Outcomes for Hemodialysis Patients Given Cardiopulmonary Resuscitation for Cardiac Arrest at Outpatient Dialysis Clinics.

BACKGROUND: Out-of-hospital cardiac arrest, the leading cause of death among patients on hemodialysis, occurs frequently within outpatient dialysis centers. Practice guidelines recommend resuscitation training for all dialysis clinic staff and on-site defibrillator availability, but the extent of staff involvement in cardiopulmonary resuscitation (CPR) efforts and its association with outcomes is unknown. METHODS: We used data from the Cardiac Arrest Registry to Enhance Survival and the Centers for Medicare & Medicaid Services dialysis facility database to identify patients who had cardiac arrest within outpatient dialysis clinics between 2010 and 2016 in the southeastern United States. We compared outcomes of patients who received dialysis staff-initiated CPR with those who did not until the arrival of emergency medical services (EMS). RESULTS: Among 398 OHCA events in dialysis clinics, 66% of all patients presented with a nonshockable initial rhythm. Dialysis staff initiated CPR in 81.4% of events and applied defibrillators before EMS arrival in 52.3%. Staff were more likely to initiate CPR among men and witness cardiac arrests, and were more likely to provide CPR within larger dialysis clinics. Staff-initiated CPR was associated with a three-fold increase in the odds of hospital discharge and favorable neurologic status on discharge. There was no overall association between staff-initiated defibrillator use and outcomes, but there was a nonsignificant trend toward improved survival to hospital discharge in the subgroup with shockable initial cardiac arrest rhythms. CONCLUSIONS: Dialysis staff-initiated CPR was associated with a large increase in survival but was only performed in 81% of cardiac arrest events. Further investigations should focus on understanding the potential facilitators and barriers to CPR in the dialysis setting.

Therapeutic Hypothermia for Patients with Out-of-Hospital Cardiac Arrest in North Carolina.

INTRODUCTION: While therapeutic hypothermia has been the standard of care for patients who suffer out-of-hospital cardiac arrest (OHCA), recent trials have led to an advisory statement recommending a focus on targeted in-hospital temperature management and against initiation of prehospital hypothermia with rapid infusion of cooled saline. The aim of this study is to review the experience with therapeutic hypothermia in North Carolina. METHODS: We studied patients who suffered OHCA in North Carolina in 2012 captured in the CARES database as part of the Heart Rescue Project. We excluded patients without return of spontaneous circulation and patients without an advanced airway placed in the field to reduce selection bias. Bivariate distributions and multivariate logistic regression models were used to examine differences in survival to discharge and positive neurological outcome. RESULTS: 847 patients were included in the analysis of pre-hospital hypothermia. Of these patients, 55% received prehospital hypothermia. Prehospital initiation of hypothermia was associated with higher survival to hospital discharge (OR 1.55, 95% CI 1.03-2.32) and improved neurologic outcome at discharge (OR 1.56 95% CI 1.01-2.40). In patients who survived to hospital admission (n = 537), in-hospital hypothermia was associated with a non-significant trend toward better survival to discharge (p = 0.18). CONCLUSION: We found that patients who received prehospital hypothermia had improved outcomes, a finding that may be due to a greater likelihood of receiving in-hospital hypothermia or a reflection of higher quality of pre-hospital care. These findings support ongoing efforts to improve all aspects of the chain of survival after cardiac arrest.

Association of Bystander and First-Responder Intervention With Survival After Out-of-Hospital Cardiac Arrest in North Carolina, 2010-2013.

IMPORTANCE: Out-of-hospital cardiac arrest is associated with low survival, but early cardiopulmonary resuscitation (CPR) and defibrillation can improve outcomes if more widely adopted. OBJECTIVE: To examine temporal changes in bystander and first-responder resuscitation efforts before arrival of the emergency medical services (EMS) following statewide initiatives to improve bystander and first-responder efforts in North Carolina from 2010-2013 and to examine the association between bystander and first-responder resuscitation efforts and survival and neurological outcome. DESIGN, SETTINGS, AND PARTICIPANTS: We studied 4961 patients with out-of-hospital cardiac arrest for whom resuscitation was attempted and who were identified through the Cardiac Arrest Registry to Enhance Survival (2010-2013). First responders were dispatched police officers, firefighters, rescue squad, or life-saving crew trained to perform basic life support until arrival of the EMS. EXPOSURES: Statewide initiatives to improve bystander and first-responder interventions included training members of the general population in CPR and in use of automated external defibrillators (AEDs), training first responders in team-based CPR including AED use and high-performance CPR, and training dispatch centers in recognition of cardiac arrest. MAIN OUTCOMES AND MEASURES: The proportion of bystander and first-responder resuscitation efforts, including the combination of efforts between bystanders and first responders, from 2010 through 2013 and the association between these resuscitation efforts and survival and neurological outcome. RESULTS: The combination of bystander CPR and first-responder defibrillation increased from 14.1% (51 of 362; 95% CI, 10.9%-18.1%) in 2010 to 23.1% (104 of 451; 95% CI, 19.4%-27.2%) in 2013 (P < .01). Survival with favorable neurological outcome increased from 7.1% (82 of 1149; 95% CI, 5.8%-8.8%) in 2010 to 9.7% (129 of 1334; 95% CI, 8.2%-11.4%) in 2013 (P = .02) and was associated with bystander-initiated CPR. Adjusting for age and sex, bystander and first-responder interventions were associated with higher survival to hospital discharge. Survival following EMS-initiated CPR and defibrillation was 15.2% (30 of 198; 95% CI, 10.8%-20.9%) compared with 33.6% (38 of 113; 95% CI, 25.5%-42.9%) following bystander-initiated CPR and defibrillation (odds ratio [OR], 3.12; 95% CI, 1.78-5.46); 24.2% (83 of 343; 95% CI, 20.0%-29.0%) following bystander CPR and first-responder defibrillation (OR, 1.70; 95% CI, 1.06-2.71); and 25.2% (109 of 432; 95% CI, 21.4%-29.6%) following first-responder CPR and defibrillation (OR, 1.77; 95% CI, 1.13-2.77). CONCLUSIONS AND RELEVANCE: Following a statewide educational intervention on rescusitation training, the proportion of patients receiving bystander-initiated CPR and defibrillation by first responders increased and was associated with greater likelihood of survival. Bystander-initiated CPR was associated with greater likelihood of survival with favorable neurological outcome.

Race Differences in Interventions and Survival After Out-of-Hospital Cardiac Arrest in North Carolina, 2010 to 2014.

Background Following the implementation of the HeartRescue project, with interventions in the community, emergency medical services, and hospitals to improve care and outcomes for out-of-hospital cardiac arrests (OHCA) in North Carolina, improved bystander and first responder treatments as well as survival were observed. This study aimed to determine whether these improvements were consistent across Black versus White individuals. Methods and Results Using the Cardiac Arrest Registry to Enhance Survival (CARES), we identified OHCA from 16 counties in North Carolina (population 3 million) from 2010 to 2014. Temporal changes in interventions and outcomes were assessed using multilevel multivariable logistic regression, adjusted for patient and socioeconomic neighborhood-level factors. Of 7091 patients with OHCA, 36.5% were Black and 63.5% were White. Black patients were younger, more females, had more unwitnessed arrests and non-shockable rhythm (Black: 81.0%; White: 75.4%). From 2010 to 2014, the adjusted probabilities of bystander cardiopulmonary resuscitation (CPR) went from 38.5% to 51.2% in White, P<0.001; and 36.9% to 45.6% in Black, P=0.002, and first-responder defibrillation went from 13.2% to 17.2% in White, P=0.002; and 14.7% to 17.3% in Black, P=0.16. From 2010 to 2014, survival to discharge only increased in White (8.0% to 11.4%, P=0.004; Black 8.9% to 9.5%, P=0.60), though, in shockable patients the probability of survival to discharge went from 24.8% to 34.6% in White, P=0.02; and 21.7% to 29.0% in Black, P=0. 10. Conclusions After the HeartRescue program, bystander CPR and first-responder defibrillation increased in both patient groups; however, survival only increased significantly for White patients.

Care and outcomes of urban and non-urban out-of-hospital cardiac arrest patients during the HeartRescue Project in Washington state and North Carolina.

AIM: We examined overall and temporal differences in out-of-hospital cardiac arrest (OHCA) care and outcomes by urban versus non-urban setting separately for North Carolina (NC) and Washington State (WA) during HeartRescue initiatives and associations of urban/non-urban settings with outcome by state. METHODS: OHCAs of presumed cardiac etiology from counties with complete registry enrollment in NC during 2010-2014 (catchment population = 3,143,809) and WA during 2011-2014 (catchment population = 3,653,506) were identified. Geospatial arrest location data and US Census classification were used to categorize urban areas with ≥50,000 versus non-urban <50,000 people. RESULTS: Included were 7731 NC cases (78.9% urban) and 4472 WA cases (85.8% urban). Bystander cardiopulmonary resuscitation (CPR) increased from 36.9% (2010) to 50.3% (2014) in NC non-urban areas versus 58.2% (2011) to 69.2% (2014) in WA; and from 39.3% to 51.1% in NC urban areas versus 52.4% to 61.8% in WA. Crude discharge survival odds ratio (OR) was 2.49 (95%CI 1.96-3.16) for urban versus non-urban NC cases not declared dead in field (N = 4241). Adjusted for age, sex, public location, bystander-witness status, time between emergency call and emergency medical service (EMS) arrival, calendar-year, bystander and first-responder CPR and defibrillation and direct PCI-center transport, OR was 1.30 (95%CI 0.98-1.73). In WA, corresponding crude and adjusted ORs were 1.38 (95%CI 0.99-1.93) and 1.46 (95%CI 1.00-2.13). In both states, bystander and first-responder CPR and defibrillation and direct PCI-hospital transport were associated with increased survival. CONCLUSIONS: During HeartRescue initiatives, bystander CPR increased in urban and non-urban locations. Bystander and first-responder interventions and direct PCI-hospital transport were associated with improved outcomes, including in non-urban areas.

Association Between Driving Distance From Nearest Fire Station and Survival of Out-of-Hospital Cardiac Arrest.

Background Firefighter first responders dispatched in parallel with emergency medical services ( EMS ) personnel for out-of-hospital cardiac arrests ( OHCA ) can provide early defibrillation to improve survival. We examined whether survival following first responder defibrillation differed according to driving distance from nearest fire station to OHCA site. Methods and Results From the CARES (Cardiac Arrest Registry to Enhance Survival) registry, we identified non- EMS witnessed OHCA s of presumed cardiac cause from 2010 to 2014 in Durham, Mecklenburg, and Wake counties, North Carolina. We used logistic regression to estimate the association between calculated driving distances (≤1, 1-1.5, 1.5-2, and >2 miles) and survival to hospital discharge following first responder defibrillation compared with defibrillation by EMS personnel. In total, 5020 OHCA s were included in the study. First responders more often applied the first automated external defibrillators at the shortest distances (≤1 mile) versus longest distances (>2 miles) (53.4% versus 46.6%, respectively, P<0.001). When compared with EMS defibrillation, first responder defibrillation within 1 mile and 1 to 1.5 miles of the nearest fire station was associated with increased survival to hospital discharge (odds ratio 2.01 [95% confidence interval 1.46-2.78] and odds ratio 1.61 [95% confidence interval 1.10-2.35], respectively). However, at the longest distances (1.5-2.0 and >2.0 miles), survival following first responder defibrillation did not differ from EMS defibrillation (odds ratio 0.77 [95% confidence interval 0.48-1.21] and odds ratio 0.97 [95% confidence interval 0.67-1.41], respectively). Conclusions Shorter driving distance from nearest fire station to OHCA location was associated with improved survival following defibrillation by first responders. These results suggest that the location of first responder units should be considered when organizing prehospital systems of OHCA care.

Association of Bystander and First-Responder Efforts and Outcomes According to Sex: Results From the North Carolina HeartRescue Statewide Quality Improvement Initiative.

Background The Institute of Medicine has called for actions to understand and target sex-related differences in care and outcomes for out-of-hospital cardiac arrest patients. We assessed changes in bystander and first-responder interventions and outcomes for males versus females after statewide efforts to improve cardiac arrest care. Methods and Results We identified out-of-hospital cardiac arrests from North Carolina (2010-2014) through the CARES (Cardiac Arrest Registry to Enhance Survival) registry. Outcomes for men versus women were examined through multivariable logistic regression analyses adjusted for (1) nonmodifiable factors (age, witnessed status, and initial heart rhythm) and (2) nonmodifiable plus modifiable factors (bystander cardiopulmonary resuscitation and defibrillation before emergency medical services), including interactions between sex and time (ie, year and year2). Of 8100 patients, 38.1% were women. From 2010 to 2014, there was an increase in bystander cardiopulmonary resuscitation (men, 40.5%-50.6%; women, 35.3%-51.8%; P for each <0.0001) and in the combination of bystander cardiopulmonary resuscitation and first-responder defibrillation (men, 15.8%-23.0%, P=0.007; women, 8.5%-23.7%, P=0.004). From 2010 to 2014, the unadjusted predicted probability of favorable neurologic outcome was higher and increased more for men (men, from 6.5% [95% confidence interval (CI), 5.1-8.0] to 9.7% [95% CI, 8.1-11.3]; women, from 6.3% [95% CI, 4.4-8.3] to 7.4% [95% CI, 5.5-9.3%]); while adjusted for nonmodifiable factors, it was slightly higher but with a nonsignificant increase for women (from 9.2% [95% CI, 6.8-11.8] to 10.2% [95% CI, 8.0-12.5]; men, from 5.8% [95% CI, 4.6-7.0] to 8.4% [95% CI, 7.1-9.7]). Adding bystander cardiopulmonary resuscitation and defibrillation before EMS (modifiable factors) did not substantially change the results. Conclusions Bystander and first-responder interventions increased for men and women, but outcomes improved significantly only for men. Additional strategies may be necessary to improve survival among female cardiac arrest patients.

Impact of Early Vasopressor Administration on Neurological Outcomes after Prolonged Out-of-Hospital Cardiac Arrest.

Introduction Vasopressors are associated with return of spontaneous circulation (ROSC), but no long-term benefit has been demonstrated in randomized trials. However, these trials did not control for the timing of vasopressor administration which may influence outcomes. Consequently, the objective of this study was to develop a model describing the likelihood of favorable neurological outcome (cerebral performance category [CPC] 1 or 2) as a function of the public safety answering point call receipt (PSAP)-to-pressor-interval (PPI) in prolonged out-of-hospital cardiac arrest. Hypothesis The likelihood of favorable neurological outcome declines with increasing PPI. METHODS: This investigation was a retrospective study of cardiac arrest using linked data from the Cardiac Arrest Registry to Enhance Survival (CARES) database (Centers for Disease Control and Prevention [Atlanta, Georgia USA]; American Heart Association [Dallas, Texas USA]; and Emory University Department of Emergency Medicine [Atlanta, Georgia USA]) and the North Carolina (USA) Prehospital Medical Information System. Adult patients suffering a bystander-witnessed, non-traumatic cardiac arrest between January 2012 and June 2014 were included. Logistic regression was used to calculate the adjusted odds ratio (OR) of neurological outcome as a function of PPI, while controlling for patient age, gender, and race; endotracheal intubation (ETI); shockable rhythm; layperson cardiopulmonary resuscitation (CPR); and field hypothermia. RESULTS: Of the 2,100 patients meeting inclusion criteria, 913 (43.5%) experienced ROSC, 618 (29.4%) survived to hospital admission, 187 (8.9%) survived to hospital discharge, and 155 (7.4%) were discharged with favorable neurological outcomes (CPC 1 or 2). Favorable neurological outcome was less likely with increasing PPI (OR=0.90; P<.01) and increasing age (OR=0.97; P<.01). Compared to patients with non-shockable rhythms, patients with shockable rhythms were more likely to have favorable neurological outcomes (OR=7.61; P<.01) as were patients receiving field hypothermia (OR=2.13; P<.01). Patient gender, non-Caucasian race, layperson CPR, and ETI were not independent predictors of favorable neurological outcome. CONCLUSION: In this evaluation, time to vasopressor administration was significantly associated with favorable neurological outcome. Among adult, witnessed, non-traumatic arrests, the odds of hospital discharge with CPC 1 or 2 declined by 10% for every one-minute delay between PSAP call-receipt and vasopressor administration. These retrospective observations support the notion of a time-dependent function of vasopressor effectiveness on favorable neurological outcome. Large, prospective studies are needed to verify this relationship. Hubble MW , Tyson C . Impact of early vasopressor administration on neurological outcomes after prolonged out-of-hospital cardiac arrest. Prehosp Disaster Med. 2017; 32(3):297-304.

Association of Public Health Initiatives With Outcomes for Out-of-Hospital Cardiac Arrest at Home and in Public Locations.

Importance: Little is known about the influence of comprehensive public health initiatives according to out-of-hospital cardiac arrest (OHCA) location, particularly at home, where resuscitation efforts and outcomes have historically been poor. Objective: To describe temporal trends in bystander cardiopulmonary resuscitation (CPR) and first-responder defibrillation for OHCAs stratified by home vs public location and their association with survival and neurological outcomes. Design, Setting, and Participants: This observational study reviewed 8269 patients with OHCAs (5602 [67.7%] at home and 2667 [32.3%] in public) for whom resuscitation was attempted using data from the Cardiac Arrest Registry to Enhance Survival (CARES) from January 1, 2010, through December 31, 2014. The setting was 16 counties in North Carolina. Exposures: Patients were stratified by home vs public OHCA. Public health initiatives to improve bystander and first-responder interventions included training members of the general population in CPR and in the use of automated external defibrillators, teaching first responders about team-based CPR (eg, automated external defibrillator use and high-performance CPR), and instructing dispatch centers on recognition of cardiac arrest. Main Outcomes and Measures: Association of resuscitation efforts with survival and neurological outcomes from 2010 through 2014. Results: Among home OHCA patients (n = 5602), the median age was 64 years, and 62.2% were male; among public OHCA patients (n = 2667), the median age was 68 years, and 61.5% were male. After comprehensive public health initiatives, the proportion of patients receiving bystander CPR increased at home (from 28.3% [275 of 973] to 41.3% [498 of 1206], P < .001) and in public (from 61.0% [275 of 451] to 70.5% [424 of 601], P = .01), while first-responder defibrillation increased at home (from 42.2% [132 of 313] to 50.8% [212 of 417], P = .02) but not significantly in public (from 33.1% [58 of 175] to 37.8% [93 of 246], P = .17). Survival to discharge improved for arrests at home (from 5.7% [60 of 1057] to 8.1% [100 of 1238], P = .047) and in public (from 10.8% [50 of 464] to 16.2% [98 of 604], P = .04). Compared with emergency medical services-initiated CPR and resuscitation, patients with home OHCA were significantly more likely to survive to hospital discharge if they received bystander-initiated CPR and first-responder defibrillation (odds ratio, 1.55; 95% CI, 1.01-2.38). Patients with arrests in public were most likely to survive if they received both bystander-initiated CPR and defibrillation (odds ratio, 4.33; 95% CI, 2.11-8.87). Conclusions and Relevance: After coordinated and comprehensive public health initiatives, more patients received bystander CPR and first-responder defibrillation at home and in public, which was associated with improved survival.

Direct Transport to a Percutaneous Cardiac Intervention Center and Outcomes in Patients With Out-of-Hospital Cardiac Arrest.

BACKGROUND: Practice guidelines recommend regional systems of care for out-of-hospital cardiac arrest. However, whether emergency medical services should bypass nonpercutaneous cardiac intervention (non-PCI) facilities and transport out-of-hospital cardiac arrest patients directly to PCI centers despite longer transport time remains unknown. METHODS AND RESULTS: Using the Cardiac Arrest Registry to Enhance Survival with geocoding of arrest location, we identified out-of-hospital cardiac arrest patients with prehospital return of spontaneous circulation and evaluated the association between direct transport to a PCI center and outcomes in North Carolina during 2012 to 2014. Destination hospital was classified according to PCI center status (catheterization laboratory immediately accessible 24/7). Inverse probability-weighted logistic regression accounting for age, sex, emergency medical services response time, clustering of county, transport time to nearest PCI center, initial heart rhythm, and prehospital ECG information was performed. Of 1507 patients with prehospital return of spontaneous circulation, 1359 (90.2%) were transported to PCI centers, of whom 873 (57.9%) bypassed the nearest non-PCI hospital and 148 (9.8%) were transported to non-PCI hospitals. Discharge survival was higher among those transported to PCI centers (33.5% versus 14.6%; adjusted odds ratio, 2.47; 95% confidence interval, 2.08-2.92). Compared with patients taken to non-PCI hospitals, odds of survival were higher for patients taken to the nearest hospital with PCI center status (odds ratio, 3.07; 95% confidence interval, 1.90-4.97) and for patients bypassing closer hospitals to PCI centers (odds ratio, 3.02; 95% confidence interval, 2.01-4.53). Adjusted survival remained significantly better across transport times of 1 to 5, 6 to 10, 11 to 20, 21 to 30, and >30 minutes. CONCLUSIONS: Direct transport to a PCI center is associated with better outcomes for out-of-hospital cardiac arrest patients, even when bypassing nearest hospital and regardless of transport time.

Comparison of team-focused CPR vs standard CPR in resuscitation from out-of-hospital cardiac arrest: Results from a statewide quality improvement initiative.

BACKGROUND: Team-focused CPR (TFCPR) is a choreographed approach to cardiopulmonary resuscitation (CPR) with emphasis on minimally interrupted high-quality chest compressions, early defibrillation, discourages endotracheal intubation and encourages use of the bag-valve-mask (BVM) and/or blind-insertion airway device (BIAD) with a ventilation rate of 8-10 breaths/min to minimize hyperventilation. Widespread incorporation of TFCPR in North Carolina (NC) EMS agencies began in 2011, yet its impact on outcomes is unknown. OBJECTIVES: To determine whether TFCPR improves survival with good neurological outcome in out-of-hospital cardiac arrest (OHCA) patients compared to standard CPR. METHODS: This retrospective cohort analysis of NC EMS agencies reporting data to the Cardiac Arrest Registry for Enhanced Survival (CARES) database from January 2010 to June 2014 included adult, non-traumatic OHCA with presumed cardiac etiology where EMS performed CPR or patient received defibrillation. Exclusions were arrest terminated per EMS policy or DNR. EMS agencies self-reported the TFCPR implementation dates. Patients were categorized as receiving either TFCPR or standard CPR. The primary outcome was good neurologic outcome at time of hospital discharge defined as Pittsburgh Cerebral Performance Category (CPC) 1-2. RESULTS: Of 14,994 OHCAs, 14,129 patients were included for analysis with a mean age 65 (IQR 50-81) years, 61% male, 7.3% with good neurologic outcome, 24.3% with shockable initial rhythm, and 71.5% receiving TFCPR. Of the 3427 (24.3%) with an initial shockable rhythm, 739 (71.9%) had a good neurological outcome. Good neurologic outcome was higher with TFCPR [836 (8.3%, 95%CI 7.7-8.8%)] vs. standard CPR [193 (4.8%, 95%CI 4.2-5.5%)]. Logistic regression controlling for demographic and arrest characteristics revealed TFCPR (OR 1.5), witnessed arrest (OR 4.3), initial shockable rhythm (OR 7.1), and in-hospital hypothermia (OR 3.3) were associated with good neurologic outcome. Mechanical CPR device (OR 0.68), CPR feedback device (OR 0.47), and endotracheal intubation (OR 0.44) were associated with less likelihood for a good neurologic outcome. CONCLUSION: In our statewide OHCA cohort, TFCPR was associated with improved survival with good neurological outcome.

The role of bystanders, first responders, and emergency medical service providers in timely defibrillation and related outcomes after out-of-hospital cardiac arrest: Results from a statewide registry.

AIM: Defibrillation by bystanders and first responders has been associated with increased survival, but limited data are available from non-metropolitan areas. We examined time from 911-call to defibrillation (according to who defibrillated patients) and survival in North Carolina. METHODS: Through the Cardiac Arrest Registry to Enhance Survival, we identified 1732 defibrillated out-of-hospital cardiac arrests from counties with complete case capture (population 2.7 million) from 2010 to 2013. RESULTS: Most patients (60.9%) were defibrillated in > 10 min. A minority (8.0%) was defibrillated < 5 min; most of these patients were defibrillated by first responders (51.8%) and bystanders (33.1%), independent of location of arrest (residential or public). Bystanders initiated cardiopulmonary resuscitation (CPR) in 49.0% of cases and defibrillated 13.4% of those. Survival decreased with increasing time to defibrillation (< 2 min: 59.1%; 2 to < 5 min: 38.5%; 5-10 min: 33.1%; > 10 min: 13.2%). Odds of survival with favorable neurologic outcome adjusted for age, sex, and bystander CPR improved with faster defibrillation (<2 min: OR 7.73 [95% CI 3.19-18.73]; 2 to < 5 min: 3.78 [2.45-5.84]; 5-10 min: 3.16 [2.42-4.12]; > 10 min: reference). CONCLUSION: Bystanders and first responders were mainly responsible for defibrillation within 5 min, independent of location of arrest. Bystanders initiated CPR in half of the cardiac arrest cases but only defibrillated a minority of those. Timely defibrillation and defibrillation by bystanders and/or first responders were strongly associated with increased survival. Strategic efforts to increase bystander and first-responder defibrillation are warranted to increase survival after out-of-hospital cardiac arrest.