EMS-treated Out-of-hospital Cardiac Arrest Research Articles

Survival After Intra-Arrest Transport vs On-Scene Cardiopulmonary Resuscitation in Children

For pediatric out-of-hospital cardiac arrest (OHCA), emergency medical services (EMS) may elect to transport to the hospital during active cardiopulmonary resuscitation (CPR) (ie, intra-arrest transport) or to continue on-scene CPR for the entirety of the resuscitative effort. The comparative effectiveness of these strategies is unclear. To evaluate the association between intra-arrest transport compared with continued on-scene CPR and survival after pediatric OHCA, and to determine whether this association differs based on the timing of intra-arrest transport. This cohort study included pediatric patients aged younger than 18 years with EMS-treated OHCA between December 1, 2005 and June 30, 2015. Data were collected from the Resuscitation Outcomes Consortium Epidemiologic Registry, a prospective 10-site OHCA registry in the US and Canada. Data analysis was performed from May 2022 to February 2024. Intra-arrest transport, defined as an initiation of transport prior to the return of spontaneous circulation, and the interval between EMS arrival and intra-arrest transport. The primary outcome was survival to hospital discharge. Patients who underwent intra-arrest transport at any given minute after EMS arrival were compared with patients who were at risk of undergoing intra-arrest transport within the same minute using time-dependent propensity scores calculated from patient demographics, arrest characteristics, and EMS interventions. We examined subgroups based on age (<1 year vs ≥1 year). Of 2854 eligible pediatric patients (median [IQR] age, 1 [0-9] years); 1691 males [59.3%]) who experienced OHCA between December 2005 and June 2015, 1892 children (66.3%) were treated with intra-arrest transport and 962 children (33.7%) received continued on-scene CPR. The median (IQR) time between EMS arrival and intra-arrest transport was 15 (9-22) minutes. In the propensity score-matched cohort (3680 matched cases), there was no significant difference in survival to hospital discharge between the intra-arrest transport group and the continued on-scene CPR group (87 of 1840 patients [4.7%] vs 95 of 1840 patients [5.2%]; risk ratio [RR], 0.81 [95% CI, 0.59-1.10]). Survival to hospital discharge was not modified by the timing of intra-arrest transport (P value for the interaction between intra-arrest transport and time to matching = .10). Among patients aged younger than 1 year, intra-arrest transport was associated with lower survival to hospital discharge (RR, 0.52; 95% CI, 0.33-0.83) but there was no association for children aged 1 year or older (RR, 1.22; 95% CI, 0.77-1.93). In this cohort study of a North American OHCA registry, intra-arrest transport compared with continued on-scene CPR was not associated with survival to hospital discharge among children with OHCA. However, intra-arrest transport was associated with a lower likelihood of survival to hospital discharge among children aged younger than 1 year.

The Public Health and Economic Impact of Drug Overdose Out-of-Hospital Cardiac Arrest in the United States

Objective To calculate disability-adjusted life years (DALY) and labor productivity loss due to drug overdose out-of-hospital cardiac arrest (DO-OHCA) and compare its contribution to the burden of disease and economic impact of all-cause nontraumatic out-of-hospital cardiac arrest (OHCA) in the US. Methods We performed a retrospective observational cohort analysis of all adult (age ≥18 years) nontraumatic emergency medical services-treated OHCA events, including those due to DO-OHCA, from the national Cardiac Arrest Registry to Enhance Survival (CARES) database from January 1, 2017 and December 31, 2020. The main outcome measures of interest were disability-adjusted life years, annual, and lifetime labor productivity loss over the 4-year study period. The findings for the study population were extrapolated to a national level using the CARES population catchment and U.S. population estimates by year. Results A total of 378,088 adult OHCA events, including 23,252 DO-OHCA (6.2%) met study inclusion criteria. The DO-OHCA DALY increased from 156,707 in 2017 to 265,692 in 2020. Per year, DO-OHCA contributed to 11.4%, 12.0%, 10.5%, and 11.4% of all OHCA DALY lost from 2017-2020, respectively. The mean annual and lifetime productivity losses for all OHCA were stable over time (annual: $47K in 2017 to $50K in 2020; lifetime: $647K in 2017 to $692K in 2020). The CARES population catchment increased by 39.8% over the study period (102.6 M in 2017 to 143.4 M in 2020). For DO-OHCA, the mean annual productivity loss was approximately 30% higher than non-DO-OHCA ($64K vs. $49K in 2020, respectively). The mean lifetime productivity loss for DO-OHCA was 2.5 times higher than non-DO-OHCA ($1.6 M vs. $630K in 2020, respectively). Conclusions The DALY due to DO-OHCA has increased over time with expansion of the CARES dataset, but its relative contribution to total OHCA DALY (all non-traumatic etiologies) remained fairly stable. The DO-OHCAs represent approximately 6% of all adult non-traumatic EMS-treated OHCA events but has a disproportionately greater economic impact. Continued efforts to reduce DO-OHCA through public health initiatives are warranted to lessen the societal impact of OHCA in the U.S.

Association between out-of-hospital cardiac arrest quality indicator and prehospital management and clinical outcomes for major trauma

IntroductionIt is unclear whether emergency medical service (EMS) agencies with good out-of-hospital cardiac arrest (OHCA) quality indicators also perform well in treating other emergency conditions. We aimed to evaluate the association of an EMS agency's non-traumatic OHCA quality indicators with prehospital management processes and clinical outcomes of major trauma. MethodsThis retrospective cross-sectional study analyzed data from registers of nationwide, population-based OHCA (adult EMS-treated non-traumatic OHCA patients from 2017 to 2018) and major trauma (adult, EMS-treated, and injury severity score ≥16 trauma patients in 2018) in South Korea. We developed a prehospital ROSC prediction model to categorize EMS agencies into quartiles (Q1-Q4) based on the observed-to-expected (O/E) ROSC ratio for each EMS agency. We evaluated the national EMS protocol compliance of on-scene management according to O/E ROSC ratio quartile. The association between O/E ROSC ratio quartiles and trauma-related early mortality was determined in a multi-level logistic regression model by adjusted odds ratios (OR) and 95 % confidence intervals (95 % CI). ResultsAmong 30,034 severe trauma patients, 4,836 were analyzed. Patients in Q4 showed the lowest early mortality rate (5.6 %, 5.5 %, 4.8 %, and 3.4 % in Q1, Q2, Q3, and Q4, respectively). In groups Q1 to Q4, increasing compliance with the national EMS on-scene management protocol (trauma center transport, basic airway management for patients with altered mentality, spinal motion restriction for patients with spinal injury, and intravenous access for patients with hypotension) was observed (p for trend <0.05). Multivariable multi-level logistic regression analysis showed significantly lower early mortality in Q4 than in Q1 (adjusted OR [95 % CI] 0.56 [0.35–0.91]). ConclusionMajor trauma patients managed by EMS agencies with high success rates in achieving prehospital ROSC in non-traumatic OHCA were more likely to receive protocol-based care and exhibited lower early mortality.

Adverse Safety Events in Emergency Medical Services Care of Children With Out-of-Hospital Cardiac Arrest

Survival for children with out-of-hospital cardiac arrest (OHCA) remains poor despite improvements in adult OHCA survival. To characterize the frequency of and factors associated with adverse safety events (ASEs) in pediatric OHCA. This population-based retrospective cohort study examined patient care reports from 51 emergency medical services (EMS) agencies in California, Georgia, Oregon, Pennsylvania, Texas, and Wisconsin for children younger than 18 years with an OHCA in which resuscitation was attempted by EMS personnel between 2013 and 2019. Medical record review was conducted from January 2019 to April 2022 and data analysis from October 2022 to February 2023. Severe ASEs during the patient encounter (eg, failure to give an indicated medication, 10-fold medication overdose). A total of 1019 encounters of EMS-treated pediatric OHCA were evaluated; 465 patients (46%) were younger than 12 months. At least 1 severe ASE occurred in 610 patients (60%), and 310 patients (30%) had 2 or more. Neonates had the highest frequency of ASEs. The most common severe ASEs involved epinephrine administration (332 [30%]), vascular access (212 [19%]), and ventilation (160 [14%]). In multivariable logistic regression, the only factor associated with severe ASEs was young age. Neonates with birth-related and non-birth-related OHCA had greater odds of a severe ASE compared with adolescents (birth-related: odds ratio [OR], 7.0; 95% CI, 3.1-16.1; non-birth-related: OR, 3.4; 95% CI, 1.2-9.6). In this large geographically diverse cohort of children with EMS-treated OHCA, 60% of all patients experienced at least 1 severe ASE. The odds of a severe ASE were higher for neonates than adolescents and even higher when the cardiac arrest was birth related. Given the national increase in out-of-hospital births and ongoing poor outcomes of OHCA in young children, these findings represent an urgent call to action to improve care delivery and training for this population.

Non-prescription drug-associated out-of-hospital cardiac arrest: Changes in incidence over time and the odds of receiving resuscitation

BackgroundMultiple jurisdictions reported a significant increase in out-of-hospital cardiac arrest (OHCA) incidence over the past decade, however the reasons for this remain unclear. We investigated how drug-associated OHCA (DA-OHCA) contributed to overall OHCA incidence, and whether the likelihood of treatment by emergency medical services (EMS) was associated with DA-OHCA classification. MethodsUsing a large provincial cardiac arrest registry, we included consecutive, non-traumatic adult OHCA from 2016–2022. We classified as drug-associated if there were historical accounts of non-prescription drug use within the preceding 24 hours or evidence of paraphernalia at the scene. We examined year-by-year trends in OHCA and DA-OHCA incidence. We also investigated the association between DA-OHCA and odds of EMS treatment using an adjusted logistic regression model. ResultsOf 33,365 EMS-assessed cases, 1,985/18,591 (11%) of EMS-treated OHCA and 887/9,200 (9.6%) of EMS-untreated OHCA were DA-OHCA. Of EMS-treated DA-OHCA, the median age was 40 years (IQR 31–51), 1,059 (53%) had a known history of non-prescription drug use, and 570 (29%) were public-location. From 2016 to 2022, EMS-treated OHCA incidence increased from 60 to 79 per 100,000 person-years; EMS-treated DA-OHCA incidence increased from 3.7 to 9.1 per 100,000 person-years. The proportion of overall OHCA classified as DA-OHCA increased from 6.1% to 11.5%. DA-OHCA was associated with greater odds of EMS treatment (AOR 1.34; 95%CI 1.13–1.58). ConclusionAlthough EMS-treated DA-OHCA incidence increased by nearly three-fold, it comprised a minority of the overall OHCA increase during the study period. DA-OHCA was associated with an increased likelihood of EMS treatment.

Utility of end-tidal carbon dioxide to guide resuscitation termination in prolonged out-of-hospital cardiac arrest

Study objectiveTo evaluate if the change in end-tidal carbon dioxide (ETCO2) over time has improved discriminatory value for determining resuscitation futility compared to a single ETCO2 value in prolonged, refractory non-shockable out-of-hospital cardiac arrest (OHCA). MethodsThis is a retrospective analysis of adult refractory non-shockable, non-traumatic OHCA patients in the Portland Cardiac Arrest Epidemiologic Registry (PDX Epistry) from 2018 to 2021. We defined refractory non-shockable OHCA cases as patients with lack of a shockable rhythm at any time or return of spontaneous circulation at any time prior to 30-min of on-scene resuscitation. We abstracted ETCO2 values first recorded after advanced airway placement and nearest to the 30-min mark of on-scene resuscitation (30 min-ETCO2) from EMS charts. The primary outcome was survival to hospital discharge. We compared 30 min-ETCO2 cutoffs of 10 mmHg and 20 mmHg to the trend (increasing or not) from initial to 30 min-ETCO2 (delta-ETCO2) using sensitivity, specificity, and area under the receiver operating curves (AUROC). ResultsOf 3837 adult OHCA, 2850 were initially non-shockable, and there were 617 (16.1%) cases of refractory non-shockable OHCA at 30-min. We excluded 320 cases without at least two ETCO2 recordings in the EMS chart, leaving 297 cases that met inclusion criteria. Of these, 176 (59.3%) were transported and 2 (0.7%) survived to discharge. Using absolute 30 min-ETCO2 cutoffs, both survivors were in the >10 mmHg group (sensitivity 100.0%, specificity 12.5%), whereas only one survivor was identified in the >20 mmHg group (sensitivity 50.0%, specificity 32.5%). Using delta-ETCO2, both survivors were in the increasing ETCO2 group (sensitivity 100.0%, specificity 60.7%). In comparing the two tests that did not misclassify survivors, the AUROC [95% CI] was higher when using delta-ETCO2 (0.803 [0.775–0.831]) compared to an absolute cutoff of 10 mmHg (0.563 [0.544–0.582]). ConclusionsNearly one-sixth of EMS-treated adult OHCA patients had refractory non-shockable arrests after at least 30 min of ongoing resuscitation. In this group, the ETCO2 trend following advanced airway placement may be more accurate in guiding termination of resuscitation than an absolute ETCO2 cutoff of 10 or 20 mmHg.

Abstract 330: Severe Adverse Safety Events in Pediatric Out-of-Hospital Cardiac Arrest Resuscitation

Introduction: Survival for children with out-of-hospital cardiac arrest (OHCA) remains poor in spite of improvements in adult OHCA survival. Hypothesis: We hypothesized that severe adverse safety events (ASEs) are common during pediatric OHCA resuscitation and that specific patterns can be identified. Methods: Retrospective cohort study of patient care reports from 51 Emergency Medical Services (EMS) agencies across the US for children less than 18 years of age with an OHCA where resuscitation was attempted by EMS providers between 2013-2019. Results: We evaluated 1,019 encounters of EMS-treated pediatric OHCA; 46% were under 12 months of age. At least one severe ASE occurred in 610 patients (60%), and 310 patients (30%) had two or more. Children under 28 days of age had the highest frequency of ASEs. The most common severe ASEs involved epinephrine administration (30%), ventilation (14%), and vascular access (19%). Logistic regression modeling found that the only factor consistently associated with severe ASEs was young age. Birth-related OHCA had 4-fold greater odds of a severe ASE compared to adolescents (95% CI 1.7-10.7) and neonates with non-birth-related OHCA had 3.2-fold greater odds of a severe ASE (95% CI 1.1-9.0). Conclusions: In this large geographically diverse cohort of children with EMS-treated OHCA, 60% experienced at least one severe ASE. The odds of a severe ASE were over 3-fold higher for neonates than adolescents, and even higher when the cardiac arrest was birth-related. Given the national increase in out of hospital births and ongoing poor outcomes of OHCA in young children, these findings are an important and urgent call to action to focus on improving care delivery and training.

Abstract 421: Automated External Defibrillator Implementation Gaps in Three Non-Urban U.S. Communities

Introduction: Automated external defibrillators (AEDs) represent a crucial component of bystander response to out-of-hospital cardiac arrest (OHCA), yet epidemiologic evidence suggests that AEDs are deployed by laypersons in less than 5% of OHCA events in the US. The reasons for low utilization remain poorly characterized, especially in rural/suburban environments. We hypothesized that in these non-urban environments, layperson AED use is mostly in commercial or public locations despite most arrests occuring in private residences. Methods: We conducted an analysis of EMS-treated atraumatic OHCA events from 3 non-urban US regions (Cumberland County, PA; Jackson, TN; Forsyth County, GA), abstracted from EMS patient care reports. Data included Utstein reporting elements, arrest location type, and response intervals as calculated by dispatch and EMS arrival times. We excluded events in skilled nursing facilities and prisons. CPR and AED delivery by laypersons was measured. Results: Between 12/8/17-12/31/21, we identified 1542 adult OHCA patients with median age 66.5 y (IQR 22.5), 37% female, 18% had initial shockable rhythms, and 75% occurred in private residences. Return of spontaneous circulation was obtained in 19% of cases. Bystander CPR was performed in 23% and AEDs were deployed by laypersons in 3%. Laypersons applied AEDs in 12% of OHCA in commercial locations, 6% of OHCA in public, and 3% of OHCA in private residences. EMS response times were 4% less than 4 min, 48% 4-9 min, and 48% &gt;9 min; prevalence of AED use was indistinguishable between time intervals of EMS response. 16% OHCA victims still had initial shockable rhythms even among the &gt;9 min EMS response cases; of these, 1% received AED use from laypersons. Conclusion: In three non-urban US regions, most arrests occurred in private residences while AED use was much more likely in public or commercial locales, suggesting an important gap in AED deployment. Even in cases with prolonged response times, many patients had shockable rhythms, suggesting an important opportunity for earlier AED deployment. Future work will test whether placement of AEDs in residential areas using trained volunteer responders in these same communities will improve OHCA response and survival outcomes.

Abstract 247: Assessing Feasibility of Proposed Extracorporeal Cardiopulmonary Resuscitation Programs in Scotland via Geospatial Modelling

Introduction: Extracorporeal cardiopulmonary resuscitation (ECPR) may improve outcomes for out-of-hospital cardiac arrest (OHCA) where return of spontaneous circulation (ROSC) is not achieved. We estimated the number of patients who may benefit from proposed in-hospital or pre-hospital ECPR programs in Scotland. Methods: EMS-treated atraumatic OHCAs occurring in Scotland between Apr. 2017-Mar. 2022 were included. We identified those likely to benefit (age 16-70, initial rhythm VF/pVT, no ROSC) and those possibly likely to benefit (age 16-70, initial rhythm PEA, no ROSC) from ECPR. To achieve timely ECPR initiation within 60 mins, we computed the number of eligible OHCAs within 15 mins’ drive time surrounding each of the 3 ECPR-capable hospitals, 6 percutaneous coronary intervention (PCI)-capable hospitals, and 28 adult emergency departments (ED) for in-hospital ECPR programs. We then computed the number of eligible OHCAs within a 45-minute drive time surrounding each of the 28 EDs and 140 ambulance stations and determined locations allowing one dedicated pre-hospital ECPR service to reach the greatest number of eligible OHCAs. We accounted for service availability based on 8 and 16-hour availability on weekdays and 24/7 availability. Results: Of the 8,962 OHCAs included, 1,108 (12.3%) were classified likely to benefit, 4,675 (52.2%) possibly likely to benefit, and 3,179 (35.5%) unlikely to benefit from ECPR. In-hospital ECPR scenarios covered up to 12.5% of eligible OHCAs at ECPR-capable hospitals, 20.9% at PCI-capable hospitals, and 64.6% at all EDs. Pre-hospital ECPR scenarios with one crew covered up to 51.0% and 54.1% when based at an ED or ambulance station respectively, which were higher than respective in-hospital scenarios at ECPR-capable or PCI-capable hospitals, and were generally comparable to ECPR availability at all 28 EDs. Conclusion: A pre-hospital ECPR service can generally reach greater numbers of OHCAs compared to in-hospital ECPR programs.

The Association of Combined Prehospital Hypotension and Hypoxia with Outcomes following Out-of-Hospital Cardiac Arrest Resuscitation

Background Prehospital post-resuscitation hypotension and hypoxia have been associated with adverse outcomes in the context of out-of-hospital cardiac arrest (OHCA). We aimed to investigate the association between clinical outcomes and post-resuscitation hypoxia alone, hypotension alone, and combined hypoxia and hypotension. Methods We used the 2018–2021 ESO annual datasets to conduct this study. All EMS-treated non-traumatic OHCA patients who had a documented prehospital return of spontaneous circulation (ROSC) and two or more SpO2 readings and systolic blood pressures recorded were evaluated for inclusion. Patients who were less than 18 years of age, pregnant, had a do-not-resuscitate order or similar, achieved ROSC after bystander CPR only, or had an EMS-witnessed cardiac arrest were excluded. Multivariable logistic regression adjusted for standard Utstein factors and highest prehospital Glasgow Coma Scale (GCS) score was used to investigate the association between hypoxia, hypotension, and outcomes. Results We analyzed data for 17,943 patients, of whom 3,979 had hospital disposition data. Hypotension and hypoxia were not documented in 1,343 (33.8%) patients, 1,144 (28.8%) had only hypoxia documented, 507 (12.7%) had only hypotension documented, and 985 (24.8%) had both hypoxia and hypotension documented. In comparison to patients who did not have documented hypotension or hypoxia, patients who had documented hypoxia (aOR: 1.76 [1.38, 2.24]), documented hypotension (aOR: 3.00 [2.15, 4.18]), and documented hypoxia and hypotension combined (aOR: 4.87 [3.63, 6.53]) had significantly increased mortality. The relationship between mortality and vital sign abnormalities (hypoxia and hypotension > hypotension > hypoxia) was observed in every evaluated subgroup. Conclusions In this large dataset, hypotension and hypoxia were independently associated with mortality both alone and in combination. Compared to patients without documented hypotension and hypoxia, patients with documented hypotension and hypoxia had nearly five-fold greater odds of mortality.

Three-year trends in out-of-hospital cardiac arrest across the world: Second report from the International Liaison Committee on Resuscitation (ILCOR)

BackgroundThe International Liaison Committee on Resuscitation (ILCOR) Research and Registries Working Group previously reported data on systems of care and outcomes of out-of-hospital cardiac arrest (OHCA) in 2015 from 16 national and regional registries. To describe the temporal trends with updated data on OHCA, we report the characteristics of OHCA from 2015 through 2017. MethodsWe invited national and regional population-based OHCA registries for voluntary participation and included emergency medical services (EMS)-treated OHCA. We collected descriptive summary data of core elements of the latest Utstein style recommendation during 2016 and 2017 at each registry. For registries that participated in the previous 2015 report, we also extracted the 2015 data. ResultsEleven national registries in North America, Europe, Asia, and Oceania, and 4 regional registries in Europe were included in this report. Across registries, the estimated annual incidence of EMS-treated OHCA was 30.0–97.1 individuals per 100,000 population in 2015, 36.4–97.3 in 2016, and 40.8–100.2 in 2017. The provision of bystander cardiopulmonary resuscitation (CPR) varied from 37.2% to 79.0% in 2015, from 2.9% to 78.4% in 2016, and from 4.1% to 80.3% in 2017. Survival to hospital discharge or 30-day survival for EMS-treated OHCA ranged from 5.2% to 15.7% in 2015, from 6.2% to 15.8% in 2016, and from 4.6% to 16.4% in 2017. ConclusionWe observed an upward temporal trend in provision of bystander CPR in most registries. Although some registries showed favourable temporal trends in survival, less than half of registries in our study demonstrated such a trend.

The association of the post-resuscitation on-scene interval and patient outcomes after out-of-hospital cardiac arrest

BackgroundAfter resuscitation from out-of-hospital cardiac arrest (OHCA) by Emergency Medical Services (EMS), the amount of time that should be dedicated to pre-transport stabilization is unclear. We examined whether the time spent on-scene after return of spontaneous circulation (ROSC) was associated with patient outcomes. MethodsWe examined consecutive adult EMS-treated OHCAs from the British Columbia Cardiac Arrest registry (January 1/2019-June 1/2021) that had on-scene ROSC (sustained to scene departure). The primary outcome was favourable neurological outcome (Cerebral Performance Category ≤ 2) at hospital discharge; secondary outcomes were re-arrest during transport and hospital-discharge survival. Using adjusted logistic regression models, we estimated the association between the post-resuscitation on-scene interval (divided into quartiles) and outcomes. ResultsOf 1653 cases, 611 (37%) survived to hospital discharge, and 523 (32%) had favourable neurological outcomes. The median post-resuscitation on-scene interval was 18.8 minutes (IQR:13.0–25.5). Compared to the first post-resuscitation on-scene interval quartile, neither the second (adjusted odds ratio [AOR] 1.19; 95% CI 0.72–1.98), third (AOR 1.10; 95% CI 0.67–1.81), nor fourth (AOR 1.54; 95% CI 0.93–2.56) quartiles were associated with favourable neurological outcomes; however, the fourth quartile was associated with a greater odds of hospital-discharge survival (AOR 1.73; 95% CI 1.05–2.85), and both the third (AOR 0.40; 95% CI 0.22–0.72) and fourth (AOR 0.44;95% CI 0.24–0.81) quartiles were associated with a lower odds of intra-transport re-arrest. ConclusionAmong resuscitated OHCAs, increased post-resuscitation on-scene time was not associated with improved neurological outcomes, but was associated with improved survival to hospital discharge and decreased intra-transport re-arrest.

Barriers to the Initiation of Telecommunicator-CPR during 9-1-1 Out-of-Hospital Cardiac Arrest Calls: A Qualitative Study

Introduction Fewer than 10% of individuals who suffer out-of-hospital cardiac arrest (OHCA) survive with good neurologic function. Bystander CPR more than doubles the chance of survival, and telecommunicator-CPR (T-CPR) during a 9-1-1 call substantially improves the frequency of bystander CPR. Objective We examined the barriers to initiation of T-CPR. Methods We analyzed the 9-1-1 call audio from 65 EMS-treated OHCAs from a single US 9-1-1 dispatch center. We initially conducted a thematic analysis aimed at identifying barriers to the initiation of T-CPR. We then conducted a conversation analysis that examined the interactions between telecommunicators and bystanders during the recognition phase (i.e., consciousness and normal breathing). Results We identified six process themes related to barriers, including incomplete or delayed recognition assessment, delayed repositioning, communication gaps, caller emotional distress, nonessential questions and assessments, and caller refusal, hesitation, or inability to act. We identified three suboptimal outcomes related to arrest recognition and delivery of chest compressions, which are missed OHCA identification, delayed OHCA identification and treatment, and compression instructions not provided following OHCA identification. A primary theme observed during missed OHCA calls was incomplete or delayed recognition assessment and included failure to recognize descriptors indicative of agonal breathing (e.g., “snoring”, “slow”) or to confirm that breathing was effective in an unconscious victim. Conclusions We observed that modifiable barriers identified during 9-1-1 calls where OHCA was missed, or treatment was delayed, were often related to incomplete or delayed recognition assessment. Repositioning delays were a common barrier to the initiation of chest compressions.

Effect of a Targeted Ambulance Treatment Quality Improvement Programme on Outcomes from Out-of-Hospital Cardiac Arrest: A Metropolitan Citywide Intervention Study.

The performance of ambulance crew affects the quality of pre-hospital treatment, which is vital to the survival for out-of-hospital cardiac arrest (OHCA) patients, yet remains suboptimal in China. In this retrospective analysis study, we aimed to examine the effect of a citywide quality improvement programme on provision of prehospital advanced life support (ALS) by emergency medical service (EMS) system. EMS-treated adult OHCA patients after the implementation of the programme (1 January 2021 to 30 June 2022) were compared with historical controls (1 June 2019 to 31 August 2020) in Suzhou. Multivariable logistic regression analysis and propensity score matching procedures were applied to compare the outcomes between two periods for total OHCA cases and subgroup of cases treated by fixed or non-fixed ambulance crews. A total of 1465 patients (pre-period/post-period: 610/855) were included. In the 1:1 matched analysis of 591 cases for each period, significant improvement (p < 0.05) was observed for the proportion of intravenous (IV) access (23.4% vs. 68.2%), advanced airway management (49.2% vs. 57.0%), and return of spontaneous circulation (ROSC) at handover (5.4% vs. 9.0%). The fixed ambulance crews performed better than non-fixed group in IV access and advanced airway management for both periods. There were significant increases in IV access (AOR 12.66, 95%CI 9.02−18.10, p < 0.001), advanced airway management (AOR 1.67, 95% CI 1.30−2.16, p < 0.001) and ROSC at handover (AOR 2.37, 95%CI 1.38−4.23, p = 0.002) after intervention in unfixed group, while no significant improvement was observed in fixed group except for IV access (AOR 7.65, 95%CI 9.02−18.10, p < 0.001). In conclusion, the quality improvement program was positively associated with the provision of prehospital ALS interventions and prehospital ROSC following OHCA. The fixed ambulance crews performed better in critical care provision and prehospital outcome, yet increased protocol adherence and targeted training could fill the underperformance of non-fixed crews efficaciously.

The association of duration of resuscitation and long-term survival and functional outcomes after out-of-hospital cardiac arrest

AimLonger emergency medical system cardiopulmonary-resuscitation-to-return of-spontaneous-circulation (EMS CPR-to-ROSC) interval has been associated with worse hospital discharge outcomes after out-of-hospital cardiac arrest (OHCA). We hypothesized that this association extends post-discharge in hospital survivors. We investigated whether pre-arrest co-morbidities influence the duration of resuscitation. MethodsWe included EMS-treated adult OHCA (January 2009 – December 2016) from British Columbia Cardiac Arrest Registry linked to provincial databases. Pre-OHCA characteristics were compared by ≤10, 10–20, and >20 min interval categories. Outcomes included survival and functional outcomes at hospital discharge and 1- and 3-year survival. We examined the relationship between CPR-to-ROSC intervals and survival using Kaplan-Meier. We examined the relationship between the CPR-to-ROSC interval (continuous variable) with all outcomes using regression models. ResultsAmong 10,241 OHCA, 4604 (45%) achieved ROSC, with a median CPR-to-ROSC interval of 15.5 (IQR 9.0–22.9) minutes. Diabetes, chronic kidney disease, and prior myocardial infarction were associated with longer CPR-to-ROSC intervals. 1245 (12.2%) survived to hospital discharge. Among hospital survivors, Kaplan-Meier survival at 1- and 3-years were 92% [95% CI 90–93%] and 84% [95% CI 82–86%] respectively; survival curves stratified by CPR-to-ROSC intervals were not statistically different. Longer CPR-to-ROSC interval was non-linearly associated with lower survival and functional outcomes at hospital discharge but not with post-discharge outcomes. ConclusionLonger CPR-to-ROSC interval was associated with lower survival at hospital discharge and was influenced by pre-arrest co-morbidities. However, these intervals were not associated with long-term survival or functional outcome among hospital survivors, suggesting early risk of longer CPR-to-ROSC intervals does not persist.

Abstract 10908: The Association of Duration of Resuscitation and Long-Term Survival and Functional Outcomes After Out-of-Hospital Cardiac Arrest

Introduction: Longer emergency medical system (EMS) CPR-to-ROSC interval has been shown to be linearly associated with worse hospital discharge outcomes for out-of-hospital cardiac arrest (OHCA). We hypothesized that this association extends post-discharge in hospital survivors. We investigated whether pre-arrest co-morbidities influence the duration of resuscitation. Methods: We included EMS-treated adult OHCA (Jan 2009 - Dec 2016) from British Columbia Cardiac Arrest Registry and provincial databases. Pre-OHCA characteristics were compared by ≤ 10, 10-20, and &gt;20 min CPR-to-ROSC interval categories. Outcomes included survival and functional outcomes at hospital discharge and 1-year, as well as 3-year post-discharge survival. We examined the relationship between CPR-to-ROSC interval categories and 1 and 3-year survival using Kaplan-Meier (KM). We examined the relationship between the CPR-to-ROSC interval (continuous variable) with all outcomes using regression models. Results: Among 10,241 OHCA, 4604 (45%) achieved ROSC, with a median CPR-to-ROSC interval of 15.5 (IQR 9.0- 22.9) min. Diabetes, chronic kidney disease, and prior MI were associated with longer CPR-to-ROSC intervals. 1245 (12.2%) survived to hospital discharge. Among hospital survivors, KM survival at 1- and 3- years were 92% [95% CI 90-93%] and 84% [95% CI 82-86%] respectively; survival curves stratified by CPR-to-ROSC intervals were not statistically different (Figure). Longer CPR-to-ROSC interval was non-linearly associated with lower survival and functional outcomes at hospital discharge but not with post-discharge outcomes. Conclusion: Longer CPR-to-ROSC interval was associated with lower survival at hospital discharge and is influenced by pre-arrest co-morbidities. However, these intervals were not associated with long-term survival or functional outcome among hospital survivors, suggesting that the early risk of longer CPR-to-ROSC intervals does not persist.

Abstract 178: Development And Validation Of The Utstein-based Machine Learning Algorithms To Predict Neurological Outcomes After Out-of-hospital Cardiac Arrest: A Retrospective Analysis Of The Pan-asian Registry

Introduction: The proportion of favorable neurologic outcome from the survival after Out-of-Hospital Cardiac Arrest (OHCA) remains poor, esp. in the Asian communities. By using the machine learning (ML) approach, we aimed to develop and validate the the Utstein-based ML algorithms to predict neurological outcomes after OHCA in this population. Methods: We conducted a retrospective analysis of data collected from the registry of Pan Asian Resuscitation Outcomes Study (PAROS) Network, an international and multi-center cohort study of OHCA across 13 countries in this region. All adult (≥ 18 years) EMS-treated OHCA patients between Jan 2009 to May 2018 in the registry were included, with variables followed the Utstein recommendations and conform to a unified taxonomy established by the network. The primary outcome was defined as good neurological outcome with cerebral performance category 1 or 2. Random splitting was used to divide the dataset into the training/validation and testing cohorts at around 2-to-1 ratio. Four supervised ML models, including Random Forest (RF), Gradient Boosting (GB), Extra Trees (ET), and CatBoost (CB) classifiers were employed to construct the prediction models, and performances were evaluated and compared with traditional logistic regression (LR) by the area under the receiver operating characteristic curve (AUC) in the testing cohort. Results: We included 194,300 records for analysis. Of them, 6,342 (3.3%) achieved good neurologic outcome. Among the constructed ML models, RF obtained the best AUC performance (0.924, 95% CI: 0.917-0.932), followed by ET (0.922, 95% CI: 0.915-0.930), CB (0.922, 95% CI: 0.915-0.930), and GB (0.910, 95% CI: 0.901-0.920). Although there was no difference in performance between each ML models, RF performed significantly better than using the traditional LR. The top important features were first arrest rhythm, age, witnessed by EMS, event location, and duration from call to EMS arrival. Conclusions: The ML approach showed excellent discriminatory performance to predict good neurologic outcome for EMS-treated OHCA patients in the Pan-Asian communities. It has the potential to save more life or provide termination-of-resuscitation if successfully implemented in the EMS system.

The number and level of first-contact emergency medical services crew and clinical outcomes in out-of-hospital cardiac arrest with dual dispatch response.

This study aimed to evaluate the association between the number and level of emergency medical technicians (EMTs) in the first-contact emergency medical services (EMS) unit and the clinical outcomes of out-of-hospital cardiac arrest (OHCA) with a dual dispatch response. Adult nontraumatic EMS-treated OHCAs between 2015 and 2018 in a nationwide database, were enrolled. The main exposure was the number and certification level of first-contact EMS crew: three versus two members, proportion of EMT intermediate level (EMT-I) over 50% versus under or equal to 50%. Good neurologic recovery was selected as the primary outcome. Multilevel multivariable logistic regression analysis was conducted to calculate adjusted odds ratios and confidence intervals. A total of 26,867 patients were enrolled and analyzed. Good neurologic recovery was different across the study groups: 5.4% in the two-member crews, 7.2% in the three-member crews, 5.9% in the low EMT-I proportion crews, and 6.8% in the high EMT-I proportion crews. In the main analysis, statistically significant differences for favorable outcomes were found between the three-member and two-member crews, and the high EMT-I proportion and low EMT-I proportion crews; for good neurologic recovery, adjusted odds ratios (95% confidence interval) were 1.23 (1.06-1.43) for three-member crews, and 1.28 (1.17-1.40) for a high EMT-I proportion. The higher number and level of first-contact EMS crew was associated with better neurologic recovery in adult nontraumatic OHCA with a dual-dispatched EMS response.

Potential Candidates for Emergency Department Initiated Extracorporeal Cardiopulmonary Resuscitation (ECPR) in a Canadian Institution.

IntroductionOut-of-hospital cardiac arrest (OHCA) patients experience poor survival. The use of extracorporeal membrane oxygenation (ECMO), a form of heart-lung bypass, in the setting of cardiac arrest, termed extracorporeal cardiopulmonary resuscitation (ECPR), has promise in improving survival with good neurologic outcomes. The study objective was to determine the number of potential annual ECPR candidates among the OHCA population in a health region within the Atlantic Canadian province of Nova Scotia.MethodsA retrospective chart review was conducted over a five-year period: January 1st, 2012 to December 31st, 2016. Consecutive non-traumatic OHCA and emergency department (ED) cardiac arrests occurring in a pre-determined catchment area (20-minute transport to ECMO center) defined by a geographic bounding box were identified. Criteria for ECPR were developed to identify candidates for activation of a “Code ECPR”: (1) age 16-70, (2) witnessed arrest, (3) no flow duration (time to CPR, including bystander) <10 minutes, (4) resuscitation >10 minutes without return of spontaneous circulation (ROSC), (5) emergency medical service (EMS) transport to hospital <20 minutes, (6) no patient factors precluding ongoing resuscitation (do not resuscitate status (DNR), palliative care involvement, or metastatic cancer), and (7) initial rhythm not asystole. Candidates were stratified by initial rhythm. Candidates were considered ultimately ED ECPR eligible if they failed conventional treatment, defined by death or resuscitation >30 minutes. Clinical data related to candidacy was extracted by an electronic query from prehospital and ED electronic records and manual chart review by three researchers.ResultsOur search yielded 561 cases of EMS-treated OHCA or in-ED arrests. Of those 204/561 (36%; 95% CI 33-40%) met the criteria for activation of a “Code ECPR”. Ultimately 79/204 (34%; 95% CI 28-41%) of those who met activation criteria were considered ED ECPR eligible; which is 14% (95% CI 11-17%) of the total number of arrests-of the total number of arrests, the initial rhythms were pulseless electrical activity (PEA) 33/79 (42%; 95% CI 32-53%) and shockable 46/79 (58%; 95% CI 47-69%).ConclusionOf all cardiac arrests in the area surrounding our ECMO center, approximately 41 per year met the criteria for a Code ECPR activation, with 16 per year ultimately being eligible for ED ECPR. This annual estimate varies based on the inclusion of initial rhythm. This provides insight into both prehospital and hospital implications of an ED ECPR program and will help guide the establishment of a program within our Nova Scotian health region. This study also provides a framework for similar investigation at other institutions contemplating ED ECPR program implementation.

Sex Differences in Incidence and Outcome of Out-of-Hospital Cardiac Arrest Within a Local Health Network.

IntroductionSex and gender differences in presentation and characteristics of out-of-hospital cardiac arrest (OHCA) are established in cohorts with presumed cardiac aetiology but not non-cardiac etiology. This study investigated the effect of sex on incidence and outcome of OHCA according to presumed and adjudicated aetiology within a local health network.MethodsPopulation-based observational cohort study of emergency medical services (EMS) attended OHCAs within an Australian local health network. Cases identified from an EMS registry between 2012-2016 were linked to a hospital registry. Age-standardised incidence and baseline characteristics were stratified by sex for EMS-treated OHCA, non-EMS witnessed presumed cardiac and obvious non-cardiac sub-cohorts, and hospitalised cases. Logistic regression was used to explore the primary outcome of survival to hospital discharge.ResultsWe identified 2,024 EMS-attended and 780 EMS-treated OHCAs. The non-EMS witnessed sub-cohorts comprised 504 presumed cardiac and 168 obvious non-cardiac OHCAs. Adjudicated aetiology was recorded in 123 hospitalised cases. Age-standardised incidence for women was almost half that of men across all groups. Across cohorts, women were generally older and arrested with a non-shockable initial rhythm in an area of low socioeconomic status. There was no sex difference in the primary outcome for the main EMS-treated cohort or in the non-cardiac sub-cohorts. The sex difference in outcome in the presumed cardiac sub-cohort was not present after multivariable adjustment.ConclusionsThere are sex differences in incidence and outcome of EMS-treated OHCA that appear to be driven by differences in susceptibility to cardiac arrhythmias and underlying etiology, rather than treatment delays or disparities.