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Background: The Utstein population is defined by non-traumatic, bystander-witnessed out-of-hospital cardiac arrest (OHCA) presenting with ventricular fibrillation (VF). It is used to compare resuscitation performance across emergency medical services (EMS) systems. We hypothesized there being a system-specific survival correlation between the current Utstein and other VF populations inclusive of unwitnessed and EMS-witnessed VF OHCA that supports expanding performance metrics to this more comprehensive population that is more representative of the actual community burden of VF OHCA. Methods: We performed a cohort investigation of all non-traumatic, VF OHCA in the Cardiac Arrest Registry to Enhance Survival from 1/1/2013-12/31/2018 among EMS agencies that treated >=100 VF OHCA. We evaluated sample size and survival with the addition of the new VF populations. We used the Pearson coefficient to assess the correlation of agency-specific survival between the current Utstein population and unwitnessed and EMS-witnessed VF OHCA. Results: A total of 107 EMS agencies treated 38,836 VF arrests: 22,918 current Utstein, 11,297 unwitnessed VF, and 4621 EMS-witnessed VF OHCA. Overall, survival was 29.8% (11,567/38,836): 33.9% (7,774/22,918) among current Utstein, 17.2% (1942/11,297) among unwitnessed VF, and 40.1% (1851/4621) among EMS-witnessed VF. For agency-specific survival outcome, the Pearson correlation was 0.52 between current the Utstein population versus combined unwitnessed and EMS-witnessed groups. For survival with Cerebral Performance Category 1-2, the Pearson correlation was 0.61. Conclusion: Expanding the Utstein population to include unwitnessed and EMS-witnessed VF OHCA achieves a simpler, more inclusive case definition that minimizes variability in case determination and increases the number of survivors and eligible population by ~50%, while still achieving a distinguishing metric of system-specific performance.

Background— Dispatcher-assisted cardiopulmonary resuscitation (DA-CPR), in which 9-1-1 dispatchers provide CPR instructions over the telephone, has been shown to nearly double the rate of bystander CPR. We sought to identify factors that hampered the identification of cardiac arrest by 9-1-1 dispatchers and prevented or delayed the provision of dispatcher-assisted CPR chest compressions. Methods and Results— We reviewed dispatch recordings for 476 out-of-hospital cardiac arrests occurring between January 1, 2011, and December 31, 2011. We found that the dispatcher correctly identified cardiac arrest in 80% of reviewed cases and 92% of cases in which they were able to assess patient consciousness and breathing. The median time to recognition of the arrest was 75 seconds. Chest compressions following dispatcher-assisted CPR instructions occurred in 62% of cases when the dispatcher had the opportunity to asses for consciousness and breathing and bystander CPR was not already started. The median time to first dispatcher-assisted CPR chest compression was 176 seconds. Conclusions— Dispatchers are able to accurately diagnose cardiac arrest over the telephone, but recognition is likely not possible in all circumstances. In some cases, recognition of cardiac arrest may be improved through training in the detection of agonal respirations. Delays in the delivery of dispatcher-assisted CPR chest compressions are common and are attributable to a mixture of dispatcher behavior and factors beyond the control of the dispatcher. Performance standards for the successful and quick recognition of cardiac arrest and delivery of first chest compressions should be adopted as metrics against which emergency medical services systems can measure their performance.

Background— Out-of-hospital cardiac arrest (OHCA) claims millions of lives worldwide each year. OHCA survival from shockable arrhythmias (ventricular fibrillation/ tachycardia) improved in several communities after implementation of American Heart Association resuscitation guidelines that eliminated “stacked” shocks and emphasized chest compressions. “Nonshockable” rhythms are now the predominant presentation of OHCA; the benefit of such treatments on nonshockable rhythms is uncertain. Methods and Results— We studied 3960 patients with nontraumatic OHCA from nonshockable initial rhythms treated by prehospital providers in King County, Washington, over a 10-year period. Outcomes during a 5-year intervention period after adoption of new resuscitation guidelines were compared with the previous 5-year historical control period. The primary outcome was 1-year survival. Patient demographics and resuscitation characteristics were similar between the control (n=1774) and intervention (n=2186) groups, among whom 471 of 1774 patients (27%) versus 742 of 2186 patients (34%), respectively, achieved return of spontaneous circulation; 82 (4.6%) versus 149 (6.8%) were discharged from hospital, 60 (3.4%) versus 112 (5.1%) with favorable neurological outcome; 73 (4.1%) versus 135 (6.2%) survived 1 month; and 48 (2.7%) versus 106 patients (4.9%) survived 1 year (all P ≤0.005). After adjustment for potential confounders, the intervention period was associated with an improved odds of 1.50 (95% confidence interval, 1.29–1.74) for return of spontaneous circulation, 1.53 (95% confidence interval, 1.14–2.05) for hospital survival, 1.56 (95% confidence interval, 1.11–2.18) for favorable neurological status, 1.54 (95% confidence interval, 1.14–2.10) for 1-month survival, and 1.85 (95% confidence interval, 1.29–2.66) for 1-year survival. Conclusion— Outcomes from OHCA resulting from nonshockable rhythms, although poor by comparison with shockable rhythm presentations, improved significantly after implementation of resuscitation guideline changes, suggesting their potential to benefit all presentations of OHCA.

Background— The dissemination and use of automated external defibrillators (AEDs) beyond traditional emergency medical services (EMS) into the community has not been fully evaluated. We evaluated the frequency and outcome of non-EMS AED use in a community experience. Methods and Results— The investigation was a cohort study of out-of-hospital cardiac arrest cases due to underlying heart disease treated by public access defibrillation (PAD) between January 1, 1999, and December 31, 2002, in Seattle and surrounding King County, Washington. Public access defibrillation was defined as out-of-hospital cardiac arrest treated with AED application by persons outside traditional emergency medical services. The EMS of Seattle and King County developed a voluntary Community Responder AED Program and registry of PAD AEDs. During the 4 years, 475 AEDs were placed in a variety of settings, and more than 4000 persons were trained in cardiopulmonary resuscitation and AED operation. A total of 50 cases of out-of-hospital cardiac arrest were treated by PAD before EMS arrival, which represented 1.33% (50/3754) of all EMS-treated cardiac arrests. The proportion treated by PAD AED increased each year, from 0.82% in 1999 to 1.12% in 2000, 1.41% in 2001, and 2.05% in 2002 ( P =0.019, test for trend). Half of the 50 persons treated with PAD survived to hospital discharge, with similar survival for nonmedical settings (45% [14/31]) and out-of-hospital medical settings (58% [11/19]). Conclusions— PAD was involved in only a small but increasing proportion of out-of-hospital cardiac arrests.

Introduction: The act of conducting a research study could potentially improve quality of care by focusing providers on the study condition or detract from care by distracting providers with complex protocols. We hypothesized that odds of receiving bystander cardiopulmonary resuscitation (CPR) would be higher during a trial of dispatcher-assisted CPR instructions than during periods immediately before and after. Methods: The investigation was a cohort study of 8,626 adult subjects who suffered non-traumatic out-of-hospital cardiac arrest prior to emergency medical services (EMS) arrival in greater King County, Washington, between January 1, 1999, and December 31, 2011. Bystander CPR status was assessed through review of audio dispatch tapes and EMS reports to classify any bystander CPR (any B-CPR). Any B-CPR was further categorized as bystander CPR with dispatcher assistance (DA-CPR) or bystander CPR without dispatcher assistance (B-CPR, no DA). We used multivariable logistic regression to evaluate the odds of any B-CPR before, during, and after the Dispatcher Assisted Resuscitation Trial (DART), a randomized trial of dispatcher-assisted CPR instruction comparing chest compressions alone with compressions plus rescue breaths, which ran from June 1, 2004, to September 30, 2009. We also evaluated whether the odds varied by type-specific B-CPR. Results: Patient and arrest circumstances were similar across the study periods. Compared to the period before DART, odds of receiving any B-CPR were higher during DART (OR=1.35, 95% CI = 1.23-1.49), but no different after OR=1.11, 0.98-1.25). Similarly, compared to the before period, the odds of DA-CPR were higher during DART (OR=1.79, 1.59-2.02) but no different after (OR=0.94, 0.80-1.10) (Table 1). Discussion: Odds of bystander CPR were higher during the study compared to periods before and after. The increase seems to be largely related to higher likelihood of DA-CPR, suggesting a possible community-wide benefit from this research protocol.

Background The incidence of sudden cardiac death is roughly 3 times greater in men than in women. However, in patients treated for out-of-hospital cardiac arrest, the relationships between sex and survival after adjustment for age and cardiac rhythm are unclear. Methods and Results In this retrospective cohort study, we examined 7069 men and 2582 women who were treated for out-of-hospital cardiac arrest in Seattle and suburban King County between 1990 and 1998. We compared successful prehospital resuscitation (hospital admission) and survival from event to discharge in men and women. Women had markedly reduced rates of ventricular fibrillation (VF), slightly older age, fewer witnessed arrests, and fewer arrests in public locations than men. Although their unadjusted resuscitation rate was lower (29% versus 32%, P P P Conclusions The lower unadjusted resuscitation and survival rates observed in women were primarily due to women’s lower incidence of VF, a relatively favorable cardiac rhythm. After adjustment for VF and other factors, women had higher resuscitation rates than men, but similar rates of survival from event to discharge.

Background —The purpose of this study was to describe the public locations of cardiac arrest and to estimate the annual incidence of cardiac arrest per site to determine optimal placement of automatic external defibrillators (AEDs). This was a retrospective cohort study. Methods and Results —Locations of cardiac arrest were abstracted from data collected by emergency medical service programs in Seattle and King County, Washington, from January 1, 1990, through December 31, 1994. Types of commercial and civic establishments were tallied and grouped into 23 location categories consistent with Standard Industrial Codes, and the number of sites within each location category was determined. With the addition of “public outdoors” and “automobiles” as categories, there were 25 location categories. During the study period, 7185 arrests occurred, 1130 (16%) of which were in public locations. An annual incidence of cardiac arrest per site was calculated. Ten location categories with 172 sites were identified as having a higher incidence of cardiac arrest (≥.03 per year per site). Thirteen location categories had a lower incidence of arrest (≤.01 per year per site). There were ≈71 000 sites within these categories. Conclusions —Placement of 276 AEDs in the 172 higher-incidence sites would have provided treatment for 134 cardiac arrest patients in a 5-year period, 60% of whom were in ventricular fibrillation. We estimate between 8 and 32 lives could be saved in 5 years. To cover the remaining 347 arrests occurring in public in a 5-year period, defibrillators would have to be placed in 71 000 sites, not including outdoors and automobiles. Placement of AEDs in public locations can be guided by the site-specific incidence of arrest.

Background— Little is known about the long-term survival effects of type-specific bystander cardiopulmonary resuscitation (CPR) in the community. We hypothesized that dispatcher instruction consisting of chest compression alone would be associated with better overall long-term prognosis in comparison with chest compression plus rescue breathing. Methods and Results— The investigation was a retrospective cohort study that combined 2 randomized trials comparing the short-term survival effects of dispatcher CPR instruction consisting either of chest compression alone or chest compression plus rescue breathing. Long-term vital status was ascertained by using the respective National and State death records through July 31, 2011. We performed Kaplan-Meier method and Cox regression to evaluate survival according to the type of CPR instruction. Of the 2496 subjects included in the current investigation, 1243 (50%) were randomly assigned to chest compression alone and 1253 (50%) were randomly assigned to chest compression plus rescue breathing. Baseline characteristics were similar between the 2 CPR groups. During the 1153.2 person-years of follow-up, there were 2260 deaths and 236 long-term survivors. Randomization to chest compression alone in comparison with chest compression plus rescue breathing was associated with a lower risk of death after adjustment for potential confounders (adjusted hazard ratio, 0.91; 95% confidence interval, 0.83–0.99; P =0.02). Conclusions— The findings provide strong support for long-term mortality benefit of dispatcher CPR instruction strategy consisting of chest compression alone rather than chest compression plus rescue breathing among adult patients with cardiac arrest requiring dispatcher assistance.

John Stewart comments that recent Guideline changes aimed at increasing CPR should consider whether a manual or automated external defibrillator (AED) is used, since interruptions are more common with the AED, and that future studies should consider defibrillator type as a potential confounder. Science suggests that the ideal resuscitation is one where CPR is not interrupted for rhythm analysis, charge, or pulse checks. The benefit of AED achieved by decreasing the interval from collapse to defibrillation …

Background— Little is known about temporal trends in survival and prognostic characteristics of patients with out-of-hospital cardiac arrest treated by emergency medical services (EMS). We hypothesized that an evolving combination of beneficial and adverse factors may contribute to temporal patterns of survival. Methods and Results— We evaluated a population-based cohort of EMS-treated adult patients with cardiac arrest (n=12 591) from 1977 to 2001 in King County, Washington. Time was grouped into an initial 5-year period and 5 successive 4-year periods. We sought to determine the potential impact of temporal changes in prognostic factors typically beyond EMS control termed “fate” factors (for example, patient age) and factors implemented by EMS termed “program” factors (programs of dispatcher-assisted cardiopulmonary resuscitation and basic life support defibrillation). Several characteristics associated with survival changed over time. Observed survival did not change over time among all patients with cardiac arrest (OR=0.98 [0.95, 1.01], trend for each successive time period) and improved over time among patients with witnessed ventricular fibrillation (OR=1.05 [1.01, 1.09]). In models that included all patients with cardiac arrest and controlled for fate factors, advancing time period was associated with an increase in survival (OR=1.08 [1.05, 1.11]). Conversely, in models that controlled for program factors, advancing time period was associated with a decrease in survival (OR=0.95 [0.93, 0.98]). Results were similar among patients with witnessed ventricular fibrillation. Conclusions— The static temporal pattern of survival from cardiac arrest appeared to result from an evolving balance of prognostic factors. Programs implemented by EMS appeared to counter adverse temporal trends in prognostic factors typically beyond EMS control.