness to act between the groups after 6 months.

CONCLUSIONS

A practical test including feedback directly after training improved the students' acquisition of practical CPR skills. Reflection did not increase further CPR skills. At 6-month follow-up, no intervention effect was found regarding willingness to make a life-saving effort.

Description of call handling in emergency medical dispatch centres in Scandinavia: recognition of out-of-hospital cardiac arrests and dispatcher-assisted CPR

BACKGROUND

The European resuscitation council have highlighted emergency medical dispatch centres as an important key player for early recognition of Out-of-Hospital Cardiac Arrest (OHCA) and in providing dispatcher assisted cardiopulmonary resuscitation (CPR) before arrival of emergency medical services. Early recognition is associated with increased bystander CPR and improved survival rates. The aim of this study is to describe OHCA call handling in emergency medical dispatch centres in Copenhagen (Denmark), Stockholm (Sweden) and Oslo (Norway) with focus on sensitivity of recognition of OHCA, provision of dispatcher-assisted CPR and time intervals when CPR is initiated during the emergency call (NO-CPR_prior), and to describe OHCA call handling when CPR is initiated prior to the emergency call (CPR_prior).

METHODS

Baseline data of consecutive OHCA eligible for inclusion starting January 1st 2016 were collected from respective cardiac arrest registries. A template based on the Cardiac Arrest Registry to Enhance Survival definition catalogue was used to extract data from respective cardiac arrest registries and from corresponding audio files from emergency medical dispatch centres. Cases were divided in two groups: NO-CPR_prior and CPR_prior and data collection continued until 200 cases were collected in the NO-CPR_prior-group.

RESULTS

NO-CPR_prior OHCA was recognised in 71% of the calls in Copenhagen, 83% in Stockholm, and 96% in Oslo. Abnormal breathing was addressed in 34, 7 and 98% of cases and CPR instructions were started in 50, 60, and 80%, respectively. Median time (mm:ss) to first chest compression was 02:35 (Copenhagen), 03:50 (Stockholm) and 02:58 (Oslo). Assessment of CPR quality was performed in 80, 74, and 74% of the cases. CPR_prior comprised 71 cases in Copenhagen, 9 in Stockholm, and 38 in Oslo. Dispatchers still started CPR instructions in 41, 22, and 40% of the calls, respectively and provided quality assessment in 71, 100, and 80% in these respective instances.

CONCLUSIONS

We observed variations in OHCA recognition in 71-96% and dispatcher assisted-CPR were provided in 50-80% in NO-CPR_prior calls. In cases where CPR was initiated prior to emergency calls, dispatchers were less likely to start CPR instructions but provided quality assessments during instructions.

Automated external defibrillators delivered by drones to patients with suspected out-of-hospital cardiac arrest

Background

Early defibrillation is critical for the chance of survival in in out-of-hospital cardiac arrest (OHCA). Drones, used to deliver automated external defibrillators (AEDs), may shorten time to defibrillation, but this has never been evaluated in real-life emergencies.

Purpose

The aim of this study was to investigate the feasibility of AED-delivery by drones in real-life cases of OHCA.

Methods

In this prospective clinical trial, three AED-equipped drones were placed within controlled airspace in Sweden, covering approximately 80,000 inhabitants (125km2). Drones were integrated in the emergency medical services for automated deployment in beyond-visual-line-of-sight flights in; a) consecutive real-life suspected OHCAs b) test-flights from 06–01–20 to 09–30–20. Primary outcome was the proportion of successful AED-deliveries when drones were dispatched in cases of suspected OHCA. Among secondary outcomes were the proportion of cases where AED-drones arrived prior to ambulance and time benefit vs. ambulance.

Results

Totally 14 cases were eligible for dispatch during the study period in which AED-drones took off in 12 alerts to suspected OHCA; with a median distance to location 3,1 km (IQR:2,8–3,4). AED-delivery was feasible within 9 meters (IQR:7,5–10,5) from the location and successful in 11 alerts, 92%. AED-drones arrived prior to ambulances in 64%, with a median time benefit of 01:52 minutes (IQR:01:35–04:54). In an additional 61 test-flights the AED-delivery success rate was 90% (55/61).

Conclusion

In this pilot study, we have shown that AED-delivery by drones in real-life cases of OHCA is feasible with a substantial time benefit and a successful delivery rate of 92%. Further technological improvements are needed to increase dispatch rate and time gains.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): Swedish heart-lung foundation

Effects of native language on CPR skills and willingness to intervene in out-of-hospital cardiac arrest after film-based basic life support training: a subgroup analysis of a randomised trial

OBJECTIVES

The aim was to investigate whether the students' native language, Swedish as native language (SNL) versus other native language (ONL), affects cardiopulmonary resuscitation (CPR) skills or willingness to act after film-based training in Swedish.

SETTING

13-year-old students in two municipalities.

DESIGN

A subgroup from a previous randomised study was analysed. During 2013 to 2014, a film-based CPR method was evaluated. Practical skills and willingness to act were assessed directly after training and after 6 months. CPR skills were evaluated using a modified Cardiff test.

PARTICIPANTS

A total of 641 students were included in the analysis (SNL, n=499; ONL, n=142).

PRIMARY AND SECONDARY OUTCOME MEASURES

Primary endpoint was the total score of the modified Cardiff test at 6 months. The secondary endpoints were total score directly after training, individual variables for the test and self-reported willingness to act.

RESULTS

At the practical test, SNL students scored better than ONL students; directly after training, 67% vs 61% of maximum score, respectively (p<0.001); at 6 months, 61% vs 56% of maximum score (p<0.001). Most students were willing to perform compressions and ventilation on a friend (SNL 85% vs ONL 84%). However, if the victim was a stranger, ONL students were more willing to perform both compressions and ventilation than SNL students (52% vs 38% after training, p<0.001; 42% vs 31% at 6 months, p=0.032). SNL students preferred to initiate chest compressions only.

CONCLUSIONS

SNL students scored slightly higher in the practical CPR skill test than ONL students. Willingness to act was generally high, however ONL students reported higher willingness to perform both compressions and ventilation if the victim was a stranger. Further research is needed to investigate how CPR educational material should be designed and simplified for optimal learning by students. Different language versions or including feedback in CPR training can be a way to increase learning.

ETHICS APPROVAL

The study was approved by the Regional Ethical Review Board of Linköping, Sweden (2013/358-31).

TRIAL REGISTRATION NUMBER

NCT03233490; Pre-results.

Swedish dispatchers’ compliance with the American Heart Association performance goals for dispatch-assisted cardiopulmonary resuscitation and its association with survival in out-of-hospital cardiac arrest: A retrospective study

Aim

We aimed 1) to investigate how Swedish dispatchers perform during emergency calls in accordance with the American Heart Association (AHA) goals for dispatcher-assisted cardiopulmonary resuscitation (DA-CPR), 2) calculate the potential impact on 30-day survival.

Methods

This observational study includes a random sample of 1000 out-of-hospital cardiac arrest (OHCA) emergency ambulance calls during 2018 in Sweden. Voice logs were audited to evaluate dispatchers’ handling of emergency calls according to the AHA performance goals. Number of possible additional survivors was estimated assuming the timeframes of the AHA performance goals was achieved.

Results

A total of 936 cases were included. An OHCA was recognized by a dispatcher in 79% (AHA goal 75%). In recognizable OHCA, dispatchers recognized 85% (AHA goal 95%). Dispatch-directed compressions were given in 61% (AHA goal 75%). Median time to OHCA recognition was 113 s [interquartile range (IQR), 62, 204 s] (AHA goal < 60 s). The first dispatch-directed compression was performed at a median time of 240 s [IQR, 176, 332 s] (AHA goal < 90 s). If eligible patients receive dispatch-directed compressions within the AHA 90 s goal, 73 additional lives may be saved; if all cases are recognized within the AHA 60 s goal, 25 additional lives may be saved.

Conclusions

The AHA policy statement serves as a benchmark for all emergency medical dispatch centres (EMDC). Additional effort is needed at Swedish EMDC to achieve AHA goals for DA-CPR. Our study suggests that if EMDC further optimize handling of OHCA calls in accordance with AHA goals, many more lives may be saved.

Drone delivery of automated external defibrillators compared with ambulance arrival in real-life suspected out-of-hospital cardiac arrests: a prospective observational study in Sweden

BACKGROUND

A novel approach to improve bystander defibrillation for out-of-hospital cardiac arrests is to dispatch and deliver an automated external defibrillator (AED) directly to the suspected cardiac arrest location by drone. The aim of this study was to investigate how often a drone could deliver an AED before ambulance arrival and to measure the median time benefit achieved by drone deliveries.

METHODS

In this prospective observational study, five AED-equipped drones were placed within two separate controlled airspaces in Sweden, covering approximately 200 000 inhabitants. Drones were dispatched in addition to standard emergency medical services for suspected out-of-hospital cardiac arrests and flight was autonomous. Alerts concerning children younger than 8 years, trauma, and emergency medical services-witnessed cases were not included. Exclusion criteria were air traffic control non-approval of flight, unfavourable weather conditions, no-delivery zones, and darkness. Data were collected from the dispatch centres, ambulance organisations, Swedish Registry for Cardiopulmonary Resuscitation, and the drone operator. Core outcomes were the percentage of cases for which an AED was delivered by a drone before ambulance arrival, and the median time difference (minutes and seconds) between AED delivery by drone and ambulance arrival. Explorative outcomes were percentage of attached drone-delivered AEDs before ambulance arrival and the percentage of cases defibrillated by a drone-delivered AED when it was used before ambulance arrival.

FINDINGS

During the study period (from April 21, 2021 to May 31, 2022), 211 suspected out-of-hospital cardiac arrest alerts occurred, and in 72 (34%) of those a drone was deployed. Among those, an AED was successfully delivered in 58 (81%) cases, and the major reason for non-delivery was cancellation by dispatch centre because the case was not an out-of-hospital cardiac arrest. In cases for which arrival times for both drone and ambulance were available (n=55), AED delivery by drone occurred before ambulance arrival in 37 cases (67%), with a median time benefit of 3 min and 14 s. Among these cases, 18 (49%) were true out-of-hospital cardiac arrests and a drone-delivered AED was attached in six cases (33%). Two (33%) had a shockable first rhythm and were defibrillated by a drone-delivered AED before ambulance arrival, with one person achieving 30-day survival. No adverse events occurred. AED delivery (not landing) was made within 15 m from the patient or building in 91% of the cases.

INTERPRETATION

AED-equipped drones dispatched in cases of suspected out-of-hospital cardiac arrests delivered AEDs before ambulance arrival in two thirds of cases, with a clinically relevant median time benefit of more than 3 min. This intervention could potentially decrease time to attachment of an AED, before ambulance arrival.

FUNDING

Swedish Heart Lung Foundation.

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.