Factors Associated With Successful Resuscitation After Out-of-Hospital Cardiac Arrest and Temporal Trends in Survival and Comorbidity

Post-Cardiac arrest outcome prediction using machine learning: A systematic review and meta-analysis

BACKGROUND

Early and reliable prognostication in post-cardiac arrest patients remains challenging, with various factors linked to return of spontaneous circulation (ROSC), survival, and neurological results. Machine learning and deep learning models show promise in improving these predictions. This systematic review and meta-analysis evaluates how effective these approaches are in predicting clinical outcomes at different time points using structured data.

METHODS

This study followed PRISMA guidelines, involving a comprehensive search across PubMed, Scopus, and Web of Science databases until March 2024. Studies aimed at predicting ROSC, survival (or mortality), and neurological outcomes after cardiac arrest through the application of machine learning or deep learning techniques with structured data were included. Data extraction followed the guidelines of the CHARMS checklist, and the bias risk was evaluated using PROBAST tool. Models reporting the AUC metric with 95 % confidence intervals were incorporated into the quantitative synthesis and meta-analysis.

RESULTS

After extracting 2,753 initial records, 41 studies met the inclusion criteria, yielding 97 machine learning and 16 deep learning models. The pooled AUC for predicting favorable neurological outcomes (CPC 1 or 2) at hospital discharge was 0.871 (95 % CI: 0.813 - 0.928) for machine learning models and 0.877 (95 % CI: 0.831-0.924) across deep learning algorithms. For survival prediction, this value was found to be 0.837 (95 % CI: 0.757-0.916). Considerable heterogeneity and high risk of bias were observed, mainly attributable to inadequate management of missing data and the absence of calibration plots. Most studies focused on pre-hospital factors, with age, sex, and initial arrest rhythm being the most frequent features.

CONCLUSION

Predictive models utilizing AI-based approaches, including machine and deep learning models exhibit enhanced effectiveness compared to previous regression algorithms, but significant heterogeneity and high risk of bias limit their dependability. Evaluating state-of-the-art deep learning models tailored for tabular data and their clinical generalizability can enhance outcome prediction after cardiac arrest.

The impact of comorbidity burden on cardiac arrest mortality: A population-based cohort study

AIM

Patients experiencing cardiac arrest are often burdened with comorbidities that increase mortality. This study examined the impact of comorbidity burden on cardiac arrest mortality by quantifying biological interaction.

METHODS

Nationwide population-based Danish cohort study of adult patients hospitalized for cardiac arrest during 1996-2021 and 5:1 matched comparisons from the general population (matched on age, sex, calendar year, and all Charlson Comorbidity Index comorbidities). Mortality rates and hazard ratios for the association between cardiac arrest and mortality was calculated according to comorbidity burden (none, low, moderate, severe). Biological interaction was examined by calculating interaction contrasts (difference in rate differences).

RESULTS

For no comorbidity burden, the 30-day mortality rate per 1,000 person-years was 18,110 in the cardiac arrest cohort and 24 in the comparison cohort (hazard ratio = 1,435). For low comorbidity burden, the 30-day mortality rate increased to 20,272 in the cardiac arrest cohort and 41 in the comparison cohort (hazard ratio = 504). The corresponding interaction contrast of 2,145 indicated that 11% of the mortality rate in patients with cardiac arrest and low comorbidity burden was explained by interaction between the two. This percentage increased to 20% for moderate and to 28% for severe comorbidity burden. Within 31-365-day follow-up, the percentage of the mortality rate explained by interaction was 28% for low, 38% for moderate, and 41% for severe comorbidity burden. The interaction effect was present for both out-of-hospital and in-hospital cardiac arrest.

CONCLUSIONS

Comorbidity burden interacted with cardiac arrest to increase mortality beyond that explained by their separate effects.

Epidemiology and survival outcomes of out-of-hospital cardiac arrest following volatile substance use in Queensland, Australia

INTRODUCTION

The deliberate inhalation of volatile substances for their psychotropic properties is a recognised public health issue that can precipitate sudden death. This study aimed to describe the epidemiological characteristics and survival outcomes of patients with out-of-hospital cardiac arrests following volatile substance use.

METHODS

We conducted a retrospective cohort analysis of all out-of-hospital cardiac arrest attended by the Queensland Ambulance Service over a ten-year period (2012-2021). Incidents were extracted from the Queensland Ambulance Service cardiac arrest registry, which collects clinical information using the Utstein-style guidelines and linked hospital data.

RESULTS

During the study period, 52,102 out-of-hospital cardiac arrests were attended, with 22 (0.04%) occurring following volatile substance use. The incidence rate was 0.04 per 100,000 population, with no temporal trends identified. The most commonly used product was deodorant cans (19/22), followed by butane canisters (2/22), and nitrous oxide canisters (1/22). The median age of patients was 15 years (interquartile range 13-23), with 14/22 male and 8/22 Indigenous Australians. Overall, 16/22 patients received a resuscitation attempt by paramedics. Of these, 12/16 were bystander witnessed, 10/16 presented in an initial shockable rhythm, and 9/16 received bystander chest compressions. The rates of event survival, survival to hospital discharge, and survival with good neurological outcome (Cerebral Performance Category 1-2) were 69% (11/16, 95% CI 41-89%), 38% (6/16, 95% CI 15-65%) and 31% (5/16, 11-59%), respectively. Eight patients in the paramedic-treated cohort that used hydrocarbon-based products were administered epinephrine during resuscitation. Of these, none subsequently survived to hospital discharge. In contrast, all six patients that did not receive epinephrine survived to hospital discharge, with 5/6 having a good neurological outcome.

CONCLUSION

Out-of-hospital cardiac arrest following volatile substance use is rare and associated with relatively favourable survival rates. Patients were predominately aged in their adolescence with Indigenous Australians disproportionately represented.

Impact of Awareness Time Interval on the Effect of Bystander Cardiopulmonary Resuscitation on Out-of-Hospital Cardiac Arrest: A Nationwide Study

PURPOSE

The awareness time interval (ATI), the time from the witnessed event to emergency medical service (EMS) activation, is an important factor influencing out-of-hospital cardiac arrest (OHCA) outcomes. Since bystander cardiopulmonary resuscitation (BCPR) is provided after cardiac arrest is recognized, the effect of BCPR may vary depending on ATI delay. We aimed to investigate whether ATI modifies the effect of BCPR on OHCA outcomes.

MATERIALS AND METHODS

A population-based observational study was conducted with EMS-treated witnessed adult (≥18 years) OHCAs between 2013 and 2018. The exposure variable was provision of BCPR. The primary outcome was a good neurological outcome defined as cerebral performance category scale 1or 2 (good CPC). Multivariable logistic regression analysis was conducted using the ATI group (-1, 1-5, 5- min) as the interaction term.

RESULTS

Of 34366 eligible OHCAs, 65.5% received BCPR. EMS was activated within 1 min in 45.9%, within 1-5 min in 29.2%, and after 5 min in 24.9% cases. In the adjusted interaction model, compared with no BCPR, a longer ATI resulted in smaller adjusted odds ratios for good CPC in the BCPR group [5.33 (4.17-6.82) for ATI ≤1 min, 5.14 (4.00-6.60) for 1-5 min, and 2.14 (1.63-2.81) for ATI >5 min].

CONCLUSION

The effect of BCPR on improving the chances for a good neurological outcome decreased as time from collapse to EMS activation increased. The importance of early recognition of OHCA and EMS activation should be emphasized in BCPR training.

Age-adjusted Charlson Comorbidity Index as effective predictor for in-hospital mortality of patients with cardiac arrest: a retrospective study

BACKGROUND

Cardiac arrest is currently one of the leading causes of mortality in clinical practice, and the Charlson Comorbidity Index (CCI) is widely utilized to assess the severity of comorbidities. We aimed to evaluate the relationship between the age-adjusted CCI score and in-hospital mortality in intensive care unit (ICU) patients with the diagnosis of cardiac arrest, which is important but less explored previously.

METHODS

This was a retrospective study including patients aged over 18 years from the MIMIC-IV database. We calculated the age-adjusted CCI using age information and ICD codes. The univariate analysis for varied predictors' differences between the survival and the non-survival groups was performed. In addition, a multiple factor analysis was conducted based on logistic regression analysis with the primary result set as hospitalization death. An additional multivariate regression analysis was conducted to estimate the influence of hospital and ICU stay.

RESULTS

A total of 1772 patients were included in our study, with median age of 66, among which 705 (39.8%) were female. Amongst these patients, 963 (54.3%) died during the hospitalization period. Patients with higher age-adjusted CCI scores had a higher likelihood of dying during hospitalization (P < 0.001; OR: 1.109; 95% CI: 1.068-1.151). With the age-adjusted CCI incorporated into the predictive model, the area under the receiver operating characteristic curve was 0.794 (CI: 0.773-0.814), showing that the prediction model is effective. Additionally, patients with higher age-adjusted CCI scores stayed longer in the hospital (P = 0.026, 95% CI: 0.056-0.896), but there was no significant difference between patients with varied age-adjusted CCI scores on the days of ICU stay.

CONCLUSION

The age-adjusted CCI is a valid indicator to predict death in ICU patients with cardiac arrest, which can offer enlightenment for both theory literatures and clinical practice.

The Impact of Prehospital and Hospital Care on Clinical Outcomes in Out-of-Hospital Cardiac Arrest

Background: In recent years, several actions have been made to shorten the chain of survival in out-of-hospital cardiac arrest (OHCA). These include placing defibrillators in public places, training first responders, and providing dispatcher-assisted CPR (DA-CPR). In this work, we aimed to evaluate the impact of these changes on patients' outcomes, including achieving return of spontaneous circulation (ROSC), survival to discharge, and survival with favorable neurological function. Methods: We retrospectively retrieved data of all calls to the national emergency medical service in Ashdod city, Israel, of individuals who underwent OHCA at the age of 18 and older between the years 2018 and 2021. Data was collected on prehospital and hospital interventions. The association between pre-hospital and hospital interventions to ROSC, survival to discharge, and neurological outcomes was evaluated. Logistic regression was used for multivariable analysis. Results: During the years 2018-2021, there were 1253 OHCA cases in the city of Ashdod. ROSC was achieved in 207 cases (32%), survival to discharge was attained in 48 cases (7.4%), and survival with favorable neurological function was obtained in 26 cases (4%). Factors significantly associated with good prognosis were shockable rhythm, witnessed arrest, DA-CPR, use of AED, and treatment for STEMI. All patients that failed to achieve ROSC outside of the hospital setting had a poor prognosis. Conclusions: This study demonstrates the prognostic role of the initial rhythm and the use of AED in OHCA. Hospital management, including STEMI documentation and catheterization, was also an important prognostication factors. Additionally, when ROSC is not achieved in the field, hospital transfer should be considered.

Clinical and Economic Burden of Out-of-Hospital Cardiac Arrest in US Commercial Insurance Population (2014 to 2019)

Little is known about the economic burden incurred by out-of-hospital cardiac arrest (OHCA) in the US commercial insurance setting. We used IBM MarketScan Commercial Claims and Encounters Database (January 2014 to March 2019) to identify patients hospitalized with OHCA based on the International Classification of Diseases codes. Patients who survived the initial OHCA episode were stratified by prognosis based on discharge setting and classified into mild (discharged home), moderate (skilled nursing facility), severe (inpatient rehabilitation or long-term hospital), and very severe (hospice) prognosis groups, respectively. Patients were followed up for 12 months after discharge for health care resource utilization and medical costs, which were inflated to year 2020. Overall, 23,512 patients with OHCA hospitalization were identified, of whom 14,667 were <65 years and 60.5% were men. The incidence of OHCA per 100,000 was steady in patients <65 years over the years (17.9 in 2014; 17.5 in 2018) but among those ≥65 years, decreased from 139.7 in 2014 to 111.1 in 2018. Total medical costs 12 months after discharge generally increased with severity of prognosis, with an average for the mild, moderate, and severe prognosis group, respectively, estimated to be $52,746, $100,394, and $130,530 among patients <65 years, and $63,194, $65,794, and $70,973 among those ≥65 years. Costs were lower for those with very severe prognosis ($7,102 for <65 years; $2,553 for ≥65 years), possibly due to high mortality. In conclusion, OHCA continues to pose a substantial clinical and economic burden on patients and the US health care system, which increases with the severity of disease prognosis.

Machine Learning Models for Survival and Neurological Outcome Prediction of Out-of-Hospital Cardiac Arrest Patients

Background

Out-of-hospital cardiac arrest (OHCA) is a major health problem worldwide, and neurologic injury remains the leading cause of morbidity and mortality among survivors of OHCA. The purpose of this study was to investigate whether a machine learning algorithm could detect complex dependencies between clinical variables in emergency departments in OHCA survivors and perform reliable predictions of favorable neurologic outcomes.

Methods

This study included adults (≥18 years of age) with a sustained return of spontaneous circulation after successful resuscitation from OHCA between 1 January 2004 and 31 December 2014. We applied three machine learning algorithms, including logistic regression (LR), support vector machine (SVM), and extreme gradient boosting (XGB). The primary outcome was a favorable neurological outcome at hospital discharge, defined as a Glasgow-Pittsburgh cerebral performance category of 1 to 2. The secondary outcome was a 30-day survival rate and survival-to-discharge rate.

Results

The final analysis included 1071 participants from the study period. For neurologic outcome prediction, the area under the receiver operating curve (AUC) was 0.819, 0.771, and 0.956 in LR, SVM, and XGB, respectively. The sensitivity and specificity were 0.875 and 0.751 in LR, 0.687 and 0.793 in SVM, and 0.875 and 0.904 in XGB. The AUC was 0.766 and 0.732 in LR, 0.749 and 0.725 in SVM, and 0.866 and 0.831 in XGB, for survival-to-discharge and 30-day survival, respectively.

Conclusions

Prognostic models trained with ML technique showed appropriate calibration and high discrimination for survival and neurologic outcome of OHCA without using prehospital data, with XGB exhibiting the best performance.

Sex differences in the association of comorbidity with shockable initial rhythm in out-of-hospital cardiac arrest

BACKGROUND

Lower survival chances after out-of-hospital cardiac arrest (OHCA) in women is associated with lower odds of a shockable initial rhythm (SIR). We hypothesized that sex differences in the prevalence of SIR are due to sex differences in comorbidities. We aimed to establish to what extent sex differences in the cumulative comorbidity burden, measured using the Charlson Comorbidity Index (CCI), or in individual comorbidities, account for the lower proportion of SIR in women.

METHODS

The association between CCI or its constituent comorbidities, and presence of SIR was studied using data (2010-2014) from a Dutch community-based OHCA registry, and included 2510 OHCA patients aged ≥18y with presumed cardiac cause.

RESULTS

The mean age was 67.8 ± 13.8y, 71% were men. Women were more often in high CCI categories than men. However, moderate or high disease burden was associated with lower odds of SIR compared to no disease burden only in men (OR 99 %CI 0.73 [0.53-1.00] and OR 0.54 [0.37-0.80] P-trend < 0.001), but not in women (1.00 [0.58-1.72] and 1.02 [0.57-1.84 P-trend 0.93). Adding CCI to a multivariable model did not alter the OR of sex with SIR. Of the individual comorbidities, only previous myocardial infarction was both differently distributed between sexes (men 22.7% vs. women 13.1%, p < 0.001) and associated with odds of SIR (higher in both sexes). Adding this variable to the model changed the association of sex with initial rhythm from 0.49 (0.38-0.64) to 0.53 (0.41-0.69).

CONCLUSION

Sex differences in comorbidities explained lower odds of SIR in women only modestly: differences in previous myocardial infarction contributed little, and cumulative comorbidity not at all.

Plasma proenkephalin A 119-159 on intensive care unit admission is a predictor of organ failure and 30-day mortality

BACKGROUND

Proenkephalin A 119-159 (penKid) has been suggested as a marker of renal failure and poor outcome. We aimed to investigate the association of penKid on ICU admission with organ dysfunction and mortality in a mixed ICU population. In this retrospective, observational study, admission penKid levels from prospectively collected blood samples of consecutive patients admitted to four Swedish ICUs were analysed. The association of penKid with day-two sequential organ failure assessment (SOFA) scores and 30-day mortality was investigated using (ordinal) logistic regression. The predictive power of penKid for 30-day mortality and dialysis was assessed using the area under the receiver operating characteristic curve (AUC).

RESULTS

Of 1978 included patients, 632 fulfilled the sepsis 3-criteria, 190 had a cardiac arrest, and 157 had experienced trauma. Admission penKid was positively associated with 30-day mortality with an odds ratio of 1.95 (95% confidence interval 1.75-2.18, p < 0.001), and predicted 30-day mortality in the entire ICU population with an AUC of 0.71 (95% confidence interval 0.68-0.73) as well as in the sepsis, cardiac arrest and trauma subgroups (AUCs of 0.61-0.84). Correction for admission plasma creatinine revealed that penKid correlated with neurological dysfunction.

CONCLUSION

Plasma penKid on ICU admission is associated with day-two organ dysfunction and predictive of 30-day mortality in a mixed ICU-population, as well as in sepsis, cardiac arrest and trauma subgroups. In addition to being a marker of renal dysfunction, plasma penKid is associated with neurologic dysfunction in the entire ICU population, and cardiovascular dysfunction in sepsis.

Repolarization and ventricular arrhythmia during targeted temperature management post cardiac arrest

BACKGROUND

Targeted temperature management (TTM) following out-of-hospital cardiac arrest (OHCA) prolongs the QT-interval but our knowledge of different temperatures and risk of arrhythmia is incomplete.

OBJECTIVE

To assess whether the QTc, QT-peak (QTp) and T-peak to T-end interval (TpTe) may be useful markers of ventricular arrhythmia in contemporary post cardiac arrest treatment.

METHODS

An ECG-substudy of the TTM-trial (TTM at 33 °C vs. 36 °C) with serial ECGs from 680 (94%) patients. Bazett's (B) and Fridericia's (F) formula were used for heart rate correction of the QT, QTp and TpTe. Ventricular arrhythmia (VT/VF) were registered during the first three days of post cardiac arrest care.

RESULTS

The QT, QTc and QTp intervals were prolonged more at 33 °C compared to 36 °C and restored to similar and lower levels after rewarming. The TpTe-interval remained between 92-100 ms throughout TTM in both groups. The QTc intervals were associated with ventricular arrhythmia, but not after adjustment for cardiac arrest characteristics. The QTp-interval was not associated with risk of ventricular arrhythmia. Heart rate corrected TpTe-intervals were associated with higher risk of arrhythmia (Odds ratio (OR): TpTe(B): 1.12 (1.02-1.23, p = 0.01 TpTe(F): 1.12 (1.02-1.23, p = 0.02) per 20 ms). Further a prolonged TpTe-interval ≥ 90 ms was consistently associated with higher risk (OR_adjusted: TpTe(B): 2.05 (1.25-3.37), p < 0.01, TpTe(F): 2.14 (1.32-3.49), p < 0.01).

CONCLUSIONS

TTM prolongs the QT-interval by prolongation of the QTp-interval without association to increased risk. The TpTe-interval is not significantly affected by core temperature, but heart rate corrected TpTe intervals are robustly associated with risk of ventricular arrhythmia.

TRIAL REGISTRATION

The TTM-trial is registered and accessible at ClinicalTrials.gov (Identifier: NCT01020916).

Association between previous health condition and outcome after cardiac arrest

INTRODUCTION

Overall survival of patients with out-of-hospital cardiac arrest (OHCA) remains low, even in those with return of spontaneous circulation (ROSC). In addition to usual prognostic characteristics, patients' medical history may also influence their outcome. This study aimed to investigate the role of pre-arrest comorbidities on hospital survival, neurological outcome and mode of death in OHCA patients with successful ROSC.

METHODS

From Jan 2012 to Sep 2017, all consecutive non-traumatic OHCA adults, admitted with a stable ROSC were included. Utstein characteristics, circumstances of arrest and interventions were prospectively recorded. Prior comorbidities were measured using the Charlson Comorbidity Index (CCI), and the population was divided into 3 groups (CCI 0, CCI 1-3 and CCI ≥ 4). The association of CCI with early and long-term mortality was assessed using logistic regression and association with withdrawal-of-life sustaining treatments (WLST) or another cause of death using multinomial regression.

RESULTS

During the study period, 777 patients were analyzed and 483 (62%) died before hospital discharge, with death rate of 49%, 60% and 70% in CCI 0, CCI 1-3 and CCI ≥ 4 respectively. After adjustment, an increase CCI was significantly associated with in-hospital mortality (OR = 2.47 [1.35-4.52], p = 0.001 for CCI 1-3; OR = 2.82 [1.49-5.33], p = 0.003 for CCI ≥ 4; ref = CCI 0). Other independent predictors were non-shockable rhythm (OR = 3.23 [2.08-5]), lack of bystander CPR (OR = 1.96 [1.22-3.13]), epinephrine dose ≥ 2 mg (OR = 5.56 [3.70-8.33]), CA to CPR ≥ 5 min (OR = 1.96 [1.28-3.03]) and CPR to ROSC ≥ 20 min (OR = 2.13 [1.39-3.23]). Using multinomial regression, an increase in CCI was associated with all modes of in-hospital death, particularly with WLST-related death (RRadj = 2.48 [1.26-4.90], p = 0.01 for CCI = 1-3 and 3.75 [1.85-8.7.58], p < 0.001 for CCI ≥ 4, reference CCI = 0).

CONCLUSION

Alteration of chronic health status, as assessed by an elevated CCI, was associated with a higher mortality and a worse neurological outcome in OHCA patients. Presence and burden of comorbidities should be considered in the evaluation of the prognosis in patients admitted in hospital after cardiac arrest.

Factors affecting outcomes in patients with cardiac arrest who receive target temperature management: The multi-center TIMECARD registry

BACKGROUND

Target temperature management (TTM) is a recommended therapy for patients after cardiac arrest (PCA). The TaIwan Network of Targeted Temperature ManagEment for CARDiac Arrest (TIMECARD) registry was established for PCA who receive TTM therapy in Taiwan. We aim to determine the variables that may affect neurologic outcomes in PCA who undergo TTM.

METHODS

We retrieved demographic variables, resuscitation variables, and cerebral performance category (CPC) scale score at hospital discharge from the TIMECARD registry. The primary outcome was a favorable neurologic outcome, defined as a CPC scale of 1 or 2 at discharge. A total of 540 PCA treated between January 2014 and September 2019 were identified from the registry. Univariate and multivariate analyses were performed to identify significant variables.

RESULTS

The mortality rate was 58.1% (314/540). Favorable neurologic outcomes were noted in 117 patients (21.7%). The factors significantly influencing the neurologic outcome (p < 0.05) were the presence of an initial shockable rhythm or pulseless electric activity, a witnessed cardiac-arrest event, bystander cardiopulmonary resuscitation, a smaller total dose of epinephrine, the diastolic blood pressure value at return of spontaneous circulation, a pre-arrest CPC score of 1, coronary angiography, new-onset seizure, and new-onset serious infection. Older patients and those with premorbid diabetes mellitus, chronic kidney disease, malignancy, obstructive lung disease, or cerebrovascular accident were more likely to have an unfavorable neurologic outcome.

CONCLUSIONS

In the TIMECARD registry, some PCA baseline characteristics, cardiac arrest events, cardiopulmonary resuscitation characteristics, and post-arrest management characteristics were significantly associated with neurologic outcomes.

Neuromonitoring After Cardiac Arrest: Can Twenty-First Century Medicine Personalize Post Cardiac Arrest Care?

Cardiac arrest survivors comprise a heterogeneous population, in which the etiology of arrest, systemic and neurologic comorbidities, and sequelae of post-cardiac arrest syndrome influence the severity of secondary brain injury. The degree of secondary neurologic injury can be modifiable and is influenced by factors that alter cerebral physiology. Neuromonitoring techniques provide tools for evaluating the evolution of physiologic variables over time. This article reviews the pathophysiology of hypoxic-ischemic brain injury, provides an overview of the neuromonitoring tools available to identify risk profiles for secondary brain injury, and highlights the importance of an individualized approach to post cardiac arrest care.

European Resuscitation Council Guidelines 2021: Epidemiology of cardiac arrest in Europe

In this section of the European Resuscitation Council Guidelines 2021, key information on the epidemiology and outcome of in and out of hospital cardiac arrest are presented. Key contributions from the European Registry of Cardiac Arrest (EuReCa) collaboration are highlighted. Recommendations are presented to enable health systems to develop registries as a platform for quality improvement and to inform health system planning and responses to cardiac arrest.

Impact of the modified SESAME ultrasound protocol implementation on patients with cardiac arrest in the emergency department

INTRODUCTION

Point-of-care (POC) ultrasound protocols are commonly used for the initial management of patients with cardiac arrest in the emergency department (ED). However, there is little published evidence regarding any mortality benefit. We compared and studied the effect of implementation of the modified SESAME protocol in terms of clinical outcomes and resuscitation management.

METHODS

This was a single-center retrospective observational study. We conducted a pre- and post-intervention study to evaluate changes in patient outcomes and management after educating emergency medicine residents and the faculty about the modified SESAME protocol. The pre-intervention period lasted from March 2018 to February 2019, and the post-intervention period lasted from May 2019 to April 2020. The modified SESAME protocol education was initiated in March 2019. Multivariate logistic regression analyses were performed to examine the associations between independent variables and outcomes.

RESULTS

A total of 334 patients were included in this study during a 24-month period. We found no significant differences between the two groups for the primary outcome of survival to hospital admission (pre-intervention group 28.9% versus post-intervention group 28.6%; P = 0.751), survival to hospital discharge (12.1% vs. 12.4%; P = 0.806), and good neurologic outcome at discharge (6.0% vs. 8.1%; P = 0.509). The proportion of resuscitation procedures of thrombolysis, emergency transfusion, tube thoracotomy, and pericardiocentesis during resuscitation increased from 0.6% in the pre-intervention period to 4.9% in the post-intervention period (P = 0.016).

CONCLUSION

We did not discover any significant survival benefits associated with the implementation of the modified SESAME protocol; however, early diagnosis of specific pathologies (pericardial effusion, possible pulmonary embolism, tension pneumothorax, and hypovolemia) and accordingly a direct increase in the resuscitation management were seen in this study. Future studies with larger sample sizes are required to examine the clinical outcomes as well as to identify the most effective POC ultrasonography protocols for non-traumatic cardiac arrests.

Hemodynamic and metabolic recovery in acute myocardial infarction-related cardiogenic shock is more rapid among patients presenting with out-of-hospital cardiac arrest

Background

Most studies in acute myocardial infarction complicated by cardiogenic shock (AMICS) include patients presenting with and without out-of-hospital cardiac arrest (OHCA). The aim was to compare OHCA and non-OHCA AMICS patients in terms of hemodynamics, management in the intensive care unit (ICU) and outcome.

Methods

From a cohort corresponding to two thirds of the Danish population, all patients with AMICS admitted from 2010–2017 were individually identified through patient records.

Results

A total of 1716 AMICS patients were identified of which 723 (42%) presented with OHCA. A total of 1532 patients survived to ICU admission. At the time of ICU arrival, there were no differences between OHCA and non-OHCA AMICS patients in variables commonly used in the AMICS definition (mean arterial pressure (MAP) (72mmHg vs 70mmHg, p = 0.12), lactate (4.3mmol/L vs 4.0mmol/L, p = 0.09) and cardiac output (CO) (4.6L/min vs 4.4L/min, p = 0.30)) were observed. However, during the initial days of ICU treatment OHCA patients had a higher MAP despite a lower need for vasoactive drugs, higher CO, SVO2 and lactate clearance compared to non-OHCA patients (p<0.05 for all). In multivariable analysis outcome was similar but cause of death differed significantly with hypoxic brain injury being leading cause in OHCA and cardiac failure in non-OHCA AMICS patients.

Conclusion

OHCA and non-OHCA AMICS patients initially have comparable metabolic and hemodynamic profiles, but marked differences develop between the groups during the first days of ICU treatment. Thus, pooling of OHCA and non-OHCA patients as one clinical entity in studies should be done with caution.

Association between prehospital prognostic factors and out-of-hospital cardiac arrest: Effect of rural-urban disparities

BACKGROUND

Out-of-hospital cardiac arrest (OHCA) is associated with a poor prognosis and a highly variable survival rate. Few studies have focused on outcomes in rural and urban groups while also evaluating underlying diseases and prehospital factors for OHCAs.

OBJECTIVE

To investigate the relationship between the patient's underlying disease and outcomes of OHCAs in urban areas versus those in rural areas.

METHODS

We reviewed the emergency medical service (EMS) database for information on OHCA patients treated between January 2015 and December 2019, and collected data on pre-hospital factors, underlying diseases, and outcomes of OHCAs. Univariate and multivariate logistic regression analyses were used to evaluate the prognostic factors for OHCA.

RESULTS

Data from 4225 OHCAs were analysed. EMS response time was shorter and the rate of attendance by EMS paramedics was higher in urban areas (p < 0.001 for both). Urban area was a prognostic factor for >24-h survival (odds ratio [OR] = 1.437, 95% confidence interval [CI]: 1.179-1.761). Age (OR = 0.986, 95% CI: 0.979-0.993). EMS response time (OR = 0.854, 95% CI: 0.811-0.898), cardiac arrest location (OR = 2.187, 95% CI: 1.707-2.795), attendance by paramedics (OR = 1.867, 95% CI: 1.483-2.347), and prehospital defibrillation (OR = 2.771, 95% CI: 2.154-3.556) were independent risk factors for survival to hospital discharge, although the influence of an urban area was not significant (OR = 1.211, 95% CI: 0.918-1.584).

CONCLUSIONS

Compared with rural areas, OHCA in urban areas are associated with a higher 24-h survival rate. Shorter EMS response time and a higher probability of being attended by paramedics were noted in urban areas. Although shorter EMS response time, younger age, public location, defibrillation by an automated external defibrillator, and attendance by Emergency Medical Technician-paramedics were associated with a higher rate of survival to hospital discharge, urban area was not an independent prognostic factor for survival to hospital discharge in OHCA patients.

Artificial neural networks improve early outcome prediction and risk classification in out-of-hospital cardiac arrest patients admitted to intensive care

Background

Pre-hospital circumstances, cardiac arrest characteristics, comorbidities and clinical status on admission are strongly associated with outcome after out-of-hospital cardiac arrest (OHCA). Early prediction of outcome may inform prognosis, tailor therapy and help in interpreting the intervention effect in heterogenous clinical trials. This study aimed to create a model for early prediction of outcome by artificial neural networks (ANN) and use this model to investigate intervention effects on classes of illness severity in cardiac arrest patients treated with targeted temperature management (TTM).

Methods

Using the cohort of the TTM trial, we performed a post hoc analysis of 932 unconscious patients from 36 centres with OHCA of a presumed cardiac cause. The patient outcome was the functional outcome, including survival at 180 days follow-up using a dichotomised Cerebral Performance Category (CPC) scale with good functional outcome defined as CPC 1–2 and poor functional outcome defined as CPC 3–5. Outcome prediction and severity class assignment were performed using a supervised machine learning model based on ANN.

Results

The outcome was predicted with an area under the receiver operating characteristic curve (AUC) of 0.891 using 54 clinical variables available on admission to hospital, categorised as background, pre-hospital and admission data. Corresponding models using background, pre-hospital or admission variables separately had inferior prediction performance. When comparing the ANN model with a logistic regression-based model on the same cohort, the ANN model performed significantly better (p = 0.029). A simplified ANN model showed promising performance with an AUC above 0.852 when using three variables only: age, time to ROSC and first monitored rhythm. The ANN-stratified analyses showed similar intervention effect of TTM to 33 °C or 36 °C in predefined classes with different risk of a poor outcome.

Conclusion

A supervised machine learning model using ANN predicted neurological recovery, including survival excellently, and outperformed a conventional model based on logistic regression. Among the data available at the time of hospitalisation, factors related to the pre-hospital setting carried most information. ANN may be used to stratify a heterogenous trial population in risk classes and help determine intervention effects across subgroups.

Age-specific trends in incidence and survival of out-of-hospital cardiac arrest from presumed cardiac cause in Denmark 2002-2014

BACKGROUND

The general cardiovascular health has improved throughout the last few decades for middle-aged and older individuals, but the incidence of several cardiovascular diseases is reported to increase in younger people. We aimed to assess the age-specific incidence and mortality rates associated with out-of-hospital-cardiac-arrest (OHCA) between 2002 and 2014.

METHODS

We used the Danish Cardiac Arrest Register to identify patients with OHCA of presumed cardiac etiology. We calculated the annual incidence rates (IR) and 30-day mortality rates (MR) in 7 age groups (18-34 years, 35-44 years, 45-54 years, 55-64 years, 65-74 years, 75-84 years and ≥85 years, and ≤50 vs. >50 years).

RESULTS

Between 2002 and 2014, IR of OHCA decreased in individuals aged 65-74 and 75-84 years (158.08 to 111.2 and 237.5 to 217.09 per 100,000 person-years) and increased in the oldest from 201.01 to 325.4 pr. 100.000 person-years. In 18-34-years incidence of OHCA increased from 1.7 to 2.6 per 100.000 person-years. When stratifying into age ≤50 vs. >50 years, the IR deviated in those >50 years (from 117.8 in 2002 to 91 in 2008 to 117.4 in 2014100,000 person-years). The prevalence of acute myocardial infarction and heart failure prior to OHCA increased in the younger patient group in contrast to the older segment (AMI: ≤50 years: 10% to 16%, vs. >50 years: 25% to 23%, heart failure: ≤50 years 6% to 14%, vs. >50 years: 21% to 24%).

CONCLUSION

Over the last decades, incidence rates of OHCA decreased in individuals aged 65-84, but increased in individuals older than 85. An increase was also observed in younger individuals, potentially indicating a need for better cardiovascular disease prevention in younger adults.

Targeted Temperature Management After Cardiac Arrest: The Montreal Heart Institute Experience

Background

Targeted temperature management (TTM) has been associated with an improvement in neurological function and survival in patients with cardiac arrest (CA) and an initially shockable rhythm. We report the Montreal Heart Institute (MHI) experience using TTM to evaluate mortality and neurological outcome in patients remaining in coma after CA, regardless of the initial rhythm.

Methods

We performed a retrospective review of all patients receiving TTM at the MHI between 2008 and 2015. Primary outcome was a composite of mortality and poor neurological outcome at hospital discharge. We also evaluated the long-term outcomes of those who initially survived to hospital discharge.

Results

A total of 147 patients (120 men, mean age 59.5 ± 12.5 years) underwent TTM at the MHI during the study period. Overall survival to hospital discharge with good neurological outcome was 45.6%. Shockable rhythm was associated with a better outcome (mortality odds ratio, 0.212; 95% confidence interval, 0.068-0.664; P = 0.008). Of the 11 initial survivors with a poor neurological status (Cerebral Performance Category ≥ 3), 4 died rapidly (within 1 month of hospital discharge), but 6 (54.5%) markedly improved their neurological status to Cerebral Performance Category 1. Long-term survival (mean follow-up of 38 ± 26 months) for those alive at hospital discharge (n = 76 patients) was 81.9%.

Conclusion

Our retrospective analysis of CA survivors treated with TTM at MHI showed good survival, similar to the published results from the landmark randomized controlled trials, despite enrolling patients with nonshockable rhythms. A significant proportion of survivors with poor neurological outcome at discharge improved at follow-up.

Comorbidity and bystander cardiopulmonary resuscitation in out-of-hospital cardiac arrest

​Objective

Cardiopulmonary resuscitation (CPR) performed before the arrival of emergency medical services (EMS) is associated with increased survival after out-of-hospital cardiac arrest (OHCA). The aim of this study was to determine whether patients who receive bystander CPR have a different comorbidity compared with patients who do not, and to determine the association between bystander CPR and 30-day survival when adjusting for such a possible difference.

​Methods

Patients with witnessed OHCA in the Swedish Registry for Cardiopulmonary Resuscitation between 2011 and 2015 were included, and merged with the National Patient Registry. The Charlson Comorbidity Index (CCI) was used to measure comorbidity. Multiple logistic regression was used to examine the effect of CCI on the association between bystander CPR and outcome.

​Results

In total, 11 955 patients with OHCA were included, 71% of whom received bystander CPR. Patients who received bystander CPR had somewhat lower comorbidity (CCI) than those who did not (mean±SD: 2.2±2.3 vs 2.5±2.4; p<0.0001). However, this difference in comorbidity had no influence on the association between bystander CPR and 30-day survival in a multivariable model including other possible confounders (OR 2.34 (95% CI 2.01 to 2.74) without adjustment for CCI and OR 2.32 (95% CI 1.98 to 2.71) with adjustment for CCI).

​Conclusion

Patients who undergo CPR before the arrival of EMS have a somewhat lower degree of comorbidity than those who do not. Taking this difference into account, bystander CPR is still associated with a marked increase in 30-day survival after OHCA.

Evaluation of the Uptake of a Prehospital Cardiac Arrest Termination of Resuscitation Rule

BACKGROUND

Previous research has focused on creation and validation of a basic life support rule for termination of resuscitation (TOR) in nontraumatic out-of-hospital cardiac arrest (OHCA) to identify patients who will not be successfully resuscitated or will not have a favorable outcome. Although now widely implemented, translational research regarding in-field compliance with TOR criteria and barriers to use is scarce.

OBJECTIVES

This project aimed to assess compliance rates, barriers to use, and effect on ambulance transport rates after implementing TOR criteria for OHCA.

METHODS

Retrospective chart review of patients ≥ 18 years with OHCA. Data from regional Emergency Medical Services agencies were collected to determine TOR rule compliance for patients meeting criteria, barriers to use, and effect of a TOR rule on ambulance transport.

RESULTS

There were 552 patients with OHCAs identified. Ninety-one patients met TOR criteria, with paramedics requesting TOR in 81 (89%) cases and physicians granting requests in 65 (80.2%) cases. Perceived barriers to TOR compliance included distraught families, nearby advanced-care paramedics, and unusual circumstances. Reasons for physician refusal of TOR requests included hospital proximity, patient not receiving epinephrine, and poor communication connection to paramedics. Total high priority transports decreased 15.6% after implementation of a TOR rule.

CONCLUSIONS

The study found high compliance after implementation of a TOR rule and identified potentially addressable barriers to TOR use. Appropriate application of a TOR rule led to reduction in high-priority ambulance transports, potentially reducing futile use of health care resources and risk of ambulance motor vehicle collisions.

Comparison of the effects of audio-instructed and video-instructed dispatcher-assisted cardiopulmonary resuscitation on resuscitation outcomes after out-of-hospital cardiac arrest

BACKGROUND

This study compared the real-world effects of audio-instructed dispatcher-assisted cardiopulmonary resuscitation (DA-CPR) and video-instructed DA-CPR on resuscitation outcomes after out-of-hospital cardiac arrest (OHCA).

METHODS

A retrospective cohort study was conducted among adult OHCA patients in whom resuscitation was attempted in 2017 in Seoul, Korea. The dispatch center of Seoul introduced video-instructed DA-CPR in 2017, whereas audio-instructed DA-CPR was first implemented in 2010. When more than two bystanders were at the scene and could handle a video-call, the dispatcher call back a video-call and provided CPR instructions. In other situations, standard audio-instructed DA-CPR was provided. The primary outcome was survival to discharge. The secondary outcome was good neurological outcome at hospital discharge. The tertiary outcome was early instruction time interval (ITI, time from call to the initiation of CPR instruction ≤90 s). The study outcomes of audio-instructed DA-CPR (audio group) and video-instructed DA-CPR (video group) were compared. The propensity score matching (PSM) method was used to increase the comparability of the two groups and the logistic regression was performed for the PSM cohort.

RESULTS

A total of 1720 eligible OHCA patients (1489 and 231 in the audio and video groups, respectively) were evaluated. The median ITI was 136 s in the audio group and 122 s in the video group (p = 0.12). The survival to discharge rates were 8.9% in the audio group and 14.3% in the video groups (p < 0.01). Good neurological outcome occurred in 5.8% and 10.4% in the audio and video groups, respectively (p < 0.01). Compared to the audio group, the AORs (95% CIs) for survival to discharge, good neurological outcome and early ITI of the video group were 1.20 (0.74-1.94), 1.28 (0.73-2.26) and 1.00 (0.70-1.43), respectively. The PSM population showed similar results as those of the original cohort.

CONCLUSION

Compared to audio-instructed DA-CPR, video-instructed DA-CPR was not associated with survival improvement in this observational study conducted in one metropolitan city. Randomized controlled trials are needed to compare the effects of video- and audio-instructed DA-CPR.

Systematic review of the relationship between comorbidity and out-of-hospital cardiac arrest outcomes

OBJECTIVES

To assess the current evidence on the effect pre-arrest comorbidity has on survival and neurological outcomes following out-of-hospital cardiac arrest (OHCA).

DESIGN

Systematic review according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses.

DATA SOURCES

MEDLINE, Ovid Embase, Scopus, CINAHL, Cochrane Library and MedNar were searched from inception to 31 December 2018.

ELIGIBILITY CRITERIA

Studies included if they examined the association between prearrest comorbidity and OHCA survival and neurological outcomes in adult or paediatric populations.

DATA EXTRACTION AND SYNTHESIS

Data were extracted from individual studies but not pooled due to heterogeneity. Quality of included studies was assessed using the Newcastle-Ottawa Quality Assessment Scale.

RESULTS

This review included 29 observational studies. There were high levels of clinical heterogeneity between studies with regards to patient recruitment, inclusion criteria, outcome measures and statistical methods used which ultimately resulted in a high risk of bias. Comorbidities reported across the studies were diverse, with some studies reporting individual comorbidities while others reported comorbidity burden using tools like the Charlson Comorbidity Index. Generally, prearrest comorbidity was associated with both reduced survival and poorer neurological outcomes following OHCA with 79% (74/94) of all reported adjusted results across 23 studies showing effect estimates suggesting lower survival with 42% (40/94) of these being statistically significant. OHCA survival was particularly reduced in patients with a prior history of diabetes (four out of six studies). However, a prearrest history of myocardial infarction appeared to be associated with increased survival in one of four studies.

CONCLUSIONS

Prearrest comorbidity is generally associated with unfavourable OHCA outcomes, however differences between individual studies makes comparisons difficult. Due to the clinical and statistical heterogeneity across the studies, no meta-analysis was conducted. Future studies should follow a more standardised approach to investigating the impact of comorbidity on OHCA outcomes.

PROSPERO REGISTRATION NUMBER

CRD42018087578.

Prehospital Double Sequential Defibrillation: A Matched Case-Control Study

OBJECTIVES

The goal of our study was to determine whether prehospital double sequential defibrillation (DSD) is associated with improved survival to hospital admission in the setting of refractory ventricular fibrillation/pulseless ventricular tachycardia (VF/pVT).

METHODS

This project is a matched case-control study derived from prospectively collected quality assurance/quality improvement data obtained from the San Antonio Fire Department out-of-hospital cardiac arrest (OHCA) database between January 2013 and December 2015. The cases were defined as OHCA patients with refractory VF/pVT who survived to hospital admission. The control group was defined as OHCA patients with refractory VF/pVT who did not survive to hospital admission. The primary variable in our study was prehospital DSD. The primary outcome of our study was survival to hospital admission.

RESULTS

Of 3,469 consecutive OHCA patients during the study period, 205 OHCA patients met the inclusion criterion of refractory VF/pVT. Using a predefined algorithm, two blinded researchers identified 64 unique cases and matched them with 64 unique controls. Survival to hospital admission occurred in 48.0% of DSD patients and 50.5% of the conventional therapy patients (p > 0.99; odds ratio = 0.91, 95% confidence interval = 0.40-2.1).

CONCLUSION

Our matched case-control study on the prehospital use of DSD for refractory VF/pVT found no evidence of associated improvement in survival to hospital admission. Our current protocol of considering prehospital DSD after the third conventional defibrillation in OHCA is ineffective.

Factors determining level of hospital care and its association with outcome after resuscitation from pre-hospital pulseless electrical activity

Background

Patients resuscitated from out-of-hospital cardiac arrest (OHCA) with pulseless electrical activity (PEA) as initial cardiac rhythm are not always treated in intensive care units (ICUs): some are admitted to high dependency units with various level of care, others to ordinary wards. Aim of this study was to describe the factors determining level of hospital care after OHCA with PEA, post-resuscitation care and survival.

Methods

Adult OHCA patients with PEA (n = 221), who were resuscitated in southern Finland between 2010 and 2013 were included, provided patient survived to hospital admission. The patients were divided into four groups according to the level of hospital care provided: ordinary ward and Level 1–3 ICUs. Differences in patient characteristics, post-resuscitation care and survival were compared between the groups.

Results

Most patients (62.4%) were treated at Level 2 ICUs. Longer time to ROSC and advanced age decreased admission rate to Level 2 or 3 post-resuscitation care, whereas good pre-arrest CPC (1–2) increased the admission rate to Level 2/3 ICUs independently. Treatment with targeted temperature management (TTM) (4.1%) or early coronary angiography (3.2%) were very rare. Prognostic decisions were made earlier in the lower treatment intensity groups (p < 0.01). One-year survival rate was 24.0, 17.1% survived with good neurological outcome. Neurological outcome was better with more intensive care. After adjustment, level of care was not independent predictor for outcome: only return of spontaneous circulation (ROSC) time, cardiac arrest cause and pre-arrest performance affected independently to 1-year survival, age and ROSC for neurologic outcome.

Conclusions

PEA are usually admitted to Level 2 ICUs for post-resuscitation care in the capital area of Finland. Age, ROSC and pre-arrest CPC were independent predictors for level of post-resuscitation care. TTM and early CAG were rare and provided only for Level 3 ICU patients. Prognostication was earlier in lower level of care units. Good neurologic survival was more common with more intensive level of post-resuscitation care. After adjustment, level of care was not independent predictor for survival or neurologic outcome: only ROSC, cardiac arrest cause and pre-arrest performance predicted 1-year survival; age and ROSC neurologic outcome.

Out-of-hospital cardiac arrests in nursing homes and primary care facilities in Pirkanmaa, Finland

BACKGROUND

Dispatching Emergency Medical Services to treat patients with deteriorating health in nursing homes and primary care facilities is common in Finland. We examined the cardiac arrest patients to describe this phenomenon. We had a special interest in patients for whom cardiopulmonary resuscitation was considered futile.

METHODS

We conducted an observational study between 1 June 2013 and 31 May 2014 in the Pirkanmaa area. We included cases in which Emergency Medical Services participated in the treatment of cardiac arrest patients in nursing homes and primary care facilities.

RESULTS

Emergency Medical Services attended to a total of 355 cardiac arrest patients, and 65 patients (18%) met the inclusion criteria. The included patients were generally older than 65 years, but otherwise heterogeneous. Nineteen patients (29%) had a valid do-not-attempt-resuscitation order, but paramedics were not informed about it in 10 (53%) of those cases. Eight (12%) of the 65 patients survived to hospital admission and 3 (5%) survived to hospital discharge with a neurologically favourable outcome. Two patients were alive 90 days after the cardiac arrest; both were younger than 70 years of age and had ventricular fibrillation as primary rhythm. There were no survivors in nursing homes.

CONCLUSIONS

The do-not-attempt-resuscitation orders were often unavailable during a cardiopulmonary resuscitation attempt. Although resuscitation attempts were futile for patients in nursing homes, some patients in primary care facilities demonstrated a favourable outcome after cardiac arrest. Emergency Medical Services seem to be able to recognise potential survivors and focus resources on their treatment.

Refractory out-of-hospital cardiac arrest with ongoing cardiopulmonary resuscitation at hospital arrival - survival and neurological outcome without extracorporeal cardiopulmonary resuscitation

Background

The prognosis in refractory out-of-hospital cardiac arrest (OHCA) with ongoing cardiopulmonary resuscitation (CPR) at hospital arrival is often considered dismal. The use of extracorporeal cardiopulmonary resuscitation (eCPR) for perfusion enhancement during resuscitation has shown variable results. We aimed to investigate outcome in refractory OHCA patients managed conservatively without use of eCPR.

Methods

We included consecutive OHCA patients with refractory arrest or prehospital return of spontaneous circulation (ROSC) in the Copenhagen area in 2002–2011.

Results

A total of 3992 OHCA patients with resuscitation attempts were included; in 2599, treatment was terminated prehospital, and 1393 (35%) were brought to the hospital either with ROSC (n = 1285, 92%) or with refractory OHCA (n = 108, 8%). Of patients brought in with refractory OHCA, 56 (52%) achieved ROSC in the emergency department. There were no differences between patients with refractory OHCA or prehospital ROSC with regard to age, sex, comorbidities, or etiology of OHCA. Time to emergency medical services (EMS) arrival was similar, whereas time to ROSC (when ROSC was achieved) was longer in refractory OHCA patients (EMS, 6 (5–9] vs. 7 [5–10] min, p = 0.8; ROSC, 15 [9–22] vs. 27 [20–41] min, p < 0.001). Independent factors associated with transport with refractory OHCA instead of prehospital termination of therapy were OHCA in public (OR, 3.6 [95% CI, 2.2–5.8]; p < 0.001), witnessed OHCA (OR, 3.7 [2.0–7.1]; p < 0.001), shockable rhythm (OR, 3.0 [1.9–4.7]; p < 0.001), younger age (OR, 1.2 [1.1–1.2]; p < 0.001), and later calendar year (OR, 1.4 [1.2–1.6]; p < 0.001). Thirty-day survival was 20% in patients with refractory OHCA compared with 42% in patients with prehospital ROSC (p < 0.001). Four of 28 refractory OHCA patients with duration of resuscitation > 60 min achieved ROSC. No difference in favorable neurological outcome in patients surviving to discharge was found (prehospital ROSC 84% vs. refractory OHCA 86%; p = 0.7).

Conclusions

Survival after refractory OHCA with ongoing CPR at hospital arrival was significantly lower than among patients with prehospital ROSC. Despite a lower survival, the majority of survivors with both refractory OHCA and prehospital ROSC were discharged with a similar degree of favorable neurological outcome, indicating that continued efforts in spite of refractory OHCA are not in vain and may still lead to favorable outcome even without eCPR.

Automated External Defibrillator Geolocalization with a Mobile Application, Verbal Assistance or No Assistance: A Pilot Randomized Simulation (AED G-MAP)

OBJECTIVE

Shockable rythms are common among victims of witnessed public out-of-hospital cardiac arrest (OHCA), but bystander defibrillation with a public automated external defibrillator (PAED) is rare. Instructions from the emergency medical dispatcher and mobile applications were developed to expedite the localization of PAEDs, but their effectiveness has not been compared.

METHODS

Participants were enrolled in a three-armed randomized simulation where they witnessed a simulated OHCA on a university campus, were instructed to locate a PAED and provide defibrillation. Participants were stratified and randomized to: (1) no assistance in finding the PAED, (2) assistance from a geolocalization mobile application (AED-Quebec), or (3) verbal assistance. Data collectors tracked each participant's time elapsed and distance traveled to shock.

RESULTS

Of the 52 volunteers participating in the study (46% male, mean age 37), 17 were randomized to the no assistance group, 18 to the mobile application group and 17 to the verbal group. Median (IQR) time to shock was, respectively, 10:00 min (7:49-10:00), 9:44 (6:30-10:00), and 5:23 (4:11-9:08), with statistically significant differences between the verbal group and the other groups (p ≤ 0.01). The success rate for defibrillation in <10 minutes was 35%, 56% and 76%. Multivariate regression of all participants pooled showed that knowledge of campus geography was the strongest predictor of shock in <10 minutes (aOR =14.3, 95% CI 1.85-99.9). Among participants without prior geographical knowledge, verbal assistance provided a trend towards decreased time to shock, but the differences over no assistance (7:28 vs. 10:00, p = 0.10) and over the mobile app (7:28 vs. 10:00, p = 0.11) were not statistically significant.

CONCLUSION

In a simulated environment, verbally providing OHCA bystanders with the nearest PAED's location appeared to be effective in reducing the time to defibrillation in comparison to no assistance and to an AED geolocalizing mobile app, but further research is required to confirm this hypothesis, ascertain the external validity of these results, and evaluate the real-life implications of these strategies.

Influence of comorbidities and clinical prediction model on neurological prognostication post out-of-hospital cardiac arrest

Background

Survival with good neurological function post out-of-hospital cardiac arrest (OHCA), defined as cerebral performance category (CPC) 1-2, ranges from 1.6% to 3% in Asia. We aim to study the influence of comorbidities and peri-OHCA event factors on neurological recovery and develop a model that can help clinicians predict neurological function among patients with post-OHCA admitted to the hospital.

Methods

This was a retrospective cohort study. All patients admitted post-OHCA from 1 January 2011 to 31 December 2015 to a tertiary centre were identified through the hospital OHCA registry. Patients who survived till hospital admission were included. Logistic regression was used to identify patient and peri-arrest factors that were significantly associated with survival with CPC 1-2. The significant factors for survival with CPC 1-2 were then put into a multivariable model and the discriminative ability was tested using the receiver operator characteristic (ROC) curve. Calibration and internal validation of the model were also performed. External validation in a small prospective cohort was also performed.

Results

In our derivation cohort of 129 patients, 30.23% survived with CPC 1-2. Significant factors associated with survival with good neurological outcomes were age-adjusted Charlson Comorbidity Index ≤5, time to first return of spontaneous circulation ≤40 min, the presence of immediate bystander cardiopulmonary resuscitation and shockable rhythms. We also developed a nomogram which showed good internal (ROC curve 0.84; 95% CI 0.77 to 0.91) and external validation (ROC curve 0.90; 95% CI 0.81 to 1.00).

Suffocation Injuries in the United States: Patient Characteristics and Factors Associated with Mortality

Introduction

Asphyxiation or suffocation injuries can result in multi-organ damage and are a major cause of morbidity and mortality among different age groups. This study aims to describe characteristics of patients presenting with suffocation injuries to emergency departments (EDs) in the United States (U.S.) and to identify factors associated with mortality in this population.

Methods

We conducted a retrospective cross-sectional study using the 2013 U.S National Emergency Department Sample database. ED visits with primary diagnoses of intentional or accidental suffocation injury, and injury by inhalation and aspiration of foreign bodies or food (ICD-9-CM codes) were included. We performed descriptive statistics to describe the study population. This was followed by multivariate analyses to identify factors associated with mortality.

Results

We included a total of 27,381 ED visits for suffocation injuries. Most suffered from either inhalation and ingestion of food causing obstruction of respiratory tract or suffocation (51.6%), or suicide and self-inflicted injury by hanging, strangulation, and suffocation (39.4%). Overall mortality was 10.9%. Over half (54.7%) of the patients were between 19 and 65 years old. Males were more common than females (59.1% vs. 40.9%). Over half of the patients (54.9%) were treated and released from the ED. Factors associated with increased mortality included male gender, young age (4-18 years), diseases of the cardiac, respiratory, genitourinary and neurologic systems, intentional self-harm, and self-payer status.

Conclusion

Mortality from suffocation injuries remains high with significant burden on children and adolescents and on patients with intentional injuries. Tailored initiatives targeting identified modifiable factors through implementation of behavioral and environmental change can reduce the risk of suffocation injury and improve clinical outcomes of affected victims.

Importance of comorbidities in comatose survivors of shockable and non-shockable out-of-hospital cardiac arrest treated with target temperature management

OBJECTIVE

Comorbidity prior to out-of-hospital cardiac arrest (OHCA) and primary rhythm in relation to survival is not well established. We aimed to assess the prognostic importance of comorbidity in relation to primary rhythm in OHCA-patients treated with Target Temperature Management (TTM).

DESIGN

Consecutive comatose survivors of OHCA treated with TTM in hospitals in the Copenhagen area between 2002-2011 were included. Utstein-based pre- and in-hospital data collection was performed. Data on comorbidity was obtained from The Danish National Patient Register and patient charts, assessed by the Charlson Comorbidity Index (CCI).

RESULTS

A total of 666 patients were included. A third (n = 233, 35%) presented with non-shockable rhythm, and they were less often male (64% vs. 82%, p < .001), and OHCA in public, witnessed OHCA, and bystander cardiopulmonary resuscitation (CPR) were less common compared to patients with a shockable primary rhythm (public: 27% vs. 48%, p < .001, witnessed: 79% vs. 90%, p < .001, bystander CPR: 47% vs. 63%, p < .001). 30-day mortality was 62% compared to 28% in patients with non-shockable and shockable rhythm, respectively. By Cox-regression analyses, any comorbidity (CCI ≥1) was the only factor independently associated with 30-day mortality in patients with non-shockable rhythm (HR =1.9 (95% CI: 1.2-2.9), p < .01), whereas in patients with shockable rhythm comorbidity was not associated with outcome after adjustment for prognostic factors (HR = 0.82 (0.55-1.2), p = .34). No significant interaction between primary rhythm and comorbidity in terms of mortality was present.

CONCLUSION

A higher comorbidity burden was independently associated with a higher 30-day mortality rate in patients presenting with non-shockable primary rhythm but not in patients with shockable rhythm.

Age discrimination in out-of-hospital cardiac arrest care: a case-control study

BACKGROUND

Although some studies have questioned whether cardiopulmonary resuscitation (CPR) in older people could be futile, age is not considered an essential out-of-hospital cardiac arrest (OHCA) prognostic factor. However, in the daily clinical practice of mobile medical teams (MMTs), age seems to be an important factor affecting OHCA care.

AIMS

The purpose of this study was to compare OHCA care and outcomes between young patients (<65 years old) and older patients.

METHODS

We performed a case-control study based on data extracted from the French National Cardiac Arrest (CA) registry. All adult patients with CA recorded between July 2011 and May 2014 were included. Each older patient was matched on three criteria: sex, initial cardiac rhythm and no-flow duration.

RESULTS

We studied 4347 pairs. We found significantly less basic life support initiation, shorter advanced cardiac life support duration, less MMT automated chest compression, less MMT ventilation and less MMT epinephrine injection in the older patients. Significant differences were also observed for return of spontaneous circulation (odds ratio (OR)=0.84, 95% confidence interval (CI) 0.77-0.92, p<0.001), transport to hospital (OR=0.58, 95% CI 0.51-0.61, p<0.001), vital status at hospital admission (OR=0.55, 95% CI 0.50-0.60, p<0.001) and vital status 30 days after CA (OR=0.42, 95% CI 0.35-0.50, p<0.001).

CONCLUSION

All OHCA guidelines, ethical statements and clinical procedures do not propose age as a discrimination criterion in OHCA care. However, in our case-control study, we notice a shorter duration and less intensive care among older patients. This finding may partly explain the lower survival rate compared with younger people.

Prognostic indicators of survival and survival prediction model following extracorporeal cardiopulmonary resuscitation in patients with sudden refractory cardiac arrest

Background

Extracorporeal cardiopulmonary resuscitation (ECPR) has been considered in selected candidates with potentially reversible causes during a limited period. Candidate selection and the identification of predictable conditions are important factors in determining outcomes during CPR in the emergency department (ED). The objective of this study was to determine the key indicators and develop a prediction model for survival to hospital discharge in patients with sudden cardiac arrest who received ECPR.

Methods

This retrospective analysis was based on a prospective cohort, which included data on CPR with ECPR-related variables. Patients with sudden cardiac arrest who received ECPR at the ED from May 2006 to June 2016 were included. The primary outcome was survival to discharge. Prognostic indicators and the prediction model were analyzed using logistic regression.

Results

Out of 111 ECPR patients, there were 18.9% survivors. Survivors showed younger age, shorter CPR duration (p < 0.05) and had tendencies of higher rate of initial shockable rhythm (p = 0.055) and higher rate of any ROSC event before ECPR (p = 0.066) than non-survivors. Eighty-one percent of survivors showed favorable neurologic outcome at discharge. In univariate analysis, the following factors were associated with survival: no preexisting comorbidities, initial serum hemoglobin level ≥14 g/dL, and mean arterial pressure ≥60 mmHg after ECPR. Based on multivariate logistic regression, predictors for survival in ECPR were as follows: age ≤56 years, no asystole as the initial arrest rhythm, CPR duration of ≤55 min, and any return of spontaneous circulation (ROSC) event before ECPR. The prediction scoring model for survival had a c-statistic of 0.875.

Conclusions

With careful consideration of differences in the inclusion criteria, the prognostic indicators and prediction scoring model for survival in our study may be helpful in the rapid decision-making process for ECPR implementation during CPR in the ED.

Effect of national implementation of utstein recommendation from the global resuscitation alliance on ten steps to improve outcomes from Out-of-Hospital cardiac arrest: a ten-year observational study in Korea

OBJECTIVES

The Utstein ten-step implementation strategy (UTIS) proposed by the Global Resuscitation Alliance, a bundle of community cardiopulmonary resuscitation (CPR) programs to improve outcomes after out-of-hospital cardiac arrests (OHCAs), has been developed. However, it is not documented whether UTIS programs are associated with better outcomes or not. The study aimed to test the association between the UTIS programme and better outcomes after OHCA.

METHODS

The study was a before- and after-intervention study. Adults OHCAs treated by emergency medical service (EMS) from 2006 to 2015 in Korea were collected, excluding patients witnessed by ambulance personnel and without outcomes. Phase 1 (2009-2011) after implementing three programs (national OHCA registry, obligatory CPR education, and public report of OHCA outcomes), and phase 2 (2012-2015) after implementing two programs (telephone-assisted CPR and EMS quality assurance programme) were compared with the control period (2006-2008) when no UTIS programme were implemented. The primary outcome was good neurological recovery (cerebral performance scale 1 or 2). We tested the association between the phases and outcomes, adjusting for confounders using a multivariate logistic regression model to calculate adjusted odds ratios (AORs) with 95% confidence intervals (CIs).

RESULTS

A total of 1 28 888 eligible patients were analysed. The control, phase 1, and phase two study groups were 19.4%, 30.5%, and 50.0% of the whole, respectively. There were significant changes in pre-hospital ROSC (0.8% in 2006 and 7.1% in 2015), survival to discharge (3.0% in 2006 and 6.1% in 2015), and good neurological recovery (1.2% in 2006 and 4.1% in 2015). The AORs (95% CIs) for good neurological recovery were 1.82 (1.53-2.15) or phase 1 and 2.21 (1.78-2.75) for phase two compared with control phase.

CONCLUSION

The national implementation of the five UTIS programs was significantly associated with better OHCA outcomes in Korea.