Association between defibrillation-to-adrenaline interval and short-term outcomes in patients with out-of-hospital cardiac arrest and an initial shockable rhythm

Aim

The optimal timing of adrenaline administration after defibrillation in patients with out-of-hospital cardiac arrest (OHCA) and an initial shockable rhythm is unknown. We investigated the association between the defibrillation-to-adrenaline interval and clinical outcomes.

Methods

Between 2011 and 2020, we enrolled 1,259,960 patients with OHCA into a nationwide prospective population-based registry in Japan. After applying exclusion criteria, 20,905 patients with an initial shockable rhythm documented at emergency medical services (EMS) arrival who received adrenaline after defibrillation were eligible for this study. Multivariable logistic regression analysis was used to predict favourable short-term outcomes: prehospital return of spontaneous circulation (ROSC), 30-day survival, or a favourable neurological outcome (Cerebral Performance Category 1 or 2) at 30 days. Patients were categorised into 2-minute defibrillation-to-adrenaline intervals up to 18 min, or more than 18 min.

Results

At 30 days, 1,618 patients (8%) had a favourable neurological outcome. The defibrillation-to-adrenaline interval in these patients was significantly shorter than in patients with an unfavourable neurological outcome [8 (5-12) vs 11 (7-16) minutes; P < 0.001]. The proportion of patients with prehospital ROSC, 30-day survival, or a favourable neurological outcome at 30 days decreased as the defibrillation-to-adrenaline interval increased (P < 0.001 for trend). Multivariable analysis revealed that a defibrillation-to-adrenaline interval of > 6 min was an independent predictor of worse prehospital ROSC, 30-day survival, or neurological outcome at 30 days when compared with an interval of 4-6 min.

Conclusion

A longer defibrillation-to-adrenaline interval was significantly associated with worse short-term outcomes in patients with OHCA and an initial shockable rhythm.

Impact of Updating the Cardiopulmonary Resuscitation Guidelines on Out-of-Hospital Shockable Cardiac Arrest: A Population-Based Cohort Study in Japan

BACKGROUND

International consensus on cardiopulmonary resuscitation (CPR) and emergency cardiovascular care science and treatment recommendations (CoSTR) have reported updates on CPR maneuvers every 5 years since 2000. However, few national population-based studies have investigated the comprehensive effectiveness of those updates for out-of-hospital cardiac arrest due to shockable rhythms. The primary objective of the present study was to determine whether CPR based on CoSTR 2005 or 2010 was associated with improved outcomes in Japan, as compared with CPR based on Guidelines 2000.

METHODS AND RESULTS

From the All-Japan Utstein Registry between 2005 and 2015, we included 73 578 adults who had shockable out-of-hospital cardiac arrest witnessed by bystanders or emergency medical service responders. The study outcomes over an 11-year period were compared between 2005 of the Guidelines 2000 era, from 2006 to 2010 of the CoSTR 2005 era, and from 2011 to 2015 of the CoSTR 2010 era. In the bystander-witnessed group, the adjusted odds ratios for favorable neurological outcomes at 30 days after out-of-hospital cardiac arrest by enrollment year increased year by year (1.19 in 2006, and 3.01 in 2015). Similar results were seen in the emergency medical service responder-witnessed group and several subgroups.

CONCLUSIONS

Compared with CPR maneuvers for shockable out-of-hospital cardiac arrest recommended in the Guidelines 2000, CPR maneuver updates in CoSTR 2005 and 2010 were associated with improved neurologically intact survival year by year in Japan. Increased public awareness and greater dissemination of basic life support may be responsible for the observed improvement in outcomes.

REGISTRATION

URL: https://www.umin.ac.jp/ctr/; Unique identifier: 000009918.

Impact of Number of Defibrillation Attempts on Neurologically Favourable Survival Rate in Patients with Out-of-Hospital Cardiac Arrest

AIM

of the study: Defibrillation plays a crucial role in early return of spontaneous circulation (ROSC) and survival of patients with out-of-hospital cardiac arrest (OHCA) and shockable rhythm. Prehospital adrenaline administration increases the probability of prehospital ROSC. However, little is known about the relationship between number of prehospital defibrillation attempts and neurologically favourable survival in patients treated with and without adrenaline.

METHODS

Using a nationwide Japanese OHCA registry database from 2006 to 2020, 1,802,084 patients with OHCA were retrospectively analysed, among whom 81,056 with witnessed OHCA and initial shockable rhythm were included. The relationship between the number of defibrillation attempts before hospital admission and neurologically favourable survival rate (cerebral performance category score of 1 or 2) at 1 month was evaluated with subgroup analysis for patients treated with and without adrenaline.

RESULTS

At 1 month, 18,080 (22.3%) patients had a cerebral performance category score of 1 or 2. In the study population, the probability of prehospital ROSC and favourable neurological survival rate were inversely associated with number of defibrillation attempts. Similar trends were observed in patients treated without adrenaline, whereas a greater number of defibrillation attempts was counterintuitively associated with favourable neurological survival rate in patients treated with prehospital adrenaline.

CONCLUSIONS

Overall, a greater number of prehospital defibrillation attempts was associated with lower neurologically favourable survival at 1 month in patients with OHCA and shockable rhythm. However, an increasing number of shocks (up to the 4th shock) was associated with better neurological outcomes when considering only patients treated with adrenaline.

Development, implementation, and refinement of a comprehensive postcardiac arrest care training course in Japan

Aim

In Japan, no training course is dedicated to postcardiac arrest care (PCAC), including venoarterial extracorporeal membrane oxygenation (VA-ECMO); thus, faculty members of the Japanese Circulation Society developed an original, comprehensive PCAC training course. This report reviews the development, implementation, and refinement of this PCAC training course.

Methods

We examined the preserved data from the Japanese Circulation Society PCAC training courses between 2014 and 2020. Data related to the learning content and number of the attendees and instructors were collected and summarized.

Results

Sixteen courses were held between August 2014 and February 2020, before the coronavirus disease 2019 (COVID-19) pandemic. A total of 677 health care providers participated: 351 doctors, 225 nurses, 62 perfusionists, five emergency medical professionals, and two pharmacists. Thirty-two attendees' data were missing. The core learning contents of all the courses included a standardized postcardiac arrest algorithm, targeted temperature management, VA-ECMO cannulation skills, and postcannulation management. Concerning curriculum evolution, extracorporeal cardiopulmonary resuscitation simulation, postarrest neurological examination and monitoring, and ultrasound-guided Seldinger technique training were added in the 4th, 5th, and 13th courses, respectively.

Conclusion

The Japanese Circulation Society PCAC training course has been developed and refined to provide an organized, comprehensive opportunity for health care providers to acquire specific knowledge and skills in PCAC and VA-ECMO.

Supplemental Oxygen and Acute Myocardial Infarction ― A Systematic Review and Meta-Analysis ―

Background: In Japan, oxygen is commonly administered during the acute phase of myocardial infarction (MI) to patients without oxygen saturation monitoring. In this study we assessed the effects of supplemental oxygen therapy, compared with ambient air, on mortality and cardiac events by synthesizing evidence from randomized controlled trials (RCTs) of patients with suspected or confirmed acute MI.

Methods and Results: PubMed was systematically searched for full-text RCTs published in English before June 21, 2020. Two reviewers independently screened the search results and appraised the risk of bias. The estimates for each outcome were pooled using a random-effects model. In all, 2,086 studies retrieved from PubMed were screened. Finally, 7,322 patients from 9 studies derived from 4 RCTs were analyzed. In-hospital mortality in the oxygen and ambient air groups was 1.8% and 1.6%, respectively (risk ratio [RR] 0.90; 95% confidence interval [CI] 0.38–2.10]); 0.8% and 0.5% of patients, respectively, experienced recurrent MI (RR 0.44; 95% CI 0.12–1.54), 1.5% and 1.6% of patients, respectively, experienced cardiac shock (RR 1.10; 95% CI 0.77–1.59]), and 2.4% and 2.0% of patients, respectively, experienced cardiac arrest (RR 0.91; 95% CI 0.43–1.94).

Conclusions: Routine supplemental oxygen administration may not be beneficial or harmful, and high-flow oxygen may be unnecessary in normoxic patients in the acute phase of MI.

Prehospital Administration of Aspirin and Nitroglycerin for Patients With Suspected Acute Coronary Syndrome ― A Systematic Review ―

Background: Recent guidelines for acute coronary syndrome (ACS) recommend prehospital administration of aspirin and nitroglycerin for ACS patients. However, there is no clear evidence to support this. We investigated the benefits and harms of prehospital administration of aspirin and nitroglycerin by non-physician healthcare professionals in patients with suspected ACS.

Methods and Results: We searched the PubMed database and used the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) approach to assess the certainty of evidence. Three retrospective studies for aspirin and 1 for nitroglycerin administered in the prehospital setting to patients with acute myocardial infarction were included. Prehospital aspirin administration was associated with significantly lower 30-day and 1-year mortality compared with aspirin administration after arrival at hospital, with odds ratios (OR) of 0.59 (95% confidence interval [CI] 0.35–0.99) and 0.47 (95% CI 0.36–0.62), respectively. Prehospital nitroglycerin administration was also associated with significantly lower 30-day and 1-year mortality compared with no prehospital administration (OR 0.34 [95% CI 0.24–0.50] and 0.38 [95% CI 0.29–0.50], respectively). The certainty of evidence was very low in both systematic reviews.

Conclusions: Our systematic reviews suggest that prehospital administration of aspirin and nitroglycerin by non-physician healthcare professionals is beneficial for patients with suspected ACS, although the certainty of evidence is very low. Further investigation is needed to determine the benefit of the prehospital administration of these agents.

Systematic Review and Meta-Analysis of Diagnostic Accuracy to Identify ST-Segment Elevation Myocardial Infarction on Interpretations of Prehospital Electrocardiograms

Background: The aim of this study was to assess and discuss the diagnostic accuracy of prehospital ECG interpretation through systematic review and meta-analyses.

Methods and Results: Relevant literature published up to July 2020 was identified using PubMed. All human studies of prehospital adult patients suspected of ST-segment elevation myocardial infarction in which prehospital electrocardiogram (ECG) interpretation by paramedics or computers was evaluated and reporting all 4 (true-positive, false-positive, false-negative, and true-negative) values were included. Meta-analyses were conducted separately for the diagnostic accuracy of prehospital ECG interpretation by paramedics (Clinical Question [CQ] 1) and computers (CQ2). After screening, 4 studies for CQ1 and 6 studies for CQ2 were finally included in the meta-analysis. Regarding CQ1, the pooled sensitivity and specificity were 95.5% (95% confidence interval [CI] 82.5–99.0%) and 95.8% (95% CI 82.3–99.1%), respectively. Regarding CQ2, the pooled sensitivity and specificity were 85.4% (95% CI 74.1–92.3%) and 95.4% (95% CI 87.3–98.4%), respectively.

Conclusions: This meta-analysis suggests that the diagnostic accuracy of paramedic prehospital ECG interpretations is favorable, with high pooled sensitivity and specificity, with an acceptable estimated number of false positives and false negatives. Computer-assisted ECG interpretation showed high pooled specificity with an acceptable estimated number of false positives, whereas the pooled sensitivity was relatively low.

Performance of the 0-Hour/1-Hour Algorithm for Diagnosing Myocardial Infarction in Patients With Chest Pain in the Emergency Department ― A Systematic Review and Meta-Analysis ―

Background: This study assessed the diagnostic performance of the 0-hour/1-hour (0/1-h) algorithm to rule in and rule out acute myocardial infarction (MI) in patients presenting to the emergency department (ED) for suspected acute coronary syndrome without ST-segment elevation, as recommended in the 2015 European Society of Cardiology (ESC) guideline.

Methods and Results: Following the Preferred Reporting Items for a Systematic Review and Meta-analysis of Diagnostic Test Accuracy (PRISMA-DTA) guidelines, a systematic review was conducted using the PubMed database from inception to March 31, 2020. We included any article published in English investigating the diagnostic performance of the ESC 0/1-h algorithm for diagnosing MI in patients with chest pain visiting the ED. Of 651 studies identified as potentially available for the study, 7 studies including 16 databases were analyzed. A meta-analysis of the diagnostic accuracy of the 0/1-h algorithm using high-sensitivity cardiac troponin I (hs-cTn) with 6 observational databases showed a pooled sensitivity of 99.3% (95% confidence interval [CI] 98.5–99.7%) and a pooled specificity of 90.1% (95% CI 80.7–95.2%). A meta-analysis of the diagnostic accuracy of 10 observational databases of the ESC 0/1-h algorithm using hs-cTn revealed a pooled sensitivity of 99.3% (95% CI 96.9–99.9%) and a pooled specificity of 91.7% (95% CI 83.5–96.1%).

Conclusions: Our results demonstrate that the ESC 0/1-h algorithm can effectively rule in and rule out patients with non-ST-segment elevation MI.

Effects of Door-In to Door-Out Time on Mortality Among ST-Segment Elevation Myocardial Infarction Patients Transferred for Primary Percutaneous Coronary Intervention ― Systematic Review and Meta-Analysis ―

Background: Primary percutaneous coronary intervention (PCI) for ST-elevation myocardial infarction (STEMI) is now widely accepted. Recent guidelines have focused on total ischemic time, because shorter total ischemic time is associated with a more favorable prognosis. The door-in to door-out (DIDO) time, defined as time from arrival at a non-PCI-capable hospital to leaving for a PCI-capable hospital, may affect STEMI patient prognosis. However, a relevant meta-analysis is lacking.

Methods and Results: We searched PubMed for clinical studies comparing short-term (30-day and in-hospital) mortality rates of STEMI patients undergoing primary PCI with DIDO times of ≤30 vs. >30 min. Two investigators independently screened the search results and extracted the data. Random effects estimators with weights calculated by the inverse variance method were used to determine pooled risk ratios. The search retrieved 1,260 studies; of these, 2 retrospective cohort studies (15,596 patients) were analyzed. In the DIDO time ≤30 and >30 min groups, the primary endpoint (i.e., in-hospital or 30-day mortality) occurred for 51 of 1,794 (2.8%) and 831 of 13,802 (6.0%) patients, respectively. The incidence of the primary endpoint was significantly lower in the DIDO time ≤30 min group (odds ratio 0.45; 95% confidence interval 0.34–0.60).

Conclusions: Our findings suggest that a DIDO time ≤30 min is associated with a lower short-term mortality rate. However, further larger systematic reviews and meta-analyses are needed to validate our findings.

Impact of Induced Therapeutic Hypothermia by Intravenous Infusion of Ice-Cold Fluids After Hospital Arrival in Comatose Survivors of Out-of-Hospital Cardiac Arrest With Initial Shockable Rhythm

BACKGROUND

The effect of in-hospital rapid cooling by intravenous ice-cold fluids for comatose survivors of out-of-hospital cardiac arrest (OHCA) is unclear.Methods and Results:From the J-PULSE-HYPO study registry, data for 248 comatose survivors with return of spontaneous circulation (ROSC) who were treated with therapeutic hypothermia (34℃ for 12-72 h) after witnessed shockable OHCA were extracted. Patients were divided into 2 groups by the median collapse-to-ROSC interval (18 min), and then into 2 groups by cooling method (rapid cooling by intravenous ice-cold fluids vs. standard cooling). The primary endpoint was favorable neurological outcome (Cerebral Performance Category of 1 or 2) at 30 days after OHCA. In the whole cohort, the shorter collapse-to-ROSC interval group had significantly higher favorable neurological outcome than the longer collapse-to-ROSC interval group (78.2% vs. 46.8%, P<0.001). In the shorter collapse-to-ROSC interval group, no significant difference was observed in favorable neurological outcome between the 2 cooling groups (rapid cooling group: 79.4% vs. standard cooling group: 77.0%, P=0.75). In the longer collapse-to-ROSC interval group, however, favorable neurological outcome was significant higher in the rapid cooling group than in the standard cooling group (60.7% vs. 33.3%, P<0.01) and the adjusted odds ratio after rapid cooling was 3.069 (95% confidence interval 1.423-6.616, P=0.004).

CONCLUSIONS

In-hospital rapid cooling by intravenous ice-cold fluids improved neurologically intact survival in comatose survivors whose collapse-to-ROSC interval was delayed over 18 min after shockable OHCA.

Evaluating Effectiveness of YouTube Videos for Teaching Medical Students CPR: Solution to Optimizing Clinician Educator Workload during the COVID-19 Pandemic

(1) Background: This study aimed to evaluate the effectiveness of using a pre-existing video on CPR to support preclinical resuscitation education for medical students; (2) Methods: In total, 129 students selected to learn CPR using a pre-existing YouTube video or the conventional screencast video by their university faculties. All students responded to the pre- and post-training multiple-choice questionnaire on the basic knowledge of CPR, and, based on their responses, an analysis of covariance (ANCOVA) was conducted to assess the comparability of effectiveness across learning modalities. (3) Results: Among the students, 49 (38.0%) students selected the YouTube video to learn about CPR and were treated as the intervention group. The mean pre-test scores and post-test scores of the YouTube and the instructor's video groups were 6.43 and 6.64, and 9.06 and 9.09, respectively. After controlling for the pre-test score effects, the results of ANCOVA did not show statistically significant differences between groups (p = 0.927), indicating comparable performance between groups that used YouTube and the instructor's videos. (4) Conclusion: Utilizing YouTube videos is a useful teaching strategy for teaching CPR knowledge, which would reduce the burden on faculty of creating screencast lecture videos for online learning on resuscitation.

Cluster Randomized Trial of Duration of Cooling in Targeted Temperature Management After Resuscitation for Cardiac Arrest

Background: The 2020 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care recommend that comatose patients with return of spontaneous circulation after cardiac arrest have targeted temperature management (TTM). However, the duration of TTM remains to be elucidated. Methods and Results: We conducted a cluster randomized trial in 10 hospitals to compare 12-24 vs. 36 h of cooling in patients with cardiac arrest who received TTM. The primary outcome was the incidence, within 1 month, of complications including bleeding requiring transfusion, infection, arrhythmias, decreasing blood pressure, shivering, convulsions, and major adverse cardiovascular events. Secondary outcomes were mortality and favorable neurological outcome (Cerebral Performance Categories 1-2) at 3 months. Random-effects models with clustered effects were used to calculate risk ratios (RR). Data of 185 patients were analyzed (12- to 24-h group, n=100 in 5 hospitals; 36-h group, n=85 in 5 hospitals). The incidence of complications within 1 month did not differ between the 2 groups (40% vs. 34%; RR 1.04, 95% confidence interval [CI] 0.67-1.61, P=0.860). Favorable neurological outcomes at 3 months were comparable between the 2 groups (64% vs. 62%; RR 0.91, 95% CI 0.72-1.14, P=0.387). Conclusions: TTM at 34℃ for 12-24 h did not significantly reduce the incidence of complications. This study did not show superiority of TTM at 34℃ for 12-24 h for neurologic outcomes.

Machine learning model for predicting out-of-hospital cardiac arrests using meteorological and chronological data

OBJECTIVES

To evaluate a predictive model for robust estimation of daily out-of-hospital cardiac arrest (OHCA) incidence using a suite of machine learning (ML) approaches and high-resolution meteorological and chronological data.

METHODS

In this population-based study, we combined an OHCA nationwide registry and high-resolution meteorological and chronological datasets from Japan. We developed a model to predict daily OHCA incidence with a training dataset for 2005-2013 using the eXtreme Gradient Boosting algorithm. A dataset for 2014-2015 was used to test the predictive model. The main outcome was the accuracy of the predictive model for the number of daily OHCA events, based on mean absolute error (MAE) and mean absolute percentage error (MAPE). In general, a model with MAPE less than 10% is considered highly accurate.

RESULTS

Among the 1 299 784 OHCA cases, 661 052 OHCA cases of cardiac origin (525 374 cases in the training dataset on which fourfold cross-validation was performed and 135 678 cases in the testing dataset) were included in the analysis. Compared with the ML models using meteorological or chronological variables alone, the ML model with combined meteorological and chronological variables had the highest predictive accuracy in the training (MAE 1.314 and MAPE 7.007%) and testing datasets (MAE 1.547 and MAPE 7.788%). Sunday, Monday, holiday, winter, low ambient temperature and large interday or intraday temperature difference were more strongly associated with OHCA incidence than other the meteorological and chronological variables.

CONCLUSIONS

A ML predictive model using comprehensive daily meteorological and chronological data allows for highly precise estimates of OHCA incidence.

Comparison of clinical outcomes between patients with pulseless-ventricular tachycardia and ventricular fibrillation in out-of-hospital cardiac arrest

Aim

While previous studies have shown that the initial documented rhythm is associated with clinical outcomes in out-of-hospital cardiac arrest (OHCA), little is known about the difference in clinical outcomes between pulseless ventricular tachycardia (p-VT) and ventricular fibrillation (VF).

Methods

From a nationwide, prospective population-based database of OHCA from 2011 to 2015, we selected bystander-witnessed adult patients who were not treated with a public automated external defibrillator. The outcomes examined were favorable 30-day neurological survival rates, 30-day survival rates, and prehospital return of spontaneous circulation (ROSC) rates. To determine the association of the initial documented rhythm with outcome, we used a logistic regression model while adjusting for patient factors and prehospital care-related factors.

Results

A total of 19,594 bystander-witnessed OHCA patients who had a shockable rhythm were included: 454 (2.3%) were p-VT and 19,140 (97.7%) were VF. Compared to VF patients, p-VT patients were older, less likely to have a cardiogenic cause, and had shorter resuscitation-related time intervals (collapse to bystander cardiopulmonary resuscitation, collapse to emergency medical services contact, collapse to first ROSC, and first defibrillation to first ROSC). After adjustment for covariates, p-VT was associated with high favorable 30-day neurological survival rates (adjusted odds ratio [OR], 1.85; 95% confidence interval [CI], 1.30-2.64, p = 0.001), 30-day survival rates (adjusted OR, 1.41; 95% CI, 1.03-1.95, p = 0.037), and prehospital ROSC rates (adjusted OR, 1.90; 95% CI, 1.42-2.55, p < 0.001).

Conclusion

In this study, patients with p-VT as the initial documented rhythm had significantly better outcomes than those with VF.

Fine particulate matter and out-of-hospital cardiac arrest of respiratory origin

Exposure to ambient air pollution increases mortality and is a leading contributor to the global disease burden [1]. Epidemiological studies have elucidated a relationship between out-of-hospital cardiac arrests (OHCAs) and air pollutants, especially particulate matter (diameter ≤2.5 μm; PM_2.5) [2, 3]. The causes of OHCA are broadly categorised as cardiac and non-cardiac [4]. A 10 µg·m⁻³ increase in PM_2.5 exposure yielded a 1.6% increase in the incidence of cardiac origin OHCA [3, 5]. However, few studies on OHCAs of non-cardiac origin, including intrinsic respiratory diseases (COPD/pneumonia/asthma) are available. We examined the association between short-term exposure to PM_2.5 and bystander-witnessed respiratory origin OHCAs, including eventual prognosis. We also investigated differences between PM_2.5 exposure-related cardiac and respiratory origin OHCAs.

Particulate matter is a potential risk factor for out-of-hospital cardiac arrests (OHCAs) of respiratory origin. The percent increase in incidence of OHCA of respiratory origin is equivalent to that of PM_2.5 exposure-related OHCAs of cardiac origin.http://bit.ly/3tDXym0

Assessment of the 2015 cardiopulmonary resuscitation guidelines for patients with out-of-hospital cardiac arrest: results from the All-Japan Utstein registry

Background

The 2015 cardiopulmonary resuscitation (CPR) guidelines have stressed that high-quality CPR improves survival from cardiac arrest (CA). In particular, the guidelines recommended that it is reasonable for rescuers to perform chest compressions at a rate of 100 to 120/min in adult CA patients. However, it is unknown whether the 2015 guidelines contributed to favorable neurological outcome in adult CA patients. The present study aimed to clarify the effects of the 2015 guidelines in adult CA patients, using the data of the All-Japan Utstein Registry, a prospective, nationwide, population-based registry of out-of-hospital CA (OHCA).

Methods

From the data of this registry between 2011 and 2016, we included adult witnessed OHCA patients due to cardiac etiology, who had non-shockable rhythm as an initial rhythm. We excluded patients who received prehospital care in 2015 because it was difficult to distinguish prehospital care based on either 2010 CPR guidelines or 2015 CPR guidelines. We also excluded patients who received bystander CPR by citizens because we cannot assess the quality of bystander CPR in this registry. Study patients were divided into five groups based on different years (figure). The endpoint was the favorable neurological outcome at 30 days after OHCA. Potential confounding factors based on biological plausibility and previous studies were included in the multivariable logistic regression analysis. These variables included the age, sex (male, female), advanced airway or not, the administration of adrenaline or not, the administration of saline or not, instructed by dispatcher or not, and time interval from call EMS to scene.

Results

The figure showed favorable neurological outcomes at 30 days. In the multivariate analysis, the adjusted odds ratio for 30-day favorable neurological outcome in OHCA patients in 2016 as compared to in 2011 was 1.32 (95% CI: 1.04–1.68, p=0.022). On the other hands, there were no significant differences from 2011 to 2014.

Conclusion

In the OHCA patients with non-shockable rhythm, the 2015 guidelines were superior to the 2010 guidelines, in terms of neurological benefits.

Figure 1

Funding Acknowledgement

Type of funding source: None

The association between neuromuscular blockade use during target temperature management and neurological outcomes

BACKGROUND

To date, no study has comprehensively analyzed the association between neuromuscular blockade (NMB) during target temperature management (TTM) and the neurological outcomes after out-of-hospital cardiac arrest (OHCA) using a multicenter dataset. We aimed to examine the association between NMB during TTM after cardiac arrest and neurological outcomes after OHCA.

METHODS

This study was a secondary analysis of the Japanese Population-based Utstein-style study with defibrillation and basic/advanced Life Support Education and implementation-Hypothermia (J-PULSE-HYPO) study registry. The exposure of the current study was the use of NMB during TTM. The primary outcome was favorable neurological outcome, i.e., a cerebral performance category of 1-2, at hospital discharge.

RESULTS

Of the 452 patients with OHCA enrolled in the J-PULSE-HYPO study, 431 were analyzed. NMB was used in 353 patients (81.9%). Multivariable logistic regression analysis revealed that NMB use was not independently associated with favorable outcomes [odds ratio (OR), 0.96; 95% confidence interval (CI), 0.42-2.18; p = .918)] or survival at discharge (OR, 0.83; 95% CI, 0.31-2.02; p = .688). After adjusting the covariates, the predicted probabilities did not reveal significant differences between NMB use and non-NMB use in the respective mean (95% CI) values for favorable neurological outcomes [53.6 (50.2-57.0) % vs. 58.0 (50.4-65.6) %, p = .304], and survival rates [77.1 (74.7-79.5) % vs. 75.8 (70.5-81.0) %, p = .647].

CONCLUSIONS

The NMB use during TTM was not associated with favorable neurological outcomes and survival rate in patients with OHCA.

Intra-day change in occurrence of out-of-hospital ventricular fibrillation in Japan: The JCS-ReSS study

BACKGROUND

Real-world evidence of out-of-hospital ventricular fibrillation (VF), especially regarding intra-day change, remains unclear. We aimed to investigate that age- and gender-dependent difference of intra-day change of VF occurrence.

METHOD

We enrolled 71,692 patients (males: 56,419 [78.7%], females: 15,273 [21.3%]) in whom cardiac VF had been documented from the 2005-2015 All-Japan Utstein Registry data. Subjects were divided into four groups: group-I (<18 years old), group-II (18-39), group-III (40-69), and group-IV (≥70). Among four groups in each of male and female, we compared the intra-day change of VF occurrence, and evaluated the risk factors of the unfavorable neurologic outcomes at 1 month after VF.

RESULTS

Regardless of age, the incidence of VF was significantly greater in male than in female subjects. In male subjects, VF in group-I, III and IV occurred higher at daytime, however, group-II had no intra-day difference because group-II had a higher VF events at midnight~ early morning compared with other aged groups (Poisson regression analysis, p = .03). While in female, each group showed similar intra-day pattern of VF occurrence. Logistic regression analysis revealed that some of the clinical parameters such as time periods from call receipt to first shock and the presence of bystander cardiopulmonary resuscitation were important for risk of 30-day neurologically unfavorable outcomes.

CONCLUSIONS

The intra-day change of VF occurrence was age-dependently different in males but not in females, suggesting age- and gender-dependent differences in underlying cardiac diseases. These might affect the significant difference in unfavorable neurologic outcome.

Improved outcomes for out-of-hospital cardiac arrest patients treated by emergency life-saving technicians compared with basic emergency medical technicians: A JCS-ReSS study report

BACKGROUND

Emergency life-saving technicians (ELSTs) are specially trained prehospital medical providers believed to provide better care than basic emergency medical technicians (BEMTs). ELSTs are certified to perform techniques such as administration of advanced airways or adrenaline and are considered to have more knowledge; nevertheless, ELSTs' effectiveness over BEMTs regarding out-of-hospital cardiac arrest (OHCA) remains unclear. We investigated whether the presence of an ELST improves OHCA patient outcomes.

METHODS

In a retrospective study of adult OHCA patients treated in Japan from 2011 to 2015, we compared two OHCA patient groups: patients transported with at least one ELST and patients transported by only BEMTs. The primary outcome measure was one-month favorable neurological outcomes, defined as Cerebral Performance Category ≤ 2. A multivariable logistic regression model was used to calculate odds ratios (ORs) and their confidence intervals (CIs) to evaluate the effect of ELSTs.

RESULTS

Included were 552,337 OHCA patients, with 538,222 patients in the ELST group and 14,115 in the BEMT group. The ELST group had a significantly higher odds of favorable neurological outcomes (2.5% vs. 2.1%, adjusted OR 1.39, 95% CI 1.17-1.66), one-month survival (4.9% vs. 4.1%, adjusted OR 1.37, 95% CI 1.22-1.54), and return of spontaneous circulation (8.1% vs. 5.1%, adjusted OR 1.90, 95% CI 1.72-2.11) compared with the BEMT group. However, ELSTs' limited procedure range (adrenaline administration or advanced airway management) did not promote favorable neurological outcomes.

CONCLUSIONS

Compared with the BEMT group, transport by the ELST group was associated with better neurological outcomes in OHCA.

Association of Fine Particulate Matter Exposure With Bystander-Witnessed Out-of-Hospital Cardiac Arrest of Cardiac Origin in Japan

IMPORTANCE

Out-of-hospital cardiac arrests (OHCAs) are a major public health concern and a leading cause of death worldwide. Exposure to ambient air pollution is associated with increases in morbidity and mortality and has been recognized as a leading contributor to global disease burden.

OBJECTIVE

To examine the association between short-term exposure to particulate matter with a diameter of 2.5 μm or smaller (PM2.5) and the incidence of OHCAs of cardiac origin and with the development of initial cardiac arrest rhythm.

DESIGN, SETTING, AND PARTICIPANTS

This case-control study used data from cases registered between January 1, 2005, and December 31, 2016, in the All-Japan Utstein Registry, a prospective, nationwide, population-based database for OHCAs across all 47 Japanese prefectures. These OHCA cases included patients who had bystander-witnessed OHCAs and for whom emergency medical services responders initiated resuscitation before hospital transfer. A case-crossover design was employed for the study analyses. A prefecture-specific, conditional logistic regression model to estimate odds ratios was applied, and a random-effects meta-analysis was used to obtain prefecture-specific pooled estimates. All analyses were performed from May 7, 2019, to January 23, 2020.

MAIN OUTCOMES AND MEASURES

The main outcome was the association of short-term PM2.5 exposure with the incidence of bystander-witnessed OHCAs of cardiac origin. The differences in the distribution of initial cardiac arrest rhythm in OHCAs among those with exposure to PM2.5 were also examined.

RESULTS

In total, 103 189 OHCAs witnessed by bystanders were included in the final analysis. Among the patients who experienced such OHCAs, the mean (SD) age was 75 (15.5) years, and 62 795 (60.9%) were men. Point estimates of the percentage increase for a 10-μg/m3 increase in PM2.5 at lag0-1 (difference in mean PM2.5 concentrations measured on the case day and 1 day before) demonstrated a statistically significantly higher incidence of OHCA across most of the 47 prefectures, without significant heterogeneity (I2 = 20.1%; P = .12). A stratified analysis found an association between PM2.5 exposure and OHCAs (% increase, 1.6; 95% CI, 0.1%-3.1%). An initial shockable rhythm, such as ventricular fibrillation or pulseless ventricular tachycardia (% increase, 0.6; 95% CI, -2.0% to 3.2%), was not associated with PM2.5 exposure. However, an initial nonshockable rhythm, such as pulseless electrical activity and asystole, was associated with PM2.5 exposure (% increase, 1.4; 95% CI, 0.1%-2.7%).

CONCLUSIONS AND RELEVANCE

Findings from this study suggest that increased PM2.5 concentration is associated with bystander-witnessed OHCA of cardiac origin that commonly presents with nonshockable rhythm. The results support measures to reduce PM2.5 exposure to prevent OHCAs of cardiac origin.

Public-access defibrillation and neurological outcomes in patients with out-of-hospital cardiac arrest in Japan: a population-based cohort study

BACKGROUND

More than 80% of public-access defibrillation attempts do not result in sustained return of spontaneous circulation in patients who have had an out-of-hospital cardiac arrest (OHCA) and a shockable heart rhythm before arrival of emergency medical service (EMS) personnel. Neurological and survival outcomes in such patients have not been evaluated. We aimed to assess the neurological status and survival outcomes in such patients.

METHODS

This is a retropective analysis of a cohort study from a prospective, nationwide, population-based registry of 1 299 784 patients who had an OHCA event between Jan 1, 2005, and Dec 31, 2015 in Japan. The primary outcome was favourable neurological outcome (Cerebral Performance Category of 1 or 2) at 30 days after the OHCA and the secondary outcome was survival at 30 days following the OHCA. This study is registered with the University Hospital Medical Information Network Clinical Trials Registry, UMIN000009918.

FINDINGS

We identified 28 019 patients with bystander-witnessed OHCA and shockable heart rhythm who had received CPR from a bystander. Of these, 2242 (8·0%) patients did not achieve return of spontaneous circulation with CPR plus public-access defibrillation, and 25 087 (89·5%) patients did not achieve return of spontaneous circulation with CPR alone before EMS arrival. The proportion of patients with a favourable neurological outcome was significantly higher in those who received public-access defibrillation than those who did not (845 [37·7%] vs 5676 [22·6%]; adjusted odds ratio [OR] after propensity score-matching, 1·45 [95% CI 1·24-1·69], p<0·0001). The proportion of patients who survived at 30 days after the OHCA was also significantly higher in those who received public-access defibrillation than those who did not (987 [44·0%] vs 7976 [31·8%]; adjusted OR after propensity score-matching, 1·31 [95% CI 1·13-1·52], p<0·0001).

INTERPRETATION

Our findings support the benefits of public-access defibrillation and greater accessibility and availability of automated external defibrillators in the community.

FUNDING

None.

Geographical Differences and the National Meeting Effect in Patients with Out-of-Hospital Cardiac Arrests: A JCS-ReSS Study Report

The "national meeting effect" refers to worse patient outcomes when medical professionals attend academic meetings and hospitals have reduced staffing. The aim of this study was to examine differences in outcomes of patients with out-of-hospital cardiac arrest (OHCA) admitted during, before, and after meeting days according to meeting location and considering regional variation of outcomes, which has not been investigated in previous studies. Using data from a nationwide, prospective, population-based, observational study in Japan, we analyzed adult OHCA patients who underwent resuscitation attempts between 2011 and 2015. Favorable one-month neurological outcomes were compared among patients admitted during the relevant annual meeting dates of three national scientific societies, those admitted on identical days the week before, and those one week after the meeting dates. We developed a multivariate logistic regression model after adjusting for confounding factors, including meeting location and regional variation (better vs. worse outcome areas), using the "during meeting days" group as the reference. A total of 40,849 patients were included in the study, with 14,490, 13,518, and 12,841 patients hospitalized during, before, and after meeting days, respectively. The rates of favorable neurological outcomes during, before, and after meeting days was 1.7, 1.6, and 1.8%, respectively. After adjusting for covariates, favorable neurological outcomes did not differ among the three groups (adjusted OR (95% CI) of the before and after meeting dates groups was 1.03 (0.83-1.28) and 1.01 (0.81-1.26), respectively. The "national meeting effect" did not exist in OHCA patients in Japan, even after comparing data during, before, and after meeting dates and considering meeting location and regional variation.

Association Between Prehospital Supraglottic Airway Compared With Bag-Mask Ventilation and Glasgow-Pittsburgh Cerebral Performance Category 1 in Patients With Out-of-Hospital Cardiac Arrest

BACKGROUND

This study examined the association between prehospital supraglottic airway (SGA) and/or epinephrine compared with bag-mask ventilation (BMV) and Glasgow-Pittsburgh cerebral performance category (CPC) 1 status in patients with out-of-hospital cardiac arrest (OHCA) using a large, nationwide, population-based registry dataset.Methods and Results:This was a post hoc analysis of the All-Japan Utstein Registry. We included patients with OHCA of cardiac origin aged ≥18 years with resuscitation performed by emergency medical services (EMS) between January 2011 and December 2015. The primary endpoint was favorable neurological outcome (CPC 1). The patients were divided into 4 groups according to the prehospital management performed by EMS: BMV group received only basic life support (BLS); epinephrine group received BLS plus epinephrine; SGA group received BLS plus SGA; and combined group received BLS plus epinephrine and SGA. Univariate and multivariable logistic regression analyses were performed for the primary endpoint. Among the 106,434 patients with OHCA, 48,847 received only BMV, 8,958 received BLS+epinephrine, 25,467 received BLS+SGA, and 15,551 received BLS+epinephrine+SGA. Using the BMV group as the reference, multivariable analysis showed that the epinephrine, SGA, and combined groups were independently associated with a reduced incidence of favorable neurological outcomes.

CONCLUSIONS

Our results indicated that compared with BLS, patients in the prehospital SGA and/or epinephrine groups had a significantly reduced incidence of CPC 1 status.

P2666Association of out-of-hospital cardiac arrest occurrence time and the survival in all-Japan utstein registry: difference between international resuscitation guidelines 2005 and 2010

Background/Introduction

Previous studies have shown that out-of-hospital cardiac arrest (OHCA) occurring at night have poor outcomes compared with OHCA occurring during daytime. On the other hand, nationwide OHCA outcomes have gradually improved in Japan.

Purpose

We sought to examine whether one-month survival of OHCA differed between daytime and nighttime occurrences, and they differed between the periods of International Resuscitation Guidelines 2005 and 2010.

Methods

Using the All-Japan Utstein Registry between 2005 and 2015, adult OHCA patients whose collapse was witnessed by a bystander and the call-to-hospital admission interval was shorter than 120 min were included in this study. OHCA patients were divided by period of the International Resuscitation Guideline 2005 and 2010. Guideline 2005 included years from 2006 to 2010, while Guideline 2010 included years from 2011 to 2015. The primary outcome was one-month survival with favorable neurological outcome, defined as Cerebral Performance Category scale of 1 or 2. Daytime, evening, and night were defined as 0700 to 1459 h, 1500 to 2259 h, and 2300 to 0659 h, respectively.

Results

Among 479,046 cases, 20.3% revealed OHCA occurring at night. OHCA patients occurring at night had lower rate of bystander cardiopulmonary resuscitation (CPR) and automated external defibrillator use than those occurring at both daytime and evening. In addition, of those who received bystander CPR, higher rate of patients received CPR by family members. OHCA patients occurring at night in both guideline periods had significantly worse one-month survival than those occurring during daytime (reference) (adjusted odds ratio, 0.69, 0.64; 95% confidence interval 0.65–0.72, 0.61–0.67; P<0.001, P<0.001, Guideline 2005 and 2010 respectively). OHCA patients occurring during daytime in Guideline 2010 had better one-month survival than those in Guideline 2005 (adjusted odds ratio, 1.29; 95% confidence interval 1.24–1.34; P<0.001).

Conclusions

One-month survival with favorable neurological outcome in OHCA patients occurring at night remains to be significantly worse than those occurring during daytime, even improved by the periods during daytime. CPR training for the family members should be more expanded and strengthened against the night time imperfection.

P1701Sex-related difference in receiving bystander cardiopulmonary resuscitation and clinical outcome among out-of-hospital cardiac arrest patients

Background

Early studies from US and Europe have reported that female out-of-hospital cardiac arrest (OHCA) patients were less likely to receive bystander cardiopulmonary resuscitation (CPR). However, little is known about sex-related difference in receiving CPR and clinical outcome among adult OHCA patients in Japan.

Methods

This study was a nation-wide, population-based observational study of OHCA in Japan from 2011 to 2015. We included all adult cardiogenic OHCA patients. We excluded patients witnessed by emergency medical services (EMS) from the present analysis. To account for the age-related difference, we stratified by age category: 18–39, 40–64, 65–79, and ≥80. To examine the association between patient sex and neurological outcome at 30-day, we fitted multivariable logistic regression model with adjustment for age, bystander CPR status, first document rhythm, dispatcher instruction and EMS response time.

Results

There were 339,317 adult cardiogenic, not EMS-witnessed OHCA patients (median age, 80; female, 43.5%) in Japan from 2011 to 2015. Overall, 171,122 (50.4%) received CPR by citizen, 34,283 (10.1%) had initial shockable rhythm, and 11,421 (3.4%) had favorable neurological status at 30-day. Female patients were more likely to receive bystander CPR (vs. male; 53.8% vs. 47.8%), and were less likely to have initial shockable rhythm (5.2% vs. 13.9%) and favorable neurological status at 30-day (1.8% vs. 4.6%) (all; p<0.001). With stratification by age category, elderly female patients (aged ≥65) were more likely to received bystander CPR (P<0.001), whereas male patients were more likely to received bystander CPR among patients aged <40. Multivariable logistic regression analysis showed that female patients had a lower rate of favorable neurological status at 30-day, compared to male patients in all age categories (all; P<0.05).

Sex difference in bystander CPR Overall Male (n=191,672) Female (n=147,645) p-value All (n=339,317) 50.4% 47.8% 53.8% <0.001 Aged 18–39 (n=6,216) 56.0% 56.9% 53.5% 0.02 Aged 40–64 (n=50,320) 48.5% 48.5% 48.3% 0.69 Aged 65–80 (n=105,141) 46.5% 45.5% 48.3% <0.001 Aged ≥80 (n=177,640) 53.2% 49.0% 56.7% <0.001

OR for neurological outcome at 30-day

Conclusion

Unlike the situation in Europe and US, female OHCA patients, especially elderly female, were more likely to receive bystander CPR in Japan. However, female patients had worse clinical outcome after OHCA. Further investigations including in-hospital treatment are needed to clarify the sex-difference in clinical outcome after OHCA.

Acknowledgement/Funding

None

Association between rewarming duration and neurological outcome in out-of-hospital cardiac arrest patients receiving therapeutic hypothermia

AIM

The European Resuscitation Council guidelines recommend a slow rate of rewarming of 0.25 °C/h-0.5 °C/h for out-of-hospital cardiac arrest (OHCA) patients receiving therapeutic hypothermia (TH). Conversely, a very slow rewarming of 1 °C/day is generally applied in Japan. The rewarming duration ranged from less than 24 h up to more than 50 h. No randomized control trials have examined the optimal rewarming speed for TH in OHCA patients. Therefore, we examined the association between the rewarming duration and neurological outcomes in OHCA patients who received TH.

METHODS

This study was a secondary analysis of the Japanese Population-based Utstein-style study with defibrillation and basic/advanced Life Support Education and implementation-Hypothermia (J-PULSE-HYPO) study registry, a multicenter prospective cohort study. Patients suffering from OHCA who received TH (target temperature, 34 °C) after the return of spontaneous circulation from 2005 to 2011 in 14 hospitals throughout Japan were enrolled. The rewarming duration was defined as the time from the beginning of rewarming at a target temperature of 34 °C until reaching 36 °C. The primary outcome was an unfavorable neurological outcome at hospital discharge, i.e., a cerebral performance category of 3-5.

RESULTS

The J-PULSE-HYPO study enrolled 452 OHCA patients. Of these, 328 were analyzed; 79.9% survived to hospital discharge, of which 56.4% had a favorable neurological outcome. Multivariable logistic regression analysis revealed that the rewarming duration was independently associated with unfavorable neurological outcomes [odds ratio (per 5 h), 0.89; 95% confidence interval, 0.79-0.99; p =  0.032].

CONCLUSION

A longer rewarming duration was significantly associated with and was an independent predictor of favorable neurological outcomes in OHCA patients who received TH.

Citizen bystander-patient relationship and 1-month outcomes after out-of-hospital cardiac arrest of cardiac origin from the All-Japan Utstein Registry: a prospective, nationwide, population-based, observational study

OBJECTIVES

The presence of a bystander witness is a crucial predictor of patient survival after out-of-hospital cardiac arrest (OHCA). However, the differences in survival and neurological outcomes among different types of citizen bystanders are not well understood.

DESIGN

We analysed data from the All-Japan Utstein Registry, a prospective, nationwide, population-based, observational study that was started in January 2005.

SETTING

The registry includes all patients with OHCA who were transported to the hospital by emergency medical service (EMS) in Japan. The type of citizen bystander was classified as family member, friend, colleague, passerby or other.

PARTICIPANTS

We analysed 210 642 patients in the registry who were 18 years or older and experienced OHCA of cardiac origin witnessed by a citizen bystander between 2005 and 2014.

PRIMARY AND SECONDARY OUTCOME MEASURES

The main outcomes were 1 month survival and 1 month survival with minimal neurological impairment.

RESULTS

Of the citizen bystander-witnessed cases, 65.1% (137 147/210 642) were witnessed by a family member. However, among patients who survived to 1 month and who had a favourable 1 month neurological outcome, much lower proportions (53.9% (10 907/20 239) and 48.9% (5722/11 696)) were witnessed by a family member. Witness by a friend, colleague or passerby was associated with good 1 month neurological function, after controlling for the patient's age, first recorded rhythm, gender, bystander cardiopulmonary resuscitation (CPR), use of a public-access automated external defibrillator, dispatcher instructions, collapse-call time and response time compared with witness by a family member (friend: OR 1.35, 95% CI 1.24 to 1.46, colleague: OR 1.63, 95% CI 1.33 to 1.98, passerby: OR 1.60, 95% CI 1.39 to 1.84).

CONCLUSIONS

One-month survival and favourable1 month neurological outcome of patients with OHCA of cardiac origin witnessed by a family member were worse than those in cases witnessed by a friend, colleague or passerby, independent of the patient characteristics and the response of EMS.

The necessity of conversion from coronary care unit to the cardiovascular intensive care unit required for cardiologists

The in-hospital mortality rate of acute myocardial infarction (AMI) has dramatically decreased due to the treatment at the coronary care unit (CCU), especially with the progress of arrhythmia therapy and reperfusion therapy. On the other hand, severe heart failure and multiple organ failure are increasing due to aging populations and multiple organ diseases. As a result, patients with AMI without complications are less likely to be admitted to the CCU, and cardiologists staying in the CCU have also decreased. The mortality rate is high when complications such as cardiogenic shock, cardiac rupture, and in-hospital cardiac arrest occur in AMI, therefore careful intensive care even in low-risk AMI is necessary. For cardiologists, mechanical ventilation, renal replacement therapy, or infection control are necessary for cardiovascular intensive care, and integrated multidisciplinary care coordinated by skilled intensive care physicians, nurses, respiratory therapists, physiotherapists, pharmacists, nutritionists, social workers, and clinical engineers is important. Therefore, for the critical care of cardiovascular diseases, it is necessary to convert from CCU to the cardiovascular intensive care unit.

Public awareness of the need to call emergency medical services following the onset of acute myocardial infarction and associated factors in Japan

Objectives

Early recognition of acute myocardial infarction (AMI) and early activation of emergency medical services (EMS) are essential to reduce delays in patient care. We investigated public awareness of the need to call EMS at onset of AMI and evaluated associated factors.

Methods

In January 2008, a nationwide population-based survey using quota sampling was conducted in Japan. The primary outcome measure was responsiveness to promptly calling EMS at AMI onset, subdivided by on-time (daytime) and off-time (nights and holidays) hours.

Results

In total, 1200 participants were surveyed. Their mean age was 46.3 years (standard deviation, 17.4), and 50.3% (n=604) were women. A total of 11.6% (n=139) answered that they would call EMS during on-time hours, and 27.5% (n=330) stated that they would call during off-time hours. Multivariable analysis showed that the participants’ age, female sex, education level, and self-confidence regarding their understanding of AMI were significant associated factors. The associated factors were almost identical during the off-time hours; only sex was no longer significant.

Conclusions

Public awareness of the need to call EMS at AMI onset in Japan was low. Previous intervention studies that were not effective may not have targeted groups with significant risk factors.

Duration of Prehospital Resuscitation Efforts After Out-of-Hospital Cardiac Arrest

BACKGROUND

During out-of-hospital cardiac arrest, it is unclear how long prehospital resuscitation efforts should be continued to maximize lives saved.

METHODS AND RESULTS

Between 2005 and 2012, we enrolled 282 183 adult patients with bystander-witnessed out-of-hospital cardiac arrest from the All-Japan Utstein Registry. Prehospital resuscitation duration was calculated as the time interval from call receipt to return of spontaneous circulation in cases achieving prehospital return of spontaneous circulation or from call receipt to hospital arrival in cases not achieving prehospital return of spontaneous circulation. In each of 4 groups stratified by initial cardiac arrest rhythm (shockable versus nonshockable) and bystander resuscitation (presence versus absence), we calculated minimum prehospital resuscitation duration, defined as the length of resuscitation efforts in minutes required to achieve ≥99% sensitivity for the primary end point, favorable 30-day neurological outcome after out-of-hospital cardiac arrest. Prehospital resuscitation duration to achieve prehospital return of spontaneous circulation ranged from 1 to 60 minutes. Longer prehospital resuscitation duration reduced the likelihood of favorable neurological outcome (adjusted odds ratio, 0.84; 95% confidence interval, 0.838-0.844). Although the frequency of favorable neurological outcome was significantly different among the 4 groups, ranging from 20.0% (shockable/bystander resuscitation group) to 0.9% (nonshockable/bystander resuscitation group; P<0.001), minimum prehospital resuscitation duration did not differ widely among the 4 groups (40 minutes in the shockable/bystander resuscitation group and the shockable/no bystander resuscitation group, 44 minutes in the nonshockable/bystander resuscitation group, and 45 minutes in the nonshockable/no bystander resuscitation group).

CONCLUSIONS

On the basis of time intervals from the shockable arrest groups, prehospital resuscitation efforts should be continued for at least 40 minutes in all adults with bystander-witnessed out-of-hospital cardiac arrest.

CLINICAL TRIAL REGISTRATION

URL: http://www.umin.ac.jp/ctr/. Unique identifier: 000009918.

Association between dental caries and out-of-hospital cardiac arrests of cardiac origin in Japan

BACKGROUND

Oral infection contributes to atherosclerosis and coronary heart disease. We hypothesized that dental caries may be associated with out-of-hospital cardiac arrests (OHCA) of cardiac origin, but not non-cardiac origin.

METHODS AND RESULTS

We compared the age-adjusted incidence of OHCA (785,591 cases of OHCA: 55.4% of cardiac origin and 44.6% of non-cardiac origin) to the age-adjusted prevalence of dental caries between 2005 and 2011 in the 47 prefectures of Japan. In both the total population and males over 65 years, the number of cases of dental caries was significantly associated with the number of OHCA of total and cardiac origin from 2005 to 2011, but not those of non-cardiac origin. In the total population, the age-adjusted prevalence of dental caries was not significantly associated with the age-adjusted incidence of OHCA (total OHCA: r correlation coefficient=0.22, p=0.14; OHCA of cardiac origin: r=0.25, p=0.09; OHCA of non-cardiac origin: r=-0.002, p=0.99). Among male patients over 65 years, the age-adjusted prevalence of dental caries was significantly associated with OHCA of total and cardiac origin, but not non-cardiac origin (total OHCA: r=0.47, p<0.001; OHCA of cardiac origin: r=0.37, p=0.01; OHCA of non-cardiac origin: r=0.28, p=0.054).

CONCLUSIONS

While oral hygiene is important in all age groups, it may be particularly associated with OHCAs of cardiac origin in males over 65 years.

Effect of Admission Glasgow Coma Scale Motor Score on Neurological Outcome in Out-of-Hospital Cardiac Arrest Patients Receiving Therapeutic Hypothermia

BACKGROUND

Because the initial (on admission) Glasgow Coma Scale (GCS) examination has not been fully evaluated in comatose survivors of cardiac arrest (CA) who receive therapeutic hypothermia (TH), the aim of the present study was to determine any association between the admission GCS motor score and neurologic outcomes in patients with out-of-hospital CA who receive TH.

METHODS AND RESULTS

In the J-PULSE-HYPO study registry, patients with bystander-witnessed CA were eligible for inclusion. Patients were divided into 3 groups based on GCS motor score (1, 2-3, and 4-5) to assess various effects on neurologic outcome. Univariate and multivariate analyses were performed to identify independent predictors of good neurologic outcome at 90 days. Of 452 patients, 302 were enrolled. There was a significant difference among the 3 patient groups with regard to neurologic outcome at 90 days in the univariate analysis. Multiple logistic regression analyses showed that the GCS motor score on admission, age >65 years, bystander cardiopulmonary resuscitation, the time from collapse to return of spontaneous circulation, and pupil size <4 mm were independent predictors of a good neurologic outcome at 90 days in cases of CA (GCS motor score, 4-5: odds ratio, 8.18; 95% confidence interval: 1.90-60.28; P<0.01).

CONCLUSIONS

GCS motor score is an independent predictor of good neurologic outcome at 90 days in patients sustaining out-of-hospital CA who receive TH.

Effectiveness of lower target temperature therapeutic hypothermia in post-cardiac arrest syndrome patients with a resuscitation interval of ≤30 min

Background

Therapeutic hypothermia (TH) is a standard strategy to reduce brain damage in post-cardiac arrest syndrome (PCAS) patients. However, it is unknown whether the target temperature should be adjusted for PCAS patients in different states.

Methods

Participants in the J-PULSE-Hypo study database were divided into lower (32.0–33.5 °C; Group L) or moderate (34.0–35.0 °C; Group M) temperature groups. Primary outcome was a favourable neurological outcome (proportion of patients with a Glasgow-Pittsburgh Cerebral Performance Category [CPC] of 1–2 on day 30). We compared between the two groups and in subgroups of patients divided by age and resuscitation interval (interval from collapse to return of spontaneous circulation) by propensity score (PS) analysis.

Results

Overall, 467 participants were analysed. The proportions of patients with favourable neurological outcomes were as follows (Group L vs. Group M) (OR; Odds ratio): all patients, 64 % (n = 42) vs. 55 % ((n = 424) (PS; OR 1.381 (0.596–3.197)), P = 0.452) and resuscitation interval ≤ 30 min, 88 % (n = 24) vs. 64 % ((n = 281) (PS; OR 7.438 (1.769–31.272)), P = 0.007).

Conclusions

PCAS patients with a resuscitation interval of <30 min may be candidates for TH with a target temperature of <34 °C.

Trial registration

University Hospital Medical Information Network (UMIN) Clinical Trials Registry UMIN000001935; available at: https://upload.umin.ac.jp/cgi-open-bin/ctr/ctr.cgi?function=brows&action=brows&type=summary&recptno=R000002348&language=J.