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Abstract Background Chest pain is a frequent cause of health care contacts. We examined the prehospital management, in-hospital discharge diagnoses, and mortality of patients calling a non-emergency and emergency medical service with chest pain. Methods The Copenhagen Emergency Medical Services (EMS) consists of a non-emergency medical helpline (calls to 1813) and emergency medical service (1-1-2 calls). We included all calls to the Copenhagen EMS with a primary complaint of chest pain from 2014 to 2018 in Copenhagen, Denmark. The outcomes were: emergency response (ambulance dispatch, other transports/self-transport/home visits, self-care, and unknown/cancelled response), in-hospital diagnosis within 7 days after the call (cardiovascular, pulmonary, or other non-cardiovascular/pulmonary) and 30-day mortality. Results Among 4,834,071 calls, 91,671 were registered with chest pain at the Copenhagen EMS. The first call for each patient was kept for analysis (n = 66,762). In total, 91.4% were referred to the hospital, 75.8% (n = 50,627) received an ambulance and 15.6% (n = 10,383) received other transport/self-transport/home visits. Overall, 26.9% (n = 17,937) were diagnosed with a cardiovascular disease, 5.2% (n = 3,490) a pulmonary disease, 52.8% (n = 35.242) other non-cardiovascular/pulmonary disease, and 15.1% (n = 10,093) received no diagnosis. Among ambulance-transported patients, the prevalence of cardiovascular discharge diagnoses was higher (32.1%) and fewer received no diagnosis (11.0%). Cardiovascular disease was less prevalent among patients not transported by ambulance and patients not referred to hospital at all (2-13.4%) and in patients ≤ 40 years of age (

Abstract Background During the COVID-19 pandemic, disturbing images of ambulances unable to respond to the demands for prehospital assistance appeared from several parts of the world. In Denmark, however, a notion occurred that the demands for emergency medical assistance declined. The purpose of this study was to compare the patients' use of the Danish Emergency Medical Services (EMS) before and during the COVID-19 pandemic. Furthermore, we investigated the overall mortality of the ambulance population, the main reason for calling the emergency medical dispatch centre, and the diagnosis assigned to the admitted patients. Methods The study was a nationwide registry-based cohort study based on the national prehospital medical records and the Danish National Patient Registry. The primary outcome was the requested number of ambulances. Secondary outcomes included the primary reason for contact with the dispatch centre (reflected by the dispatch criteria), patient mortality, and the diagnoses assigned to the patients transported to the hospital by ambulance during the COVID-19 pandemic in Denmark in March–December 2020. Comparisons were made using a similar period in 2019 before the pandemic. Results In comparison with the baseline values before the pandemic, the total number of patients treated by the EMS was reduced by 4.5% during the COVID-19 pandemic. The number of patients transported to the hospital during the pandemic was similarly reduced by 3.5%. Compared with baseline values, fewer were patients hospitalised with respiratory diseases during the pandemic (a reduction of 53.3% from April 2019 to April 2020). Compared to the baseline period, there were significant increases in both the 48-h mortality (from 1.4% to 1.5%) and the 30-day mortality (from 4.9% to 5.4%) (p

Objective: Glucagon-like peptide-1 receptor agonists (GLP-1 RAs) improve cardiovascular outcomes in patients with type 2 diabetes, but few studies have studied the risk of out-of-hospital cardiac arrest (OHCA). We investigated whether GLP-1 RA use reduce OHCA risk in type 2 diabetes when compared to dipeptidyl peptidase-4 inhibitor (DPP-4i) use. Methods: We identified all patients having a redeemed prescription of a glucose-lowering drug between 1995 and 2019 and excluded patients with a first-time redeemed prescription consisting of insulin. Within this cohort, we nested a case-control population comprising all OHCA-cases from presumed cardiac causes between 2013 and 2019. OHCA-cases were matched 1:5 to non-OHCA controls of the same sex and age on the date of OHCA. The odds ratios (ORs) and corresponding 95% confidence intervals (95%-CIs) of OHCA were reported comparing GLP-1 RAs versus DPP-4is. Results: We identified 3,618 OHCA-cases from presumed cardiac causes and matched them to 18,090 non-OHCA controls. GLP-1 RAs were used by 269 (7.44%) cases and 1297 (7.17%) controls, and conferred no increase in the overall odds of OHCA compared with DPP-4i use (OR:0.89, 95%-CI 0.74–1.07). However, stratification according to sex revealed that OHCA risk was significantly reduced in women (OR:0.59, 95%-CI 0.40–0.86) but not in men (OR:1.01, 95%-CI 0.82–1.26, P-value interaction:0.0093). The OR of OHCA did not vary significantly when stratifying for age, duration of diabetes, chronic kidney disease, or presence of cardiovascular disease. Conclusion: Our findings indicate that GLP-1 RA use is not associated with a reduced risk of OHCA in Danish individuals with type 2 diabetes when compared to DPP-4is.

Background Following international guidelines, communities have deployed automated external defibrillators at train stations without substantive evidence. Methods and Results We geocoded public out‐of‐hospital cardiac arrests (OHCAs) (2016–2020), automated external defibrillators, and train stations. The stations were divided into the following groups according to passenger flow: 1 (0–499), 2 (500–4999), 3 (5000–9999), and 4 (>10 000) passengers per day. Risk ratios (RRs) were calculated using Poisson regression of rates, and odds ratios (ORs) were analyzed through logistic regression. OHCAs at train stations accounted for 102 (2.3%) of 4467 public OHCAs. The incidence rate (IR) and RR for OHCAs were for group 1: IR, 0.02 OHCA per station per year, RR, 1.0 (reference); group 2: IR, 0.07, RR, 4.1 (95% CI, 2.3–7.3); group 3: IR, 0.25, RR, 12.7 (95% CI, 6.2–25.9); and group 4: IR, 0.34, RR, 16.3 (95% CI, 8.6–30.9). Compared with other public OHCAs, OHCAs at train stations were just as likely to receive bystander cardiopulmonary resuscitation (OR, 1.13 [95% CI, 0.60–2.12]). However, they had higher odds of bystander defibrillation (OR, 1.66 [95% CI, 1.06–2.58]), were more likely to achieve return of spontaneous circulation (OR, 1.88 [95% CI, 1.24–2.85]), and survive 30 days (OR, 2.37 [95% CI, 1.57–3.59]). Conclusions The incidence of OHCAs at train stations was associated with passenger flow, with the busiest stations having a 16‐fold higher risk of OHCAs than the lowest. OHCAs at train stations had better outcomes compared with other public OHCAs.

Background: Ongoing opioid treatment can potentially modify symptoms of myocardial infarction (MI) and cause a lack of recognition and treatment delay. Objectives: The purpose of this study was to examine MI symptoms and the time to hospitalization for patients in ongoing opioid treatment compared to patients without ongoing opioid treatment. Methods: We evaluated calls to the Copenhagen Emergency Medical Services in Denmark from 2014 to 2018. Calls were included when followed by hospitalization and a diagnosis of MI. Symptoms of MI and the time from call to hospitalization in patients in ongoing opioid treatment initiated prior to the onset of MI were compared to a control group of MI patients without opioid treatment. Results: In total, 6,633 calls were included; 552 calls from patients in opioid treatment and 6,081 calls from controls. Patients in opioid treatment were older and had more comorbidities than controls. Chest pain was less prevalent in MI patients in opioid treatment compared to controls (adjOR: 0.70; 95% CI: 0.57-0.85). The median time from the call to hospitalization was longer in patients in opioid treatment than in controls (50 vs 47 minutes; P = 0.006). Conclusions: In calls to the Emergency Medical Services, opioid treatment initiated prior to the onset of MI was associated with less frequent chest pain in MI. Therefore, awareness of ongoing opioid treatment may improve telephone triage of patients with MI, as symptom presentation in opioid-treated patients may differ and potentially challenge and delay the emergency response.

Abstract Introduction Most cardiac arrest survivors are classified with mild to moderate cognitive impairment; roughly, 50% experience long-term neurocognitive impairment. Postarrest challenges complicate participation in society and are associated with social issues such as failure to resume social activities and impaired return to work. The effectiveness of rehabilitation interventions for out-of-hospital cardiac arrest survivors are sparsely described, but the body of evidence describes high probabilities of survivors not returning to work, returning to jobs with modified job descriptions, returning to part-time employment, and often in combination with extensive unmet rehabilitation needs. Hence, there is a need to develop and test a pragmatic individual targeted intervention to facilitate return to work (RTW) in survivors of OHCA. The overall aim of the ROCK trial is to evaluate the effectiveness of a comprehensive individually tailored multidisciplinary rehabilitation intervention for survivors of OHCA on RTW compared to usual care. Methods and analysis The ROCK trial is a two-arm parallel group multicentre investigator-initiated pragmatic randomized controlled superiority trial with primary endpoint measured 12 months after the cardiac arrest. Adult survivors who were part of the labour force prior to the OCHA and had at least 2 years until they are qualified to receive retirement state pensions are eligible for inclusion. Survivors will be randomized 1:1 to usual care group or usual care plus a comprehensive tailored rehabilitation intervention focusing on supporting RTW. After comprehensive assessment of individual rehabilitation needs, the intervention is ongoingly coordinated within a multidisciplinary rehabilitation team, and the intervention can be delivered for up until 12 months. Data for the primary outcome will be obtained from the national register on social transfer payments. The primary outcome will be analysed using logistic regression assessing RTW status at 12 months adjusting for the intervention and age at OHCA, sex, marital status, and occupation prior to OHCA. Discussion The ROCK trial is the first RCT to investigate the effectiveness of a rehabilitation intervention focusing on return to work after cardiac arrest. Trial registration ClinicalTrials.gov NCT05173740. Registered on May 2018

Aim Conflicting results have been reported regarding the association between fluoroquinolones (FQs) and the risk of out-of-hospital cardiac arrest (OHCA). In particular, it has not become clear whether OHCA in FQ users is related to the inherent comorbidities or whether there is a direct pro-arrhythmic effect of FQs. Therefore, we studied the relation between FQs and OHCA in the general population.Methods Through Danish nationwide registries, we conducted a nested case–control study with OHCA cases of presumed cardiac causes and age/sex/OHCA date-matched non-OHCA controls from the general population. Conditional logistic regression models with adjustments for well-known risk factors of OHCA were employed to estimate the OR with 95% CI of OHCA comparing FQs with amoxicillin.Results The study population consisted of 46 578 OHCA cases (mean: 71 years (SD: 14.40), 68.8% men) and 232 890 matched controls. FQ was used by 276 cases and 328 controls and conferred no increase in the odds of OHCA compared with amoxicillin use after controlling for the relevant confounders (OR: 0.91 (95% CI: 0.71 to 1.16)). The OR of OHCA associated with FQ use did not vary significantly by age (OR≤65: 0.96 (95% CI: 0.53 to 1.74), OR>65: 0.88 (95% CI: 0.67 to 1.16), p value interaction=0.7818), sex (ORmen: 0.96 (95% CI: 0.70 to 1.31), ORwomen: 0.80 (95% CI: 0.53 to 1.20), p value interaction=0.9698) and pre-existing cardiovascular disease (ORabsent: 1.02 (95% CI: 0.57 to 1.82), ORpresent: 0.98 (95% CI: 0.75 to 1.28), p value interaction=0.3884), including heart failure (ORabsent: 0.93 (95% CI: 0.72 to 1.22), ORpresent: 1.11 (95% CI: 0.61 to 2.02), p value interaction=0.7083) and ischaemic heart disease (ORabsent: 0.85 (95% CI: 0.64 to 1.12), ORpresent: 1.38 (95% CI: 0.86 to 2.21), p value interaction=0.6230).Conclusion Our findings do not support an association between FQ exposure and OHCA in the general population. This lack of association was consistent in men and women, in all age categories, and in the presence or absence of cardiovascular disease.

Background Defibrillation is essential for achieving return of spontaneous circulation (ROSC) following out‐of‐hospital cardiac arrest (OHCA) with shockable rhythms. This study aimed to investigate if the type of defibrillator used was associated with ROSC in OHCA. Methods and Results This study included adult patients with OHCA from the Danish Cardiac Arrest Registry from 2016 to 2021 with at least 1 defibrillation by the emergency medical services. We used multivariable logistic regression and a difference‐in‐difference analysis, including all patients with or without emergency medical services shock to assess the causal inference of using the different defibrillator models (LIFEPAK or ZOLL) for OHCA defibrillation. Among 6516 patients, 77% were male, the median age (quartile 1; quartile 3) was 70 (59; 79), and 57% achieved ROSC. In total, 5514 patients (85%) were defibrillated using LIFEPAK (ROSC: 56%) and 1002 patients (15%) were defibrillated using ZOLL (ROSC: 63%). Patients defibrillated using ZOLL had an increased adjusted odds ratio (aOR) for ROSC compared with LIFEPAK (aOR, 1.22 [95% CI, 1.04–1.43]). There was no significant difference in 30‐day mortality (aOR, 1.11 [95% CI, 0.95–1.30]). Patients without emergency medical services defibrillation, but treated by ZOLL‐equipped emergency medical services, had a nonsignificant aOR for ROSC compared with LIFEPAK (aOR, 1.10 [95% CI, 0.99–1.23]) and the difference‐in‐difference analysis was not statistically significant (OR, 1.10 [95% CI, 0.91–1.34]). Conclusions Defibrillation using ZOLL X Series was associated with increased odds for ROSC compared with defibrillation using LIFEPAK 15 for patients with OHCA. However, a difference‐in‐difference analysis suggested that other factors may be responsible for the observed association.

Abstract Background Inflammation in ST-segment elevation myocardial infarction (STEMI) is an important contributor to both acute myocardial ischemia and reperfusion injury after primary percutaneous coronary intervention (PCI). Methylprednisolone is a glucocorticoid with potent anti-inflammatory properties with an acute effect and is used as an effective and safe treatment of a wide range of acute diseases. The trial aims to investigate the cardioprotective effects of pulse-dose methylprednisolone administered in the pre-hospital setting in patients with STEMI transferred for primary PCI. Methods This trial is a randomized, blinded, placebo-controlled prospective clinical phase II trial. Inclusion will continue until 378 patients with STEMI have been evaluated for the primary endpoint. Patients will be randomized 1:1 to a bolus of 250 mg methylprednisolone intravenous or matching placebo over a period of 5 min in the pre-hospital setting. All patients with STEMI transferred for primary PCI at Rigshospitalet, Copenhagen University Hospital, Denmark, will be screened for eligibility. The main eligibility criteria are age ≥ 18 years, acute onset of chest pain with

Abstract Here we report the results of a study on the association between drug delivery via intravenous route or intraosseous route in out-of-hospital cardiac arrest. Intraosseous drug delivery is considered an alternative option in resuscitation if intravenous access is difficult or impossible. Intraosseous uptake of drugs may, however, be compromised. We have performed a retrospective cohort study of all Danish patients with out-of-hospital cardiac arrest in the years 2016–2020 to investigate whether mortality is associated with the route of drug delivery. Outcome was 30-day mortality, death at the scene, no prehospital return of spontaneous circulation, and 7- and 90-days mortality. 17,250 patients had out-of-hospital cardiac arrest. 6243 patients received no treatment and were excluded. 1908 patients had sustained return of spontaneous circulation before access to the vascular bed was obtained. 2061 patients were unidentified, and 286 cases were erroneously registered. Thus, this report consist of results from 6752 patients. Drug delivery by intraosseous route is associated with increased OR of: No spontaneous circulation at any time (OR 1.51), Death at 7 days (OR 1.94), 30 days (2.02), and 90 days (OR 2.29). Intraosseous drug delivery in out-of-hospital cardiac arrest is associated with overall poorer outcomes than intravenous drug delivery.

Abstract Aim The study aimed to investigate whether a bystander’s emotional stress state affects dispatcher-assisted cardiopulmonary resuscitation (DA-CPR) in out-of-hospital cardiac arrest (OHCA). The primary outcome was initiation of chest compressions (Yes/No). Secondarily we analysed time until chest compressions were initiated and assessed how dispatchers instructed CPR. Method The study was a retrospective, observational study of OHCA emergency calls from the Capital Region of Denmark. Recorded calls were evaluated by five observers using a pre-defined code catalogue regarding the variables wished investigated. Results Included were 655 OHCA emergency calls, of which 211 callers were defined as emotionally stressed. When cardiac arrest was recognized, chest compressions were initiated in, respectively, 76.8% of cases with an emotionally stressed caller and 73.9% in cases with a not emotionally stressed caller (2.18 (0.80–7.64)). Cases with an emotionally stressed caller had a longer time until chest compressions were initiated compared to cases with a not emotionally stressed caller, however non-significant (164 s. vs. 146 s.; P = 0.145). The dispatchers were significantly more likely to be encouraging and motivating, and to instruct on speed and depth of chest compressions in cases with an emotionally stressed caller compared to cases with a not emotionally stressed caller (1.64 (1.07–2.56); 1.78 (1.13–2.88)). Barriers to CPR were significantly more often reported in cases with an emotionally stressed caller compared to cases with a not emotionally stressed caller (1.83 (1.32–2.56)). Conclusion There was no significant difference in initiation of chest compressions or in time until initiation of chest compressions in the two groups. However, the dispatchers were overall more encouraging and motivating, and likely to instruct on speed and depth of chest compressions when the caller was emotionally stressed. Furthermore, barriers to CPR were more often reported in cases with an emotionally stressed caller compared to cases with a not emotionally stressed caller. Trial registration We applied for ethical approval from The Danish National Committee on Health Research Ethics, but formal approval was waived. We received permission for storage of data and to use these for research of OHCAs in the Capital Region of Denmark by Danish Data Protection Agency (P-2021-670) and Danish Health Authorities (R-2,005,114). The study is registered at ClinicalTrials (NTC05113706).

Abstract Background Parents often contact out-of-hours services due to worry concerning febrile children, despite the children rarely being severely ill. As telephone triage of children is challenging, many children are referred to hospital assessment. This study investigated if video triage resulted in more children staying at home. Secondary aims included safety, acceptability and feasibility of this new triage tool. Methods In this prospective quality improvement study, nurse call-handlers enrolled febrile children aged 3 months-5 years to video or telephone triage (1:1), with follow-up within 48 h after call. The setting was an out-of-hours call-center for non-urgent illness in Copenhagen, Denmark, receiving over 1 million calls annually and predominately staffed by registered nurses. Main outcome measure was difference in number of children assessed at hospital within 8 h after call between video-and telephone triage group. Rates of feasibility, acceptability and safety (death, lasting means, transfer to intensive care unit) were compared between the triage groups. Results There was no difference in triage outcome (home care vs. hospital referral) or number of patients assessed at hospital between triage groups. However, more video triaged patients received in-hospital treatment, testing and hospitalization. Conclusion Video triage was feasible to conduct, acceptable to parents and as safe as telephone triage. The study did not show that more children stayed at home after video triage, possibly because the allocation strategy was not upheld, as video triage sometimes was chosen in cases of complex and severe symptoms, and this likely has changed study outcome. Trial registration: Clinicaltrials.gov.: Id NCT04074239. Registered 2019-08-30. https://clinicaltrials.gov/ct2/show/study/NCT04074239

Although recommended in the European Resuscitation Council (ERC) and European Society of Intensive Care Medicine (ESICM) Guidelines, a framework for delivering post-cardiac arrest care in a systematic manner in dedicated high-volume cardiac arrest centers is lacking in the existing literature.To our knowledge, the Copenhagen Framework is the only established framework of its kind. The framework comprises management of out-of-hospital cardiac arrest (OHCA) survivors, and follow-up, and rehabilitation. The framework also incorporates research projects on cardiac arrest survivors and their close family members. The overall aim of this paper is to describe a framework made in order to bridge the gaps between international recommendations and delivering high-quality post-resuscitation clinical care, improving the continuity of care for OHCA survivors, access to post-CA rehabilitation, a seamless transition to everyday life, and ultimately patient outcomes in the future.

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.

IntroductionAccurately predicting patient outcomes is crucial for improving healthcare delivery, but large-scale risk prediction models are often developed and tested on specific datasets where clinical parameters and outcomes may not fully reflect local clinical settings. Where this is the case, whether to opt for de-novo training of prediction models on local datasets, direct porting of externally trained models, or a transfer learning approach is not well studied, and constitutes the focus of this study. Using the clinical challenge of predicting mortality and hospital length of stay on a Danish trauma dataset, we hypothesized that a transfer learning approach of models trained on large external datasets would provide optimal prediction results compared to de-novo training on sparse but local datasets or directly porting externally trained models.MethodsUsing an external dataset of trauma patients from the US Trauma Quality Improvement Program (TQIP) and a local dataset aggregated from the Danish Trauma Database (DTD) enriched with Electronic Health Record data, we tested a range of model-level approaches focused on predicting trauma mortality and hospital length of stay on DTD data. Modeling approaches included de-novo training of models on DTD data, direct porting of models trained on TQIP data to the DTD, and a transfer learning approach by training a model on TQIP data with subsequent transfer and retraining on DTD data. Furthermore, data-level approaches, including mixed dataset training and methods countering imbalanced outcomes (e.g., low mortality rates), were also tested.ResultsUsing a neural network trained on a mixed dataset consisting of a subset of TQIP and DTD, with class weighting and transfer learning (retraining on DTD), we achieved excellent results in predicting mortality, with a ROC-AUC of 0.988 and an F2-score of 0.866. The best-performing models for predicting long-term hospitalization were trained only on local data, achieving an ROC-AUC of 0.890 and an F1-score of 0.897, although only marginally better than alternative approaches.ConclusionOur results suggest that when assessing the optimal modeling approach, it is important to have domain knowledge of how incidence rates and workflows compare between hospital systems and datasets where models are trained. Including data from other health-care systems is particularly beneficial when outcomes are suffering from class imbalance and low incidence. Scenarios where outcomes are not directly comparable are best addressed through either de-novo local training or a transfer learning approach.

Background High‐quality cardiopulmonary resuscitation (CPR) is associated with improved survival from out‐of‐hospital cardiac arrest and includes chest compression depth, chest compression rate, and chest compression fraction within international guideline recommendations. Previous studies have demonstrated divergent results of real‐time feedback on CPR performance and patient outcomes. This study investigated the association between emergency medical service CPR quality and real‐time CPR feedback for out‐of‐hospital cardiac arrest. Methods and Results This study collected out‐of‐hospital cardiac arrest data within the Capital Region of Denmark and compared CPR quality delivered by ambulance personnel. Data were collected in 2 consecutive phases from October 2018 to February 2020. Median chest compression depth was 6.0 cm (no feedback) and 5.9 cm (real‐time feedback) (P=0.852). Corresponding proportion of guideline‐compliant chest compressions for depth was 16.6% and 28.7%, respectively (P

Introduction In Denmark, multiple national initiatives have been associated with improved bystander defibrillation and survival following out-of-hospital cardiac arrest (OHCA) in public places. However, OHCAs in residential neighbourhoods continue to have poor outcomes. The Cardiac Arrest in Residential Areas with MoBile volunteer responder Activation trial aims to improve bystander defibrillation and survival following OHCA in residential neighbourhoods with a high risk of OHCA. The intervention consists of: (1) strategically deployed automated external defibrillators accessible at all hours, (2) cardiopulmonary resuscitation (CPR) training of residents and (3) recruitment of residents for a volunteer responder programme.Methods and analysis This is a prospective, pair-matched, cluster-randomised, superiority trial with clusters of 26 residential neighbourhoods, testing the effectiveness of the intervention in a real-world setting. The areas are randomised for intervention or control. Intervention and control areas will receive the standard OHCA emergency response, including volunteer responder activation. However, targeted automated external defibrillator deployment, CPR training and volunteer responder recruitment will only be provided in the intervention areas. The primary outcome is bystander defibrillation, and the secondary outcome is 30-day survival. Data on patients who had an OHCA will be collected through the Danish Cardiac Arrest Registry.Ethics and dissemination Approval to store OHCA data has been granted from the Legal Office, Capital Region of Denmark (j.nr: 2012-58-0004, VD-2018-28, I-Suite no: 6222, and P-2021-670). In Denmark, formal approval from the ethics committee is only obtainable when the study regards testing medicine or medical equipment on humans or using genome or diagnostic imagine as data source. The Ethics Committee of the Capital Region of Denmark has evaluated the trial and waived formal approval unnecessary (H-19037170). Results will be published in peer-reviewed papers and shared with funders, stakeholders, and housing organisations through summaries and presentations.Trial registration number ClinicalTrials.gov Registry (NCT04446585).

Abstract Background Myocardial infarction (MI) patients presenting without chest pain are a diagnostic challenge. They receive suboptimal prehospital management and have high mortality. To elucidate potential benefits of improved management, we analysed expected outcome among non-chest pain MI patients if hypothetically they (1) received emergency ambulances/acetylsalicylic acid (ASA) as often as observed for chest pain patients, and (2) all received emergency ambulance/ASA. Methods We sampled calls to emergency and non-emergency medical services for patients hospitalized with MI within 24 h and categorized calls as chest pain/non-chest pain. Outcomes were 30-day mortality and a 1-year combined outcome of re-infarction, heart failure admission, and mortality. Targeted minimum loss-based estimation was used for all statistical analyses. Results Among 5418 calls regarding MI patients, 24% (1309) were recorded with non-chest pain. In total, 90% (3689/4109) of chest pain and 40% (525/1309) of non-chest pain patients received an emergency ambulance, and 73% (2668/3632) and 37% (192/518) of chest pain and non-chest pain patients received prehospital ASA. Providing ambulances to all non-chest pain patients was not associated with improved survival. Prehospital administration of ASA to all emergency ambulance transports of non-chest pain MI patients was expected to reduce 30-day mortality by 5.3% (CI 95%: [1.7%;9%]) from 12.8% to 7.4%. No significant reduction was found for the 1-year combined outcome (2.6% CI 95% [− 2.9%;8.1%]). In comparison, the observed 30-day mortality was 3% among ambulance-transported chest pain MI patients. Conclusions Our study found large differences in the prehospital management of MI patients with and without chest pain. Improved prehospital ASA administration to non-chest pain MI patients could possibly reduce 30-day mortality, but long-term effects appear limited. Non-chest pain MI patients are difficult to identify prehospital and possible unintended effects of ASA might outweigh the potential benefits of improving the prehospital management. Future research should investigate ways to improve the prehospital recognition of MI in the absence of chest pain.

Abstract Background Patients resuscitated from out-of-hospital cardiac arrest (OHCA) have a high morbidity and mortality risk and often develop post-cardiac arrest syndrome (PCAS) involving systemic inflammation. The severity of the inflammatory response is associated with adverse outcome, with anoxic irreversible brain injury as the leading cause of death following resuscitated OHCA. The study aimed to investigate the anti-inflammatory and neuroprotective effect of pre-hospital administration of a high-dose glucocorticoid following OHCA. Methods The study is an investigator-initiated, randomized, multicenter, single-blinded, placebo-controlled, clinical trial. Inclusion will continue until one hundred twenty unconscious OHCA patients surviving a minimum of 72 h are randomized. Intervention is a 1:1 randomization to an infusion of methylprednisolone 250 mg following a minimum of 5 min of sustained return of spontaneous circulation in the pre-hospital setting. Methylprednisolone will be given as a bolus infusion of 1 × 250 mg (1 × 4 mL) over a period of 5 min. Patients allocated to placebo will receive 4 mL of isotonic saline (NaCl 0.9%). Main eligibility criteria are OHCA of presumed cardiac cause, age ≥ 18 years, Glasgow Coma Scale ≤ 8, and sustained ROSC for at least 5 min. Co-primary endpoint: Reduction of interleukin-6 and neuron-specific-enolase. Secondary endpoints: Markers of inflammation, brain, cardiac, kidney and liver damage, hemodynamic and hemostatic function, safety, neurological function at follow-up, and mortality. A research biobank is set up with blood samples taken daily during the first 72 h from hospitalization to evaluate primary and secondary endpoints. Discussion We hypothesize that early anti-inflammatory steroid treatment in the pre-hospital setting can mitigate the progression of PCAS following resuscitated OHCA. Primary endpoints will be assessed through analyses of biomarkers for inflammation and neurological damage taken during the first 72 h of admission. Trial registration EudraCT number: 2020-000855-11 ; submitted March 30, 2020 ClinicalTrials.gov Identifier: NCT04624776; submitted October 12, 2020, first posted November 10, 2020

Objective: During cardiac arrest, current guidelines recommend attempting intravenous access first and to consider intraosseous access if intravenous access is unsuccessful or impossible. However, these recommendations are only based on very low-certainty evidence. Therefore, the “Intravenous vs Intraosseous Vascular Access During Out-of-Hospital Cardiac Arrest“ (IVIO) trial aims to determine whether there is a difference in patient outcomes depending on the type of vascular access attempted during out-of-hospital cardiac arrest. This current article describes the clinical IVIO trial. Methods: The IVIO trial is an investigator-initiated, randomised trial of intravenous vs. intraosseous vascular access during adult non-traumatic out-of-hospital cardiac arrest in Denmark. The intervention will consist of minimum two attempts (if unsuccessful on the first attempt) to successfully establish intravenous or intraosseous vascular access during cardiac arrest. The intraosseous group will be further randomised to the humeral or tibial site. The primary outcome is sustained return of spontaneous circulation and key secondary outcomes include survival and survival with a favourable neurological outcome at 30 days. A total of 1,470 patients will be included. Results: The trial started in March 2022 and the last patient is anticipated to be included in the spring of 2024. The primary results will be reported after 90-day follow-up and are anticipated in mid-2024. Conclusion: The current article describes the design of the Danish IVIO trial. The findings of this trial will help inform future guidelines for selecting the optimal vascular access route during out-of-hospital cardiac arrest.

Introduction: Smartphone technology is increasingly used to engage lay people as volunteer responders in resuscitation attempts. Attention has recently been drawn to how resuscitation attempts may impact bystanders. Attempting resuscitation in out-of-hospital cardiac arrests (OHCA) may be an overwhelming experience and, in some cases, difficult to cope with. We developed a volunteer responder follow-up program to systematically measure the psychological and physical impact on volunteer responders dispatched for OHCAs. Methods and Results: The nationwide Danish volunteer responder program dispatches volunteer responders for presumed cardiac arrests. 90 min after notification of a potential nearby cardiac arrest, all volunteer responders receive a survey, and are asked to self-report their mental state of mind after the event. The volunteer responders are also asked to disclose any physical injury they sustained in relation to the event. Volunteer responders who report severe mental effects are offered a defusing conversation by a trained nurse. Between 1 September 2017 and 31 December 2022, the Danish volunteer responder program has alerted 177,866 volunteer responders for 10,819 presumed cardiac arrest alerts. Of 177,866 alerted volunteers responders, 62,711 accepted the alarm. In the same period, 7,317 cancelled their registration. From January 2019 to 31 December 31 2022, a total of 535 volunteer responders were offered a defusing consultation. Conclusion: The Danish volunteer responder follow-up program is carried out to assess the psychological and physical risks of responding to a suspected OHCA. We suggest a survey-based method for systematic screening of volunteer responders that allow volunteer responders to report any physical injury or need of psychological follow-up. The person providing defusing should be a trained and experienced healthcare professional.

Background Survival from out‐of‐hospital cardiac arrest (OHCA) varies across regions. The aim of this study was to evaluate the association between urbanization (rural, suburban, and urban areas), bystander interventions (cardiopulmonary resuscitation and defibrillation), and 30‐day survival from OHCAs in Denmark. Methods and Results We included OHCAs not witnessed by ambulance staff in Denmark from January 1, 2016, to December 31, 2020. Patients were divided according to the Eurostat Degree of Urbanization Tool in rural, suburban, and urban areas based on the 98 Danish municipalities. Poisson regression was used to estimate incidence rate ratios. Logistic regression (adjusted for ambulance response time) tested differences between the groups with respect to bystander interventions and survival, according to degree of urbanization. A total of 21 385 OHCAs were included, of which 8496 (40%) occurred in rural areas, 7025 (33%) occurred in suburban areas, and 5864 (27%) occurred in urban areas. Baseline characteristics, as age, sex, location of OHCA, and comorbidities, were comparable between groups. The annual incidence rate ratio of OHCA was higher in rural areas (1.54 [95% CI, 1.48–1.58]) compared with urban areas. Odds for bystander cardiopulmonary resuscitation were lower in suburban (0.86 [95% CI, 0.82–0.96]) and urban areas (0.87 [95% CI, 0.80–0.95]) compared with rural areas, whereas bystander defibrillation was higher in urban areas compared with rural areas (1.15 [95% CI, 1.01–1.31]). Finally, 30‐day survival was higher in suburban (1.13 [95% CI, 1.02–1.25]) and urban areas (1.17 [95% CI, 1.05–1.30]) compared with rural areas. Conclusions Degree of urbanization was associated with lower rates of bystander defibrillation and 30‐day survival in rural areas compared with urban areas.

Abstract Background People experiencing homelessness (PEH) and associated shelter workers may be at higher risk of infection with “Severe acute respiratory syndrome coronavirus 2” (SARS-CoV-2). The aim of this study was to determine the prevalence of SARS-CoV-2 among PEH and shelter workers in Denmark. Design and methods In November 2020, we conducted a nationwide cross-sectional seroprevalence study among PEH and shelter workers at 21 recruitment sites in Denmark. The assessment included a point-of-care test for antibodies against SARS-CoV-2, followed by a questionnaire. The seroprevalence was compared to that of geographically matched blood donors considered as a proxy for the background population, tested using a total Ig ELISA assay. Results We included 827 participants in the study, of whom 819 provided their SARS-CoV-2 antibody results. Of those, 628 were PEH (median age 50.8 (IQR 40.9–59.1) years, 35.5% female) and 191 were shelter workers (median age 46.6 (IQR 36.1–55.0) years and 74.5% female). The overall seroprevalence was 6.7% and was similar among PEH and shelter workers (6.8% vs 6.3%, p = 0.87); and 12.2% among all participants who engaged in sex work. The overall participant seroprevalence was significantly higher than that of the background population (2.9%, p

Abstract Background COVID-19 is thought to be more prevalent among ethnic minorities and individuals with low socioeconomic status. We aimed to investigate the prevalence of SARS-CoV-2 antibodies during the COVID-19 pandemic among citizens 15 years or older in Denmark living in social housing (SH) areas. Methods We conducted a study between January 8th and January 31st, 2021 with recruitment in 13 selected SH areas. Participants were offered a point-of-care rapid SARS-CoV-2 IgM and IgG antibody test and a questionnaire concerning risk factors associated with COVID-19. As a proxy for the general Danish population we accessed data on seroprevalence from Danish blood donors (total Ig ELISA assay) in same time period. Results Of the 13,279 included participants, 2296 (17.3%) were seropositive (mean age 46.6 (SD 16.4) years, 54.2% female), which was 3 times higher than in the general Danish population (mean age 41.7 (SD 14.1) years, 48.5% female) in the same period (5.8%, risk ratios (RR) 2.96, 95% CI 2.78–3.16, p > 0.001). Seropositivity was higher among males (RR 1.1, 95% CI 1.05–1.22%, p = 0.001) and increased with age, with an OR seropositivity of 1.03 for each 10-year increase in age (95% CI 1.00–1.06, p = 0.031). Close contact with COVID-19-infected individuals was associated with a higher risk of infection, especially among household members (OR 5.0, 95% CI 4.1–6.2 p

Objectives Smartphone dispatch of volunteer responders for out-of-hospital cardiac arrest (OHCA) is implemented worldwide. While basic life support courses prepare participants to provide CPR, the courses rarely address the possibility of meeting a family member or relative in crisis. This study aimed to examine volunteer responders’ provision of support to relatives of cardiac arrest patients and how relatives experienced the interaction with volunteer responders.Design In this qualitative study, we conducted 16 semistructured interviews with volunteer responders and relatives of cardiac arrest patients.Setting Interviews were conducted face to face and by video and recorded and transcribed verbatim.Participants Volunteer responders dispatched to cardiac arrests and relatives of cardiac arrest patients were included in the study. Participants were included from all five regions of Denmark.Results A thematic analysis was performed with inspiration from Braun and Clarke. We identified three themes: (1) relatives’ experiences of immediate relief at arrival of assistance, (2) volunteer responders’ assessment of relatives’ needs and (3) the advantage of being healthcare educated.Conclusions Relatives to out-of-hospital cardiac arrest patients benefited from volunteer responders’ presence and support and experienced the mere presence of volunteer responders as supportive. Healthcare-educated volunteer responders felt confident and skilled to provide care for relatives, while some non-healthcare-educated volunteer responders felt they lacked the proper training and knowledge to provide emotional support for relatives. Future basic life support courses should include a lesson on how to provide emotional support to relatives of cardiac arrest patients.

Objectives We aim to explore undertriage and overtriage in a high-risk patient population and explore patient characteristics and call characteristics associated with undertriage and overtriage in both randomly selected and in high-risk telephone calls to out-of-hours primary care (OOH-PC).Design Natural quasi-experimental cross-sectional study.Setting Two Danish OOH-PC services using different telephone triage models: a general practitioner cooperative with GP-led triage and the medical helpline 1813 with computerised decision support system-guided nurse-led triage.Participants We included audio-recorded telephone triage calls from 2016: 806 random calls and 405 high-risk calls (defined as patients ≥30 years calling with abdominal pain).Main outcome measures Twenty-four experienced physicians used a validated assessment tool to assess the accuracy of triage. We calculated the relative risk (RR) for clinically relevant undertriage and overtriage for a range of patient characteristics and call characteristics.Results We included 806 randomly selected calls (44 clinically relevant undertriaged and 54 clinically relevant overtriaged) and 405 high-risk calls (32 undertriaged and 24 overtriaged). In high-risk calls, nurse-led triage was associated with significantly less undertriage (RR: 0.47, 95% CI 0.23 to 0.97) and more overtriage (RR: 3.93, 95% CI 1.50 to 10.33) compared with GP-led triage. In high-risk calls, the risk of undertriage was significantly higher for calls during nighttime (RR: 2.1, 95% CI 1.05 to 4.07). Undertriage tended to be more likely for calls concerning patients ≥60 years compared with 30–59 years (11.3% vs 6.3%) in high-risk calls. However, this result was not significant.Conclusion Nurse-led triage was associated with less undertriage and more overtriage compared with GP-led triage in high-risk calls. This study may suggest that to minimise undertriage, the triage professionals should pay extra attention when a call occurs during nighttime or concerns elderly. However, this needs confirmation in future studies.

Objective Patients with stress-related disorders and anxiety are at increased risk of developing cardiovascular disease. However, the risk of out-of-hospital cardiac arrest (OHCA) is scarcely investigated. We aimed to establish whether long-term stress (post-traumatic stress disorder, adjustment disorder) or anxiety is associated with OHCA in the general population.Methods We conducted a nested case–control study in a nationwide cohort of individuals between 1 June 2001 and 31 December 2015 in Denmark. Cases were OHCA patients with presumed cardiac causes. Each case was matched by age, sex and date of OHCA with 10 non-OHCA controls from the general population. HRs for OHCA were derived from Cox models after controlling for common OHCA risk factors. Stratified analyses were performed according to sex, age and pre-existing cardiovascular disease.Results We included 35 195 OHCAs and 351 950 matched controls (median age 72 years; 66.8% male). Long-term stress conditions were diagnosed in 324 (0.92%) OHCA cases and 1577 (0.45%) non-OHCA controls, and were associated with higher rate of OHCA (HR 1.44, 95% CI 1.27 to 1.64). Anxiety was diagnosed in 299 (0.85%) OHCA cases and 1298 (0.37%) controls, and was associated with increased rate of OHCA (HR 1.56, 95% CI1.37 to 1.79). We found no interaction with sex, age or history of cardiovascular diseases.Conclusion Patients with stress-related disorders or anxiety have an increased rate of OHCA. This association applies equally to men and women and is independent from the presence of cardiovascular disease. Awareness of the higher risks of OHCA in patients with stress-related disorders and anxiety is important when treating these patients.

ABSTRACT The aim of this study was to provide information about immunity against COVID-19 along with risk factors and behavior among employees in day care facilities and preschools (DCS) in Denmark. In collaboration with the Danish Union of Pedagogues, during February and March 2021, 47,810 members were offered a point-of-care rapid SARS-CoV-2 antibody test (POCT) at work and were invited to fill in an electronic questionnaire covering COVID-19 exposure. Seroprevalence data from Danish blood donors (total Ig enzyme-linked immunosorbent assay [ELISA]) were used as a proxy for the Danish population. A total of 21,018 (45%) DCS employees completed the questionnaire and reported their POCT result {median age, 44.3 years (interquartile range [IQR], [32.7 to 53.6]); females, 84.1%}, of which 20,267 (96.4%) were unvaccinated and included in analysis. A total of 1,857 (9.2%) participants tested seropositive, significantly higher than a seroprevalence at 7.6% (risk ratio [RR], 1.2; 95% confidence interval [CI], 1.14 to 1.27) among 40,541 healthy blood donors (median age, 42 years [IQR, 28 to 53]; males, 51.3%). Exposure at work (RR, 2.9; 95% CI, 2.3 to 3.6) was less of a risk factor than exposure within the household (RR, 12.7; 95% CI, 10.2 to 15.8). Less than 25% of participants reported wearing face protection at work. Most of the participants expressed some degree of fear of contracting COVID-19 both at work and outside work. SARS-CoV-2 seroprevalence was slightly higher in DCS staff than in blood donors, but possible exposure at home was associated with a higher risk than at work. DCS staff expressed fear of contracting COVID-19, though there was limited use of face protection at work. IMPORTANCE Identifying at-risk groups and evaluating preventive interventions in at-risk groups is imperative for the ongoing pandemic as well as for the control of future epidemics. Although DCS staff have a much higher risk of being infected within their own household than at their workplace, most are fearful of being infected with COVID-19 or bringing COVID-19 to work. This represents an interesting dilemma and an important issue which should be addressed by public health authorities for risk communication and pandemic planning. This study design can be used in a strategy for ongoing surveillance of COVID-19 immunity or other infections in the population. The findings of this study can be used to assess the need for future preventive interventions in DCS, such as the use of personal protective equipment.

Results We identified 35 195 OHCA cases and 351 950 matched controls without OHCA (median age 72 years and 66.8% male). Patients with sarcoidosis had higher rate of OHCA compared with the general population after adjustments for common OHCA risk factors (HR 1.51, 95% CI 1.19 to 1.92). This increased OHCA rate occurred in women (HR 2.11, 95% CI 1.42 to 3.12) but not in men (HR 1.27, 95% CI 0.93 to 1.72; p value interaction=0.033), and was larger in patients with than without heart failure (HRheart failure: 2.59, 95% CI 1.42 to 4.73; HRno heart failure: 1.33, 95% CI 1.01 to 1.74; p value interaction: 0.007). The HR associated with sarcoidosis did not vary by the presence of ischaemic heart disease.Conclusion Patients with sarcoidosis have a higher OHCA rate than the general population. This increased OHCA rate occurred in women but not in men, and was larger in patients with than without heart failure.

BackgroundYoung children are among the most frequent patients at medical call centers, even though they are rarely severely ill. Respiratory tract symptoms are among the most prevalent reasons for contact in pediatric calls. Triage of children without visual cues and through second-hand information is perceived as difficult, with risks of over- and under-triage.ObjectiveTo study the safety and feasibility of introducing video triage of young children with respiratory symptoms at the medical helpline 1813 (MH1813) in Copenhagen, Denmark, as well as impact on patient outcome.MethodsProspective quality improvement study including 617 patients enrolled to video or standard telephone triage (1:1) from February 2019-March 2020. Data originated from MH1813 patient records, survey responses, and hospital charts. Primary outcome was difference in patients staying at home eight hours after the call. Secondary outcomes weas hospital outcome, feasibility and acceptability. Adverse events (intensive care unit admittance, lasting injuries, death) were registered. Logistic regression was used to test the effect on outcomes. The COVID-19 pandemic shut the study down prematurely.ResultsIn total, 54% of the included patients were video-triaged., and 63% of video triaged patients and 58% of telephone triaged patients were triaged to stay at home, (p = 0.19). Within eight and 24 hours, there was a tendency of fewer video-triaged patients being assessed at hospitals: 39% versus 46% (p = 0.07) and 41% versus 49% (p = 0.07), respectively. At 24 hours after the call, 2.8% of the patients were hospitalized for at least 12 hours. Video triage was highly feasible and acceptable (>90%) and no adverse events were registered.ConclusionVideo triage of young children with respiratory symptoms at a medical call center was safe and feasible. Only about 3% of all children needed hospitalization for at least 12 hours. Video triage may optimize hospital referrals and increase health care accessibility.

Summary: Background: Ethnicity might impact out-of-hospital cardiac arrest (OHCA) risk, but it has scarcely been studied in Europe. We aimed to assess whether ethnicity influenced the risk of OHCA of cardiac cause in Danish immigrants and its interplay with risk factors for OHCA and socioeconomic status. Methods: This nationwide study included all immigrants between 18 and 80 years present in Denmark at some point between 2001 and 2020. Regions of origin were defined as Africa, Arabic countries, Asia, Eastern Europe, Latin America, and Western countries. OHCAs with presumed cardiac cause were identified from the Danish Cardiac Arrest Registry. Findings: Overall, among 1,011,565 immigrants, a total of 1,801 (0.2%) OHCAs (median age 64 (Q1-Q3 53–72) years, 72% males) occurred. The age- and sex- standardized (reference: Western countries) incidence of OHCA (/1,00,000 person-years) was 34.6 (27.8–43.4) in African, 34.1 (30.4–38.4) in Arabic, 33.5 (29.3–38.2) in Asian, 35.6 (31.9–39.6) in Eastern European, and 16.2 (9.0–27.2) in Latin American immigrants. When selecting Western origin as a reference, and after adjusting on OHCA risk factors, Arabic (HR 1.18, 95%CI 1.04–1.35; P=0.01), Eastern European (HR 1.28, 95%CI 1.13–1.46; P

AimThe primary aim was to investigate the association between alarm acceptance compared to no-acceptance by volunteer responders, bystander intervention, and survival in out-of-hospital cardiac arrest.Materials and methodsThis retrospective observational study included all suspected out-of-hospital cardiac arrests (OHCAs) with activation of volunteer responders in the Capital Region of Denmark (1 November 2018 to 14 May 2019), the Central Denmark Region (1 November 2018 to 31 December 2020), and the Northern Denmark Region (14 February 2020 to 31 December 2020). All OHCAs unwitnessed by Emergency Medical Services (EMS) were analyzed on the basis on alarm acceptance and arrival before EMS. The primary outcomes were bystander cardio-pulmonary resuscitation (CPR), bystander defibrillation and secondary outcome was 30-day survival. A questionnaire sent to all volunteer responders was used with respect to their arrival status.ResultsWe identified 1,877 OHCAs with volunteer responder activation eligible for inclusion and 1,725 (91.9%) of these had at least one volunteer responder accepting the alarm (accepted). Of these, 1,355 (79%) reported arrival status whereof 883 (65%) arrived before EMS. When volunteer responders accepted the alarm and arrived before EMS, we found increased proportions and adjusted odds ratio for bystander CPR {94 vs. 83%, 4.31 [95% CI (2.43–7.67)] and bystander defibrillation [13 vs. 9%, 3.16 (1.60–6.25)]} compared to cases where no volunteer responders accepted the alarm.ConclusionWe observed a fourfold increased odds ratio for bystander CPR and a threefold increased odds ratio for bystander defibrillation when volunteer responders accepted the alarm and arrived before EMS.

Abstract Background Medical dispatchers have limited information to assess the appropriate emergency response when citizens call the emergency number. We explored whether live video from bystanders’ smartphones changed emergency response and was beneficial for the dispatcher and caller. Methods From June 2019 to February 2020, all medical dispatchers could add live video to the emergency calls at Copenhagen Emergency Medical Services, Denmark. Live video was established with a text message link sent to the caller’s smartphone using GoodSAM®. To avoid delayed emergency response if the video transmission failed, the medical dispatcher had to determine the emergency response before adding live video to the call. We conducted a cohort study with a historical reference group. Emergency response and cause of the call were registered within the dispatch system. After each video, the dispatcher and caller were given a questionnaire about their experience. Results Adding live video succeeded in 838 emergencies (82.2% of attempted video transmissions) and follow-up was possible in 700 emergency calls. The dispatchers’ assessment of the patients’ condition changed in 51.1% of the calls (condition more critical in 12.9% and less critical in 38.2%), resulting in changed emergency response in 27.5% of the cases after receiving the video (OR 1.58, 95% CI: 1.30–1.91) compared to calls without video. Video was added more frequently in cases with sick children or unconscious patients compared with normal emergency calls. The dispatcher recognized other or different disease/trauma in 9.9% and found that patient care, such as the quality of cardiopulmonary resuscitation, obstructed airway or position of the patient, improved in 28.4% of the emergencies. Only 111 callers returned the questionnaire, 97.3% of whom felt that live video should be implemented. Conclusions It is technically feasible to add live video to emergency calls. The medical dispatcher’s perception of the patient changed in about half of cases. The odds for changing emergency response were 58% higher when video was added to the call. However, use of live video is challenging with the existing dispatch protocols, and further implementation science is necessary.

Abstract Background Citizen responder programmes dispatch volunteer citizens to initiate resuscitation in nearby out-of-hospital cardiac arrests (OHCA) before the Emergency Medical Services (EMS) arrival. Little is known about the interaction between citizen responders and EMS personnel during the resuscitation attempt. In the Capital Region of Denmark, emergency physicians are dispatched to all suspected OHCAs. The aim of this study was to evaluate how emergency physicians perceived the collaboration with citizen responders during resuscitation attempts. Method This cross-sectional study was conducted through an online questionnaire. It included all 65 emergency physicians at Copenhagen EMS between June 9 and December 13, 2019 (catchment area 1.8 million). The questionnaire examined how emergency physicians perceived the interaction with citizen responders at the scene of OHCA (use of citizen responders before and after EMS arrival, citizen responders’ skills in cardiopulmonary resuscitation (CPR), and challenges in this setting). Results The response rate was 87.7% (57/65). Nearly all emergency physicians (93.0%) had interacted with a citizen responder at least once. Of those 92.5%(n = 49) considered it relevant to activate citizen responders to OHCA resuscitation, and 67.9%(n = 36) reported the collaboration as helpful. When citizen responders arrived before EMS, 75.5%(n = 40) of the physicians continued to use citizen responders to assist with CPR or to carry equipment. Most (84.9%, n = 45) stated that citizen responders had the necessary skills to perform CPR. Challenges in the collaboration were described by 20.7%(n = 11) of the emergency physicians and included citizen responders being mistaken for relatives, time-consuming communication, or crowding problems during resuscitation. Conclusion Emergency physicians perceived the collaboration with citizen responders as valuable, not only for delivery of CPR, but were also considered an extra helpful resource providing non-CPR related tasks such as directing the EMS to the arrest location, carrying equipment and taking care of relatives.

Aim: Many efforts have been made to train the Danish population in cardiopulmonary resuscitation (CPR) and automated external defibrillator (AED) use. We assessed CPR and AED training levels among the broad Danish population and volunteer responders. Methods: In November 2018, an electronic cross-sectional survey was sent to (1) a representative sample of the general Danish population (by YouGov) and (2) all volunteer responders in the Capital Region of Denmark. Results: A total of 2,085 people from the general population and 7,768 volunteer responders (response rate 36%) completed the survey. Comparing the general Danish population with volunteer responders, 81.0% (95% CI 79.2–82.7%) vs. 99.2% (95% CI 99.0–99.4%) p

Abstract 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-CPRprior), and to describe OHCA call handling when CPR is initiated prior to the emergency call (CPRprior). 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-CPRprior and CPRprior and data collection continued until 200 cases were collected in the NO-CPRprior-group. Results NO-CPRprior 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. CPRprior 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-CPRprior 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.

Abstract Background Dispatcher-assisted cardiopulmonary resuscitation (DA-CPR) increases neurologically intact survival in out-of-hospital cardiac arrest (OHCA) according to several studies. This systematic review summarizes neurologically intact survival outcomes of DA-CPR in comparison with bystander-initiated CPR and no bystander CPR in OHCA. Methods The systematic review was conducted according to the PRISMA guidelines. All studies including adult and/or pediatric OHCAs that compared DA-CPR with bystander-initiated CPR or no bystander CPR were included. Primary outcome was neurologically intact survival at discharge, one-month or longer. Studies were searched for in PubMed (MEDLINE), EMBASE, and the Cochrane Library databases. The risk of bias was evaluated using the Newcastle-Ottawa Scale. Results The search string generated 4742 citations of which 33 studies were eligible for inclusion. Due to overlapping study populations, the review included 14 studies. All studies were observational. The study populations were heterogeneous and included adult, pediatric and mixed populations. Some studies reported only witnessed cardiac arrests, arrests of cardiac ethiology, and/or shockable rhythm. The individual studies scored between six and nine on the Newcastle-Ottawa Scale of risk of bias. The median neurologically intact survival at hospital discharge with DA-CPR was 7.0% (interquartile range (IQR): 5.1–10.8%), with bystander-initiated CPR 7.5% (IQR: 6.6–10.2%), and with no bystander CPR 4.4% (IQR: 2.0–9.0%) (four studies). At one-month neurologically intact survival with DA-CPR was 3.1% (IQR: 1.6–3.4%), with bystander-initiated CPR 5.7% (IQR: 5.0–6.0%), and with no bystander CPR 2.5% (IQR: 2.1–2.6%) (three studies). Conclusion Both DA-CPR and bystander-initiated CPR increase neurologically intact survival compared with no bystander CPR. However, DA-CPR demonstrates inferior outcomes compared with bystander-initiated CPR. Early CPR is crucial, thus in cases where bystanders have not initiated CPR, DA-CPR provides an opportunity to improve neurologically intact survival following OHCA. Variability in OHCA outcomes across studies and multiple confounding factors were identified.

Abstract Background Telephone triage within out-of-hours (OOH) services aims to ascertain the urgency of a caller’s medical condition in order to determine the correct type of health care needed, ensuring patient safety. To improve the triage process by increasing patient-centred communication, a triage tool has been developed, whereby callers are asked to rate their degree-of-worry (DOW) as a measure of self-evaluated urgency. Studies show that low socioeconomic status (SES), being single and non-Western ethnicity are associated to low self-rated health and high morbidity and these factors may also be associated with high DOW. The aim of this paper was to examine if low SES, being single and non-Western ethnicity were associated to high DOW of callers contacting OOH services. Methods A prospective cohort study design, at the OOH services for the Capital Region of Denmark. Over 2 weeks, 6869 of 38,787 callers met the inclusion criteria: ≥18 years, patients themselves or close relative/friend, reported DOW, had a valid personal identification number and gave informed consent. Callers were asked to report their DOW (1 = minimal worry to 5 = maximal worry), which was dichotomized into low (1–3) and high (4, 5) DOW and linked to data from electronical medical records and Statistics Denmark. Socioeconomic factors (education and annual household income), marital status and ethnicity were assessed in relation to DOW by logistic regression. Results High DOW was reported by 38.2% of the participants. Low SES (low educational level; OR 1.5, 95% CI 1.3–1.7 and low annual household income; 1.5, 1.3–1.6) was associated with high DOW and so too was being single; 1.2, 1.1–1.3 and of non-Western ethnicity; 2.9, 2.5–3.4. Conclusions Knowledge of the association of low SES, marital status as single and non-Western ethnicity with high DOW among callers to OOH services may give call handlers a better understanding of callers’ DOW. If this does not correspond to the call handler’s perception of urgency, this knowledge may further encourage patient-centred communication, aid the triage process and increase patient safety. A better understanding of socioeconomic variables and their relation to callers’ DOW gives direction for future research to improve telephone triage of OOH services.

Abstract Objective Telephone triage manages patient flow in acute care, but a lack of visual cues and vague descriptions of symptoms challenges clinical decision making. We aim to investigate the association between the caller’s subjective perception of illness severity expressed as “degree-of-worry” (DOW) and hospital admissions within 48 h. Design and setting A prospective cohort study was performed from January 24th to February 9th, 2017 at the Medical Helpline 1813 (MH1813) in Copenhagen, Denmark. The MH1813 is a primary care out-of-hours service. Participants Of 38,787 calls received at the MH1813, 11,338 met the inclusion criteria (caller being patient or close friend/relative and agreement to participate). Participants rated their DOW on a 5-point scale (1 = minimum worry, 5 = maximum worry) before talking to a call handler. Main outcome measure Information on hospitalization within 48 h after the call, was obtained from the Danish National Patient Register. The association was assessed using logistic regression in three models: 1) crude, 2) age-and-gender adjusted and 3) age, gender, co-morbidity, reason for calling and caller status adjusted. Results A total of 581 participants (5.1%) were admitted to the hospital, of whom 170 (11.3%) presented with a maximum DOW, with a crude odds ratio (OR) for hospitalization of 6.1 (95% confidence interval (CI) 3.9 to 9.6) compared to minimum DOW. Estimates showed dose-response relationship between DOW and hospitalization. In the fully adjusted model, the ORs decreased to 3.1 (95%CI 2.0 to 5.0) for DOW = 5, 3.2 (2.0 to 5.0) for DOW = 4, 1.6 (1.0 to 2.6) for DOW = 3 and 0.8 (0.5 to 1.4) for DOW = 2 compared to minimum DOW. Conclusion Patients’ self-assessment of illness severity as DOW was associated with subsequent hospital admission. Further, it may be beneficial in supporting clinical decision making in telephone triage. Finally, it might be useful as a measure to facilitate patient participation in the triage process.

Background: Geographical setting is seldomly taken into account when investigating out-of-hospital cardiac arrest (OHCA). It is a common notion that living in rural areas means a lower chance of fast and effective helpwhen suffering a time-critical event. This retrospective cohort study investigates this hypothesis and compares across healthcare-divided administrative regions. Methods: We included only witnessed OHCAs to minimize the risk that outcome was predetermined by time to caller arrival and/or recognition. Arrests were divided into public and residential. Residential arrests were categorized according to population density of the area in which they occurred. We investigated incidence, EMS response time and 30-day survival according to area type and subsidiarily by healthcare-divided administrative region. Results: The majority (71%) of 8,579 OHCAs were residential, and 53.2% of all arrests occurred in the most densely populated cell group amongst residential arrests. This group had a median EMS response time of six minutes, whereas the most sparsely populated group had a median of 10 minutes. Public arrests also had a median response time of six minutes. 30-day survival was highest in public arrests (38.5%, [95% CI 36.9;40.1]), and varied only slightly with no statistical significance between OHCAs in densely and sparsely populated areas from 14.8% (95% CI 14.4;15.2) and 13.4% (95% CI 12.2;14.7). Conclusion: Our study demonstrates that while EMS response times in Denmark are longer in the rural areas, there is no statistically significant decrease in survival compared to the most densely populated areas.

Background Little is known about how COVID‐19 influenced engagement of citizen responders dispatched to out‐of‐hospital cardiac arrest (OHCA) by a smartphone application. The objective was to describe and analyze the Danish Citizen Responder Program and bystander interventions (both citizen responders and nondispatched bystanders) during the first COVID‐19 lockdown in 2020. Methods and Results All OHCAs from January 1, 2020, to June 30, 2020, with citizen responder activation in 2 regions of Denmark were included. We compared citizen responder engagement for OHCA in the nonlockdown period (January 1, 2020, to March 10, 2020, and April 21, 2020, to June 30, 2020) with the lockdown period (March 11, 2020, to April 20, 2020). Data are displayed in the order lockdown versus nonlockdown period. Bystander cardiopulmonary resuscitation rates did not differ in the 2 periods (99% versus 92%; P=0.07). Bystander defibrillation (9% versus 14%; P=0.4) or return‐of‐spontaneous circulation (23% versus 23%; P=1.0) also did not differ. A similar amount of citizen responders accepted alarms during the lockdown (6 per alarm; interquartile range, 6) compared with the nonlockdown period (5 per alarm; interquartile range, 5) (P=0.05). More citizen responders reported performing chest‐compression‐only cardiopulmonary resuscitation during lockdown compared with nonlockdown (79% versus 59%; P=0.0029), whereas fewer performed standardized cardiopulmonary resuscitation, including ventilations (19% versus 38%; P=0.0061). Finally, during lockdown, more citizen responders reported being not psychologically affected by attending an OHCA compared with nonlockdown period (68% versus 56%; P

Background We aim to examine diurnal and weekday variations in citizen responder availability and intervention at out‐of‐hospital cardiac arrest (OHCA) resuscitation. Methods and Results We included confirmed OHCAs where citizen responders were activated by a smartphone application in the Capital Region of Denmark between September 1, 2017 and August 31, 2018. OHCAs were analyzed by time of day (daytime: 07:00 am–03:59 pm, evening: 4:00–11:59 pm, and nighttime: 12:00–06:59 am) and day of week (Monday–Friday or Saturday–Sunday/public holidays). We included 438 OHCAs where 6836 citizen responders were activated. More citizen responders accepted alarms in the evening (mean 4.8 [95% CI, 4.4–5.3]) compared with daytime (3.7 [95% CI, 3.4–4.4]) and nighttime (1.8 [95% CI, 1.5–2.2]) (P

Background Treatment with an automated external defibrillator (AED) improves outcome in out‐of‐hospital cardiac arrest (OHCA). Audiovisual feedback from an AED may assist bystanders achieve higher quality cardiopulmonary resuscitation. However, the association between audiovisual feedback and clinical outcomes is not well assessed in real‐life OHCA. The aim of this study was to assess the association between audiovisual feedback from an AED used in bystander resuscitation with rates of return of spontaneous circulation (ROSC) and 30‐day survival in a real‐life cohort of patients with OHCA. Methods and Results We included 325 patients treated with bystander AED use before arrival of emergency medical services during 2016 to 2019 from the Capital Region of Denmark. Patients were divided into a “feedback” and a “nonfeedback” group, depending on presence of audiovisual feedback from the AED. Audiovisual feedback was defined as voice prompts with continuous feedback to ongoing resuscitation. Rates of ROSC upon hospital admission and 30‐day survival were assessed, and univariate and multivariable models were applied to decide the association to audiovisual feedback. Multivariable models were adjusted for sex, age, primary heart rhythm, and location of OHCA. A total of 155 (48%) patients had a bystander AED applied with audiovisual feedback and 170 (52%) without audiovisual feedback. A lower rate of ROSC was found in the feedback group compared with the nonfeedback group (33% [n=51] versus 45% [n=76]; P=0.03). No association was observed between AV feedback and 30‐day survival (feedback=27% [n=42] and nonfeedback=31% [n=53]; P=0.49). In the unadjusted logistic regression model, audiovisual feedback was associated with a decreased chance of ROSC (odds ratio, 0.61; 95% CI, 0.38–0.95; P=0.03), which remained significant after adjusted analysis (odds ratio, 0.53; 95% CI, 0.29–0.97; P=0.04), whereas we found no significant association between audiovisual feedback and 30‐day survival in the unadjusted and adjusted analyses. Conclusions Audiovisual feedback from an AED used by bystanders was associated with a lower chance of ROSC at hospital admission, but we found no significant difference in 30‐day survival. Focus on early and correct bystander cardiopulmonary resuscitation and AED use remain key for OHCA survival.

Background Pediatric out-of-hours calls are common, as parents worry and seek reassurance and shared responsibility. Nevertheless, most children assessed in this context are not seriously ill. Conventional telephone triage lacks visual cues and is further limited by third part communication in calls concerning children. We investigated implementation of video triage in two previous studies. The aim of the present study was to investigate 1) How video triage versus telephone triage in children was experienced by parents and call-handlers, and 2) call-handlers’ evaluation of the video triage projects. Methods We triangulated data from surveys and interviews in five sub-studies. Sub-study 1: Parents’ experience of video triage reported in closed-ended questionnaire items using quantitative analysis; Sub-study 2: Parents’ experience of video triage reported as questionnaire free-text using qualitative content analysis; Sub-study 3: Call-handlers’ experience of video triage reported in closed-ended questionnaire items using quantitative analysis; and Sub-studies 4 and 5: Individual interviews of call-handlers’ experience of 1) video triage using thematic analysis and 2) the video triage project using process evaluation. Results Most parents’ comments regarding video triage were positive (n = 164, 83%). Video triage was perceived as reassuring and reducing the likelihood of misunderstandings and unnecessary hospital visits. Call-handlers experienced that video triage improved patient assessment and caller reassurance. Some call-handlers complained that the time allocated for study participation was inadequate and requested a more accessible video set-up. Both parents and call-handlers were significantly more satisfied and reassured after video triage than after telephone triage and suggested video triage as a permanent option. Conclusion Video triage was appreciated by parents and call-handlers and was recommended as a permanent option. The call-handlers suggested that designated time for participation in the studies would have been desirable in this busy call-center. We recommend video triage as a contemporary solution in out-of-hours service.

ABSTRACT “Testing Denmark” is a national, large-scale, epidemiological surveillance study of SARS-CoV-2 in the Danish population. Between September and October 2020, approximately 1.3 million people (age >15 years) were randomly invited to fill in an electronic questionnaire covering COVID-19 exposures and symptoms. The prevalence of SARS-CoV-2 antibodies was determined by point-of care rapid test (POCT) distributed to participants’ home addresses. In total, 318,552 participants (24.5% invitees) completed the study and 2,519 (0.79%) were seropositive. Of the participants with a prior positive PCR test (n = 1,828), 29.1% were seropositive in the POCT. Although seropositivity increased with age, participants 61 years and over reported fewer symptoms and were tested less frequently. Seropositivity was associated with physical contact with SARS-CoV-2 infected individuals (risk ratio [RR] 7.43, 95% CI: 6.57–8.41), particular in household members (RR 17.70, 95% CI: 15.60–20.10). A greater risk of seropositivity was seen in home care workers (RR 2.09, 95% CI: 1.58–2.78) compared to office workers. A high degree of adherence with national preventive recommendations was reported (e.g., >80% use of face masks), but no difference were found between seropositive and seronegative participants. The seroprevalence result was somewhat hampered by a lower-than-expected performance of the POCT. This is likely due to a low sensitivity of the POCT or problems reading the test results, and the main findings therefore relate to risk associations. More emphasis should be placed on age, occupation, and exposure in local communities. IMPORTANCE To date, including 318,522 participants, this is the largest population-based study with broad national participation where tests and questionnaires have been sent to participants’ homes. We found that more emphasis from national and local authorities toward the risk of infection should be placed on age of tested individuals, type of occupation, as well as exposure in local communities and households. To meet the challenge that broad nationwide information can be difficult to gather. This study design sets the stage for a novel way of conducting studies. Additionally, this study design can be used as a supplementary model in future general test strategy for ongoing monitoring of COVID-19 immunity in the population, both from past infection and from vaccination against SARS-CoV-2, however, with attention to the complexity of performing and reading the POCT at home.

ABSTRACT Most individuals seroconvert after infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), but being seronegative is observed in 1 to 9%. We aimed to investigate the risk factors associated with being seronegative following PCR-confirmed SARS-CoV-2 infection. In a prospective cohort study, we screened health care workers (HCW) in the Capital Region of Denmark for SARS-CoV-2 antibodies. We performed three rounds of screening from April to October 2020 using an enzyme-linked immunosorbent assay (ELISA) method targeting SARS-CoV-2 total antibodies. Data on all participants’ PCR for SARS-CoV-2 RNA were captured from national registries. The Kaplan-Meier method and Cox proportional hazards models were applied to investigate the probability of being seronegative and the related risk factors, respectively. Of 36,583 HCW, 866 (2.4%) had a positive PCR before or during the study period. The median (interquartile range [IQR]) age of 866 HCW was 42 (31 to 53) years, and 666 (77%) were female. After a median of 132 (range, 35 to 180) days, 21 (2.4%) of 866 were seronegative. In a multivariable model, independent risk factors for being seronegative were self-reported asymptomatic or mild infection hazard ratio (HR) of 6.6 (95% confidence interval [CI], 2.6 to 17; P < 0.001) and body mass index (BMI) of ≥30, HR 3.1 (95% CI, 1.1 to 8.8; P = 0.039). Only a few (2.4%) HCW were not seropositive. Asymptomatic or mild infection as well as a BMI above 30 were associated with being seronegative. Since the presence of antibodies against SARS-CoV-2 reduces the risk of reinfection, efforts to protect HCW with risk factors for being seronegative may be needed in future COVID-19 surges. IMPORTANCE Most individuals seroconvert after infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), but negative serology is observed in 1 to 9%. We found that asymptomatic or mild infection as well as a BMI above 30 were associated with being seronegative. Since the presence of antibodies against SARS-CoV-2 reduces the risk of reinfection, efforts to protect HCW with risk factors for being seronegative may be needed in future COVID-19 surges.

Background: Activating citizen responders may increase survival after out-of-hospital cardiac arrest (OHCA) but could induce significant psychological impact on the citizen responders. We examined psychological impact among citizen responders within the first days following resuscitation attempt. Methods and Results: A mobile phone application to activate citizen responders to perform cardiopulmonary resuscitation (CPR) was implemented in the Capital Region of Denmark. All dispatched citizen responders (September 2017 to May 2019) received a survey 90 minutes after an alarm, including self-rating of perceived psychological impact on a scale of 1–4.Of 5,395 included citizen responders, most (88.6%) completed the survey within 24 hours.The majority reported no psychological impact (68.6%), whereas 24.7%, 5.5% and 1.2% reported low, moderate, or severe impact, respectively. Severe impact was more commonly reported in the following groups: No CPR training (3.8% vs 1.2%, p = 0.02), age

Background Citizen responder programs are implemented worldwide to dispatch volunteer citizens to participate in out‐of‐hospital cardiac arrest resuscitation. However, the risk of injuries in relation to activation is largely unknown. We aimed to assess the risk of physical injury for dispatched citizen responders. Methods and Results Since September 2017, citizen responders have been activated through a smartphone application when located close to a suspected cardiac arrest in the Capital Region of Denmark. A survey was sent to all activated citizen responders, including a specific question about risk of acquiring an injury during activation. We included all surveys from September 1, 2017, to May 15, 2020. From May 15, 2019, to May 15, 2020, we followed up on all survey nonresponders by phone call, e‐mail, or text messages to examine if nonresponders were at higher risk of severe or fatal injuries. In 1665 suspected out‐of‐hospital cardiac arrests, 9574 citizen responders were dispatched and 76.6% (7334) answered the question regarding physical injury. No injury was reported by 99.3% (7281) of the responders. Being at risk of physical injury was reported by 0.3% (24), whereas 0.4% (26) reported an injury (25 minor injuries and 1 severe injury [ankle fracture]). When following up on nonresponders (2472), we reached 99.1% (2449). No one reported acquired injuries, and only 1 reported being at risk of injury. Conclusions We found low risk of physical injury reported by volunteer citizen responders dispatched to out‐of‐hospital cardiac arrest. Risk of injury should be considered and monitored as a safety measure in citizen responder programs.

Background Little is known about the psychological risks of dispatched citizen responders who have participated in resuscitation attempts. Methods and Results A cross‐sectional survey study was performed with 102 citizen responders who participated in a resuscitation attempt from July 23, 2018, to August 22, 2018, in the Capital Region of Denmark. Psychological distress, defined as symptoms of posttraumatic stress disorder, was assessed 3 weeks after the resuscitation attempt and measured with the Impact of Event Scale‐Revised. Perceived stress was measured with the Perceived Stress Scale. Individual differences were assessed as the personality traits of agreeableness, conscientiousness, extraversion, neuroticism, and openness to experience with the Big Five Inventory, general self‐efficacy, and coping mechanisms (Brief Coping Orientation to Problems Experienced Inventory). Associations between continuous variables were examined with the Pearson correlation. The associations between psychological distress levels and contextual factors and individual differences were analyzed in multivariable linear regression models to determine factors independently associated with psychological distress levels. The mean overall posttraumatic stress disorder score was 0.65 of 12; the mean perceived stress score was 7.61 of 40. The most common coping mechanisms were acceptance and emotional support. Low perceived stress was significantly associated with high general self‐efficacy, and high perceived stress was significantly associated with high scores on neuroticism and openness to experience. Non–healthcare professionals were less likely to report symptoms of posttraumatic stress disorder. Conclusions Citizen responders who participated in resuscitation reported low levels of psychological distress. Individual differences were significantly associated with levels of psychological distress and should be considered when engaging citizen responders in resuscitation.