Utilization and cost-effectiveness of school and community center AED deployment models in Canadian cities.

BACKGROUND: The optimal locations and cost-effectiveness of placing automated external defibrillators (AEDs) for out-of-hospital cardiac arrest (OHCAs) in urban residential neighbourhoods are unclear. METHODS: We used prospectively collected data from 2016 to 2018 from the British Columbia OHCA Registry to examine the utilization and cost-effectiveness of hypothetical AED deployment in municipalities with a population of over 100 000. We geo-plotted OHCA events using seven hypothetical deployment models where AEDs were placed at the exteriors of public schools and community centers and fetched by bystanders. We calculated the "radius of effectiveness" around each AED within which it could be retrieved and applied to an individual prior to EMS arrival, comparing automobile and pedestrian-based retrieval modes. For each deployment model, we estimated the number of OHCAs within the "radius of effectiveness". RESULTS: We included 4017 OHCAs from ten urban municipalities. The estimated radius of effectiveness around each AED was 625 m for automobile and 240 m for pedestrian retrieval. With AEDs placed outside each school and community center, 2567 (64%) and 605 (15%) of OHCAs fell within the radii of effectiveness for automobile and pedestrian retrieval, respectively. For each AED, there was an average of 1.20-2.66 and 0.25-0.61 in-range OHCAs per year for automobile retrieval and pedestrian retrieval, respectively, depending on the deployment model. All of our proposed surpassed the cost-effectiveness threshold of 0.125 OHCA/AED/year provided > 5.3-11.6% in-range AEDs were brought-to-scene. CONCLUSIONS: The systematic deployment of AEDs at schools and community centers in urban neighbourhoods may result in increased application and be a cost-effective public health intervention.

Incremental gains in response time with varying base location types for drone-delivered automated external defibrillators.

INTRODUCTION: Drone-delivered automated external defibrillators (AEDs) may reduce delays to defibrillation for out-of-hospital cardiac arrests (OHCAs). We sought to determine how integration of drones and selection of drone bases between emergency service stations (i.e., paramedic, fire, police) would affect 9-1-1 call-to-arrival intervals. METHODS: We identified all treated OHCAs in southern Vancouver Island, British Columbia, Canada from Jan. 2014 to Dec. 2020. We developed mathematical models to select 1-5 optimal drone base locations from each of: paramedic stations, fire stations, police stations, or an unrestricted grid-based set of points to minimize drone travel time to OHCAs. We evaluated models on the estimated first response interval assuming that drones were integrated with existing OHCA response. We compared median response intervals with historical response, as well as across drone base locations. RESULTS: A total of 1610 OHCAs were included in the study with a historical median response interval of 6.4 minutes (IQR 5.0-8.6). All drone-integrated response systems significantly reduced the median response interval to 4.2-5.4 minutes (all P < 0.001), with grid-based stations using 5 drones resulting in the lowest response interval (4.2 minutes). Median response times between drone base location types differed by 6-16 seconds, all comparisons of which were statistically significant (all P < 0.02). CONCLUSION: Integrating drone-delivered AEDs into OHCA response may reduce first response intervals, even with a small quantity of drones. Implementing drone response with only one emergency service resulted in similar response metrics regardless of the emergency service hosting the drone base and was competitive with unrestricted drone base locations.

The association of pH values during the first 24 h with neurological status at hospital discharge and futility among patients with out-of-hospital cardiac arrest.

STUDY OBJECTIVE: Post-resuscitation prognostic biomarkers for out-of-hospital cardiac arrest (OHCA) outcomes have not been fully elucidated. We examined the association of acid-base blood values (pH) with patient outcomes and calculated the pH test performance to predict prognosis. METHODS: This was a post-hoc analysis of data from the continuous chest compression trial, which enrolled non-traumatic adult emergency medical system-treated OHCA in Canada and the United States. We examined cases who survived a minimum of 24 h post hospital arrival. The independent variables of interest were initial pH, final pH, and the change in pH (δpH). The primary outcome was neurological status at hospital discharge, with favorable status defined as modified Rankin Scale (mRS) ≤ 3. We reported adjusted odds ratios for favorable neurological outcome using multivariable logistic regression models. We calculated the test performance of increasing pH thresholds in 0.1 increments to predict unfavorable neurological status (defined as mRS >3) at hospital discharge. RESULTS: We included 4189 patients. 32% survived to hospital discharge with favorable neurological status. In the adjusted analysis, higher initial pH (OR 6.82; 95% CI 3.71-12.52) and higher final pH (OR 7.99; 95% CI 3.26-19.62) were associated with higher odds of favorable neurological status. pH thresholds with highest positive predictive values were initial pH < 6.8 (92.5%; 95% CI 86.2 %-98.8%) and final pH < 7.0 (100%; 95% CI 95.2 %-100%). CONCLUSION: In patients with OHCA, pH values were associated with patients' subsequent neurological status at hospital discharge. Final pH may be clinically useful to predict unfavorable neurological status at hospital discharge.

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

AIM: While 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. METHODS: We 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. RESULTS: Among 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). CONCLUSION: Women 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.