Dispatch of lay responders to out-of-hospital cardiac arrests

Background and aim Out-of-hospital cardiac arrest (OHCA) remains a major public-health problem affecting around 300 000 Europeans each year. If treatment is not started within a couple of minutes the chances of survival are slim. One important predictor of survival is the time from call to start of treatment. To reduce this time frame, different strategies, in addition to emergency medical services (EMS), such as widespread deployment of automated external defibrillators (AEDs) and dispatch of fire fighters and police officers have been implemented. The aim of this thesis is to study the implementation and effects of a third additional resource, lay responders dispatched by the emergency dispatch center. The aim of study 1 was to evaluate the technical function and performance of a lay responder system during a run-in phase. The aim of study 2 was to measure the travelling speed and response time of the dispatched lay responders. In study 3 the aim was to investigate the emotional response, both positive and negative, wellbeing and post-traumatic stress disorder, among dispatched lay responders. In study 4 the aim was to investigate if lay responders instructed to fetch a public AED by using a smartphone application could increase the bystander use of AEDs before arrival of EMS, fire fighters and police officers. Methods and results In study 1 data from the smartphone application were collected and linked to cardiac arrest data from the Swedish Register for Cardiopulmonary Resuscitation (SRCR). During six months in 2016 the system was activated 685 times. 224 of these cases were EMS treated OHCAs. After exclusion of EMS-witnessed cases (n=11) and cases with missing survey data (n=15), 198 cases remained in the analytical sample. The results showed that dispatched lay responders reached the scene in 116 cases (58%), in 51 (26%) cases before the EMS. An AED was attached 17 times (9%) and defibrillated 4 times (2%). The median Euclidian distance to travel to perform CPR was 560 meters (IQR=332-860) compared with 1280 (IQR=748-1776) among for those who were directed to fetch an AED. In study 2, data on lay responder movement were collected from the smartphone application. During the 7-month study period 1406 suspected OHCAs were included. In these calls, 9058 lay responders accepted the mission and 2176 reached the scene of the suspected cardiac arrest (the study population). Among all cases the median travelling speed was 2.3 meters/sec (IQR=1.4–4.0) while the response time was 6.2 minutes, and the travelling distance was 956 meters (IQR=480–1661). In the most densely populated areas the median travelling speed was 1.8 meters/sec compared with 3.1 in the least densely populated areas. In study 3 we included 886 unexposed and 1389 exposed lay-responders. The lay responders were divided into 3 groups; unexposed, exposed-1 (who tried, but failed to reach the scene before EMS) and exposed-2 (who either reached the scene before EMS or performed CPR). Using the two dimensions of the Swedish Core Affect Scales (SCAS), valence and activation the results suggested that exposed lay responders showed higher activation (Exp-1=7.5, Exp-2=7.6) than unexposed lay responders (7.0) (p<0.001). Exposed lay responders had lower valence (Exp-1=6.3, Exp-2=6.3) compared with unexposed lay responders (6.8) (p<0.001). PCL-6 mean scores were highest in the unexposed group (10.4) compared with the exposed group (Exp-1=8.8, Exp-2=9.2) (p=0.007). There were no differences in the WHO wellbeing index, (Un-Exp: 77.7; Exp-1: 77.8; Exp-2: 78.2) (p=0.963). In Study 4, cases of suspected OHCA were randomly assigned to either an intervention group, where the majority of lay responders (4/5) were guided to the nearest AED, or to a control group, where all lay responders were directed to perform CPR. Data from the smartphone application system were linked to data from the SRCR. During the 13-month study period 2553 suspected OHCAs were randomized. Among these, 815 (32%) were EMS-treated. The AED attachment rate was 13.2% in the intervention group compared with 9.4 in the control group (p=0.087). In both groups combined, 29.3% of all bystanders attached AEDs, and 35.3% of all cases of bystander CPR were performed by a dispatched lay responder. Conclusions The conclusion from the first run-in study (study 1) was that it is feasible to dispatch lay responders to suspected OHCAs but that further system improvements are needed to reduce the time to defibrillation. The results from study 2 suggested that lay responders travel faster than previously estimated and that the travelling speed is dependent on population density, information that may be used for simulation studies as well as in configurations in app-based systems. Study 3 showed that lay responders rated the experience as high-energy and mostly positive. No indication of harm was seen, as the lay responders had low post-traumatic stress scores and high levels of general wellbeing at follow-up. Study 4 revealed that smartphone dispatch of lay responders to public AEDs did not increase the AED attachment rate before arrival of the EMS or first responders, versus smartphone dispatch to perform CPR. If dispatched lay responders arrived prior to the EMS, the likelihood of bystander AED use and CPR was increased

Prescribed fire is an effective restoration measure for increasing boreal fungal diversity

Intensive forestry practices have had a negative impact on boreal forest biodiversity; as a consequence, the need for restoration is pressing. Polypores (wood-inhabiting fungi) are key decomposers of dead wood, but, due to a lack of coarse woody debris (CWD) in forest ecosystems, many species are under threat. Here, we study the long-term effects on polypore diversity of two restoration treatments: creating CWD by felling whole trees and prescribed burning. This large-scale experiment is located in spruce-dominated boreal forests in southern Finland. The experiment has a factorial design (n = 3) including three levels of created CWD (5, 30, and 60 m(3) ha(-1)) crossed with burning or no burning. In 2018, 16 years after launching the experiment, we inventoried polypores on 10 experimentally cut logs and 10 naturally fallen logs per stand. We found that overall polypore community composition differed between burned and unburned stands. However, only red-listed species abundances and richness were positively affected by prescribed burning. We found no effects of CWD levels created mechanically by felling of trees. We show, for the first time, that prescribed burning is an effective measure for restoring polypore diversity in a late-successional Norway spruce forest. Burning creates CWD with certain characteristics that differ from what is created by CWD restoration by felling trees. Prescribed burning promotes primarily red-listed species, demonstrating its effectiveness as a restoration measure to promote diversity of threatened polypore species in boreal forests. However, because the CWD that the burning creates will decrease over time, to be functional, prescribed burns need to be applied regularly on the landscape scale. Large-scale and long-term experimental studies, such as this one, are invaluable for establishing evidence-based restoration strategies

Political jiu-jitsu, a price the powerful do not have to pay? : A quantitative study of the influence of power on the consequences of state repression against non-violent campaigns

This thesis presents a quantitative study that aims to investigate whether Brian Martin is right in his theory about how more powerful actors have a greater capacity to prevent outrage and anger after opressions and thus suffer less from political jiu-jitsu, a process in which oppression becomes counterproductive. This is done by looking at whether more powerful regimes getaway more easily with repressing nonviolent campaigns. By designing a measuring scale for the scope of political jiu-jitsu, the connection between the scope and three different aspects of power - national capacity, wealth and state oppression - is investigated. The results shows that the more powerful the oppressive states are in terms of national capacity and wealth, the less extensive political jiu-jitsu. On the other hand, a higher degree of state oppression results in more extensive political jiu-jitsu. The results linked to the degree of staterepression are statistically significant and it can thus be said that the differences in the extent of political jiu-jitsu are not due to chance. The results indicate that more powerful states getaway with repressing nonviolent campaigns more easily, if power is measured in terms ofnational capacity or wealth. If, on the other hand, power is measured in the amount of noppression, it is more costly for the states that exercise more oppression

A brisk walk—Real-life travelling speed of lay responders in out-of-hospital cardiac arrest

Background: Defibrillation by public Automated External Defibrillators (AEDs) before EMS arrival is associated with high survival rates. Previous recommendSations suggest that an AED should be placed within a 1–1.5 min “brisk walk” from a cardiac arrest. Current guidelines hold no recommendation. The real-time it takes for a volunteer to retrieve an AED in a public setting has not been studied. Methods: Global Positioning System data and Geographical Information Systems methods were used to track the movement of mobile phone dispatched lay responders in two large Swedish areas. The distance and the travelling time were calculated from when the lay responder received the call, until they were within 25 m from the coordinate of the suspected OHCA sent by the dispatch centre. Results: During 7 months, a total of 2176 persons were included in the final analysis. The median travelling speed was 2.3 (IQR = 1.4–4.0) metres per second (m/s) among all cases with a response time of 6.2 min. The corresponding travelling distance was 956 m (IQR = 480–1661). In the most densely populated areas (>8000 inhabitants/km2) the response time was 1.8 m/s compared to 3.1 in the least densely populated areas (0–1500 inhabitants/km2). Conclusion: The median travelling speed of all lay responders dispatched to suspected OHCAs was 2.3 m/s. In densely populated areas the travelling speed was 1.8 m/s. This can be used as support in guidelines for planning placement of AEDs, in simulation studies, as well as in configuration of mobile-based dispatch systems

Long-Term Effects of Oxygen Therapy on Death or Hospitalization for Heart Failure in Patients With Suspected Acute Myocardial Infarction

Background: In the DETO2X-AMI trial (Determination of the Role of Oxygen in Suspected Acute Myocardial Infarction), we compared supplemental oxygen with ambient air in normoxemic patients presenting with suspected myocardial infarction and found no significant survival benefit at 1 year. However, important secondary end points were not yet available. We now report the prespecified secondary end points cardiovascular death and the composite of all-cause death and hospitalization for heart failure. Methods: In this pragmatic, registry-based randomized clinical trial, we used a nationwide quality registry for coronary care for trial procedures and evaluated end points through the Swedish population registry (mortality), the Swedish inpatient registry (heart failure), and cause of death registry (cardiovascular death). Patients with suspected acute myocardial infarction and oxygen saturation of ≥90% were randomly assigned to receive either supplemental oxygen at 6 L/min for 6 to 12 hours delivered by open face mask or ambient air. Results: A total of 6629 patients were enrolled. Acute heart failure treatment, left ventricular systolic function assessed by echocardiography, and infarct size measured by high-sensitive cardiac troponin T were similar in the 2 groups during the hospitalization period. All-cause death or hospitalization for heart failure within 1 year after randomization occurred in 8.0% of patients assigned to oxygen and in 7.9% of patients assigned to ambient air (hazard ratio, 0.99; 95% CI, 0.84–1.18; P=0.92). During long-term follow-up (median [range], 2.1 [1.0–3.7] years), the composite end point occurred in 11.2% of patients assigned to oxygen and in 10.8% of patients assigned to ambient air (hazard ratio, 1.02; 95% CI, 0.88–1.17; P=0.84), and cardiovascular death occurred in 5.2% of patients assigned to oxygen and in 4.8% assigned to ambient air (hazard ratio, 1.07; 95% CI, 0.87–1.33; P=0.52). The results were consistent across all predefined subgroups. Conclusions: Routine use of supplemental oxygen in normoxemic patients with suspected myocardial infarction was not found to reduce the composite of all-cause mortality and hospitalization for heart failure, or cardiovascular death within 1 year or during long-term follow-up. Clinical Trial Registration: URL: https://www.clinicaltrials.gov. Unique identifier: NCT01787110