Out-of-hospital Cardiac Arrest Location Research Articles

Gender-specific differences in return-to-spontaneous circulation and outcome after out-of-hospital cardiac arrest: Results of sixteen-year-state-wide initiatives

AimSeveral studies reported a lower proportion of laypeople cardio-pulmonary resuscitation (CPR) in female victims of out-of-hospital cardiac arrest (OHCA). We aimed to verify how sixteen-years of state-wide initiatives impacted on gender-differences in OHCA treatment and survival. MethodsAll the 2481 consecutive OHCAs of presumed cardiac origin occurred between 2002 and 2018 in the Swiss Ticino Canton and in which a resuscitation was attempted, were included. Emergency medical system (EMS)-witnessed OHCAs were excluded. ResultsTime from call to CPR decreased from 9-min in 2002–2006 to 5-min in 2015–2018 (p<0.01) and until 2014, it was longer in women. Survival to discharge increased overall from 11% in 2002–2006 to 23% in 2015–2018 (p<0.001) related to telephone-assisted CPR development (period 2011–2014) and first responder and layperson recruitment via a mobile application (period 2015–2018). In males, survival increased from 12% to 25% (p=0.001) with a statistically significant increase in odds of survival in 2007–2010 (OR 1.6 95%CI 1.1–2.3; p=0.001), in 2011–2014 (OR 2 95%CI 1.4–2.8; p=0.001), and in 2015–2018 (2.4 95%CI 1.7–3.3; p=0.001) compared to 2002–2006. On the other hand, in females, survival increased from 7% to 18% (p<0.001), with a corresponding increase in the odds of survival of almost 3 times from 2002–2006 to 2015–2018 time period (OR 2.9 95%CI 1.5–5.8, p=0.001). No difference in survival probability was observed according to gender when adjusted for age, presenting rhythm, year-groups, OHCA location, EMS arrival time, witnessed status and laypeople-CPR. ConclusionsState-wide initiatives can significantly increase the chances of survival in both male and female victims of OHCAs, by increasing the probability to receive CPR in a shorter time span.

Pre-hospital factors and survival after out-of-hospital cardiac arrest according to population density, a nationwide study

AimThis study aimed to examine the impact of population density on bystander cardiopulmonary resuscitation (CPR) and survival after out-of-hospital cardiac arrest (OHCA). MethodsThrough the Danish Cardiac Arrest Registry (2001–2013), OHCAs ≥18 years of presumed cardiac cause were identified, and divided according to the OHCA location in four population density groups (inhabitants/km2) based on urban/rural area-definitions: low (<300/km2), medium (300–1499/km2), high (1500–2999/km2), very high (>3000/km2). The association between population density, bystander cardiopulmonary resuscitation (CPR) and survival was examined using logistic regression, adjusted for age, sex, comorbitidies and calendar-year. Results18,248 OHCAs were identified. Patients in areas of high compared to low population density were older, more often female, had more comorbidities, more witnessed arrests (very high: 59.6% versus low: 55.0%), shorter response time (very high: 10min versus low: 14min), but less bystander CPR (very high: 34.3% versus low: 45.1%). Thirty-day survival was higher in areas of higher population density (very high: 10.2% vs. low 5.3%), also in best-cases of witnessed arrests with bystander CPR and response time <10min (very high: 33.6% versus low: 13.8%). The same trends were found in adjusted analyses with lower odds for bystander CPR (odds ratio [OR] 0.55 95% confidence interval [CI] 0.46–0.66) and higher odds for 30-day survival (OR 2.78, 95%CI 1.95–3.96) in the highest population density areas compared to low. ConclusionsHaving an OHCA in higher populated areas were found associated with less bystander CPR, but higher survival. Identification of area-related factors can help target future pre-hospital care.

Smartphone Activation of Citizen Responders to Facilitate Defibrillation in Out-of-Hospital Cardiac Arrest

BackgroundDispatching citizen responders through a smartphone application (app) holds the potential to increase bystander cardiopulmonary resuscitation (CPR) and defibrillation in out-of-hospital cardiac arrest (OHCA). ObjectivesThis study investigated arrival at the OHCA location of app-dispatched citizen responders before the Emergency Medical Services (EMS) and the association with bystander CPR and bystander defibrillation. MethodsSuspected OHCAs with alerted citizen responders from September 1, 2017, to August 31, 2018, were included. Citizen responders located 1.8 km (1.1 miles) from the OHCA were dispatched to start CPR or retrieve an automated external defibrillator. OHCAs where at least 1 citizen responder arrived before EMS were compared with OHCAs where EMS arrived first. In both groups, random bystanders could be present before the arrival of citizen responders and the EMS. Primary outcomes were bystander CPR and bystander defibrillation, which included CPR and defibrillation by citizen responders and random bystanders. ResultsCitizen responders were alerted in 819 suspected OHCAs, of which 438 (53.5%) were confirmed cardiac arrests eligible for inclusion. At least 1 citizen responder arrived before EMS in 42.0% (n = 184) of all included OHCAs. When citizen responders arrived before EMS, the odds for bystander CPR increased (odds ratio: 1.76; 95% confidence interval: 1.07 to 2.91; p = 0.027) and the odds for bystander defibrillation more than tripled (odds ratio: 3.73; 95% confidence interval: 2.04 to 6.84; p < 0.001) compared with OHCAs in which citizen responders arrived after EMS. ConclusionsArrival of app-dispatched citizen responders before EMS was associated with increased odds for bystander CPR and a more than 3-fold increase in odds for bystander defibrillation. (The HeartRunner Trial; NCT03835403)

Public access defibrillators: Gender-based inequities in access and application

AimWhile public access automated external defibrillator (AED) programs appear to improve outcomes in out-of-hospital cardiac arrest (OHCA) it is unclear if men and women benefit equally. We examined gender-based differences in OHCA location to determine what proportion were potentially eligible for public access AED application, and if patient gender was associated with AED utilization. MethodsWe analyzed data from the Resuscitation Outcomes Consortium registry (2011–2015). We compared differences in OHCA locations by gender. We fit multivariate logistic regression models, restricted to public location OHCAs and public-location cases with bystander intervention, to calculate the association between gender and public access AED application. ResultsAmong 61 473 cases, 34% were female and 50% had bystander resuscitation. The incidence of public OHCA was 8.8% for women and 18% for men (risk difference 9.2%, 95% CI 8.7–9.7%). Women had significantly fewer OHCAs on roadways, in public buildings, places of recreation, and farms, but more in homes, non-acute healthcare facilities, and residential institutions. Female gender was associated with a lower odds of AED application in public OHCA (adjusted OR 0.76, 95% CI 0.64–0.90) and public-location cases with bystander interventions (adjusted OR 0.83, 95% CI 0.71–0.99). ConclusionWomen had fewer OHCA in public locations that may have public access AEDs. Even among public location OHCA with bystander interventions, women were less likely to have public access AED applied. Initiatives to optimize AED locations and to engage the public with gender-specific resuscitation training may improve outcomes in women with OHCA.

Abstract 411: Location of Collapse is Independently Associated With Initial Rhythm and Survival in Out-Of-Hospital Cardiac Arrest

Introduction: Out-of-hospital cardiac arrest (OHCA) at a home location is associated with lower rates of shockable initial rhythm (SIR) and survival than OHCA at a public location. While this is generally attributed to unfavourable resuscitation characteristics, it might also be explained by differences in pre-existing disease or medication use between patients with OHCA at home and those in public. We compared medical history and medication use between home and public OHCA patients, and determined whether these factors explain the association between OHCA location and SIR or survival. Methods: Data from ARREST, an OHCA registry in the Netherlands, were used (Jan 2009 - Dec 2012). We assessed the association between OHCA location and a) presence of SIR and b) survival to hospital discharge in a multivariable regression analysis taking medical history, medication use, resuscitation characteristics and demographics into account. Next, the relative contribution of the abovementioned variables to variance in both outcome measures was estimated using the Nagelkerke test. Results: In total, 1724 patients were included (1278 [74.1%] home OHCA, 446 [25.9%] public OHCA). OHCA location was significantly associated with rates of SIR (home 39.1%, public 75.1%; P &lt;0.01) and survival to hospital discharge (home 17.2%, public 47.3%; P &lt;0.01). Adding resuscitation characteristics to models of SIR rate and survival rate resulted in the largest increase in explained variance (Figure 1A and 1B), whereas adding pre-existing disease or medication use to the models resulted in only a limited increase in explained variance (Figure 1A and 1B). Conclusions: Location of OHCA remains significantly associated with lower rates of SIR and survival, even when adjusted for medical history, medication use, resuscitation characteristics and demographics; an unexplained gap remains. Both medical history and medication use only explain a modest proportion of the variance of SIR and survival.

Simulating Public Buses as a Mobile Platform for Deployment of Publicly Accessible Automated External Defibrillators

Introduction: Public access defibrillation (PAD) programs seek to optimize locations of automated external defibrillators (AEDs) to minimize the time from out-of-hospital cardiac arrest (OHCA) recognition to defibrillation. Most PAD programs have focused on static AED (S-AED) locations in high traffic areas; pervasive electronic data infrastructure incorporating real-time geospatial data opens the possibility for AED deployment on mobile infrastructure for retrieval by nearby non-passengers. Performance characteristics of such systems are not known. Hypothesis: We hypothesized that publicly accessible AEDs located on buses would increase publicly accessible AED coverage and reduce AED retrieval time relative to statically located AEDs. Methods: S-AED sites in Pittsburgh, PA were identified and consolidated to 1 AED per building for analysis (n = 582). Public bus routes and schedules were obtained from the Port Authority of Allegheny County. OHCA locations and times were obtained from the Pittsburgh site of the Resuscitation Outcomes Consortium. Two simulations were conducted to assess the characteristics and impact of AEDs located on buses. In Simulation #1, geographic coverage area of AEDs located on buses (B-AEDs) was estimated using a 1/8th mile (201 m) retrieval radius during weekday, Saturday and Sunday periods. Cumulative geographic coverage across each period of the week was compared to S-AED coverage and the added coverage provided by B-AEDs was calculated. In Simulation #2, spatiotemporal event coverage was estimated for historical OHCA events, assuming constraints designed to reflect real world AED retrieval scenarios. Event coverage and AED retrieval time were compared between B-AEDs and S-AEDs across periods of the week and residential/nonresidential spatial areas. Results: Cumulative geographic coverage by S-AEDs was 23% across all periods, assuming uniform access hours. B-AEDs alone versus B-AEDs + S-AEDs covered 20% vs. 34% (weekday), 14% + 30% (Saturday), and 10% + 28% (Sunday). There was no statistically significant difference in 3-minute historical AED accessibility between only B-AEDs and only S-AEDs in standalone deployments (12% vs. 14%). However, when allowing for retrieval of either type of AED in the same scenario, event coverage was improved to 22% (p < 0.001). Conclusion: Deployment of B-AEDs may improve AED coverage but not as a standalone deployment strategy.

Bystander cardiopulmonary resuscitation and long-term outcomes in out-of-hospital cardiac arrest according to location of arrest.

Bystander cardiopulmonary resuscitation (CPR) has increased in several countries following nationwide initiatives to facilitate bystander resuscitative efforts in out-of-hospital cardiac arrest (OHCA). We examined the importance of public or residential location of arrest on temporal changes in bystander CPR and outcomes. From the nationwide Danish Cardiac Arrest Registry, all OHCAs from 2001 to 2014 of presumed cardiac cause and between 18 and 100 years of age were identified. Arrests witnessed by emergency medical services personnel were excluded. Of 25505 OHCAs, 26.4% (n = 6738) and 73.6% (n = 18767) were in public and residential locations, respectively. Bystander CPR increased during 2001-2014 in both locations: from 36.4% [95% confidence interval (CI) 30.6-42.6%] to 83.1% (95% CI 80.0-85.8%) in public (P < 0.001) and from 16.0% (95% CI 13.2-19.3%) to 61.0% (95% CI 58.7-63.2%) in residential locations (P < 0.001). Concurrently, 30-day survival increased in public from 6.4% (95% CI 4.0-10.0%) to 25.2% (95% CI 22.1-28.7%) (P < 0.001), and in residential from 2.9% (95% CI 1.8-4.5%) to 10.0% (95% CI 8.7-11.4%) (P < 0.001). Among 2281 30-day survivors, 1-year risk of anoxic brain damage/nursing home admission during 2001-2014 decreased from 18.8% (95% CI 6.6-43.0%) to 6.8% (95% CI 3.9-11.8%) in public (P < 0.001), whereas the corresponding change was insignificant in residential locations from 11.8% (95% CI 3.3-34.3) to 17.6% (95% CI 12.7-23.9%) (P = 0.52). During 2001-2014, bystander CPR and 30-day survival more than doubled in both public and residential OHCA locations. A significant decrease in anoxic brain damage/nursing home admission was observed among 30-day survivors in public, but not among survivors from residential OHCAs.

Modeling a novel hypothetical use of postal collection boxes as automated external defibrillator access points

IntroductionOptimizing placement of Automated External Defibrillators (AED) can increase survival after an out-of-hospital cardiac arrest (OHCA). Using postal collection boxes (PCB) as locations for AEDs could potentially enhance accessibility and streamline maintenance. In this study, we modeled the hypothetical effects of deploying AEDs at PCB locations. HypothesisWe hypothesized that PCB-AEDs would increase AED coverage overall and in residential areas, and reduce the distance from OHCA to an AED. MethodsAEDs in Pittsburgh, PA were identified by the University of Pittsburgh Resuscitation Logistics and Informatics Venture (n=747). PCB locations were obtained from the United States Postal Service (n=479). OHCA locations from 2009 to 2014 were obtained from the Pittsburgh site of the Resuscitation Outcomes Consortium. AED coverage assuming a ¼ mile radius around each AED was estimated for known AEDs, PCB-AEDs (hypothetical AED locations), and known AEDs augmented by PCB-AEDs, both overall and for residential and non-residential zones. Linear distance from each OHCA to the nearest AED was calculated and compared between the sets. ResultsThe set of known AEDs augmented with PCB-AEDs covered more of the city overall (55% vs 30%), as well as greater proportions of residential (62% vs 27%) and non-residential areas (45% vs 30%). The median distance from OHCA to AED was significantly shorter when known AEDs were augmented with PCB-AEDs (0.12mi vs 0.32mi; p=0.001). ConclusionAugmenting existing publicly accessible AEDs with AEDs deployed at PCBs can increase AED spatial coverage in both residential and non-residential areas, and reduce the distance from AED to OHCA.

Measuring the impact of emergency medical services (EMS) on out-of-hospital cardiac arrest survival in a developing country: A key metric for EMS systems' performance.

Out-of-hospital cardiac arrest (OHCA) can be used to evaluate the overall performance of the emergency medical services’ (EMS) system. This study assessed the impact of EMS on OHCA survival rates in a setting where the prehospital system is underdeveloped.A retrospective chart review was carried out over a 5-year period of all adult OHCA patients admitted to the emergency department (ED) of a tertiary care center in Lebanon.A total of 271 patients with OHCA (179 [66.1%] men, mean age of 69.9 [standard deviation = 15.0 years] were enrolled. The most common OHCA location was residence/home (58.7%). The majority of arrests were witnessed (51.7%) with 6.1% witnessed by EMS; 211 patients (75.6%) were transported to the ED by EMS. Prehospital cardiopulmonary resuscitation (CPR) was done by EMS for 43.2% of the patients, whereas only 4.4% received CPR from a family member/bystander. Prehospital automated external defibrillator use was documented in 1.5% of cases in the prehospital setting. Only 2 patients had return of spontaneous circulation prior to ED arrival. Most patients (96.7%) were resuscitated in the ED. Patients presented to the ED mostly in asystole (79.3%). Forty-three patients (15.9%) survived to hospital admission and 13 (4.8%) were discharged alive with over half of them (53.8%) had a good neurological outcome upon discharge (cerebral performance category 1 or 2).Survival of EMS-treated OHCA victims in Lebanon is not as expected. Medical oversight of EMS activities is needed to link EMS activities to clinical outcomes and improve survival from cardiac arrest in Lebanon.

A Descriptive Analysis of Therapeutic Hypothermia Application Across Adult Age Groups.

Therapeutic hypothermia (TH) has been recommended for comatose adults recovering from out-of-hospital cardiac arrest (OHCA) for a decade. However, TH has never been evaluated in a randomized control trial in patients aged 75 or older. How the administration of TH varies across age groups experiencing an OHCA is unknown. The objective was to describe the use of TH across predefined age groups with an emphasis on geriatric OHCA survivors using data compiled through Cardiac Arrest Registry to Enhance Survival (CARES). We hypothesized that TH provision would decline in patients aged 75 or older. This was a secondary analysis of prospectively collected and verified registry data. The study was Institutional Review Board exempt. Through December 2013, CARES had 130,852 completed records for consideration. All nontraumatic adult index arrests of presumed cardiac etiology with attempted resuscitation were study eligible. Sustained return of spontaneous circulation with survival to hospital admission was a prerequisite for inclusion. Exclusion criteria were as follows: records before November 2010 when TH became a mandatory reporting field; pre-existing Do Not Resuscitate directive; missing TH status or outcome classification; and OHCA location and timing variables potentially affecting treatment decisions or eligibility. All records in our final sample were categorized (TH or no TH) for descriptive analysis. Our final sample size was 11,533. The percentage of patients <75 who received TH was 58.5% (95% CI: 57.5-59.6) and 46.4% (95% CI: 44.5-48.3) for those 75 or older. There was no difference in the rate of TH across the age groups from <25 to 65-74 (p = 0.205). Treatment rates significantly decreased from age 75-84 to 95+ (p < 0.001). There is a significant decline in the provision of TH at age 75 years within CARES. Further research is needed to determine if age is an independent predictor of TH underutilization in the elderly.

STATEWIDE INITIATIVES IMPROVE THE CARE AND OUTCOMES OF PATIENTS WITH OUT-OF-HOSPITAL CARDIAC ARREST AT HOME AND IN PUBLIC LOCATIONS: RESULTS FROM THE HEARTRESCUE PROJECT

Statewide public health initiatives improve bystander cardiopulmonary resuscitation (CPR) and first-responder defibrillation for out-of-hospital cardiac arrest (OHCA). Little is known about the impact of these initiatives according to OHCA location, particularly at home, where resuscitation efforts

Employment and residential characteristics in relation to automated external defibrillator locations

Survival from out-of-hospital cardiac arrest (OHCA) is generally poor and varies by geography. Variability in automated external defibrillator (AED) locations may be a contributing factor. To inform optimal placement of AEDs, we investigated AED access in a major US city relative to demographic and employment characteristics. This was a retrospective analysis of a Philadelphia AED registry (2,559 total AEDs). The 2010 US Census and the Local Employment Dynamics database by ZIP code was used. Automated external defibrillator access was calculated as the weighted areal percentage of each ZIP code covered by a 400-m radius around each AED. Of 47 ZIP codes, only 9% (4) were high-AED-service areas. In 26% (12) of ZIP codes, less than 35% of the area was covered by AED service areas. Higher-AED-access ZIP codes were more likely to have a moderately populated residential area (P = .032), higher median household income (P = .006), and higher paying jobs (P =. 008). The locations of AEDs vary across specific ZIP codes; select residential and employment characteristics explain some variation. Further work on evaluating OHCA locations, AED use and availability, and OHCA outcomes could inform AED placement policies. Optimizing the placement of AEDs through this work may help to increase survival.

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

We 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. Non-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. Among 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. Survival 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.

Trends in survival among elderly patients with out-of-hospital cardiac arrest: a prospective, population-based observation from 1999 to 2011 in Osaka

BackgroundLittle is known about the improvement in out-of-hospital cardiac arrest (OHCA) survival among elderly patients. The aim of this study was to evaluate the trends in the survival after bystander-witnessed OHCA of cardiac origin in this age group. MethodsThis prospective, population-based, observation of the whole population of Osaka, Japan included consecutive OHCA patients aged ≥65 years with emergency responder resuscitation attempts from January 1999 to December 2011. The primary outcome measure was one-month survival with neurologically favorable outcome, and the trends in the outcome from OHCA were evaluated by location. Multiple logistic regression analysis was used to assess factors that were potentially associated with neurologically favorable outcome. ResultsDuring the study period, a total of 10,876 bystander-witnessed OHCA of cardiac origin were eligible for our analyses. In whole arrests, the proportion of one-month survival with neurologically favorable outcome improved from 1.4% in 1999 to 4.8% in 2011 (P for trend <0.001). The proportion of neurologically favorable outcome in homes and public places improved from 0.7% in 1999 to 3.2% in 2011 (P for trend <0.001) and from 4.2% in 1999 to 20.9% in 2011 (P for trend <0.001), respectively, whereas, in nursing homes, the proportion of neurologically favorable outcome did not improve. In a multivariate analysis, bystander-initiated cardiopulmonary resuscitation and emergency response time were significant predictors for neurologically favorable outcome. ConclusionsIn this population, survival from OHCA among elderly patients significantly improved during the study period, but the trends differed by the OHCA location.

Abstract 182: Risk of Cardiac Arrest by Location Type to Guide Future AED Placement in a Large Urban Center

Introduction: Public access defibrillation (PAD) programs can improve survival from out-of-hospital cardiac arrest (OHCA). We aimed to identify high risk public locations which should be prioritized for automated external defibrillator (AED) placement. Objectives: 1) To determine the average annual incidence of cardiac arrest by location type within the study area, 2) To describe current registered PAD deployment by location type. Methods: An observational cohort study using the Resuscitation Outcomes Consortium Epistry database. We included all public location, non-traumatic, EMS-treated OHCAs from January 1, 2006 to June 30, 2010 in the City of Toronto. The total site counts in each location category were derived from a city planning database and used as the denominator in calculating average annual per site cardiac arrest incidence. AED locations were obtained from an EMS registry. Two investigators independently categorized each OHCA and AED location. Disagreements were resolved by consensus. Results: There were 1297 OHCAs, of which 571 occurred on streets and could not be associated with a specific location type, leaving 726 eligible cases. The average age was 58±17.5 years, 82.7% were male and 13.9% survived to hospital discharge. Of all included patients, 44.9% had bystander CPR attempted and 9.5% had a bystander apply a defibrillator. Table 1 contains data from the top 15 location types ranked on average annual OHCAs per individual site. There were 1616 AED covered locations in the City of Toronto. 57.3% of the registered AED sites were elementary and secondary schools, 16.0% were post secondary schools, 7.8% were offices and 4% were community or recreation centres. Conclusions: We have identified location types with highest risk for cardiac arrest. Most registered AEDs have been placed at Elementary and Secondary Schools which are relatively low risk for OHCA. Our data can guide future AED deployment to increase availability for use in public location OHCA.

Surrogate Markers of Transport Distance for Out-of-Hospital Cardiac Arrest Patients

Background. Transport of out-of-hospital cardiac arrest (OHCA) patients expeditiously to appropriately equipped hospitals is of paramount importance. Objective. We sought to test the correlation of the centroids of geographic units with the actual transport distance for OHCA patients in order to determine the most appropriate surrogate marker of location for future planning, protocol development, and research projects. Methods. This was a prospective, observational analysis of OHCA events in Portland, Oregon. Using geographic information systems (GISs), the locations of OHCA events and receiving hospitals were identified and geocoded for visual inspection and analysis. Transport distance was calculated via network transport distance and Euclidean distance from multiple surrogate markers of location (centroids of ZIP code, census tract, census block group, and census block). Actual distance from the location of the event was then compared with these surrogate markers to determine the accuracy of alternative markers of OHCA location. Results. Two hundred seventy patients had location data recorded, 163 of whom were transported to a hospital for further care. The median transport distance was 5.17 miles. The transport distance of OHCA patients from the centroid of the census block had the best correlation (R2 = 0.99) with actual transport distance, whereas the use of the centroid of ZIP codes as a surrogate location had the lowest correlation (R2 = 0.21). Conclusions. The use of centroids of census blocks via network distance is a valid surrogate for actual location of an OHCA event when calculating transport distance.