Analysis of out-of-hospital cardiac arrest location and public access defibrillator placement in Metropolitan Phoenix,Arizona

ObjectivesAutomated external defibrillators (AEDs) improve outcomes from out-of-hospital cardiac arrest (OHCA) but are infrequently used. We sought to compare the locations of OHCAs and AEDs in metropolitan Phoenix, Arizona.MethodsPublic location OHCAs and AEDs were geocoded utilizing a statewide OHCA database (1/2010–12/2012) and AED registry. OHCAs were mapped using kernel-density estimation and overlapped with AED placements. Spearman's rho was obtained to determine the correlation between OHCA incidents and AED locations.ResultsA total of 654 consecutive public location OHCAs and all 1704 non-medical facility AEDs registered in the study area were included in the analysis. High OHCA incident areas lacking AEDs were identified in the kernel-density surface map. OHCA event/AED correlation analysis showed a weak correlation (Spearman's rho = 0.283; p = 0.002). Events occurred most frequently at locations categorized as “In Cars/Roads/Parking lots” (190/654, 29.1%) and there were no identified AEDs for these areas. AEDs were placed most frequently in “Public business/Office/Workplace” and cardiac arrests occurred with the second highest frequency in this location type.ConclusionThere was a weak correlation between OHCA events and deployed AEDs. It was possible to identify areas where OHCAs occurred frequently but AEDs were lacking. The ability to correlate the sites of OHCAs and AED locations is a necessary step toward improving the effectiveness of public access defibrillation.     

Survival after Public Access Defibrillation in Stockholm,Sweden – A striking success

BackgroundIn Stockholm, a first responder system and a Public Access Defibrillation (PAD) program has been implemented. Additionally, the number of “unregulated” public Automated External Defibrillators (AEDs) sold “over-the-counter” has increased. The aim of this study was to evaluate the impact on survival from different defibrillation strategies in cases of out-of-hospital cardiac arrest (OHCA) available for PAD.Methods and ResultsDesign: Retrospective study of all OHCAs in Stockholm, 2006–2012. Witnessed OHCAs occurring outside home with cardiac origin and ventricular fibrillation were considered subjects for PAD. The sites within the PAD program increased from 60 to 135 while the number of unregulated AEDs outside the PAD program increased from 178 to 5016.Of 6532 OHCAs, 7% (n = 474) were defined as subjects for PAD. Of these, 69% (n = 326) were defibrillated by the EMS, 11% (n = 53) by first responders and 16% (n = 74) by public AEDs. Survival to one month was 31% (n = 101) for cases defibrillated by the EMS, 42% (n = 22) when defibrillated by first responders and 70% (n = 52) when defibrillated by a public AED. The AEDs within the PAD program constituted 2.6% of all public AEDs and were used in 28% (n = 21) of cases when a public AED was used.ConclusionsIn OHCAs available for PAD, 70% of patients survived if a public AED was used. Both the structured AED program as well as the spread of unregulated AEDs was associated with very high survival rates, but the structured approach was more efficient in relation to the number of AEDs used.     

Engaging a whole community in resuscitation

BackgroundSurvival after out-of-hospital cardiac arrest (OHCA) is influenced by each link in the chain of survival. On the Danish island of Bornholm (population 42,000, area 588 km²) none survived an OHCA in 2001–2003. Therefore, we designed a multifaceted community-based approach aiming at strengthening each link in the chain of survival.The purpose of this study was to evaluate the effect of implementation of the intervention on bystander basic life support (BLS) rates and survival to hospital discharge after OHCA.MethodsLaypersons completed 24-min DVD-based-self-instruction BLS courses in schools and workplaces or 4-h BLS/automated external defibrillator (AED) courses. The local television station had broadcasts about resuscitation. The ambulance personnel were trained and the staff at the island hospital completed BLS courses or more advanced courses.ResultsDuring 2 years 9226 people (22% of the population) completed the short course and 2453 (6% of the population) completed the 4-h course. The number of AEDs increased from 3 to 147. The bystander BLS rate for OHCAs with a presumed cardiac aetiology (N = 96, incidence 114/100,000 person-years) was 47% [95% CI 30–50] and for witnessed OHCAs (N = 35) it increased significantly from 22% (2004) to 74% [95% CI 58–86]. The AEDs were deployed in 9 cases. Survival to discharge for all-rhythms OHCA was 5.4% [95% CI 2–12], and for witnessed ventricular fibrillation (N = 17) 18% [95% CI 5–42].ConclusionStrengthening all links in the chain of survival was associated with significant increases in bystander BLS rates and survival after OHCA on a rural island.     

Treatment and outcome of out-of-hospital cardiac arrest in outpatient health care facilities

AimWe evaluated the frequency and effectiveness of basic and advanced life support (ALS) interventions by medical professionals when out-of-hospital cardiac arrest (OHCA) occurred in ambulatory healthcare clinics before emergency medical services (EMS) arrival.MethodsNon-traumatic OHCAs in adults were systematically characterized over a 15 year period by their occurrence in clinics, at home, or in non-medical public locations, and outcomes compared between matched cohorts from each group.ResultsAmong 7784 patients, 6098 OHCA occurred at home, 1612 in non-medical public locations and 74 in clinics. Compared to non-medical public locations, clinic patients with OHCA were older, more often women and more frequently shocked; clinic arrests were more often witnessed, less likely to be of cardiac cause and to occur before EMS arrival. Compared to home, more clinic arrests were witnessed, occurred after EMS arrival, had bystander CPR, shockable rhythms and were defibrillated. When OHCA occurred before EMS arrival, 51 of 56 clinic patients (91%) received CPR, a defibrillator applied to 23 (41%), 17 (30%) were shocked, 4 (7%) intubated, and 7 (13%) received intravenous medications from facility personnel. Of these, only pre-EMS defibrillator use was associated with improved outcome. Among matched patients, OHCA survival was higher in clinics than at home (42% vs 26%, p = 0.029), but comparable to other public locations.ConclusionsSurvival from OHCA in clinics was comparable to non-medical public locations, and higher than at home. Alongside CPR, use of defibrillators was associated with improved survival and worth prioritizing over other interventions before EMS arrival regardless of OHCA location.     

Characteristics of lifesaving from drowning as reported by the Swedish Fire and Rescue Services 1996-2010

AimWe aimed to describe characteristics associated with rescue from drowning as reported by the Swedish Fire and Rescue Services (SFARS) and their association with survival from the Out of Hospital Cardiac Arrest (OHCA) registry.MethodThis retrospective study is based on the OHCA registry and the Swedish Civil Contingencies Agency (SCCA) registry. All emergency calls (1996–2010) where the SFARS were dispatched were included (n = 7175). For analysis of survival, OHCAs that matched events from the SCCA registry were included (n = 250).ResultsCalls to lakes and ponds were predominant (35% of all calls reported). Rescues were more likely in cold water, <10 °C (45%), in open water (80%) and in April–September (68%). Median delay from a call to arrival of rescue services was 8 min, while it was 9 min for rescue diving units.Of all OHCA cases, the victim was found at the surface in 47% and underwater in 38%. In events where rescue divers were used, victims were significantly younger than in non-diving cardiac arrests and the mean diving depth was 6.3 ± 5.8 m. Overall survival to one month was 5.6% (13% in diving and 4.7% in non-diving cases; p = 0.07).ConclusionIn half of more than 7000 drowning-related calls to the SFARS during 15 years of practice, water rescue was needed. In all treated OHCA cases, the majority were found at the surface. Only in a small percentage did rescue diving take place. In these cases, survival did not appear to be poorer than in non-diving cases.     

Comparison of out-of-hospital cardiac arrest occurring before and after paramedic arrival: Epidemiology,survival to hospital discharge and 12-month functional recovery

BackgroundDespite immediate resuscitation, survival rates following out-of-hospital cardiac arrests (OHCA) witnessed by emergency medical service (EMS) are reportedly low. We sought to compare survival and 12-month functional recovery outcomes for OHCA occurring before and after EMS arrival.MethodsBetween 1st July 2008 and 30th June 2013, we included 8648 adult OHCA cases receiving an EMS attempted resuscitation from the Victorian Ambulance Cardiac Arrest Registry, and categorised them into five groups: bystander witnessed cases ± bystander CPR, unwitnessed cases ± bystander CPR, and EMS witnessed cases. The main outcomes were survival to hospital and survival to hospital discharge. Twelve-month survival with good functional recovery was measured in a sub-group of patients using the Extended Glasgow Outcome Scale (GOSE).ResultsBaseline and arrest characteristics differed significantly across groups. Unadjusted survival outcomes were highest among bystander witnessed cases receiving bystander CPR and EMS witnessed cases, however outcomes differed significantly between these groups: survival to hospital (46.0% vs. 53.4% respectively, p < 0.001); survival to hospital discharge (21.1% vs. 34.9% respectively, p < 0.001). When compared to bystander witnessed cases receiving bystander CPR, EMS witnessed cases were associated with a significant improvement in the risk adjusted odds of survival to hospital (OR 2.02, 95% CI: 1.75–2.35), survival to hospital discharge (OR 6.16, 95% CI: 5.04–7.52) and survival to 12 months with good functional recovery (OR 5.56, 95% CI: 4.18–7.40).ConclusionWhen compared to OHCA occurring prior to EMS arrival, EMS witnessed arrests were associated with significantly higher survival to hospital discharge rates and favourable neurological recovery at 12-month post-arrest.     

Association of emergent and elective percutaneous coronary intervention with neurological outcome and survival after out-of-hospital cardiac arrest in patients with and without a history of heart disease

BackgroundIt is unclear whether the benefits of post-resuscitative percutaneous coronary intervention (PCI) are equally observed across out-of-hospital cardiac arrests (OHCAs) with different clinical presentations. The purpose of this study was to assess the effect of PCI in outcomes of OHCA and to compare patient prognosis by history of heart disease (HD) and presentations of nonshockable vs. shockable arrest rhythm by electrocardiogram (ECG).MethodsA population-based observational study was conducted on OHCAs of cardiac etiology in Korea who survived to admission between 2009 and 2013. Multivariable logistic regression analyses were conducted to assess the associations between PCI and outcomes (favorable neurological outcome and survival-to-discharge) and to test the interaction effects of PCI with history of HD and with presence of shockable rhythm.ResultsA total of 9762 OHCAs were analyzed. PCI was done in 1140 (11.7%), and neurological recovery were observed in 45.7% of the PCI group and 13.3% of the untreated group. Effects of PCI on neurological recovery were observed similarly in patients with and without history of HD (OR = 2.33 (1.62–3.35) and OR = 2.37 (1.95–2.89), respectively). PCI was associated with survival-to-discharge only in patients without history of HD (OR = 1.80 (1.51–2.15)). PCI was associated with neurological recovery and survival-to-discharge in both shockable and nonshockable rhythms, although the estimates were relatively higher in those with nonshockable rhythms (OR for neurological recovery = 2.60 (2.04–3.32); and OR for survival = 1.78 (1.46–2.17)).ConclusionsThis study corroborates that PCI is an advantageous treatment option for all patients with OHCA regardless of established diagnosis with HD and presentations of shockable rhythm.     

Urban and rural differences in out-of-hospital cardiac arrest in Ireland

BackgroundMore than a third of Ireland's population lives in a rural area, defined as the population residing in all areas outside clusters of 1500 or more inhabitants. This presents a challenge for the provision of effective pre-hospital resuscitation services. In 2012, Ireland became one of three European countries with nationwide Out-of-Hospital Cardiac Arrest (OHCA) register coverage. An OHCA register provides an ability to monitor quality and equity of access to life-saving services in Irish communities.AimTo use the first year of national OHCAR data to assess differences in the occurrence, incidence and outcomes of OHCA where resuscitation is attempted and the incident is attended by statutory Emergency Medical Services between rural and urban settings.MethodsThe geographical coordinates of incident locations were identified and co-ordinates were then classified as ‘urban’ or ‘rural’ according to the Irish Central Statistics Office (CSO) definition.Results1798 OHCA incidents were recorded which were attended by statutory Emergency Medical Services (EMS) and where resuscitation was attempted. There was a higher percentage of male patients in rural settings (71% vs. 65%; p = 0.009) but the incidence of male patients did not differ significantly between urban and rural settings (26 vs. 25 males/100,000 population/year p = 0.353). A higher proportion of rural patients received bystander cardiopulmonary resuscitation (B-CPR) 70% vs. 55% (p ≤ 0.001), and had defibrillation attempted before statutory EMS arrival (7% vs. 4% (p = 0.019), respectively). Urban patients were more likely to receive a statutory EMS response in 8 min or less (33% vs. 9%; p ≤ 0.001). Urban patients were also more likely to be discharged alive from hospital (6% vs. 3%; p = 0.006) (incidence 2.5 vs. 1.1/100,000 population/year; p ≤ 0.001).Multivariable analysis of survival showed that the main variable of interest i.e. urban vs. rural setting was also independently associated with discharge from hospital alive (OR 3.23 (95% CI 1.43–7.31)).ConclusionThere are significant disparities in the incidence of resuscitation attempts in urban and rural areas. There are challenges in the provision of services and subsequent outcomes from OHCA that occur outside of urban areas requiring novel and innovative solutions. An integrated community response system is necessary to improve metrics around OHCA response and outcomes in rural areas.     

The combined use of mechanical CPR and a carry sheet to maintain quality resuscitation in out-of-hospital cardiac arrest patients during extrication and transport

BackgroundQuality of manual cardiopulmonary resuscitation (CPR) during extrication and transport of out-of-hospital cardiac arrest victims is known to be poor. Performing manual CPR during ambulance transport poses significant risk to the attending emergency medical services crew. We sought to use pre-hospital video recording to objectively analyse the impact of introducing mechanical CPR with an extrication sheet (Autopulse, Zoll) to an advanced, second-tier cardiac arrest response team.MethodsThe study was conducted prospectively using defibrillator downloads and analysis of pre-hospital video recording to measure the quality of CPR during extrication from scene and ambulance transport of the OHCA patient. Adult patients with non-traumatic OHCA were included. The interruption to manual CPR to during extrication and to deploy the mechanical CPR device was analysed.ResultsIn the manual CPR group, 53 OHCA cases were analysed for quality of CPR during extrication. The median time that chest compression was interrupted to allow the patient to be carried from scene to the ambulance was 270 s (IQR 201–387 s). 119 mechanical CPR cases were analysed. The median time interruption from last manual compression to first Autopulse compression was 39 s (IQR 29–47 s). The range from last manual compression to first Autopulse compression was 14–118 s.ConclusionMechanical CPR used in combination with an extrication sheet can be effectively used to improve the quality of resuscitation during extrication and ambulance transport of the refractory OHCA patient. The time interval to deploy the mechanical CPR device can be shortened with regular simulation training.     

Interventional strategies associated with improvements in survival for out-of-hospital cardiac arrests in Singapore over 10 years

AimWe aim to study if there has been an improvement in survival for Out-of-Hospital Cardiac Arrest (OHCA) in Singapore, the effects of various interventional strategies over the past 10 years, and identify strategies that contributed to improved survival.MethodsRates of OHCA survival were compared between 2001–2004 and 2010–2012, using nationwide data for all OHCA presenting to EMS and public hospitals. A multivariate logistic regression model for survival to discharge was constructed to identify strategies with significant impact.ResultsA total of 5453 cases were included, 2428 cases from 2001 to 2004 and 3025 cases from 2010 to 2012. There was significant improvement in Utstein (witnessed, shockable) survival to discharge from 2001–2004 (2.5%) to 2010–2012 (11.0%), adjusted odds ratio (OR) 9.6 [95% CI: 2.2–41.9]). Overall survival to discharge increased from 1.6% to 3.2% (adjusted OR 2.2 [1.5–3.3]). Bystander CPR rates increased from 19.7% to 22.4% (p = 0.02). The multivariate regression model (adjusted for important non-modifiable risk factors) showed that response time <8 min (OR 1.5 [1.0–2.3]), bystander AED (OR 5.8 [2.0–16.2]), and post-resuscitation hypothermia (OR 30.0 [11.5–78.0]) were significantly associated with survival to hospital discharge. Conversely, pre-hospital epinephrine (OR 0.6 [0.4–0.9]) was associated negatively with survival.ConclusionsOHCA survival has improved in Singapore over the past 10 years. Improvement in response time, public AEDs and post-resuscitation hypothermia appear to have contributed to the increase in survival. Singapore's experience might suggest that developing EMS systems should focus on reducing times to basic life support, including bystander defibrillation and post-resuscitation care.     

Primary respiratory arrest recognised by emergency medical technicians and followed by cardiac arrest in Japan: identification of a subgroup of EMT-witnessed cardiac arrests with an extremely poor outcome

ReviewSome unconscious patients are found to be in primary respiratory arrest (PRA) by emergency medical technicians (EMTs). In contrast to citizens, EMTs manage PRA with artificial ventilation but not with cardiopulmonary resuscitation (CPR). This study aimed to investigate the characteristics and outcomes of PRA prior to EMT arrival and compare these data with those of a PRA-related group: patients with out-of-hospital cardiac arrests (OHCAs).MethodsBaseline data were prospectively collected by fire departments for their adult (16 years or older) OHCA and PRA patients from April 2003 through March 2010. We extracted those who had PRA prior to EMT arrival. The EMT- and bystander-witnessed OHCA patients who underwent CPR were also extracted as control groups.ResultsThere were 178 cases of PRA prior to EMT arrival. The majority (164/178) of these individuals were in a deep coma and met the criteria for the initiation of bystander CPR. Approximately 61% (108/178) of these PRAs were followed by cardiac arrests, which were classified as EMT-witnessed OHCAs by the Utstein template. The EMTs manually ventilated the patients until the cardiac arrest occurred. The 1-Y survival of this subgroup was the lowest of the PRA and PRA-related OHCA subgroups and was significantly lower than that of bystander-witnessed OHCAs with bystander CPR, when trauma and terminal illness cases were excluded (adjusted odds ratio = 3.888 (1.103–24.827)).ConclusionsWe identified a subgroup of PRAs with unexpectedly poor outcomes. The BLS guidelines for healthcare providers including EMTs should be re-evaluated by a large prospective study.     

Derivation and initial application of a standard population for out-of-hospital cardiac arrest (SPOHCA)

AimWhile adjusting data for age, sex, race and/or socio-economic status is well established in out-of-hospital cardiac arrest (OHCA) research, there are shortcomings to reporting and comparing population-based OHCA outcomes. The purpose of this study was to derive a case-based standard population specific to EMS treated adult OHCA (SPOHCA) in the U.S., and demonstrate its application.MethodsThe proposed SPOHCA was developed from three sources of multi-site OHCA data: the Cardiac Arrest Registry to Enhance Survival (CARES); the National EMS Information System (NEMSIS); and a published report from the Resuscitation Outcomes Consortium (ROC). OHCA data from a single EMS system were then used to demonstrate the application of SPOHCA. We report raw survival, population-based survival adjusted to the U.S. population, and the new SPOHCA-adjusted survival.ResultsObserved raw survival was 12.3%. Adjustment to the demographic make-up of the adult U.S. population produced an adjusted incidence of 94.2 OHCA per 100,000 p-y, with a survival rate of 9.8 per 100,000 p-y. Using the proposed SPOHCA to adjust survival data produced an adjusted survival rate of 12.4%.ConclusionA case-based standard population provides for more practical interpretation of reported OHCA outcomes. We encourage a more widespread effort involving multiple stakeholders to further explore the effects of adjusting OHCA outcomes using the proposed SPOHCA instead of population-based demographics.     

The impact of a pre-hospital critical care team on survival from out-of-hospital cardiac arrest

AimTo assess the impact of a pre-hospital critical care team (CCT) on survival from out-of-hospital cardiac arrest (OHCA).MethodsWe undertook a retrospective observational study, comparing OHCA patients attended by advanced life support (ALS) paramedics with OHCA patients attended by ALS paramedics and a CCT between April 2011 and April 2013 in a single ambulance service in Southwest England. We used multiple logistic regression to control for an anticipated imbalance of prognostic factors between the groups. The primary outcome was survival to hospital discharge. All data were collected independently of the research.Results1851 cases of OHCA were included in the analysis, of which 1686 received ALS paramedic treatment and 165 were attended by both ALS paramedics and a CCT. Unadjusted rates of survival to hospital discharge were significantly higher in the CCT group, compared to the ALS paramedic group (15.8% and 6.5%, respectively, p < 0.001). After adjustment using multiple logistic regression, the effect of CCT treatment was no longer statistically significant (OR 1.54, 95% CI 0.89–2.67, p = 0.13). Subgroup analysis of OHCA with first monitored rhythm of ventricular fibrillation or pulseless ventricular tachycardia showed similar results.ConclusionPre-hospital critical care for OHCA was not associated with significantly improved rates of survival to hospital discharge. These results are in keeping with previously published studies. Further research with a larger sample size is required to determine whether CCTs can improve outcome in OHCA.     

Prognostic implication of out-of-hospital cardiac arrest in patients with cardiogenic shock and acute myocardial infarction

ObjectivesTo compare outcome in patients with acute myocardial infarction (MI) and cardiogenic shock (CS) presenting with and without out-of-hospital cardiac arrest (OHCA).BackgroundDespite general improvement in outcome after acute MI, CS remains a leading cause of death in acute MI patients with a high 30-day mortality rate. OHCA on top of cardiogenic shock may further increase mortality in these patients resulting in premature withdrawal of supportive therapy, but this is not known.Methods and resultsIn a retrospective study from 2008 to 2013, 248 consecutive patients admitted alive to a tertiary centre with the diagnosis of CS and acute MI were enrolled, 118 (48%) presented with OHCA and 130 (52%) without (non-OHCA patients). Mean lactate level at admission was significantly higher in OHCA patients compared with non-OCHA patients (9 mmol/l (SD 6) vs. 6 mmol/l (SD 4) p < 0.0001). Co-morbidities were more prevalent in the non-OHCA group. By univariate analysis age (Hazard ratio (HR) = 1.02 [CI 1.00–1.03], p = 0.01) and lactate at admission (HR = 1.06 [CI 1.03–1.09], p < 0.001), but not OHCA (HR = 1.1 [CI 0.8–1.4], p = NS) was associated with mortality. In multivariate analysis, only age (HR = 1.02 [CI 1.01–1.04], p = 0.003) and lactate level at admission (HR = 1.06 [1.03–1.09], p < 0.001) were independent predictors of mortality. One-week mortality was 63% in the OHCA group and 56% in the non-OHCA group, p = NS.ConclusionOHCA is not an independent predictor of mortality in patients with acute MI complicated by cardiogenic shock. This should encourage active intensive treatment of CS patients regardless of OHCA.     

Prospective determination of medical necessity for ambulance transport by paramedics

ObjectiveIt has been estimated that between 11% and 61% of ambulance transports to emergency departments are not medically necessary. This study's objective was to analyze paramedic ability to determine the medical necessity of ambulance transport to the emergency department.MethodsParamedics prospectively assessed adult patients transported to an emergency department during a six-week period. The setting was an urban, all advanced life support, public utility model emergency medical services (EMS) system with 58,000 transports per year. Paramedics determined medical necessity of patient transport based on the following five criteria: 1) need for out-of-hospital intervention; 2) need for expedient transport; 3) potential for self-harm; 4) severe pain; or 5) other. On arrival in the emergency department, the emergency physician made a blinded determination based on the same criteria. Kappa statistics were used to assess agreement.ResultsData forms were completed on 825 of 1,420 (58%) patients transported. Emergency physicians determined 248 (30%) transports were not necessary, paramedics 236 (29%), with agreement in 76.2% (K = 0.42) of cases. Paramedics undertriaged 92 patients (11%). Rates of agreement on the five criteria were: 1) 71.9% (K = 0.43); 2) 77.7% (K = 0.22); 3) 89.6% (K = 0.40); 4) 89.6 (K = 0.32); and 5) 82.2% (K = 0.29).ConclusionsParamedics and emergency physicians agreed that a significant percentage of patients did not require ambulance transport to the emergency department. Despite only moderate agreement regarding which patients needed transport, the undertriage rate was low.     

Rise and Shock: Optimal Defibrillator Placement in a High-rise Building

Objective: Out-of-hospital cardiac arrests (OHCA) in high-rise buildings experience lower survival and longer delays until paramedic arrival. Use of publicly accessible automated external defibrillators (AED) can improve survival, but “vertical” placement has not been studied. We aim to determine whether elevator-based or lobby-based AED placement results in shorter vertical distance travelled (“response distance”) to OHCAs in a high-rise building. Methods: We developed a model of a single-elevator, n-floor high-rise building. We calculated and compared the average distance from AED to floor of arrest for the two AED locations. We modeled OHCA occurrences using floor-specific Poisson processes, the risk of OHCA on the ground floor (λ₁) and the risk on any above-ground floor (λ). The elevator was modeled with an override function enabling direct travel to the target floor. The elevator location upon override was modeled as a discrete uniform random variable. Calculations used the laws of probability. Results: Elevator-based AED placement had shorter average response distance if the number of floors (n) in the building exceeded three quarters of the ratio of ground-floor OHCA risk to above-ground floor risk (λ₁/λ) plus one half (n ≥ 3λ₁/4λ + 0.5). Otherwise, a lobby-based AED had shorter average response distance. If OHCA risk on each floor was equal, an elevator-based AED had shorter average response distance. Conclusions: Elevator-based AEDs travel less vertical distance to OHCAs in tall buildings or those with uniform vertical risk, while lobby-based AEDs travel less vertical distance in buildings with substantial lobby, underground, and nearby street-level traffic and OHCA risk.     

Advantage of CPR-first over call-first actions for out-of-hospital cardiac arrests in nonelderly patients and of noncardiac aetiology

AimTo assess the benefit of immediate call or cardiopulmonary resuscitation (CPR) for survival from out-of-hospital cardiac arrests (OHCAs).MethodsOf 952,288 OHCAs in 2005–2012, 41,734 were bystander-witnessed cases without prehospital involvement of physicians but with bystander CPR (BCPR) on bystander's own initiative. From those OHCAs, we finally extracted the following three call/BCPR groups: immediate Call + CPR (N = 10,195, emergency call/BCPR initiated at 0 or 1 min after witness, absolute call–BCPR time interval = 0 or 1 min), immediate Call-First (N = 1820, emergency call placed at 0 or 1 min after witness, call-to-BCPR interval = 2–4 min), immediate CPR-First (N = 5446, BCPR initiated at 0 or 1 min after witness, BCPR-to-call interval = 2–4 min). One-month neurologically favourable survivals were compared among the groups. Critical comparisons between Call-First and CPR-First groups were made considering arrest aetiology, age, and bystander–patient relationship after confirming the interactions among variables.ResultsThe overall survival rates in immediate Call + CPR, Call-First, and CPR-First groups were 11.5, 12.4, and 11.5%, respectively without significant differences (p = 0.543). Subgroup analyses by multivariate logistic regression following univariate analysis disclosed that CPR-first group is more likely to survive in subgroups of noncardiac aetiology (adjusted odds ratio; 95% confidence interval, 2.01; 1.39–2.98) and of nonelderly OHCAs (1.38; 1.09–1.76).ConclusionsImmediate CPR-first action followed by an emergency call without a large delay may be recommended when a bystander with sufficient skills to perform CPR witnesses OHCAs in nonelderly people and of noncardiac aetiology.     

Interaction effects between hypothermia and diabetes mellitus on survival outcomes after out-of-hospital cardiac arrest

ObjectivesMild therapeutic hypothermia (MTH) is the core hospital intervention to enhance neurological outcome after out-of-hospital cardiac arrest (OHCA). Diabetes mellitus (DM) has been known to be a harmful risk factor on survival after OHCA. This study aimed to investigate whether the effect of MTH on brain recovery after OHCA differed between patients with or without DM.MethodsWe used a Korean national OHCA database composed of hospital and ambulance data. We included adult OHCA patients who survived to admission with presumed cardiac etiology during the study period from 2009 to 2013. We excluded cases without hospital outcome data. The primary exposure was MTH, which included all kinds of cooling methods that had been initiated within 6 h after return of spontaneous circulation. DM was coded positive when the patient had a clinical history diagnosed by a physician before an OHCA event. The endpoints were discharge with good neurological recovery (cerebral performance category 1 or 2) and survival to discharge. We compared outcomes between MTH vs. non-MTH groups using multivariable logistic regression with an interaction term between MTH and DM for calculating adjusted odds ratios (AORs) and 95% confidence intervals (CIs) after adjusting for potential confounders.ResultsAmong 9735 patients following OHCA survived to hospital admission with cardiac etiology, MTH was performed in 16.5%. History of DM was observed in 25.4% among MTH group and 27.4% in non-MTH group (p = 0.09). MTH group showed better outcomes than non-MTH group; 23.6% vs. 15.7% for good neurological recovery (p < 0.01). AOR (95% CI) of MTH for good neurological recovery for all study groups was 1.23 (1.03–1.47). In the interaction model, AOR (95% CI) of MTH for good neurological recovery was 1.40 (1.16–1.70) in patients without DM vs. 0.69 (0.46–1.04) in patients with DM. For survival to discharge, the effects of MTH were different in patients without DM (1.97 (1.70–2.29)) and patients with DM (1.23 (0.96–1.57)).ConclusionDM modified the effect of MTH on survival and neurological outcomes for OHCA survivors. MTH is significantly associated with good neurological recovery in patients without DM, but not in patients with DM.     

Impact of time to return of spontaneous circulation on neuroprotective effect of targeted temperature management at 33 or 36 degrees in comatose survivors of out-of hospital cardiac arrest

AimTime to Return of Spontaneous Circulation (ROSC) has a plausible relation to severity of hypoxic injury before and during resuscitation in Out-of-Hospital Cardiac Arrest (OHCA), and has consistently been associated with adverse outcome. The effect of Targeted Temperature Management (TTM) may not be similar over the full spectrum of time to ROSC. This study investigated the possible beneficial effect of targeting 33 °C over 36 °C on the prognostic importance of time to ROSC.MethodsIn predefined sub-study of the TTM-trial (NEJM 2013) we investigated the relationship between time to ROSC, level of TTM and mortality and neurological outcome as assessed by the Cerebral Performance Category (CPC) scale and modified Rankin Scale (mRS) after 180 days.ResultsProlonged time to ROSC was significantly associated with increased mortality with a hazard ratio (HR) of 1.02 per minute (95% CI 1.01–1.02). Level of TTM did not modify the association of time to ROSC and mortality, p_interaction = 0.85. Prolonged time to ROSC was associated with reduced odds of surviving with a favorable neurological outcome for CPC (p = 0.008 for CPC 1–2) and mRS (p = 0.17, mRS 0–3) with no significant interaction with level of TTM.ConclusionTime to ROSC remains a significant prognostic factor in comatose OHCA patients with regards to risk of death and risk of adverse neurological outcome. For any time to ROSC, targeting 33 °C in TTM was not associated with benefit with regards to reducing mortality or risk of adverse neurological outcome compared to targeting 36 °C.