Comparing outcomes of out-of-hospital cardiac arrest patients with initial shockable rhythm in Singapore and Osaka using population-based databases.

BACKGROUND: Previous research indicated outcomes among refractory out-of-hospital cardiac arrest (OHCA) patients with initial shockable rhythm were different in Singapore and Osaka, Japan, possibly due to the differences in access to extracorporeal cardiopulmonary resuscitation. However, this previous study had a risk of selection bias. To address this concern, this study aimed to evaluate the outcomes between Singapore and Osaka for OHCA patients with initial shockable rhythm using only population-based databases. METHODS: This was a secondary analysis of two OHCA population-based databases in Osaka and Singapore, including adult OHCA patients with initial shockable rhythm. A machine-learning-based prediction model was derived from the Osaka data (n = 3088) and applied to the PAROS-SG data (n = 2905). We calculated the observed-expected ratio (OE ratio) for good neurological outcomes observed in Singapore and the expected derived from the data in Osaka by dividing subgroups with or without prehospital ROSC. RESULTS: The one-month good neurological outcomes in Osaka and Singapore among patients with prehospital ROSC were 70% (791/1,125) and 57% (440/773), and among patients without prehospital ROSC were 10% (196/1963) and 2.8% (60/2,132). After adjusting patient characteristics, the outcome in Singapore was slightly better than expected from Osaka in patients with ROSC (OE ratio, 1.067 [95%CI 1.012 to 1.125]), conversely, it was worse than expected in patients without prehospital ROSC (OE ratio, 0.238 [95%CI 0.173 to 0.294]). CONCLUSION: This study showed the outcomes of OHCA patients without prehospital ROSC in Singapore were worse than expected derived from Osaka data even using population-based databases. (249/250 words).

Outcome assessment for out-of-hospital cardiac arrest patients in Singapore and Japan with initial shockable rhythm.

BACKGROUND: Singapore and Osaka in Japan have comparable population sizes and prehospital management; however, the frequency of ECPR differs greatly for out-of-hospital cardiac arrest (OHCA) patients with initial shockable rhythm. Given this disparity, we hypothesized that the outcomes among the OHCA patients with initial shockable rhythm in Singapore were different from those in Osaka. The aim of this study was to evaluate the outcomes of OHCA patients with initial shockable rhythm in Singapore compared to the expected outcomes derived from Osaka data using machine learning-based prediction models. METHODS: This was a secondary analysis of two OHCA databases: the Singapore PAROS database (SG-PAROS) and the Osaka-CRITICAL database from Osaka, Japan. This study included adult (18-74 years) OHCA patients with initial shockable rhythm. A machine learning-based prediction model was derived and validated using data from the Osaka-CRITICAL database (derivation data 2012-2017, validation data 2018-2019), and applied to the SG-PAROS database (2010-2016 data), to predict the risk-adjusted probability of favorable neurological outcomes. The observed and expected outcomes were compared using the observed-expected ratio (OE ratio) with 95% confidence intervals (CI). RESULTS: From the SG-PAROS database, 1,789 patients were included in the analysis. For OHCA patients who achieved return of spontaneous circulation (ROSC) on hospital arrival, the observed favorable neurological outcome was at the same level as expected (OE ratio: 0.905 [95%CI: 0.784-1.036]). On the other hand, for those who had continued cardiac arrest on hospital arrival, the outcomes were lower than expected (shockable rhythm on hospital arrival, OE ratio: 0.369 [95%CI: 0.258-0.499], and nonshockable rhythm, OE ratio: 0.137 [95%CI: 0.065-0.235]). CONCLUSION: This observational study found that the outcomes for patients with initial shockable rhythm but who did not obtain ROSC on hospital arrival in Singapore were lower than expected from Osaka. We hypothesize this is mainly due to differences in the use of ECPR.

In-hospital extracorporeal cardiopulmonary resuscitation for patients with out-of-hospital cardiac arrest: an analysis by time-dependent propensity score matching using a nationwide database in Japan.

BACKGROUND: Extracorporeal cardiopulmonary resuscitation (ECPR) has been proposed as a rescue therapy for patients with refractory cardiac arrest. This study aimed to evaluate the association between ECPR and clinical outcomes among patients with out-of-hospital cardiac arrest (OHCA) using risk-set matching with a time-dependent propensity score. METHODS: This was a secondary analysis of the JAAM-OHCA registry data, a nationwide multicenter prospective study of patients with OHCA, from June 2014 and December 2019, that included adults (≥ 18 years) with OHCA. Initial cardiac rhythm was classified as shockable and non-shockable. Patients who received ECPR were sequentially matched with the control, within the same time (minutes) based on time-dependent propensity scores calculated from potential confounders. The odds ratios with 95% confidence intervals (CI) for 30-day survival and 30-day favorable neurological outcomes were estimated for ECPR cases using a conditional logistic model. RESULTS: Of 57,754 patients in the JAAM-OHCA registry, we selected 1826 patients with an initial shockable rhythm (treated with ECPR, n = 913 and control, n = 913) and a cohort of 740 patients with an initial non-shockable rhythm (treated with ECPR, n = 370 and control, n = 370). In these matched cohorts, the odds ratio for 30-day survival in the ECPR group was 1.76 [95%CI 1.38-2.25] for shockable rhythm and 5.37 [95%CI 2.53-11.43] for non-shockable rhythm, compared to controls. For favorable neurological outcomes, the odds ratio in the ECPR group was 1.11 [95%CI 0.82-1.49] for shockable rhythm and 4.25 [95%CI 1.43-12.63] for non-shockable rhythm, compared to controls. CONCLUSION: ECPR was associated with increased 30-day survival in patients with OHCA with initial shockable and even non-shockable rhythms. Further research is warranted to investigate the reproducibility of the results and who is the best candidate for ECPR.

Timing of computed tomography imaging in adult patients with severe trauma: A nationwide cohort study in Japan.

PURPOSE: Computed tomography (CT) has become essential for the management of trauma patients. However, appropriate timing of CT acquisition remains undetermined. The purpose of this study was to assess the relationship between time to CT acquisition and mortality among adult patients with severe trauma. METHODS: We conducted a retrospective cohort study using data from the Japan Trauma Data Bank, which had 256 participating institutions from all over Japan between 2004 and 2018. Patients were categorized upon arrival as either severe trunk trauma with signs of shock or severe head trauma with coma and separately analyzed. Cases were further divided into three groups based on time elapsed between arrival at hospital and CT acquisition as immediate (0-29 min), intermediate (30-59 min), or late (≥60 min). Primary outcome was mortality on discharge, and multivariate logistic regression with adjusting for confounders was used for evaluation. RESULTS: A total of 8467 (3640 in immediate group, 3441 in intermediate group, 1386 in late group) with trunk trauma patients and 6762 (4367 in immediate group, 2031 in intermediate group, 364 in late group) with head trauma patients were eligible for analysis included in the trunk and head trauma groups, respectively. The trunk trauma patients with shock on hospital arrival was 56.4% (4773/8467), and the head trauma patients with deep coma upon EMS arrival was 44.2% (2988/6762). Mortality rate gradually increased from 5.7% to 15.8% with prolonged time to CT imaging among trunk trauma patients. Multivariate logistic regression for death on discharge among trunk trauma patients yielded an adjusted odds ratio of 1.79 (95% confidence interval: 1.42-2.27) for the late group compared to the immediate group. In contrast, among head trauma patients, an adjusted odds ratio was 0.93 (95% confidence interval: 0.71-1.20) for the late group compared to the immediate group. CONCLUSION: CT scan at or after 60 min was associated with increased death on discharge among patients with severe trunk trauma but not in those with severe head trauma.

Impact of the COVID-19 Pandemic on Prehospital Intervention and Survival of Patients With Out-of-Hospital Cardiac Arrest in Osaka City, Japan.

BACKGROUND: The coronavirus disease (COVID-19) pandemic may have influenced the prehospital emergency care and deaths of individuals experiencing an out-of-hospital cardiac arrest (OHCA).Methods and Results: We analyzed the registry data of 2,420 and 2,371 OHCA patients in Osaka City, Japan in 2019 and 2020, respectively, according to the 3 waves of the COVID-19 pandemic. Patient outcomes were compared using multivariable logistic regression analyses with the 2019 data as the reference. Bystander cardiopulmonary resuscitation (CPR) was initiated significantly less frequently in 2020 than in 2019 (2019: 48.0%, 2020: 42.7%, P<0.001), particularly during the first wave (2019: 47.2%, 2020: 42.9%, P=0.046) and second wave (2019: 48.1%, 2020: 41.2%, P=0.010), but not during the third wave (2019: 49.2%, 2020: 44.1%, P=0.066). The public-access automated external defibrillator was less frequently applied during the first wave (2019: 12.6%, 2020: 9.9%, P=0.043), with no significant difference during the second wave (2019: 12.5%, 2020: 12.8%, P=0.863) and third wave (2019: 13.7%, 2020: 13.0%, P=0.722). There was a significant difference in 1-month survival with favorable neurological outcomes (2019: 4.6%, 2020: 3.3%, P=0.018), with a 28% reduction in the adjusted odds ratio in 2020 (0.72; 95% confidence interval: 0.52-0.99, P=0.044). CONCLUSIONS: Bystander CPR and neurologically favorable outcomes after OHCA decreased significantly during the COVID-19 pandemic in Japan.

Clinical Phenotyping of Out-of-Hospital Cardiac Arrest Patients With Shockable Rhythm　- Machine Learning-Based Unsupervised Cluster Analysis.

BACKGROUND: The hypothesis of this study is that latent class analysis could identify the subphenotypes of out-of-hospital cardiac arrest (OHCA) patients associated with the outcomes and allow us to explore heterogeneity in the effects of extracorporeal cardiopulmonary resuscitation (ECPR).Methods and Results:This study was a retrospective analysis of a multicenter prospective observational study (CRITICAL study) of OHCA patients. It included adult OHCA patients with initial shockable rhythm. Patients from 2012 to 2016 (development dataset) were included in the latent class analysis, and those from 2017 (validation dataset) were included for evaluation. The association between subphenotypes and outcomes was investigated. Further, the heterogeneity of the association between ECPR implementation and outcomes was explored. In the study results, a total of 920 patients were included for latent class analysis. Three subphenotypes (Groups 1, 2, and 3) were identified, mainly characterized by the distribution of partial pressure of O2(PO2), partial pressure of CO2(PCO2) value of blood gas assessment, cardiac rhythm on hospital arrival, and estimated glomerular filtration rate. The 30-day survival outcomes were varied across the groups: 15.7% in Group 1; 30.7% in Group 2; and 85.9% in Group 3. Further, the association between ECPR and 30-day survival outcomes by subphenotype groups in the development dataset was as varied. These results were validated using the validation dataset. CONCLUSIONS: The latent class analysis identified 3 subphenotypes with different survival outcomes and potential heterogeneity in the effects of ECPR.

Public-access defibrillation and favorable neurological outcome after out-of-hospital cardiac arrest during the COVID-19 pandemic in Japan.

BACKGROUND: Early public-access defibrillation (PAD) effectively improves the outcomes of out-of-hospital cardiac arrests (OHCA), but several strategies implemented to prevent the spread of coronavirus disease 2019 (COVID-19) could decrease the availability of PAD and worsen outcomes after OHCA. Previous studies have reported conflicting findings, and there is a paucity of nationwide observations. This study aims to investigate the impact of COVID-19 on PAD and OHCA outcomes using a nationwide OHCA registry in Japan, where PAD is well-documented. METHODS: This secondary analysis of the All-Japan Utstein Registry, a prospective population-based nationwide registry of OHCA patients, included patients aged ≥ 18 years with bystander-witnessed OHCA and an initial shockable rhythm who were transported to medical facilities between January 1, 2005, and December 31, 2020. The analytical parameters of this study were the proportion of patients who underwent PAD and patients with one-month survival with favorable neurological outcomes, defined as a cerebral performance category score of 1 or 2. We compared the data between 2019 and 2020 using a multivariable logistic regression analysis. RESULTS: During the study period, 1,930,273 OHCA patients were registered; of these, 78,302 were eligible for the analysis. Before the COVID-19 pandemic, the proportion of OHCA patients who underwent PAD and demonstrated favorable neurological outcomes increased gradually from 2005 to 2019 (P for trend < 0.001). The proportion of patient who had PAD were 17.7% (876/4959) in 2019 and 15.1% (735/4869) in 2020, respectively. The proportion of patient who displayed favorable neurological outcomes were 25.1% (1245/4959) in 2019 and 22.8% (1109/4869) in 2020, respectively. After adjusting for potential confounders, a significant reduction in the proportion of PAD was observed compared to that in 2019 (adjusted odds ratio [AOR], 0.86; 95% confidence interval [CI], 0.76-0.97), while no significant reduction was observed in favorable neurological outcomes (AOR, 0.97; 95% CI 0.87-1.07). CONCLUSION: The proportion of PAD clearly decreased in 2020, probably due to the COVID-19 pandemic in Japan. In contrast, no significant reduction was observed in favorable neurological outcomes.

Early prognostic impact of serum sodium level among out-of-hospital cardiac arrest patients: a nationwide multicentre observational study in Japan (the JAAM-OHCA registry).

Dysnatremia is an electrolytic disorder commonly associated with mortality in various diseases. However, little is known about dysnatremia in out-of-hospital cardiac arrest (OHCA) cases. Here, we investigated the association between serum sodium level on hospital arrival and neurological outcomes after OHCA. This nationwide hospital-based observational study (The Japanese Association for Acute Medicine Out-of-Hospital Cardiac Arrest registry) enrolled patients with OHCA between 2014 and 2017. We included adult patients aged ≥ 18 years with non-traumatic OHCA who achieved return of spontaneous circulation (ROSC) and whose serum sodium level on hospital arrival was available. Based on the serum sodium level, patients were divided into three levels: hyponatremia (Na < 135 mEq/L), normal sodium level (Na ≥ 135 or ≤ 145 mEq/L), and hypernatremia (Na > 145 mEq/L). The primary outcome was 1-month survival with favourable neurological outcomes. Altogether, 34 754 patients with OHCA were documented, and 5160 patients with non-traumatic OHCA and who achieved ROSC were eligible for our analyses. The proportion of favourable neurological outcomes was highest in patients with normal sodium levels at 17.6% (677/3854), followed by patients with hyponatremia at 8.2% (57/696) and patients with hypernatremia at 5.7% (35/610). Moreover, hyponatremia and hypernatremia were associated with a decreased probability of favourable neurological outcomes compared with normal sodium level (vs. hyponatremia, adjusted odds ratio [AOR] 0.97, 95% confidence interval [CI] 0.95-0.99; vs. hypernatremia, AOR 0.96, 95% CI 0.94-0.98). Hypo- and hypernatremia on hospital arrival were associated with a decreased probability of favourable neurological outcomes in patients with non-traumatic OHCA who achieved ROSC.

Oxyhaemoglobin Level Measured Using Near-Infrared Spectrometer Is Associated with Brain Mitochondrial Dysfunction After Cardiac Arrest in Rats.

Cerebral blood oxygenation (CBO), measured using near-infrared spectroscopy (NIRS), can play an important role in post-cardiac arrest (CA) care as this emerging technology allows for noninvasive real-time monitoring of the dynamic changes of tissue oxygenation. We recently reported that oxyhaemoglobin (oxy-Hb), measured using NIRS, may be used to evaluate the quality of chest compressions by monitoring the brain tissue oxygenation, which is a critical component for successful resuscitation. Mitochondria are the key to understanding the pathophysiology of post-CA oxygen metabolism. In this study, we focused on mitochondrial dysfunction, aiming to explore its association with CBO parameters such as oxy-Hb and deoxyhaemoglobin (deoxy-Hb) or tissue oxygenation index (TOI). Male Sprague-Dawley rats were used in the study. We applied NIRS between the nasion and the upper cervical spine. Following 10 min of CA, the rats underwent cardiopulmonary resuscitation (CPR) with a bolus injection of 20 µg/kg epinephrine. At 10 and 20 min after CPR, brain, and kidney tissues were collected. We isolated mitochondria from these tissues and evaluated the association between CBO and mitochondrial oxygen consumption ratios. There were no significant differences in the mitochondrial yields (10 vs. 20 min after resuscitation: brain, 1.33 ± 0.68 vs. 1.30 ± 0.75 mg/g; kidney, 19.5 ± 3.2 vs. 16.9 ± 5.3 mg/g, respectively). State 3 mitochondrial oxygen consumption rates, known as ADP-stimulated respiration, demonstrated a significant difference at 10 vs. 20 min after CPR (brain, 170 ± 26 vs. 115 ± 17 nmol/min/mg protein; kidney, 170 ± 20 vs. 130 ± 16 nmol/min/mg protein, respectively), whereas there was no significant difference in ADP non-dependent state 4 oxygen consumption rates (brain, 34.0 ± 6.7 vs. 31.8 ± 10 nmol/min/mg protein; kidney, 29.8 ± 4.8 vs. 21.0 ± 2.6 nmol/min/mg protein, respectively). Consequently, the respiratory control ratio (RCR = state 3/state 4) showed a significant difference over time, but this was only noted in the brain (brain, 5.0 ± 0.29 vs. 3.8 ± 0.64; kidney, 5.8 ± 0.53 vs. 6.2 ± 0.25 nmol/min/mg protein, respectively). The oxy-Hb levels had a dynamic change after resuscitation, and they had a significant association with the RCR of the brain mitochondria (r = 0.8311, p = 0.0102), whereas deoxy-Hb and TOI did not (r = -0.1252, p = 0.7677; r = 0.4186, p = 0.302, respectively). The RCRs of the kidney mitochondria did not have a significant association with CBO (oxy-Hb, r = -0.1087, p = 0.7977; deoxy-Hb, r = 0.1565, p = 0.7113; TOI, r = -0.1687, p = 0.6896, respectively). The brain mitochondrial respiratory dysfunction occurred over time, and it was seen at the time points between 10 and 20 min after CPR. The oxy-Hb level was associated with brain mitochondrial dysfunction during the early post-resuscitation period.

Association between initial body temperature on hospital arrival and neurological outcome among patients with out-of-hospital cardiac arrest: a multicenter cohort study (the CRITICAL study in Osaka, Japan).

BACKGROUND: The association between spontaneous initial body temperature on hospital arrival and neurological outcomes has not been sufficiently studied in patients after out-of-hospital cardiac arrest (OHCA). METHODS: From the prospective database of the Comprehensive Registry of Intensive Care for OHCA Survival (CRITICAL) study in Osaka, Japan, we enrolled all patients with OHCA of medical origin aged > 18 years for whom resuscitation was attempted and who were transported to participating hospitals between 2012 and 2019. We excluded patients who were not witnessed by bystanders and treated by a doctor car or helicopter, which is a car/helicopter with a physician. The patients were categorized into three groups according to their temperature on hospital arrival: ≤35.9 °C, 36.0-36.9 °C (normothermia), and ≥ 37.0 °C. The primary outcome was 1-month survival, with a cerebral performance category of 1 or 2. Multivariable logistic regression analyses were performed to evaluate the association between temperature and outcomes (normothermia was used as the reference). We also assessed this association using cubic spline regression analysis. RESULTS: Of the 18,379 patients in our database, 5014 witnessed adult OHCA patients of medical origin from 16 hospitals were included. When analyzing 3318 patients, OHCA patients with an initial body temperature of ≥37.0 °C upon hospital arrival were associated with decreased favorable neurological outcomes (6.6% [19/286] odds ratio, 0.51; 95% confidence interval, 0.27-0.95) compared to patients with normothermia (16.4% [180/1100]), whereas those with an initial body temperature of ≤35.9 °C were not associated with decreased favorable neurological outcomes (11.1% [214/1932]; odds ratio, 0.78; 95% confidence interval, 0.56-1.07). The cubic regression splines demonstrated that a higher body temperature on arrival was associated with decreased favorable neurological outcomes, and a lower body temperature was not associated with decreased favorable neurological outcomes. CONCLUSIONS: In adult patients with OHCA of medical origin, a higher body temperature on arrival was associated with decreased favorable neurologic outcomes.

Trends in In-Hospital Advanced Management and Survival of Out-of-Hospital Cardiac Arrest Among Adults From 2013 to 2017　- A Multicenter, Prospective Registry in Osaka, Japan.

BACKGROUND: The aim of our study was to investigate in detail the temporal trends in in-hospital characteristics, actual management, and survival, including neurological status, among adult out-of-hospital cardiac arrest (OHCA) patients in recent years.Methods and Results:From the prospective database of the Comprehensive Registry of Intensive Care for OHCA Survival (CRITICAL) study in Osaka, Japan, we enrolled all OHCA patients aged ≥18 years for whom resuscitation was attempted, and who were transported to participating hospitals between the years 2013 and 2017. The primary outcome measure was 1-month survival with favorable neurological outcome after OHCA. Temporal trends in in-hospital management and favorable neurological outcome among adult OHCA patients were assessed. Of the 11,924 patients in the database, we included a total of 10,228 adult patients from 16 hospitals. As for in-hospital advanced treatments, extracorporeal cardiopulmonary resuscitation (ECPR) use increased from 2.4% in 2013 to 4.3% in 2017 (P for trend <0.001). However, the proportion of adult OHCA patients with favorable neurological outcome did not change during the study period (from 5.7% in 2013 to 4.4% in 2017, adjusted odds ratio (OR) for 1-year increment: 0.98 (95% confidence interval: 0.94-1.23)). CONCLUSIONS: In this target population, in-hospital management such as ECPR increased slightly between 2013 and 2017, but 1-month survival with favorable neurological outcome after adult OHCA did not improve significantly.

Predictive value of sarcopenic findings in the psoas muscle on CT imaging among patients with sepsis.

PURPOSE: This study aimed to determine the association between sarcopenic findings of the psoas muscle and mortality in patients with sepsis; further, it aimed to assess its clinical utility, in addition to the sequential organ failure assessment (SOFA) score, in predicting mortality. METHOD: This retrospective single-center cohort study included adult patients with sepsis, who were admitted to the intensive care unit, between January 2012 and December 2018. The cross-sectional area of the psoas muscle at the L3 level was measured using computed tomography (CT) images, following which the subjects were categorized as "Above middle," "Middle," and "Sarcopenic." The association between sarcopenic findings and 90-day mortality was investigated by logistic regression analysis. A "modified SOFA score," by adding sarcopenic findings to the SOFA score, was developed and evaluated for its predictive performance. RESULTS: Here, 255 patients with sepsis, who were admitted to the intensive care unit (median age, 76 [64-84] years; SOFA score, 9 [5-14]), were included. The adjusted odds ratio for the "Middle" and "Sarcopenic" groups for 90-day mortality was 2.40 (95% confidence interval [CI]: 0.93-6.15) and 3.67 (95% CI: 1.39-9.68), respectively. The c-statistics of the SOFA and modified SOFA score was 0.731 [95% CI: 0.650-0.799] and 0.749 [95% CI: 0.673-0.813]. On decision curve analysis, a little additional net benefit was observed on using the modified SOFA score. CONCLUSION: The results suggested an association of the sarcopenic findings of the psoas muscle on CT imaging with 90-day mortality; however, the modified SOFA had few additional clinical values to that of SOFA in predicting 90-day mortality.

Relationship between the number of pediatric patients with rotavirus and telephone triage for associated symptoms.

BACKGROUND: Earlier syndromic surveillance may be effective in preventing the spread of infectious disease. However, there has been no research on syndromic surveillance for rotavirus. The study aimed to assess the relationship between the incidence of rotavirus infections and the number of telephone triages for associated symptoms in pediatric patients under 4 years old in Osaka prefecture, Japan. METHODS: This was a retrospective observational study for which the study period was the 3 years between January 2015 and December 2017. We analyzed data on children under 4 years old who were triaged by telephone triage nurses using software. The primary endpoint was the number of rotavirus patients under 4 years triaged old per week. Using a linear regression model, we calculated the R square value of the regression model to assess the relationship between the number of patients with rotavirus and the number of telephone triages made for associated symptoms. Covariates in the linear regression model were the week number indicating seasonality and the weekly number of telephone triages related to rotavirus symptoms such as stomachache and vomiting. RESULTS: During the study period, there were 102,336 patients with rotavirus, and the number of people triaged by telephone was 123,720. The highest correlation coefficient was 0.921 in the regression model with the number of telephone triages for "stomachache + nausea/vomiting" and "stomachache + diarrhea + nausea/vomiting". CONCLUSION: The number of telephone triage symptoms was positively related to the incidence of pediatric patients with rotavirus in a large metropolitan area of Japan.

Effect of Adrenaline on Cerebral Blood Oxygenation Measured by NIRS in a Rat Asphyxia Cardiac Arrest Model.

Adrenaline is an important pharmacologic treatment during cardiac arrest (CA) for resuscitation. Recent studies suggest that adrenaline increases the likelihood of return of spontaneous circulation (ROSC) but does not contribute to improving neurological outcomes of CA. The mechanisms have not been elucidated yet. A bimodal increase in mean arterial pressure (MAP) is observed after adrenaline injection in rodent CA models [17]. In this study, we focused on alteration of systemic arterial pressure in conjunction with the measurement of cerebral blood oxygenation (CBO) such as oxyhemoglobin (Oxy-Hb), deoxyhemoglobin (Deoxy-Hb), and tissue oxygenation index (TOI) by near-infrared spectroscopy (NIRS). Male Sprague-Dawley rats were used. We attached NIRS between the nasion and the upper cervical spine. Rats underwent 10-minute asphyxia to induce CA. Then, cardiopulmonary resuscitation (CPR) was started, followed by a 20 µg/kg of bolus adrenaline injection at 30 seconds of CPR. This injection accelerated the first increase in MAP, and ROSC was observed with an abrupt increase in CBO. Interestingly, the second increase in MAP, once it exceeded a certain value, was accompanied by paradoxical decreases of Oxy-Hb and TOI, while Deoxy-Hb increased. Based on this finding, we compared Oxy-Hb, Deoxy-Hb, and TOI at the first MAP ≈ 100 mmHg and the second MAP ≈ 100 mmHg. The average of Oxy-Hb and TOI from the 13 animals significantly decreased at the second increase in MAP over 100 mmHg, while Deoxy-Hb significantly increased. NIRS identified a decrease in Oxy-Hb after ROSC. These findings may be a clue to understanding the mechanism of how and why adrenaline alters the neurological outcomes of CA post-resuscitation.

Evaluation of the Quality of Chest Compression with Oxyhemoglobin Level by Near-Infrared Spectroscopy in a Rat Asphyxia Cardiac Arrest Model.

The real-time evaluation of chest compression during cardiopulmonary resuscitation is important to increase the chances of survival from a cardiac arrest (CA). In addition, cerebral oxygen level measured by near-infrared spectroscopy (NIRS) plays an important role as an indicator of return of spontaneous circulation. Recently, we developed a new method to improve the quality of chest compression using a thoracic pump in conjunction with the classic cardiac pump in a rat asphyxia CA model. This study evaluated the quality of chest compression using NIRS in male Sprague-Dawley rats. NIRS was attached between the nasion and the upper cervical spine, and rats underwent 10 minute asphyxia CA. After CA, we alternately performed three different types of chest compression (cardiac, thoracic, and cardiac plus thoracic pumps) every 30 seconds for up to 4 and a half minutes. We measured the oxyhemoglobin (Oxy-Hb), deoxyhemoglobin (Deoxy-Hb), and tissue oxygenation index (TOI) and compared these values between the groups. Oxy-Hb was significantly different among the groups (cardiac, thoracic, and cardiac plus thoracic, 1.5 ± 0.9, 4.4 ± 0.7, and 5.9 ± 2.1 µmol/L, p < 0.01, respectively), while Deoxy-Hb and TOI were not (Deoxy-HB -2.7 ± 1.2, -1.1 ± 3.2, and -1.6 ± 10.1 µmol/L; TOI, 1.8 ± 1.8, 5.5 ± 1.3, and 9.5 ± 8.0%, respectively). Oxy-Hb showed potential to evaluate the quality of chest compression in a rat asphyxia CA model.

Effect of Adrenaline on Cerebral Blood Oxygenation Measured by NIRS in a Rat Asphyxia Cardiac Arrest Model.

Adrenaline is an important pharmacologic treatment during cardiac arrest (CA) for resuscitation. Recent studies suggest that adrenaline increases the likelihood of return of spontaneous circulation (ROSC) but does not contribute to improving neurological outcomes of CA. The mechanisms have not been elucidated yet. A bimodal increase in mean arterial pressure (MAP) is observed after adrenaline injection in rodent CA models (Okuma et al. Intensive Care Med Exp 7(1), 2019). In this study, we focused on alteration of systemic arterial pressure in conjunction with the measurement of cerebral blood oxygenation (CBO) such as oxyhemoglobin (Oxy-Hb), deoxyhemoglobin (Deoxy-Hb), and tissue oxygenation index (TOI) by near-infrared spectroscopy (NIRS). Male Sprague-Dawley rats were used. We attached NIRS between the nasion and the upper cervical spine. Rats underwent 10 minute asphyxia to induce CA. Then, cardiopulmonary resuscitation (CPR) was started, followed by a 20 µg/kg of bolus adrenaline injection at 30 seconds of CPR. This injection accelerated the first increase in MAP, and ROSC was observed with an abrupt increase in CBO. Interestingly, the second increase in MAP, once it exceeded a certain value, was accompanied by paradoxical decreases of Oxy-Hb and TOI while Deoxy-Hb increased. Based on this finding, we compared Oxy-Hb, Deoxy-Hb, and TOI at the first MAP ≈ 100 mmHg and the second MAP ≈ 100 mmHg. The average of Oxy-Hb and TOI from the 13 animals significantly decreased at the second increase in MAP over 100 mmHg while Deoxy-Hb significantly increased. NIRS identified a decrease in Oxy-Hb after ROSC. These findings may be a clue in understanding the mechanism of how and why adrenaline alters the neurological outcomes of CA post resuscitation.

Assessment of Cerebral Blood Oxygenation by Near-Infrared Spectroscopy before and after Resuscitation in a Rat Asphyxia Cardiac Arrest Model.

Clinical investigators have focused on the real-time evaluation of cerebral blood oxygenation (CBO) by near-infrared spectroscopy (NIRS) during cardiopulmonary resuscitation (CPR). A previous study showed that an abrupt increase of oxy-hemoglobin (Hb) level and tissue oxygenation index (TOI) was associated with the timing of return of spontaneous circulation (ROSC). However, it is not clear how TOI alters before and after CPR including a period of cardiac arrest (CA). Therefore, this study aimed to assess CBO with asphyxia CA and its association with CPR to ROSC in rats. Male Sprague-Dawley rats were used. We attached NIRS (NIRO-200NX, Hamamatsu Photonics, Japan) from the nasion to the upper cervical spine in rats. A ten-minute asphyxia was given to induce CA. After CA, mechanical ventilation was restarted, and manual CPR was performed. We examined the mean arterial pressure (MAP), end-tidal carbon dioxide (ETCO2), and Oxy/Deoxy-Hb and TOI. Out of 14 rats, 11 obtained sustained ROSC. After the induction of asphyxia, a rapid drop of TOI was observed, followed by a subsequent increase of Oxy-Hb, Deoxy-Hb, and TOI with CPR. Recent CPR guidelines suggest the use of ETCO2 during CPR since its abrupt increase is a reasonable indicator of ROSC. In this study, abrupt increases in MAP, ETCO2, and TOI were observed at the time of ROSC. TOI can be an alternative to ETCO2 for identifying ROSC after CA, and it also has the capability of monitoring CBO during and after CPR.

Characteristics and Outcomes of Out-of-Hospital Cardiac Arrest in Educational Institutions in Japan　- All-Japan Utstein Registry.

BACKGROUND: Although schools are key places that conduct cardiopulmonary resuscitation (CPR) and public-access defibrillation (PAD) programs, out-of-hospital cardiac arrest (OHCA) in educational institutions is poorly understood. This study describes the characteristics and outcomes of such OHCAs.Methods and Results:Data for OHCAs of any cause occurring in educational institutions between 2013 and 2015 were extracted from the All-Japan Utstein Registry. Patient characteristics and outcomes were documented. Subjects were divided into 6 age groups (0-1, 2-5, 6-11, 12-14, 15-17, and ≥18 years). Among the 783 eligible OHCA patients, most received bystander CPR regardless of age, ranging from 73.9% in those aged ≥18 years to 90.0% in those aged 2-5 years. However, the proportion receiving PAD differed by age group, ranging from 2.9% in those aged 0-1 years to 66.7% in those aged 12-14 years. The proportion of patients with 1-month survival with favorable neurological outcome differed significantly by age group, being extremely low among patients aged 0-1 years (zero for OHCA of cardiac origin), but high among patients aged 6-11, 12-14, and 15-17 years (69.2%, 77.5%, and 70.0%, respectively) for OHCA of cardiac origin. CONCLUSIONS: The outcomes of OHCA occurring in educational institutions, where PAD is available, differed significantly by age.

Impact of Bystander Cardiopulmonary Resuscitation and Dispatcher Assistance on Survival After Out-of-Hospital Cardiac Arrest Among Adult Patients by Location of Arrest.

We investigated the impact of bystander-initiated cardiopulmonary resuscitation (CPR), dispatcher assistance (DA), and location of arrest on survival and outcomes after out-of-hospital cardiac arrest (OHCA).From a nationwide population-based registry of OHCA patients in Japan, we enrolled adult patients with bystander-witnessed OHCA of medical origin between 2013 and 2015. The primary outcome measure was a neurologically favorable outcome, defined by cerebral performance category 1 or 2. Multivariable logistic regression analysis was used to assess the effects of bystander CPR and DA by location of arrest. A total of 104,621 cases were included (15,984 bystander CPR without DA [15.3%], 40,087 bystander CPR with DA [38.3%], and 48,550 no bystander CPR [46.4%]). In public locations, both the bystander-CPR-with-DA group (22.9% [1,068/4,665]; adjusted odds ratio (AOR), 1.62; 95% confidence interval (CI), 1.43-1.85) and the bystander-CPR-without-DA group (25.8% [918/3,557]; AOR, 1.43; 95% CI, 1.24-1.65) had neurologically favorable outcomes compared with the no-bystander-CPR group (9.9% [610/6,133]). In residential locations, the AORs were 1.44 (95% CI, 1.22-1.70) in the bystander-CPR-without-DA group and 1.60 (95% CI, 1.45-1.77) in the bystander-CPR-with-DA group. However, in nursing homes, bystander CPR was not associated with improved outcomes of OHCA, regardless of the implementation of DA.Bystander CPR with or without DA had better outcomes after OHCA in residential and public locations but not in nursing homes.

Poor Long-Term Survival of Out-of-Hospital Cardiac Arrest in Children.

The effect of post-cardiac arrest care in children with out-of-hospital cardiac arrest (OHCA) has not been adequately established, and the long-term outcome after pediatric OHCA has not been sufficiently investigated. We describe here detailed in-hospital characteristics, actual management, and survival, including neurological status, 90 days after OHCA occurrence in children with OHCA transported to critical care medical centers (CCMCs).We analyzed the database of the Comprehensive Registry of Intensive Care for OHCA Survival (CRITICAL) study, which is a multicenter, prospective observational data registry designed to accumulate both pre- and in-hospital data on OHCA treatments. We enrolled all consecutive pediatric patients aged <18 years who had an OHCA and for whom resuscitation was attempted and who were transported to CCMCs between 2012 and 2016.A total of 263 pediatric patients with OHCA were enrolled. The average age of the patients was 6.3 years, 38.0% were aged < 1 year, and 60.8% were male. After hospital arrival, 4.9% of these pediatric patients received defibrillation; 1.9%, extracorporeal life support; 6.5%, target temperature management; and 88.2% adrenaline administration. The proportions of patients with 90-day survival and a pediatric cerebral performance category (PCPC) score of 1 or 2 were 6.1% and 1.9%, respectively. The proportion of patients with a PCPC score of 1 or 2 at 90 days after OHCA occurrence did not significantly improve during the study period.The proportion of pediatric patients with a 90-day PCPC score of 1 or 2 transported to CCMCs was extremely low, and no significant improvements were observed during the study period.