Out-of-hospital Cardiac Arrest Outcomes Research Articles

Extracorporeal cardiopulmonary resuscitation in out-of-hospital cardiac arrest (OHCA): a four years experience

Abstract Funding Acknowledgements Type of funding sources: None. Introduction Refractory cardiac arrest, defined as the absence of sustained return of spontaneous circulation (ROSC) despite advanced life support (ALS), remains common and is burden by poor outcome. The Extracorporeal Cardiopulmonary Resuscitation (E-CPR) may benefit organ perfusion, potentially improving OHCA outcomes. Purpose The aim of this study was to evaluate outcome of patients with refractory OHCA managed with E-CPR. Methods Single centre prospective observational registry of all patients with OHCA treated with E-CPR from 1 September 2017 to 28 February 2021. The enrolment to E-CPR was defined according to hospital protocol. Results We enrolled 166 patients with OHCA. Out of 59, 39 cases (66,1%) were included in E-CPR program. Prevalence of shockable rhythms was 59%. Survival at discharge from ICU was 10,2% (4 patients; 3 of them discharged with CPC 1-2 and all with ventricular fibrillation at presentation). E-CPR versus patients without refractory arrest have been compared: patients in the E-CPR group were younger (p=0,0002), had lower mean arterial pressure at ROSC and higher SOFA score (p<0,0001). NSE values between survivor (53,8 ± 17,9 mcg/L) and non-survivor (104,8 ± 44,2 mcg/L) at 24 hours were statistically significant (p=0,0669) as well as lactate clearance in the first 48 hours (p=0,001). In the univariate regression model serum lactate at admission (p<0,001; 95% CI 0,87 to 6,83), longer low flow time (p<0,002; 95% CI 0,99 to 1,29) and lower mean arterial pressure (p<0,01; 95% CI 0,99 to 1,29) were associated to mortality. Whereas only lactates (p<0,001; 95% CI 0,092 to 4,56) and low flow time (p<0,001; 95% CI 0,092 to 0,17) retained the association in the multivariate model (figure 1 for ROC curves). Conclusion Mortality rate in OHCA remains unacceptably high. Patients undertaking E-CPR have worsen hemodynamic and clinical parameters at admission, likely to consequence of refractory cardiac arrest. Low-flow time and lactates level are related to higher mortality as expression of worsen metabolic condition related to hypoperfusion state in patients with delayed ROSC.

The impact of COVID-19 on incidence and outcomes from out-of-hospital cardiac arrest (OHCA) in Texas

IntroductionEmerging research demonstrates lower rates of bystander cardiopulmonary resuscitation (BCPR), public AED (PAD), worse outcomes, and higher incidence of OHCA during the COVID-19 pandemic. We aim to characterize the incidence of OHCA during the early pandemic period and the subsequent long-term period while describing changes in OHCA outcomes and survival. MethodsWe analyzed adult OHCAs in Texas from the Cardiac Arrest Registry to Enhance Survival (CARES) during March 11–December 31 of 2019 and 2020. We stratified cases into pre-COVID-19 and COVID-19 periods. Our prehospital outcomes were bystander cardiopulmonary resuscitation (BCPR), public AED use (PAD), sustained ROSC, and prehospital termination of resuscitation (TOR). Our hospital survival outcomes were survival to hospital admission, survival to hospital discharge, good neurological outcomes (CPC Score of 1 or 2) and Utstein bystander survival. We created a mixed effects logistic regression model analyzing the association between the pandemic on outcomes, using EMS agency as the random intercept. ResultsThere were 3619 OHCAs (45.0% of overall study population) in 2019 compared to 4418 (55.0% of overall study population) in 2020. Rates of BCPR (46.2% in 2019 to 42.2% in 2020, P < 0.01) and PAD (13.0% to 7.3%, p < 0.01) decreased. Patient survival to hospital admission decreased from 27.2% in 2019 to 21.0% in 2020 (p < 0.01) and survival to hospital discharge decreased from 10.0% in 2019 to 7.4% in 2020 (p < 0.01). OHCA patients were less likely to receive PAD (aOR = 0.5, 95% CI [0.4, 0.8]) and the odds of field termination increased (aOR = 1.5, 95% CI [1.4, 1.7]). ConclusionsOur study adds state-wide evidence to the national phenomenon of long-term increased OHCA incidence during COVID-19, worsening rates of BCPR, PAD use and survival outcomes.

Does age influence out-of-hospital cardiac arrest incidence and outcomes among women? Insights from the Paris SDEC.

Age and sex disparities in out-of-hospital cardiac arrest (OHCA) have been described. Reproductive age may have a protected effect on females vs. males, although results are conflicting. We aimed to clarify this using the Paris Sudden Death Expertise Centre (SDEC) registry. The Paris SDEC registry collects OHCAs occurring in the Greater Paris Area. We included all OHCAs of presumed cardiac causes occurring between 2013 and 2018. Patients were divided into age groups: 1-13, 13-50, 50-75, and >75 years. Sex and age disparities in OHCA incidence and outcomes were analysed using multivariable negative binomial and logistic regression models. There were 19 782 OHCAs meeting inclusion criteria: 0.37% aged 1-13 years, 12.4% aged 13-50 years, 40.4% aged 50-75 years, and 46.9% aged >75 years. Adjusted incidence rate ratios (IRRs) in females vs. males were for the youngest to the older age groups: 1.29 [95% confidence interval (CI) 0.78-2.13], 0.54 [0.49-0.59], 0.60 [0.56-0.64], and 0.75 [0.67-0.84]. At reproductive age, females were more likely than males to have a return of spontaneous circulation [adjusted odds ratio (OR) 1.60 (1.27-2.02)], to be alive at hospital admission [OR: 1.49 (1.18-1.89)]. In both sexes, patients aged 13-50 years were more likely to survive at hospital discharge than those aged 50-75 years [males: OR 1.81 (1.49-2.20), females: 2.24 (1.54-3.25)]. However, at reproductive age, no sex disparity was observed in survival at hospital discharge [OR: 1.16 (0.75-1.80)]. Incidence rate ratios were similar between pre- and post-menopausal aged patients. At reproductive age, no sex disparity in survival at hospital discharge was observed, suggesting that menopausal status may not influence OHCA occurrence and prognosis.

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.

Association between Mode of Transport and Patient Outcomes in the Emergency Department following Out-of-Hospital Cardiac Arrest: A Single-Center Retrospective Study

Background Out-of-hospital cardiac arrest (OHCA) remains a health problem worldwide, carrying a high mortality rate. Comparison of emergency department (ED) return of spontaneous circulation (ROSC) after OHCA in relation to emergency medical services (EMS) and non-EMS modes of transportation to the hospital was conducted to assess the impact points of the EMS system in Thailand. Methods This retrospective observational study enrolled all OHCA patients who visited the ED of Ramathibodi Hospital, a tertiary university hospital in Bangkok, between January 1, 2008, and May 31, 2020. Patients were differentiated into EMS and non-EMS groups according to mode of transportation to the ED. Patients’ characteristics and comorbidities, witnessed arrests, bystander chest compression, initial rhythm, and resuscitation treatment were documented. ED-sustained ROSC, ED survival, 30-day survival, and 30-day survival with good cerebral performance category (CPC) scores were monitored and recorded. Multivariate logistic analyses were performed to assess factors influencing clinical outcomes. Results A total of 339 patients were enrolled, 117 (34.51%) of whom were in the EMS transport group. There were no differences between the EMS and non-EMS groups in ED-sustained ROSC (adjusted odds ratio [aOR], 0.99; 95% confidence interval [CI], 0.58–1.70; P = 0.98), or ED survival (aOR, 0.99; 95% CI, 0.57–1.71; P = 0.97). There were also no differences in 30-day survival or 30-day survival with good CPC score between the two groups. Conclusions In our cohort data of OHCA, ED-sustained ROSC and ED survival outcomes were not superior in the EMS transportation group. Evidence to show that EMS transportation affected 30-day survival and 30-day good CPC score was also lacking. Thus, public promotion of Thailand’s EMS system is advocated with a simultaneous improvement of EMS response to enhance OHCA outcomes.

Clinical Validation of Cardiac Arrest Hospital Prognosis (CAHP) Score and MIRACLE2 Score to Predict Neurologic Outcomes after Out-of-Hospital Cardiac Arrest.

Background. Out-of-hospital cardiac arrest (OHCA) remains a challenge for emergency physicians, given the poor prognosis. In 2020, MIRACLE2, a new and easier to apply score, was established to predict the neurological outcome of OHCA. Objective. The aim of this study is to compare the discrimination of MIRACLE2 score with cardiac arrest hospital prognosis (CAHP) score for OHCA neurologic outcomes. Methods. This retrospective cohort study was conducted between January 2015 and December 2019. Adult patients (>17 years) with cardiac arrest who were brought to the hospital by an emergency medical service crew were included. Deaths due to trauma, burn, drowning, resuscitation not initiated due to pre-ordered “do not resuscitate” orders, and patients who did not achieve return of spontaneous circulation were excluded. Receiver operating characteristic curve analysis with Youden Index was performed to calculate optimal cut-off values for both scores. Results. Overall, 200 adult OHCA cases were analyzed. The threshold of the MIRACLE2 score for favorable neurologic outcomes was 5.5, with an area under the curve (AUC) value of 0.70 (0.61–0.80, p < 0.001); the threshold of the CAHP score was 223.4, with an AUC of 0.77 (0.68–0.86, p < 0.001). On setting the MIRACLE2 score cut-off value, we documented 64.7% sensitivity (95% confidence interval [CI], 56.9–71.9%), 66.7.0% specificity (95% CI, 48.2–82.0%), 90.8% positive predictive value (PPV; 95% CI, 85.6–94.2%), and 27.2% negative predictive value (NPV; 95% CI, 21.4–33.9%). On establishing a CAHP cut-off value, we observed 68.2% sensitivity (95% CI, 60.2–75.5%), 80.6% specificity (95% CI, 62.5–92.6%), 94.6% PPV (95% CI, 88.6%–98.0%), and 33.8% NPV (95% CI, 23.2–45.7%) for unfavorable neurologic outcomes. Conclusions. The CAHP score demonstrated better discrimination than the MIRACLE2 score, affording superior sensitivity, specificity, PPV, and NPV; however, the CAHP score remains relatively difficult to apply. Further studies are warranted to establish scores with better discrimination and ease of application.

Extracorporeal Life-support for Out-of-hospital Cardiac Arrest: A Nationwide Multicenter Study.

Despite potential clinical roles of extracorporeal life support (ECLS) for out-of-hospital cardiac arrest (OHCA) compared to that of conventional cardiopulmonary resuscitation (CCPR), use of ECLS for OHCA is not strongly endorsed by current clinical guidelines. The purpose of this study is to investigate the clinical roles of extracorporeal life support (ECLS) compared with that of conventional cardiopulmonary resuscitation (CCPR) for out-of-hospital cardiac arrest (OHCA) patients. The outcomes of OHCA between 2015 and 2020, enrolled in the Korean Cardiac Arrest Research Consortium (KoCARC), a multicenter OHCA patient registry including 65 participating hospitals throughout the Republic of Korea (ClinicalTrials.gov, number NCT03222999). Differences in clinical features were adjusted by matching the propensity for ECLS. The primary outcome was 30-day neurologically favorable survival with cerebral performance category of 1 or 2. Restricted mean survival time (RMST) was used to compare outcomes between groups. Of 12,006 patients included, ECLS was applied to 272 patients (2.2%). The frequency of neurologically favorable survival was higher in the ECLS group than the CCPR group (RMST difference, 5.5 days [95% CI, 4.1-7.0 days], P < 0.001). In propensity score-matched 271 pairs, the clinical outcome of ECLS and CCPR did not differ to a statistically significant extent (RMST difference, 0.4 days [95% CI -1.6 to 2.5 days], P = 0.67). Subgroup analyses revealed that the clinical roles of ECLS was evident in patients with nonshockable rhythm or CPR time ≥20 min (RMST difference, 2.7 days [95% CI 0.5-4.8 days], P = 0.015), but not in patients without these features (RMST difference, -3.7 days [95% CI -7.6 to 0.2 days], P = 0.07). In this real-world data analysis, ECLS compared to CCPR did not result in better overall clinical outcomes of OHCA. The clinical efficacy of ECLS may be limited to a subgroup of high-risk patients.

Comparison between Prehospital Mechanical Cardiopulmonary Resuscitation (CPR) Devices and Manual CPR for Out-of-Hospital Cardiac Arrest: A Systematic Review, Meta-Analysis, and Trial Sequential Analysis.

In pre-hospital settings, efficient cardiopulmonary resuscitation (CPR) is challenging; therefore, the application of mechanical CPR devices continues to increase. However, the evidence of the benefits of using mechanical CPR devices in pre-hospital settings for adult out-of-hospital cardiac arrest (OHCA) is controversial. This meta-analysis compared the effects of mechanical and manual CPR applied in the pre-hospital stage on clinical outcomes after OHCA. Cochrane Library, PubMed, Embase, and ClinicalTrials.gov were searched from inception until October 2021. Studies comparing mechanical and manual CPR applied in the pre-hospital stage for survival outcomes of adult OHCA were eligible. Data abstraction, quality assessment, meta-analysis, trial sequential analysis (TSA), and grading of recommendations, assessment, development, and evaluation were conducted. Seven randomized controlled and 15 observational studies were included. Compared to manual CPR, pre-hospital use of mechanical CPR showed a positive effect in achieving return of spontaneous circulation (ROSC) and survival to admission. No difference was found in survival to discharge and discharge with favorable neurological status, with inconclusive results in TSA. In conclusion, pre-hospital use of mechanical CPR devices may benefit adult OHCA in achieving ROSC and survival to admission. With low certainty of evidence, more well-designed large-scale randomized controlled trials are needed to validate these findings.

Temporal trends of suicide-related non-traumatic out-of-hospital cardiac arrest characteristics and outcomes with the COVID-19 pandemic

BackgroundJurisdictions have reported COVID-19-related increases in the incidence and mortality of non-traumatic out-of-hospital cardiac arrest (OHCA). We hypothesized that changes in suicide incidence during the COVID-19 pandemic may have contributed to these changes. We investigated whether the COVID-19 pandemic was associated with changes in the: (1) incidence of suicide-related OHCA, and (2) characteristics and outcomes of such cases. MethodsWe used the provincial British Columbia Cardiac Arrest Registry, including non-traumatic emergency medical system (EMS)-assessed OHCA, to compare suicide-related OHCA (defined as clear self-harm or a priori communication of intent) one-year prior to, and one year after, the start of the COVID-19 pandemic (March 15, 2020). We calculated differences in incidence (with 95% CI), overall and within subgroups of mechanism (hanging, suffocation, poisoning, or unclear mechanism), and in case characteristics and hospital-discharge favourable neurological outcomes (CPC 1–2). ResultsOf 13,785 EMS-assessed OHCA, we included 274/6430 (4.3%) pre-pandemic and 221/7355 (3.0%) pandemic-period suicide-related cases. The median age was 43 years (IQR 30–57), 157 (32%) were female, and 7 (1.4%) survived with favourable neurological status. Suicide-related OHCA incidence decreased from 5.4 pre-pandemic to 4.3 per 100 000 person-years (-1.1, 95% CI −2.0 to −0.28). Hanging-related OHCA incidence also decreased. Patient characteristics and hospital discharge outcomes between periods were similar. ConclusionSuicide-related OHCA incidence decreased with the COVID-19 pandemic and we did not detect changes in patient characteristics or outcomes, suggesting that suicide is not a contributor to increases in COVID-related OHCA incidence or mortality. Overall suicide-related OHCA outcomes in both time periods were poor.

Out-of-hospital cardiac arrests and bystander response by socioeconomic disadvantage in communities of New South Wales, Australia

Background & aimBystander response to out-of-hospital cardiac arrest (OHCA) may relate to area-level factors, including socioeconomic status (SES). We aimed to examine whether OHCA among individuals in more disadvantaged areas are less likely to receive bystander cardiopulmonary resuscitation (CPR) compared to those in more advantaged areas. MethodsWe analysed data on OHCAs in New South Wales, Australia collected prospectively through a statewide, population-based register. We excluded non-medical arrests; arrests witnessed by a paramedic; occurring in a medical centre, nursing home, police station; or airport, and among individuals with a Do-Not-Resuscitate order. Area-level SES for each arrest was defined using the Australian Bureau of Statistics’ Index of Relative Socioeconomic Disadvantage and its relationship to likelihood of receiving bystander CPR was examined using hierarchical logistic regression models. ResultsOverall, 39% (6622/16,914) of arrests received bystander CPR (71% of bystander-witnessed). The OHCA burden in disadvantaged areas was higher (age-standardised incidence 76–87/100,000/year in more disadvantaged quintiles 1–4 versus 52 per 100,000/year in most advantaged quintile 5). Bystander CPR rates were lower (38%) in the most disadvantaged quintile and highest (42%) in the most advantaged SES quintile. In adjusted models, younger age, being bystander-witnessed, arresting in a public location, and urban location were all associated with greater likelihood of receiving bystander CPR; however, the association between area-level SES and bystander CPR rate was not significant. ConclusionsThere are lower rates of bystander CPR in less advantaged areas, however after accounting for patient and location characteristics, area-level SES was not associated with bystander CPR. Concerted efforts to engage with communities to improve bystander CPR in novel ways could improve OHCA outcomes.

Effect of large-scale disasters on bystander-initiated cardiopulmonary resuscitation in family-witnessed, friend-witnessed and colleague-witnessed out-of-hospital cardiac arrest: a retrospective analysis of prospectively collected, nationwide, population-based data

ImportanceThe effect of large-scale disasters on bystander cardiopulmonary resuscitation (BCPR) performance is unknown.ObjectiveTo investigate whether and how large-scale earthquake and tsunami as well as subsequent nuclear pollution influenced BCPR performance...

The epidemiology of out-of-hospital cardiac arrest in Australia and New Zealand: A binational report from the Australasian Resuscitation Outcomes Consortium (Aus-ROC)

IntroductionThe Australasian Resuscitation Outcomes Consortium (Aus-ROC) out-of-hospital cardiac arrest (OHCA) Epistry (Epidemiological Registry) now covers 100% of Australia and New Zealand (NZ). This study reports and compares the Utstein demographics, arrest characteristics and outcomes of OHCA patients across our region. MethodsWe included all OHCA cases throughout 2019 as submitted to the Epistry by the eight Australian and two NZ emergency medical services (EMS). We calculated crude and age-standardised incidence rates and performed a national and EMS regional comparison. ResultsWe obtained data for 31,778 OHCA cases for 2019: 26,637 in Australia and 5,141 in NZ. Crude incidence was 107.9 per 100,000 person-years in Australia and 103.2/100,000 in NZ. Overall, the majority of OHCAs occurred in adults (96%), males (66%), private residences (76%), were unwitnessed (63%), of presumed medical aetiology (83%), and had an initial monitored rhythm of asystole (64%). In non-EMS-witnessed cases, 38% received bystander CPR and 2% received public defibrillation. Wide variation was seen between EMS regions for all OHCA demographics, arrest characteristics and outcomes. In patients who received an EMS-attempted resuscitation (13,664/31,778): 28% (range across EMS = 13.1% to 36.7%) had return of spontaneous circulation (ROSC) at hospital arrival and 13% (range across EMS = 9.9% to 20.7%) survived to hospital discharge/30-days. Survival in the Utstein comparator group (bystander-witnessed in shockable rhythm) varied across the EMS regions between 27.4% to 42.0%. ConclusionOHCA across Australia and NZ has varied incidence, characteristics and survival. Understanding the variation in survival and modifiable predictors is key to informing strategies to improve outcomes.

A Comparison of the Performance of Out-of-hospital Cardiac Arrest Score and Standard Severity Scores in Predicting Hospital Mortality and Neurological Consequence in Out-of-hospital Cardiac Arrest Patients

Objective: There is limited data to determine the performance of general and specific severity score in out-of-hospital cardiac arrest (OHCA) patients. Hence, we compared the performance of the OHCA score with Acute Physiology and Chronic Health Evaluation (APACHE) and Simplified Acute Physiology Score (SAPS) to predict outcome in OHCA patients.Material and Methods: A retrospective study was conducted in a mixed intensive care unit of a tertiary hospital. The primary outcome was in-hospital mortality. The secondary outcome was poor neurological outcome.Results: A total of 190 OHCA patients were enrolled. The OHCA score had moderate discrimination with an area under the receiver operating characteristic curve (AUC) 0.77 (95% CI 0.7-0.837) whereas discrimination of APACHE II-IV, SAPS II, and SAPS 3 were good with an AUC more than 0.8. The actual hospital mortality rate was 64.7%. The OHCA score predicted hospital mortality of 95.3±8.4, which significantly overestimated the mortality with standardized mortality ratio 0.68 (95% CI 0.56-0.81). However, all severity scores revealed poor calibration. Additionally, overall performance of APACHE II-IV, SAPS II and SAPS 3 were better than the OHCA score. For secondary outcome, discrimination of the OHCA score was moderate with an AUC 0.790 (95% CI 0.700-0.878) whereas other severity scores demonstrated good discrimination with AUC more than 0.8.Conclusion: APACHE II-IV, SAPS II, and SAPS 3 indicated superior overall performance and demonstrated good discrimination for predicting hospital mortality and unfavorable neurological consequence better than the OHCA score. However, all severity scores attested poor calibration, therefore, specific scores for OHCA patients should be modified.

Sex Disparities in Prehospital Advanced Cardiac Life Support in Out-of-Hospital Cardiac Arrest in South Korea

Objective Sex disparities have been reported in the prehospital and in-hospital care among patients with out-of-hospital cardiac arrest (OHCA). The aim of this study was to investigate the association between sex and prehospital advanced cardiac life support (ACLS) interventions provided by emergency medical services (EMS). Methods This was a cross-sectional observational study using a nationwide OHCA registry in South Korea. The study included adult OHCAs with presumed cardiac etiology from January 2016 to December 2019. The main exposure was the sex of the victim, and the primary outcomes were prehospital ACLS interventions, including advanced airway management (AAM), intravenous access (IV), and epinephrine (EPI) administration. Multivariable logistic regression analysis accounted for age group, health insurance, comorbidities, place of arrest, urbanization level, witness status, bystander CPR and initial rhythm was performed to calculate adjusted odds ratios (AORs) with 95% confidence intervals (95% CIs). Results Among 71,154 eligible patients, females with OHCA received less prehospital ACLS interventions than males: risk difference, (95% CIs) −2.76 (-3.41;-2.11) for AAM, −6.03 (-6.79;-5.27) for IV, and −3.81 (-4.37;-3.25) for EPI. In multivariable logistic regression analysis, female sex was significantly associated with a lower probability of prehospital ACLS provision: AOR, (95% CIs) 0.87 (0.84-0.91) for AAM, 0.85 (0.82-0.88) for IV, and 0.81 (0.77-0.84) for EPI. Conclusion Compared to male patients, female patients were less likely to receive prehospital ACLS. This offers opportunities for EMS systems to reduce disparities and to improve compliance with OHCA resuscitation guidelines and outcomes through quality improvement and educational interventions.

Decreases in out of hospital cardiac arrest (OHCA) outcome metrics persist when known COVID patients are excluded from analysis.

A decline in OHCA performance metrics during the pandemic has been reported in the literature but the cause is still not known. The Montgomery County Fire and Rescue Service (MCFRS) observed a decline in both the rate of return of spontaneous circulation (ROSC) and the proportion of resuscitations that resulted in cerebral performance category (CPC) 1 or 2 discharge of the patient beginning in March of 2020. This study examines whether the decline in these performance metrics persists when known COVID positive patients are excluded from the analysis. Two samples of OHCA patients for similar time periods (one year apart) before and after the start of the COVID pandemic were developed. A database of known COVID positive patients among EMS encounters was used to identify and exclude COVID positive patients. OHCA outcomes in these two groups were then compared using a Chi-square test and Fisher's exact test for difference in proportions and Analysis of Variance (ANOVA) for difference in means. A two-stage multivariable logistic regression model was used to develop odds ratios for achieving ROSC and CPC 1 or 2 discharge in each period. After excluding known COVID patients, 32.5% of the patients in the pre-COVID period achieved ROSC compared to 25.1% in the COVID period (p=0.007). 6% of patients in the pre-COVID period were discharged with CPC 1 or 2 compared to 3.2% from the COVID era (p=0.026). Controlling for all available patient characteristics, patients undergoing OHCA resuscitation prior to be beginning of the pandemic were 1.2 times more likely to achieve ROSC and 1.6 times more likely to be discharged with CPC 1 or 2 than non-COVID patients in the pandemic era sample. When known COVID patients are excluded, pre-pandemic OHCA resuscitation patients were more likely to achieve ROSC and CPC 1 or 2 discharge. The prevalence of known COVID positive patients among all OHCA resuscitations during the pandemic was not sufficient to fully account for the marked decrease in both ROSC and CPC 1 or 2 discharges. Other causative factors must be sought.

Community Initiatives to Promote Basic Life Support Implementation-A Scoping Review.

Introduction: Early intervention of bystanders (the first links of the chain of survival) have been shown to improve survival and good neurological outcomes of patients suffering out-of-hospital cardiac arrest (OHCA). Many initiatives have been implemented to increase the engagement of communities in early basic life support (BLS) and cardiopulmonary resuscitation (CPR), especially of lay people with no duty to respond. A better knowledge of the most effective initiatives might help improve survival and health system organization. Aim of the scoping review: To assess the impact of specific interventions involving lay communities on bystander BLS rates and other consistent clinical outcomes, and to identify relevant knowledge gaps. Methods: This scoping review was part of the continuous evidence evaluation process of the International Liaison Committee on Resuscitation (ILCOR), and was performed following the Preferred Reporting Items for Systematic reviews and Meta-Analyses extension for Scoping Reviews. We performed a literature search using the PubMed, EMBASE, and Cochrane databases until 1 February 2021. The screening process was conducted based on predefined inclusion/exclusion criteria, and for each included study, we performed data extraction focusing on the type of intervention implemented, and the impact of these interventions on the specific OHCAs outcomes. Results: Our search strategy identified 19 eligible studies, originating mainly from the USA (47.4%) and Denmark (21%). The type of intervention included in 57.9% of cases was a community CPR training program, in 36.8% bundled interventions, and in 5.3% mass-media campaigns. The most commonly reported outcome for OHCAs was bystander CPR rate (94.7%), followed by survival to hospital discharge (36.8%), proportion of people trained (31.6%), survival to hospital discharge with good neurological outcome (21%), and Return of Spontaneous Circulation (10.5%). Community training programs and bundled interventions improved bystander CPR in most of the included studies. Conclusion: Based on the results of our scoping review, we identified the potential benefit of community initiatives, such as community training in BLS, even as part of bundled intervention, in order to improve bystander CPR rates and patient outcomes.

Maximum expected survival rate model for public access defibrillator placement

AimMathematical optimization of automated external defibrillator (AED) placement has demonstrated potential to improve survival of out-of-hospital cardiac arrest (OHCA). Existing models mostly aim to improve accessibility based on coverage radius and do not account for detailed impact of delayed defibrillation on survival. We aimed to predict OHCA survival based on time to defibrillation and developed an AED placement model to directly maximize the expected survival rate. MethodsWe stratified OHCAs occurring in Singapore (2010–2017) based on time to defibrillation and developed a regression model to predict the Utstein survival rate. We then developed a novel AED placement model, the maximum expected survival rate (MESR) model. We compared the performance of MESR with a maximum coverage model developed for Canada that was shown to be generalizable to other settings (Denmark). The survival gain of MESR was assessed through 10-fold cross-validation for placement of 20 to 1000 new AEDs in Singapore. Statistical analysis was performed using χ2 and McNemar’s tests. ResultsDuring the study period, 15,345 OHCAs occurred. The power-law approximation with R2 of 91.33% performed best among investigated models. It predicted a survival of 54.9% with defibrillation within the first two minutes after collapse that was reduced by more than 60% without defibrillation within the first 4 minutes. MESR outperformed the maximum coverage model with P-value < 0.05 (<0.0001 in 22 of 30 experiments). ConclusionWe developed a novel AED placement model based on the impact of time to defibrillation on OHCA outcomes. Mathematical optimization can improve OHCA survival.

Positive association between ambulance double-crewing and OHCA outcomes: A New Zealand observational study

Background and objectivesNew Zealand emergency medical service (EMS) crewing configurations generally place one (single) or two (double) crew on each responding ambulance unit. Recent studies demonstrated that double-crewing was associated with improved survival from out-of-hospital cardiac arrest (OHCA), therefore single-crewed ambulances have been phased out. We aimed to determine the association between this crewing policy change and OHCA outcomes in New Zealand. MethodsThis is a retrospective observational study using data from the St John OHCA Registry on patients treated during two different time periods: the Pre-Period (1 October 2013–30 June 2015), when single-crewed ambulances were in use by EMS, and the Post-Period (1 July 2016–30 June 2018) when single-crewed ambulances were being phased out. Geographic areas identified as having low levels of double crewing during the Pre-Period were selected for investigation. The outcome of survival to thirty-days post-OHCA was investigated using logistic regression analysis. ResultsThe proportion of double-crewed ambulances arriving at OHCA events increased in the Post-Period (81.8%) compared to the Pre-Period (67.5%) (p ≤ 0.001). Response times decreased by two minutes (Pre-Period: median 8 min, IQR [6–11], Post-Period: median 6 min, IQR [4–9]; p ≤ 0.001). Thirty-day survival was significantly improved in the Post-Period (OR 1.63, 95%CI (1.04–2.55), p = 0.03). ConclusionsAn association between improved OHCA survival following increased responses by double-crewed ambulances was demonstrated. This study suggests that improvements in resourcing are associated with improved OHCA outcomes.

Predicting Survived Events in Nontraumatic Out-of-Hospital Cardiac Arrest: A Comparison Study on Machine Learning and Regression Models.

Prediction of early outcomes of nontraumatic out-of-hospital cardiac arrest (OHCA) by emergency physicians is inaccurate. Our aim was to develop and validate practical machine learning (ML)-based models to predict early outcomes of nontraumatic OHCA for use in the emergency department (ED). We compared their discrimination and calibration performances with the traditional logistic regression (LR) approach. Between October 1, 2017 and March 31, 2020, prehospital resuscitation was performed on 17,166 OHCA patients. There were 8157 patients 18 years or older with nontraumatic OHCA who received continued resuscitation in the ED included for analysis. Eleven demographic and resuscitation predictor variables were extracted to predict survived events, defined as any sustained return of spontaneous circulation until in-hospital transfer of care. Prediction models based on random forest (RF), multilayer perceptron (MLP), and LR were created with hyperparameter optimization. Model performances on internal and external validation were compared using discrimination and calibration statistics. The three models showed similar discrimination performances with c-statistics values of 0.712 (95% confidence interval [CI] 0.711-0.713) for LR, 0.714 (95% CI 0.712-0.717) for RF, and 0.712 (95% CI 0.710-0.713) for MLP models on external validation. For calibration, MLP model had a better performance (slope of calibration regression line=1.10, intercept=-0.09) than LR (slope=1.17, intercept=-0.11) and RF (slope=1.16, intercept= -0.10). Two practical ML-based and one regression-based clinical prediction models of nontraumatic OHCA for survived events were developed and validated. The ML-based models did not outperform LR in discrimination, but the MLP model showed a better calibration performance.

Racial and Socioeconomic Disparities in Out-Of-Hospital Cardiac Arrest Outcomes: Artificial Intelligence-Augmented Propensity Score and Geospatial Cohort Analysis of 3,952 Patients

Introduction Social disparities in out-of-hospital cardiac arrest (OHCA) outcomes are preventable, costly, and unjust. We sought to perform the first large artificial intelligence- (AI-) guided statistical and geographic information system (GIS) analysis of a multiyear and multisite cohort for OHCA outcomes (incidence and poor neurological disposition). Method We conducted a retrospective cohort analysis of a prospectively collected multicenter dataset of adult patients who sequentially presented to Houston metro area hospitals from 01/01/07-01/01/16. Then AI-based machine learning (backward propagation neural network) augmented multivariable regression and GIS heat mapping were performed. Results Of 3,952 OHCA patients across 38 hospitals, African Americans were the most likely to suffer OHCA despite representing a significantly lower percentage of the population (42.6 versus 22.8%; p < 0.001). Compared to Caucasians, they were significantly more likely to have poor neurological disposition (OR 2.21, 95%CI 1.25–3.92; p=0.006) and be discharged to a facility instead of home (OR 1.39, 95%CI 1.05–1.85; p=0.023). Compared to the safety net hospital system primarily serving poorer African Americans, the university hospital serving primarily higher income commercially and Medicare insured patients had the lowest odds of death (OR 0.45, p < 0.001). Each additional $10,000 above median household income was associated with a decrease in the total number of cardiac arrests per zip code by 2.86 (95%CI -4.26- -1.46; p < 0.001); zip codes with a median income above $54,600 versus the federal poverty level had 14.62 fewer arrests (p < 0.001). GIS maps showed convergence of the greater density of poor neurologic outcome cases and greater density of poorer African American residences. Conclusion This large, longitudinal AI-guided analysis statistically and geographically identifies racial and socioeconomic disparities in OHCA outcomes in a way that may allow targeted medical and public health coordinated efforts to improve clinical, cost, and social equity outcomes.