Out‐of‐hospital cardiac arrest (OHCA) is a major cause of death in the Western world with an estimated number of 275 000 treated with resuscitation attempts by the Emergency Medical Services (EMS) in ...Europe each year. Overall survival rates remain low, and most studies indicate that around 1 out 10 will survive to 30 days. Amongst the strongest factors associated with survival in OHCA is first recorded rhythm amendable to defibrillation, early defibrillation and prompt initiation of cardiopulmonary resuscitation (CPR). Overall, CPR started prior to EMS arrival has repeatedly been shown to be associated with survival rates 2–3 times higher compared with no such initiation. The primary goal of CPR is to generate sufficient blood flow to vital organs, mainly the brain and heart, until restoration of spontaneous circulation can be achieved. Barriers to the initiation of CPR by bystanders in OHCA include fear of being incapable, causing harm, and transmission of infectious diseases. Partly due to these barriers, and low rates of CPR, the concept of CPR with compression only was proposed as a simpler form of resuscitation with the aim to be more widely accepted by the public in the 1990s. But how reliable is the evidence supporting this simpler form of CPR, and are the outcomes after CO‐CPR comparable to standard CPR?
In a national perspective, to describe survival among patients found in ventricular fibrillation or pulseless ventricular tachycardia witnessed by a bystander and with a presumed cardiac aetiology ...and answer two principal questions: (1) what are the changes over time? and (2) which are the factors of importance?
Observational register study.
Sweden.
All patients included in the Swedish Out of Hospital Cardiac Arrest Register between 1 January 1990 and 31 December 2009 who were found in bystander-witnessed ventricular fibrillation with a presumed cardiac aetiology. Interventions Bystander cardiopulmonary resuscitation (CPR) and defibrillation.
Survival to 1 month.
In all, 7187 patients fulfilled the set criteria. Age, place of out-of-hospital cardiac arrest (OHCA) and gender did not change. Bystander CPR increased from 46% to 73%; 95% CI for OR 1.060 to 1.081 per year. The median delay from collapse to defibrillation increased from 12 min to 14 min (p for trend 0.0004). Early survival increased from 28% to 45% (95% CI 1.044 to 1.065) and survival to 1 month increased from 12% to 23% (95% CI 1.058 to 1.086). Strong predictors of early and late survival were a short interval from collapse to defibrillation, bystander CPR, female gender and OHCA outside the home.
In a long-term perspective in Sweden, survival to 1 month after ventricular fibrillation almost doubled. This was associated with a marked increase in bystander CPR. Strong predictors of outcome were a short delay to defibrillation, bystander CPR, female gender and place of collapse.
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.
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.
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.
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.
The use of an automated external defibrillator (AED) prior to EMS arrival can increase 30-day survival in out-of-hospital cardiac arrest (OHCA) significantly. Drones or unmanned aerial vehicles (UAV) ...can fly with high velocity and potentially transport devices such as AEDs to the site of OHCAs. The aim of this explorative study was to investigate the feasibility of a drone system in decreasing response time and delivering an AED.
Data of Global Positioning System (GPS) coordinates from historical OHCA in Stockholm County was used in a model using a Geographic Information System (GIS) to find suitable placements and visualize response times for the use of an AED equipped drone. Two different geographical models, urban and rural, were calculated using a multi-criteria evaluation (MCE) model. Test-flights with an AED were performed on these locations in rural areas.
In total, based on 3,165 retrospective OHCAs in Stockholm County between 2006-2013, twenty locations were identified for the potential placement of a drone. In a GIS-simulated model of urban OHCA, the drone arrived before EMS in 32 % of cases, and the mean amount of time saved was 1.5 min. In rural OHCA the drone arrived before EMS in 93 % of cases with a mean amount of time saved of 19 min. In these rural locations during (n = 13) test flights, latch-release of the AED from low altitude (3-4 m) or landing the drone on flat ground were the safest ways to deliver an AED to the bystander and were superior to parachute release.
The difference in response time for EMS between urban and rural areas is substantial, as is the possible amount of time saved using this UAV-system. However, yet another technical device needs to fit into the chain of survival. We know nothing of how productive or even counterproductive this system might be in clinical reality.
To use drones in rural areas to deliver an AED in OHCA may be safe and feasible. Suitable placement of drone systems can be designed by using GIS models. The use of an AED equipped drone may have the potential to reduce time to defibrillation in OHCA.
Cardiac disease is the most common cause of mortality in Western countries, with most deaths due to out‐of‐hospital cardiac arrest (OHCA). In Sweden, 5000–10 000 OHCAs occur annually. During the last ...decade, the time from cardiac arrest to start of cardiopulmonary resuscitation (CPR) and defibrillation has increased, whereas survival has remained unchanged or even increased. Resuscitation of OHCA patients is based on the ‘chain‐of‐survival’ concept, including early (i) access, (ii) CPR, (iii) defibrillation, (iv) advanced cardiac life support and (v) post‐resuscitation care. Regarding early access, agonal breathing, telephone‐guided CPR and the use of ‘track and trigger systems’ to detect deterioration in patients' condition prior to an arrest are all important. The use of compression‐only CPR by bystanders as an alternative to standard CPR in OHCA has been debated. Based on recent findings, guidelines recommend telephone‐guided chest compression‐only CPR for untrained rescuers, but trained personnel are still advised to give standard CPR with both compressions and ventilation, and the method of choice for this large group remains unclear and demands for a randomized study. Data have shown the benefit of public access defibrillation for dispatched rescuers (e.g. police and fire fighters) but data are not as strong for the use of automated defibrillators (AEDs) by trained or untrained rescuers. Postresuscitation, use of therapeutic hypothermia, the importance of specific prognostic survival factors in the intensive care unit and the widespread use of percutaneous coronary intervention have all been considered. Despite progress in research and improved treatment regimens, most patients do not survive OHCA. Particular areas of interest for improving survival include (i) identification of high‐risk patients prior to their arrest (e.g. early warning symptoms and genes); (ii) increased use of bystander CPR training (e.g. in schools) and simplified CPR techniques; (iii) better identification of high‐incidence sites and better recruitment of AEDs (via mobile phone solutions?); (iv) improved understanding of the use of therapeutic hypothermia; (v) determining which patients should undergo immediate coronary angiography on hospital admission; and (vi) clarifying the importance of extracorporeal membrane oxygenation during CPR.
Although ozone (O3) and other pollutants have been associated with cardiovascular morbidity and mortality, the effects of O3 on out-of-hospital cardiac arrest (OHCA) have rarely been addressed and ...existing studies have presented inconsistent findings. The objective of this study was to determine the effects of short-term exposure to air pollution including O3 on the occurrence of OHCA, and assess effect modification by season, age, and gender.
A total of 5973 Emergency Medical Service-assessed OHCA cases in Stockholm County 2000-10 were obtained from the Swedish cardiac arrest register. A time-stratified case-crossover design was used to analyse exposure to air pollution and the risk of OHCA. Exposure to O3, PM2.5, PM10, NO2, and NOx was defined as the mean urban background level during 0-2, 0-24, and 0-72 h before the event and control time points. We adjusted for temperature and relative humidity. Ozone in urban background was associated with an increased risk of OHCA for all time windows. The respective odds ratio (confidence interval) for a 10 µg/m(3) increase was 1.02 (1.01-1.05) for a 2-h window, 1.04 (1.01-1.07) for 24-h, and 1.05 (1.01-1.09) for 3 day. The association with 2-h O3 was stronger for events that occurred outdoors: 1.13 (1.06-1.21). We observed no effects for other pollutants and no effect modification by age, gender, or season.
Short-term exposure to moderate levels of O3 is associated with an increased risk of OHCA.
Out-of-hospital cardiac arrest (OHCA) is a major cause of death in the Western world. In this study we aimed to investigate the relationship between area-level socioeconomic status (SES) and 30-day ...survival after OHCA. We hypothesised that high SES at an area level is associated with an improved chance of 30-day survival.
Patients with OHCA in Stockholm County between 1 January 2006 and 31 December 2015 were analysed retrospectively. To quantify area-level SES, we linked the patient's home address to 250 × 250/1000 × 1000 meter grids with aggregated information about income and education. We constructed multivariable logistic regression models in which area-level SES measures were adjusted for age, sex, emergency medical services response time, witnessed status, initial rhythm, aetiology, location and year of cardiac arrest.
We included 7431 OHCAs. There was significantly greater 30-day survival (p=0.003) in areas with a high proportion of university-educated people. No statistically significant association was seen between median disposable income and 30-day survival. The adjusted OR for 30-day survival among patients in the highest educational quintile was 1.70 (95% CI 1.15 to 2.51) compared with patients in the lowest educational quintile. We found no significant interaction for sex. Positive trend with increasing area-level education was seen in both men and women but the trend was only statistically significant among men (p=0.012) CONCLUSIONS: Survival to 30 days after OHCA is positively associated with the average educational level of the residential area. Area-level income does not independently predict 30-day survival after OHCA.
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.
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.
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.
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.
Background
Intensive care unit (ICU) patients are transfused with blood products for a number of reasons, from massive ongoing hemorrhage, to mild anemia following blood sampling, combined with bone ...marrow depression due to critical illness. There's a paucity of data on transfusions in ICUs and most studies are based on audits or surveys. The aim of this study was to provide a complete picture of ICU‐related transfusions in Sweden.
Methods
We conducted a register based retrospective cohort study with data on all adult patient admissions from 82 of 84 Swedish ICUs between 2010 and 2018, as recorded in the Swedish Intensive Care Register. Transfusions were obtained from the SCANDAT‐3 database. Descriptive statistics were computed, characterizing transfused and nontransfused patients. The distribution of blood use comparing different ICUs was investigated by computing the observed proportion of ICU stays with a transfusion, as well as the expected proportion.
Results
In 330,938 ICU episodes analyzed, at least one transfusion was administered for 106,062 (32%). For both red‐cell units and plasma, the fraction of patients who were transfused decreased during the study period from 31.3% in 2010 to 24.6% in 2018 for red‐cells, and from 16.6% in 2010 to 9.4% in 2018 for plasma. After adjusting for a range of factors, substantial variation in transfusion frequency remained, especially for plasma units.
Conclusion
Despite continuous decreases in utilization, transfusions remain common among Swedish ICU patients. There is considerable unexplained variation in transfusion rates. More research is needed to establish stronger critiera for when to transfuse ICU patients.
Submersion time is a strong predictor for death in drowning, already 10 min after submersion, survival is poor. Traditional search efforts are time-consuming and demand a large number of rescuers and ...resources. We aim to investigate the feasibility and effectiveness of using drones combined with an online machine learning (ML) model for automated recognition of simulated drowning victims.
This feasibility study used photos taken by a drone hovering at 40 m altitude over an estimated 3000 m2 surf area with individuals simulating drowning. Photos from 2 ocean beaches in the south of Sweden were used to (a) train an online ML model (b) test the model for recognition of a drowning victim.
The model was tested for recognition on n = 100 photos with one victim and n = 100 photos with no victims. In drone photos containing one victim (n = 100) the ML model sensitivity for drowning victim recognition was 91% (95%CI 84.9%–96.2%) with a median probability score that the finding was human of 66% (IQR 52−71). In photos with no victim (n = 100) the ML model specificity was 90% (95%CI: 83.9%–95.6%). False positives were present in 17.5% of all n = 200 photos but could all be ruled out manually as false objects.
The use of a drone and a ML model was feasible and showed satisfying effectiveness in identifying a submerged static human simulating drowning in open water and favorable environmental conditions. The ML algorithm and methodology should be further optimized, again tested and validated in a real-life clinical study.
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