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Introduction: Controlled ventilation is important in OHCA resuscitation, but there are few validated methods for accurate detection of ventilations. We sought to utilize changes in thoracic impedance (TI) to characterize resuscitation ventilations in the Pragmatic Airway Resuscitation Trial (PART). Methods: We analyzed CPR process files collected from adult OHCA enrolled in PART. We limited the analysis to cases with simultaneous capnography ventilation recordings at the Dallas-Ft Worth site. We identified ventilation waveforms in the thoracic impedance signal by applying automated signal processing with adaptive filtering techniques to remove overlying artifacts from chest compressions. We correlated detected ventilations with the end-tidal capnography signal. We determined the amplitudes (Ai, Ae) and durations (Di, De) of both insufflation and exhalation phases of the ventilation impedance signal (Figure 1). We compared differences between laryngeal tube (LT) and endotracheal intubation (ETI) airway management during mechanical or manual chest compressions using Mann-Whitney U-test. Results: We included 303 CPR process cases in the analysis; 209 manual (77 ETI, 132 LT), 94 mechanical (41 ETI, 53 LT). Ventilation Ai and Ae were higher for ETI than LT in both manual (ETI: Ai 0.71Ω, Ae 0.70Ω vs LT: Ai 0.46Ω Ae 0.45Ω, p Conclusion: Compared with LT, ETI thoracic impedance ventilation insufflation and exhalation amplitude were higher while duration did not differ. TI may provide a novel approach to characterizing ventilation during OHCA.

Objective: Compared with traditional out-of-hospital cardiac arrest (OHCA) trial outcomes such as hospital survival, alternative outcomes such as intensive care unit-free (IFD) and ventilator-free days (VFD) have potential advantages including requiring smaller sample sizes to detect significant differences. Few studies have evaluated these outcomes in OHCA. We sought to evaluate the utility and validity of IFD and VFD as candidate outcomes for OHCA trials. Methods: We analyzed data from the Pragmatic Airway Resuscitation Trial (PART), which tested laryngeal tube (LT) vs. endotracheal intubation (ETI) airway strategies in adult OHCA. We defined IFD as the number of days alive and permanently out of ICU during the first 30 days after the OHCA event. We examined IFD distribution and correlation with Modified Rankin Scale (MRS). To test associations with trial interventions, we applied a range of analytic strategies, including modeling IFD as continuous (Generalized Estimating Equations - GEE), non-parametric (Wilcoxon Rank-Sum test - WRS) and count (zero-inflated negative binomial regression - ZINB) data. We also modeled time-to-ICU discharge using a survival model with death as a competing risk. We repeated the analysis assessing VFD. Results: IFD was available for 2,898 of 3,004 patients. IFD was skewed and J-shaped; 91% IFD=0 and 5.3% IFD≥22. Mean (±SD) IFD was 2.0±6.6 days; 21.2±7.5 days for survivors. IFD varied by intervention (LT 2.4±7.2, ETI 1.6±5.8 days). IFD and VFD strongly correlated with MRS (ρ= -0.88, -0.89). LT was associated with increased IFD using GEE, WRS, and ZINB, but not competing risks model. (Table) LT was associated with increased VFD using GEE and WRS, but not ZINB or competing risks models. Conclusion: IFD and VFD differentiated OHCA interventions, suggesting their utility. IFD and VFD were highly correlated with MRS, suggesting validity. IFD and VFD have important features that may influence OHCA trial design.

Introduction: Current patterns of use of coronary angiography (CAG) among out-of-hospital cardiac arrest (OHCA) patients based on ST segment elevation (STE) on post-resuscitation ECG are not well described. Methods: Using data from the Continuous Chest Compressions trial between 2011 and 2016, we identified OHCA patients who survived to hospitalization. We examined rates of CAG across different trial clusters in the overall cohort and among pre-specified subgroups with presumed cardiac etiology of arrest e.g. initial shockable rhythm and STE on presenting ECG. Results: Of 26,148 OHCA patients across 49 trial clusters, 5608 survived to hospital admission. The mean age of patients was 64 years, with 65% men and 43% with initial shockable rhythm. Among patients with initial shockable rhythm 44% had STE on initial ECG compared with 18% of patients with initial non-shockable rhythm. Use of CAG was significantly higher in patients presenting with STE compared with no STE on initial ECG irrespective of initial rhythm: 70% vs. 31%, pFigure ). This variation persisted among pre-specified subgroups with the proportion of patients within a trial cluster receiving CAG ranged from 11% - 75% for patients with initial shockable rhythm, 0% to 19% with initial non-shockable rhythm, 16% - 82% with STE, 2% - 28% without STE and 0% - 63% in patients with initial shockable rhythm and no STE on presenting ECG ( Figure ). Conclusion: There is a higher use of CAG in STE and shockable cardiac arrest, consistent with presumed cardiac etiology of arrest; however, there is large variation in the use of CAG across sites, even among patients with a presumed cardiac etiology of cardiac arrest suggesting challenges with interpretation of current guidelines.

Background: Bystander cardiopulmonary resuscitation (B-CPR) delivery and survival from sudden cardiac arrest (SCA) varies at the neighborhood-level with poorer outcomes seen in predominantly black neighborhoods. Despite Latinos being the fastest growing minority population in the US, few studies have assessed whether the proportion of Latinos in a neighborhood is associated with B-CPR delivery and survival from SCA. Objective: We sought to assess whether there is variation in B-CPR rates and survival by neighborhood-level ethnicity. We hypothesized that neighborhoods with a higher proportion of Latinos are associated with lower B-CPR rates and lower survival. Methods: We conducted a retrospective cohort study, using data from the Resuscitation Outcomes Consortium (ROC) Epistry Registry US sites. Neighborhoods were classified by census tract, based on percentage of Latino residents: < 25%, 25%-50%, 51%-75%, or > 75%. We independently modelled the likelihood of receipt of layperson B-CPR and survival by neighborhood-level ethnicity controlling for site and patient-level confounding characteristics. Results: From 2011-2015, ROC collected 27,481 US arrest events; after excluding pediatric arrests, those witnessed by EMS, or occurred in a healthcare or institutional facility, 18,544 were included. B-CPR was administered in 37% events. Among neighborhoods with 75% Latino residents. B-CPR delivery varied by patient ethnicity with Latinos being less likely to receive B-CPR compared to Whites (OR: 0.73 (CI: 0.62-0.88), p75% Latino: OR: 0.75 (CI: 0.62-0.90), p75% Latino: OR: 0.62 (CI: 0.47-0.81), p Conclusion: Individuals in predominantly Latino neighborhoods were less likely to receive B-CPR and had lower likelihood of survival. These findings could inform future messaging around B-CPR educational initiatives targeting largely Latino neighborhoods.

Background: There is an urgent need to identify strategies which improve outcomes for out-of-hospital cardiac arrest (OHCA). Determining the optimal access route to deliver medications during resuscitation from OHCA may be one such strategy. Methods: Using data from the Continuous Chest compression trial between 2011 and 2016, we examined rates of sustained return of spontaneous circulation (ROSC) i.e. ROSC on ER arrival, survival to discharge and survival with favorable neurological function (modified Rankin scale ≤3) among patients with attempted IV and IO access. Results: Among 19,731 patients with available access information, IO or IV access was attempted in 3,068 (15.5%) and 16,663 (84.5%) patients, respectively and was successful in 2,975 (97%) and 15,485 (92%) of these patients. Overall, patients with attempted IO access were younger, more likely female, received less bystander CPR, had lower proportions of shockable and witnessed arrests, marginally faster times to access and to epinephrine administration, and less frequently received therapeutic hypothermia and coronary angiography as compared with patients with IV access ( Table ) . Unadjusted rates of sustained ROSC, discharge survival and survival with favorable neurological function were significantly lower in patients with attempted IO access ( Table) . After adjustment for age, sex, initial rhythm, bystander CPR, public location, witnessed status, EMS response time and trial cluster, attempted IO access was associated with lower sustained ROSC rates (OR 0.79, 95% CI 0.71-0.89, p Conclusions: Among patients with OHCA, intraosseous access was attempted in 1 in 7 OHCA patients and associated with worse ROSC rates but no difference in survival. Further studies are necessary to elucidate the optimal access route among OHCA patients.

Background: Previous studies examining sex-based differences among out-of-hospital cardiac arrest (OHCA) patients have been conflicting. Methods: Patients with OHCA enrolled in the Continuous Chest Compression trial between 2011 and 2016 were included in the present analysis. Hierarchical multivariable logistic regression models were constructed to evaluate the association between sex and sustained ROSC i.e. ROSC on ER arrival, discharge survival and survival with favorable neurological function after adjustment for age, witnessed status, presenting rhythm, public location, bystander CPR, resuscitation duration, and EMS response time. Results: Among 22,540 OHCA patients, 8,099 (35.9%) were women. Women were older (median 71 vs. 67 years), received less bystander CPR (45% vs. 47%), and had a lower proportion of cardiac arrests that were witnessed (39% vs. 45%) or had an initial shockable rhythm (15% vs. 28%, pTable ) but no difference in likelihood of discharge survival and survival with favorable neurological function. In the adjusted landmark analysis beginning after achieving ROSC, women had significantly lower likelihood of discharge survival and survival with favorable neurological function ( Table ) . Conclusions: Among resuscitated OHCA patients, women have a higher likelihood of achieving sustained ROSC despite a higher burden of poor prognostic factors. However, after successful ROSC, the likelihood of discharge survival is significantly lower in women (vs. men). Future studies are needed to understand how care provided post-ROSC may modify the sex-disparities in discharge survival outcomes.

Background The Utstein elements provide measures for comparing out-of-hospital cardiac arrest (OHCA) care and outcomes within and across communities. Whether these measures sufficiently predict survival and explain variation in outcome is not well studied. Hypotheses Utstein data elements predict survival to hospital discharge but explain only a portion of survival variation. Methods Design Prospective, population-based cohort using uniform data definitions. Setting Ten North American sites participating in the Resuscitation Outcomes Consortium, a prehospital emergency care network. Population Persons ≥ 20 years with OHCA from 12/1/2005 – 11/30/2006 (n=9582). Analyses We used logistic regression to assess association between Utstein elements and survival and to determine whether they accounted for site survival differences. We evaluated measures of residual variance to assess what proportion of outcome variation the Utstein elements predicted. Results Survival was 7.0% overall. Utstein elements were associated with survival (Table ). Relationships were similar when restricted to those with ventricular fibrillation. In analyses assessing variance of residuals, Utstein elements collectively accounted for 15% of variation in survival. Site was also associated with survival, ranging from 3.7% to 15.6%. In multivariable analyses, site association was not attenuated by adjusting for Utstein elements. Conclusion Although Utstein elements predict survival, they account for a modest portion of variation overall and do not explain survival differences across sites. Additional factors should be investigated to understand and potentially improve OHCA outcome.