Mattias Ringh

Early Cardiopulmonary Resuscitation in Out-of-Hospital Cardiac Arrest

BACKGROUND Three million people in Sweden are trained in cardiopulmonary resuscitation (CPR). Whether this training increases the frequency of bystander CPR or the survival rate among persons who have out-of-hospital cardiac arrests has been questioned. METHODS We analyzed a total of 30,381 out-of-hospital cardiac arrests witnessed in Sweden from January 1, 1990, through December 31, 2011, to determine whether CPR was performed before the arrival of emergency medical services (EMS) and whether early CPR was correlated with survival. RESULTS CPR was performed before the arrival of EMS in 15,512 cases (51.1%) and was not performed before the arrival of EMS in 14,869 cases (48.9%). The 30-day survival rate was 10.5% when CPR was performed before EMS arrival versus 4.0% when CPR was not performed before EMS arrival (P<0.001). When adjustment was made for a propensity score (which included the variables of age, sex, location of cardiac arrest, cause of cardiac arrest, initial cardiac rhythm, EMS response time, time from collapse to call for EMS, and year of event), CPR before the arrival of EMS was associated with an increased 30-day survival rate (odds ratio, 2.15; 95% confidence interval, 1.88 to 2.45). When the time to defibrillation in patients who were found to be in ventricular fibrillation was included in the propensity score, the results were similar. The positive correlation between early CPR and survival rate remained stable over the course of the study period. An association was also observed between the time from collapse to the start of CPR and the 30-day survival rate. CONCLUSIONS CPR performed before EMS arrival was associated with a 30-day survival rate after an out-of-hospital cardiac arrest that was more than twice as high as that associated with no CPR before EMS arrival. (Funded by the Laerdal Foundation for Acute Medicine and others.).

Mobile-Phone Dispatch of Laypersons for CPR in Out-of-Hospital Cardiac Arrest

BACKGROUND Cardiopulmonary resuscitation (CPR) performed by bystanders is associated with increased survival rates among persons with out-of-hospital cardiac arrest. We investigated whether rates of bystander-initiated CPR could be increased with the use of a mobile-phone positioning system that could instantly locate mobile-phone users and dispatch lay volunteers who were trained in CPR to a patient nearby with out-of-hospital cardiac arrest. METHODS We conducted a blinded, randomized, controlled trial in Stockholm from April 2012 through December 2013. A mobile-phone positioning system that was activated when ambulance, fire, and police services were dispatched was used to locate trained volunteers who were within 500 m of patients with out-of-hospital cardiac arrest; volunteers were then dispatched to the patients (the intervention group) or not dispatched to them (the control group). The primary outcome was bystander-initiated CPR before the arrival of ambulance, fire, and police services. RESULTS A total of 5989 lay volunteers who were trained in CPR were recruited initially, and overall 9828 were recruited during the study. The mobile-phone positioning system was activated in 667 out-of-hospital cardiac arrests: 46% (306 patients) in the intervention group and 54% (361 patients) in the control group. The rate of bystander-initiated CPR was 62% (188 of 305 patients) in the intervention group and 48% (172 of 360 patients) in the control group (absolute difference for intervention vs. control, 14 percentage points; 95% confidence interval, 6 to 21; P<0.001). CONCLUSIONS A mobile-phone positioning system to dispatch lay volunteers who were trained in CPR was associated with significantly increased rates of bystander-initiated CPR among persons with out-of-hospital cardiac arrest. (Funded by the Swedish Heart-Lung Foundation and Stockholm County; ClinicalTrials.gov number, NCT01789554.).

Mobile phone technology identifies and recruits trained citizens to perform CPR on out-of-hospital cardiac arrest victims prior to ambulance arrival

AIM In a two-parted study, evaluate a new concept were mobile phone technology is used to dispatch lay responders to nearby out-of-hospital cardiac arrests (OHCAs). METHODS Mobile phone positioning systems (MPS) can geographically locate selected mobile phone users at any given moment. A mobile phone service using MPS was developed and named Mobile Life Saver (MLS). Simulation study: 25 volunteers named mobile responders (MRs) were connected to MLS. Ambulance time intervals from 22 consecutive OHCAs in 2005 were used as controls. The MRs randomly moved in Stockholm city centre and were dispatched to simulated OHCAs (identical to controls) if they were within a 350 m distance. Real life study: during 25 weeks 1271-1801 MRs trained in CPR were connected to MLS. MLS was activated at the dispatch centre in parallel with ambulance dispatch when an OHCA was suspected. The MRs were dispatched if they were within 500 m from the suspected OHCA. RESULTS Simulation study: mean response time for the MRs compared to historical ambulance time intervals was reduced by 2 min 20s (44%), p<0.001, (95% CI, 1 min 5s - 3 min 35s). The MRs reached the simulated OHCA prior to the historical control in 72% of cases. Real life study: the MLS was triggered 92 times. In 45% of all suspected and in 56% of all true OHCAs the MRs arrived prior to ambulance. CPR was performed by MRs in 17% of all true OHCAs and in 30% of all true OHCAs if MRs arrived prior to ambulance. CONCLUSION Mobile phone technology can be used to identify and recruit nearby CPR-trained citizens to OHCAs for bystander CPR prior to ambulance arrival.

Out of hospital cardiac arrest outside home in Sweden, change in characteristics, outcome and availability for public access defibrillation

BackgroundA large proportion of patients who suffer from out of hospital cardiac arrest (OHCA) outside home are theoretically candidates for public access defibrillation (PAD). We describe the change in characteristics and outcome among these candidates in a 14 years perspective in Sweden.MethodsAll patients who suffered an OHCA in whom cardiopulmonary resuscitation (CPR) was attempted between 1992 and 2005 and who were included in the Swedish Cardiac Arrest Register (SCAR). We included patients in the survey if OHCA took place outside home excluding crew witnessed cases and those taken place in a nursing home.Results26% of all OHCAs (10133 patients out of 38710 patients) fulfilled the inclusion criteria. Within this group, the number of patients each year varied between 530 and 896 and the median age decreased from 68 years in 1992 to 64 years in 2005 (p for trend = 0.003). The proportion of patients who received bystander CPR increased from 47% in 1992 to 58% in 2005 (p for trend < 0.0001). The proportion of patients found in ventricular fibrillation (VF) declined from 56% to 50% among witnessed cases (p for trend < 0.0001) and a significant (p < 0.0001) decline was also seen among non witnessed cases.The median time from cardiac arrest to defibrillation among witnessed cases was 12 min in 1992 and 10 min in 2005 (p for trend = 0.029). Survival to one month among all patients increased from 8.1% to 14.0% (p for trend = 0.01). Among patients found in a shockable rhythm survival increased from 15.3% in 1992 to 27.0% in 2005 (p for trend < 0.0001).ConclusionIn Sweden, there was a change in characteristics and outcome among patients who suffer OHCA outside home. Among these patients, bystander CPR increased, but the occurrence of VF decreased. One-month survival increased moderately overall and highly significantly among patients found in VF, even though the time to defibrillation changed only moderately.

The implementation of a dual dispatch system in out-of-hospital cardiac arrest is associated with improved short and long term survival.

Aims: To determine the impact of a dual dispatch system, using fire fighters as first responders, in out-of-hospital cardiac arrest (OHCA) on short (30 days) and long term (three years) survival, and, to investigate the potential differences regarding in-hospital factors and interventions between the patient groups, such as the use of therapeutic hypothermia and cardiac catheterization. Methods and results: OHCAs from 2004 (historical controls) and 2006–2009 (intervention period) were included. During the intervention period, fire fighters equipped with automated external defibrillators (AEDs) were dispatched in suspected OHCA. Logistic regression analyses of outcome data included: the intervention with dual dispatch, sex, age, location, aetiology, witnessed status, bystander-cardiopulmonary resuscitation, first rhythm and therapeutic hypothermia. In total, 2581 OHCAs were included (historical controls n=620, intervention period n=1961). Fire fighters initiated cardiopulmonary resuscitation and connected an AED before emergency medical services’ arrival in 41% of the cases. The median time from dispatch to arrival of first responder or emergency medical services shortened from 7.7 in the control period to 6.7 min in the intervention period (p<0.001). The 30-day survival improved from 3.9% to 7.6% (p=0.001), adjusted odds ratio 2.8 (confidence interval 1.6–4.9). Survival to three years increased from 2.4% to 6.5% (p<0.001), adjusted odds ratio 3.8 (confidence interval 1.9–7.6). In the logistic regression analysis including in-hospital factors we found no outcome benefit of therapeutic hypothermia. Conclusions: The implementation of a dual dispatch system using fire fighters in OHCA was associated with increased 30-day and three-year survival. No major differences in the in-hospital treatment were seen between the studied patient groups.

The survival benefit of dual dispatch of EMS and fire-fighters in out-of-hospital cardiac arrest may differ depending on population density – A prospective cohort study

BACKGROUND Outcome after out-of-hospital cardiac arrest (OHCA) varies between contexts. Dual dispatching of fire-fighters or police in addition to emergency medical services (EMS) has the potential to increase survival, but the effect in urban vs. rural areas is unknown. The aim of this study was to determine the effects of dual dispatching on response times and outcome in regions with different population density. METHODS AND RESULTS The study design was a prospective cohort study of EMS-treated OHCAs from 2004 (historical controls, only EMS dispatch) and 2006-2009 (intervention, dual dispatch of EMS and fire-fighters), with data on exact geographical coordinates. Patients were divided into four subgroups depending on population density: rural (<250 persons/km2), suburban (250-2999/km2), urban (3000-5999/km2) and downtown (≥6000/km2). Totally, 2513 OHCAs were included (historical controls, n=571 and intervention, n=1942). Median time to arrival of first unit shortened significantly in all subgroups, ranging from 0.8 to 3.2 min, with the main time gain in the rural area. There were significant differences in 30-day survival between the historical controls vs. the intervention group in the suburban population (3.1% vs. 7.0%, p=0.02) and in downtown (4.1 vs. 14.6, p=0.04). In the urban population the difference was 2.7 vs. 6.9% (p=0.06) and in the rural population (4.7 vs. 5.3, p=0.82). CONCLUSIONS Dual dispatch of fire-fighters and EMS in OHCA significantly reduced response times in all studied regions. The 30-day survival increased significantly in the downtown and suburban populations, while a limited impact was seen in the rural areas.

Expanding the first link in the chain of survival – Experiences from dispatcher referral of callers to AED locations

INTRODUCTION Early use of automated external defibrillators (AED) increases survival in cases of out-of-hospital cardiac arrest (OHCA). Dispatchers play important roles in identifying OHCA, dispatching ambulances and providing callers with telephone-assisted cardiopulmonary resuscitation. Guidelines recommend that AED registries be linked to dispatch centres as tools to refer callers to nearby AED. AIM The aim of this study was to investigate to what extent dispatchers, when provided with a tool to display AED locations and accessibility, referred callers to nearby AED. METHODS An application providing real-time visualization of AED locations and accessibility was implemented at four dispatch centres in Sweden. Dispatchers were instructed to refer callers to nearby AED when OHCA was suspected. Such cases were prospectively collected, and geographic information systems were used to identify those located ≤100m from an AED. Audio recordings of emergency calls were assessed to evaluate the AED referral rate. RESULTS Between February and August 2014, 3009 suspected OHCA calls were received. In 6.6% of those calls (200/3009), an AED was ≤100m from the suspected OHCA. The AED was accessible and the caller was not alone on scene in 24% (47/200) of these cases. In two of those 47 cases (4.3%), the dispatcher referred the caller to the AED. CONCLUSION Despite a tool for dispatchers to refer callers to a nearby AED, referral was rare. Only a minority of the suspected OHCA cases occurred ≤100m from an AED. We identified AED accessibility and callers being alone on scene as obstacles for AED referral.

Time to Delivery of an Automated External Defibrillator Using a Drone for Simulated Out-of-Hospital Cardiac Arrests vs Emergency Medical Services

Time to Delivery of an Automated External Defibrillator Using a Drone for Simulated Out-of-Hospital Cardiac Arrests vs Emergency Medical Services Out-of-hospital cardiac arrest (OHCA) affects approximately 55 of 100 000 inhabitants per year in the United States, with low survival (8%-10%).1 Reducing time to defibrillation is the most important factor for increasing survival in OHCA.2,3 Unmanned aerial systems, commonly called drones, can be activated by a dispatcher and sent to an address provided by a 911 caller. The drone may carry an automated external defibrillator (AED) to the location of an OHCA so that a bystander can detach and use it. Theoretical geographical information system models have shown that drones carrying an AED can reduce response times in rural areas.4,5 However, whether they reduce response times in a real-life situation is unknown. This study compared the time to delivery of an AED using fully autonomous drones for simulated OHCAs vs emergency medical services (EMS).

Drug therapy in cardiac arrest: a review of the literature

The aim of this study was to review the literature on human studies of drug therapy in cardiac arrest during the last 25 years. In May 2015, a systematic literature search was performed in PubMed, Embase, the Cochrane Library, and CRD databases. Prospective interventional and observational studies evaluating a specified drug therapy in human cardiac arrest reporting a clinical endpoint [i.e. return of spontaneous circulation (ROSC) or survival] and published in English 1990 or later were included, whereas animal studies, case series and reports, studies of drug administration, drug pharmacology, non-specified drug therapies, preventive drug therapy, drug administration after ROSC, studies with primarily physiological endpoints, and studies of traumatic cardiac arrest were excluded. The literature search identified a total of 8936 articles. Eighty-eight articles met our inclusion criteria and were included in the review. We identified no human study in which drug therapy, compared with placebo, improved long-term survival. Regarding adrenaline and amiodarone, the drugs currently recommended in cardiac arrest, two prospective randomized placebo-controlled trials, were identified for adrenaline, and one for amiodarone, but they were all underpowered to detect differences in survival to hospital discharge. Of all reviewed studies, only one recent prospective study demonstrated improved neurological outcome with one therapy over another using a combination of vasopressin, steroids, and adrenaline as the intervention compared with standard adrenaline administration. The evidence base for drug therapy in cardiac arrest is scarce. However, many human studies on drug therapy in cardiac arrest have not been powered to identify differences in important clinical outcomes such as survival to hospital discharge and favourable neurological outcome. Efforts are needed to initiate large multicentre prospective randomized clinical trials to evaluate both currently recommended and future drug therapies.

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

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