Effects of advanced life support on patients who suffered cardiac arrest outside of hospital and were defibrillated.

BACKGROUND: The effects and relative benefits of advanced airway management and epinephrine on patients with out-of-hospital cardiac arrest (OHCA) who were defibrillated are not well understood. METHODS: This was a prospective observational study. Using data of all out-of-hospital cardiac arrest cases occurring between 2005 and 2013 in Japan, hierarchical logistic regression and conditional logistic regression along with time-dependent propensity matching were performed. Outcome measures were survival and minimal neurological impairment [cerebral performance category (CPC) 1 or 2] at 1month after the event. RESULTS: We analyzed 37,873 cases that met the inclusion criteria. Among propensity-matched patients, advanced airway management and/or prehospital epinephrine use was related to decreased rates of 1-month survival (adjusted odds ratio 0.88, 95% confidence interval 0.80 to 0.97) and CPC (1, 2) (adjusted odds ratio 0.56, 95% confidence interval 0.48 to 0.66). Advanced airway management was related to decreased rates of 1-month survival (adjusted odds ratio 0.89, 95% confidence interval 0.81to 0.98) and CPC (1, 2) (adjusted odds ratio 0.54, 95% confidence interval 0.46 to 0.64) in patients who did not receive epinephrine, whereas epinephrine use was not related to the outcome measures. CONCLUSIONS: In defibrillated patients with OHCA, advanced airway management and/or epinephrine are related to reduced long-term survival, and advanced airway management is less beneficial than epinephrine. However, the proportion of patients with OHCA who responded to an initial shock was very low in the study subjects, and the external validity of our findings might be limited.

Rationale and study design of the Japan environment and children's study (JECS).

BACKGROUND: There is global concern over significant threats from a wide variety of environmental hazards to which children face. Large-scale and long-term birth cohort studies are needed for better environmental management based on sound science. The primary objective of the Japan Environment and Children's Study (JECS), a nation-wide birth cohort study that started its recruitment in January 2011, is to elucidate environmental factors that affect children's health and development. METHODS/DESIGN: Approximately 100,000 expecting mothers who live in designated study areas will be recruited over a 3-year period from January 2011. Participating children will be followed until they reach 13 years of age. Exposure to environmental factors will be assessed by chemical analyses of bio-specimens (blood, cord blood, urine, breast milk, and hair), household environment measurements, and computational simulations using monitoring data (e.g. ambient air quality monitoring) as well as questionnaires. JECS' priority outcomes include reproduction/pregnancy complications, congenital anomalies, neuropsychiatric disorders, immune system disorders, and metabolic/endocrine system disorders. Genetic factors, socioeconomic status, and lifestyle factors will also be examined as covariates and potential confounders. To maximize representativeness, we adopted provider-mediated community-based recruitment. DISCUSSION: Through JECS, chemical substances to which children are exposed during the fetal stage or early childhood will be identified. The JECS results will be translated to better risk assessment and management to provide healthy environment for next generations.

Prehospital lactated ringer's solution treatment and survival in out-of-hospital cardiac arrest: a prospective cohort analysis.

BACKGROUND: No studies have evaluated whether administering intravenous lactated Ringer's (LR) solution to patients with out-of-hospital cardiac arrest (OHCA) improves their outcomes, to our knowledge. Therefore, we examined the association between prehospital use of LR solution and patients' return of spontaneous circulation (ROSC), 1-month survival, and neurological or physical outcomes at 1 month after the event. METHODS AND FINDINGS: We conducted a prospective, non-randomized, observational study using national data of all patients with OHCA from 2005 through 2009 in Japan. We performed a propensity analysis and examined the association between prehospital use of LR solution and short- and long-term survival. The study patients were ≥18 years of age, had an OHCA before arrival of EMS personnel, were treated by EMS personnel, and were then transported to hospitals. A total of 531,854 patients with OHCA met the inclusion criteria. Among propensity-matched patients, compared with those who did not receive pre-hospital intravenous fluids, prehospital use of LR solution was associated with an increased likelihood of ROSC before hospital arrival (odds ratio [OR] adjusted for all covariates [95% CI] = 1.239 [1.146-1.339] [p<0.001], but with a reduced likelihood of 1-month survival with minimal neurological or physical impairment (cerebral performance category 1 or 2, OR adjusted for all covariates [95% CI] = 0.764 [0.589-0.992] [p = 0.04]; and overall performance category 1 or 2, OR adjusted for all covariates [95% CI] = 0.746 [0.573-0.971] [p = 0.03]). There was no association between prehospital use of LR solution and 1-month survival (OR adjusted for all covariates [95% CI] = 0.960 [0.854-1.078]). CONCLUSION: In Japanese patients experiencing OHCA, the prehospital use of LR solution was independently associated with a decreased likelihood of a good functional outcome 1 month after the event, but with an increased likelihood of ROSC before hospital arrival. Prehospital use of LR solution was not associated with 1-month survival. Further study is necessary to verify these findings. Please see later in the article for the Editors' Summary.

Real-time NMR monitoring of protein-folding kinetics by a recycle flow system for temperature jump.

An NMR method was developed that allows for real-time monitoring of reactions (on the order of seconds) induced by a temperature jump. In a recycle flow system, heating and cooling baths were integrated, with the latter inside the NMR probe. A refolding reaction of ribonuclease A was triggered by rapid cooling and monitored by a series of NMR measurements over 12 s. Data were processed by principal component analysis, in which a factor related to the structural change with an exponential rate constant of 0.2-0.7 s(-1) was successfully separated from factors related to baseline instability and/or noise. Temperature dependency of the rate constant revealed the entropy-driven formation of the transition state of the refolding reaction.

Association between blood levels of PCDDs/PCDFs/dioxin-like PCBs and history of allergic and other diseases in the Japanese population.

BACKGROUND: Previous studies reported that exposure to dioxins was associated with an increased risk of various diseases in general populations. OBJECTIVES: The aim of this study was to examine the association between levels of dioxins in blood and allergic and other diseases. METHODS: We conducted a cross-sectional study on 1,063 men and 1,201 women (aged 15-76 years), who were living throughout Japan and not occupationally exposed to dioxins, during 2002-2010. In fasting blood samples, polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and dioxin-like PCBs (DL-PCBs) were analyzed by isotope dilution high-resolution gas chromatography/mass spectrometry. We obtained information on life style and self-reported history of diseases using a questionnaire. Blood pressure, blood levels of hemoglobin A1c, and serum lipids were also measured. Multiple logistic regression models were used to analyze the association between dioxin levels in blood and various diseases. RESULTS: Toxic equivalents of PCDDs/PCDFs and total dioxins showed significant inverse dose-response relationships with atopic dermatitis, after adjustments for potential confounders. The highest quartile for total dioxins had an adjusted odds ratio of 0.26 (95 % confidence interval 0.08-0.70) compared to the reference group (first quartile). The odds ratios for hypertension, diabetes mellitus, hyperlipidemia, gout in men, and gynecologic diseases in women significantly increased with increasing toxic equivalents of PCDDs/PCDFs, DL-PCBs, and total dioxins in blood. CONCLUSIONS: The present findings suggest that background exposure to dioxins was associated with reduced risk of atopic dermatitis. The results also support the idea that low-level exposure to dioxins is associated with an increased risk of diabetes, hypertension, and hyperlipidemia.

Prehospital epinephrine use and survival among patients with out-of-hospital cardiac arrest.

CONTEXT: Epinephrine is widely used in cardiopulmonary resuscitation for out-of-hospital cardiac arrest (OHCA). However, the effectiveness of epinephrine use before hospital arrival has not been established. OBJECTIVE: To evaluate the association between epinephrine use before hospital arrival and short- and long-term mortality in patients with cardiac arrest. DESIGN, SETTING, AND PARTICIPANTS: Prospective, nonrandomized, observational propensity analysis of data from 417 188 OHCAs occurring in 2005-2008 in Japan in which patients aged 18 years or older had an OHCA before arrival of emergency medical service (EMS) personnel, were treated by EMS personnel, and were transported to the hospital. MAIN OUTCOME MEASURES: Return of spontaneous circulation before hospital arrival, survival at 1 month after cardiac arrest, survival with good or moderate cerebral performance (Cerebral Performance Category [CPC] 1 or 2), and survival with no, mild, or moderate neurological disability (Overall Performance Category [OPC] 1 or 2). RESULTS: Return of spontaneous circulation before hospital arrival was observed in 2786 of 15,030 patients (18.5%) in the epinephrine group and 23,042 of 402,158 patients (5.7%) in the no-epinephrine group (P < .001); it was observed in 2446 (18.3%) and 1400 (10.5%) of 13,401 propensity-matched patients, respectively (P < .001). In the total sample, the numbers of patients with 1-month survival and survival with CPC 1 or 2 and OPC 1 or 2, respectively, were 805 (5.4%), 205 (1.4%), and 211 (1.4%) with epinephrine and 18,906 (4.7%), 8903 (2.2%), and 8831 (2.2%) without epinephrine (all P <.001). Corresponding numbers in propensity-matched patients were 687 (5.1%), 173 (1.3%), and 178 (1.3%) with epinephrine and 944 (7.0%), 413 (3.1%), and 410 (3.1%) without epinephrine (all P <.001). In all patients, a positive association was observed between prehospital epinephrine and return of spontaneous circulation before hospital arrival (adjusted odds ratio [OR], 2.36; 95% CI, 2.22-2.50; P < .001). In propensity-matched patients, a positive association was also observed (adjusted OR, 2.51; 95% CI, 2.24-2.80; P < .001). In contrast, among all patients, negative associations were observed between prehospital epinephrine and long-term outcome measures (adjusted ORs: 1-month survival, 0.46 [95% CI, 0.42-0.51]; CPC 1-2, 0.31 [95% CI, 0.26-0.36]; and OPC 1-2, 0.32 [95% CI, 0.27-0.38]; all P < .001). Similar negative associations were observed among propensity-matched patients (adjusted ORs: 1-month survival, 0.54 [95% CI, 0.43-0.68]; CPC 1-2, 0.21 [95% CI, 0.10-0.44]; and OPC 1-2, 0.23 [95% CI, 0.11-0.45]; all P < .001). CONCLUSION: Among patients with OHCA in Japan, use of prehospital epinephrine was significantly associated with increased chance of return of spontaneous circulation before hospital arrival but decreased chance of survival and good functional outcomes 1 month after the event.

Influence of hospital capabilities and prehospital time on outcomes of thrombectomy for stroke in Japan from 2013 to 2016.

To determine whether increasing thrombectomy-capable hospitals with moderate comprehensive stroke center (CSC) capabilities is a valid alternative to centralization of those with high CSC capabilities. This retrospective, nationwide, observational study used data from the J-ASPECT database linked to national emergency medical service (EMS) records, captured during 2013-2016. We compared the influence of mechanical thrombectomy (MT) use, the CSC score, and the total EMS response time on the modified Rankin Scale score at discharge among patients with acute ischemic stroke transported by ambulance, in phases I (2013-2014, 1461 patients) and II (2015-2016, 3259 patients). We used ordinal logistic regression analyses to analyze outcomes. From phase I to II, MTs increased from 2.7 to 5.5%, and full-time endovascular physicians per hospital decreased. The CSC score and EMS response time remained unchanged. In phase I, higher CSC scores were associated with better outcomes (1-point increase, odds ratio [95% confidence interval]: 0.951 [0.915-0.989]) and longer EMS response time was associated with worse outcomes (1-min increase, 1.007 [1.001-1.013]). In phase II, neither influenced the outcomes. During the transitional shortage of thrombectomy-capable hospitals, increasing hospitals with moderate CSC scores may increase nationwide access to MT, improving outcomes.

Correlations of fish intake and plasma docosahexaenoic acid levels with each congener of PCDDs/PCDFs/dioxin-like PCBs in blood from the Japanese population.

PURPOSE: The purpose of the present study was to investigate the factors associated with blood levels of each congener of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and dioxin-like polychlorinated biphenyls (DL-PCBs) in the Japanese population. METHODS: A cross-sectional study was performed on 1,656 subjects (755 men and 901 women) aged 15-73 years, who were living in 90 different areas of 30 prefectures in Japan. Blood levels of 29 PCDD, PCDF, and DL-PCB congeners were determined by high-resolution gas chromatography/mass spectrometry. In addition, a questionnaire survey on life style, including dietary habit, was carried out. RESULTS: The median total toxicity equivalent (TEQ) was 17 pgTEQ/g lipid. After adjustment for age, sex, body mass index, smoking habit, and consumption of other food groups, six PCDDs/PCDFs with 4-6 substituted chlorine atoms and 10 DL-PCBs, but not HeptaCDD/F or OctaCDD, showed significant positive correlations with the frequency of intake of fish and shellfish. Furthermore, significant positive relationships were also found between plasma levels of docosahexaenoic acid (DHA), a biomarker of fish intake, and 10 PCDDs/PCDFs with 4-6 chlorine atoms and 10 DL-PCBs. The partial correlation coefficients with plasma DHA were significantly higher for DL-PCBs than for PCDDs/PCDFs, and partial correlation coefficients for PCDDs/PCDFs significantly decreased with increasing number of chlorine atoms (Spearman r = -0.80, P = 0.001). CONCLUSIONS: Blood levels of PCDDs/PCDFs with 4-6 chlorine atoms and DL-PCBs were positively associated with fish intake in the Japanese population. These results may be explained by the higher degree of bioaccumulation of these congeners in fish and shellfish in the ecosystem, and the high consumption of fish among the Japanese population.

[Statistics concerning patients of out-of-hospital cardiac arrests in Japan].

The Fire and Disaster Management Agency (FDMA) of Japan started a nationwide, population-based, cohort study in 2005 and keeps collecting the ambulance transportation records of out-of-hospital cardiac arrests in Japan based on the standardized Utstein style. By analyzing the outcomes of bystander-witnessed arrests among patients who had ventricular fibrillation and arrests, the rate of survival at 1 month is 11.4% and the rate of survival with minimal neurologic impairment at 1 month is 7.1%. The rate of survival at 1 month and the rate of survival with minimal neurologic impairment at 1 month are improved by bystander (family member or other) CPR, early CPR by EMS personnel, and the administration of a shock with the use of a public-access AED. It is important to improvement the ambulance service system by using these statistical data.

A longitudinal study of trends in blood dioxins and dioxin-like compounds levels in residents from two locations in Japan during 2002-2006.

To investigate the recent changes in background exposure to dioxin-related compounds, the concentrations of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and dioxin-like polychlorinated biphenyls (dl-PCBs) in the blood of individual residents in Japan were repeatedly examined. Twenty-six subjects (mean age, 52.7 +/- 1.8) from District A and 23 subjects (mean age, 56.1 +/- 1.2) from District B were longitudinally analyzed from 2002 to 2006. District A is a rural area in Osaka prefecture, and District B is an urban area in Saitama prefecture. For the longitudinal analysis of these concentrations, we used the generalized estimating equation (GEE). The PCDD + PCDF concentrations decreased significantly between 2002 and 2006 (p < 0.0001), but the concentrations of dl-PCBs declined to a smaller degree over the 5-year period. A time x body mass index (BMI) interaction suggests that the reduction rate of blood PCDDs + PCDFs and dl-PCB concentrations in subjects with a BMI greater than the 75th percentile is lower than that of subjects with a BMI less than the 75th percentile from 2002 to 2004 over the 5-year period. From other reports on the dietary intake of PCDDs, PCDFs, and dl-PCBs in Japan, the total amount of daily dioxin intake decreased, but the percentage of dl-PCBs increased yearly in the first half of the 2000s. The reason for the difference in the 5-year change in blood concentrations between PCDDs +PCDFs and dl-PCBs may be explained by the yearly change in the dietary dioxin intake.

[Epidemiological research on children's environmental health].

In accordance with the Declaration of the Environment Leaders of the Eight on Children's Environmental Health (Miami Declaration) in 1997, the Japanese government (the Ministry of Environment, Japan) organized a commission tasked to discuss issues related to the present situation of the environmental health of children (Advisory Commission for Children's Environmental Health). Epidemiological research on children's environmental health has been recommended as one of the priority projects by the commission because the effects of environmental factors on children's health are clarified by only studies using children as subjects, particularly, a birth cohort study, and not by animal experiments. The Advisory Committee of Epidemiological Research on Children's Environmental Health was established in 2007 and decided to start a nationwide birth cohort study following up children from pregnancy to 12 years old. Under the Advisory Committee, a working group composed of scientific experts, including epidemiologists, toxicologists, obstetricians, orthopedists, and statisticians, was organized in 2008. Pilot studies are going to be conducted in several areas in Japan with the support of the working group. Study hypotheses will also be decided by the working group soon. The full-scale survey will start in 2010.

Inconsistency in the Standard of Care-Toward Evidence-Based Management of Exertional Heat Stroke.

Tokyo 2020 Summer Olympics are projected to experience environmental heat stress that surpasses the environmental conditions observed in the Atlanta (1996), Athens (2004), Beijing (2008), and Rio (2016) Summer Olympics. This raises particular concerns for athletes who will likely to be exposed to extreme heat during the competitions. Therefore, in mass-participation event during warm season, it is vital for the hosting organization to build preparedness and resilience against heat, including appropriate treatment, and management strategies for exertional heat stroke (EHS). However, despite the existing literature regarding the evidence-based management of EHS, rectal thermometry and whole-body cold-water immersion are not readily accepted by medical professionals outside of the sports, and military medicine professionals. Current Japanese medical standard is no exception in falling behind on evidence-based management of EHS. Therefore, the first aim of this paper is to elucidate the inconsistency between the standard of care provided in Japan for EHS and what has been accepted as the gold standard by the scientific literature. The second aim of this paper is to provide optimal EHS management strategies that should be implemented at the Tokyo 2020 Summer Olympics from organizational level to maximize the safety of athletes and to improve organizational resilience to heat. The risk of extreme heat is often neglected until a catastrophic incidence occurs. It is vital for the Japanese medical leadership and athletic communities to re-examine the current EHS management strategies and implement evidence-based countermeasure for EHS to expand the application of scientific knowledge.

Grand Sumo Tournaments and Out-of-Hospital Cardiac Arrests in Tokyo.

BACKGROUND: Sumo wrestling is a demanding sport. Although watching sumo wrestling may have cardiovascular effects, no studies of this relationship have been performed. Thus, we aimed to evaluate the association between sumo wrestling tournaments and the rate of out-of-hospital cardiac arrests. METHODS AND RESULTS: We counted the daily number of patients aged 18 to 110 years who had an out-of-hospital cardiac arrest of presumed-cardiac origin in the Tokyo metropolis between 2005 and 2014. A Poisson regression was used to model out-of-hospital cardiac arrests of presumed-cardiac origin per day. Exposure days were the days on which a sumo tournament was held and broadcast, whereas control days were all other days. Events that occurred on exposure days were compared with those that occurred on control days. Risk ratios for out-of-hospital cardiac arrests on Grand Sumo tournaments days compared with control days were estimated. In total, 71 882 out-of-hospital cardiac arrests met the inclusion criteria. We recorded a 9% increase in the occurrence of out-of-hospital cardiac arrests on the day of a sumo tournament compared with control days. In patients aged 75 to 110 years, we found a 13% increase in the occurrence of out-of-hospital cardiac arrests on the day of a sumo tournament compared with control days. CONCLUSIONS: We found a significant increase in the occurrence of out-of-hospital cardiac arrests on the days of sumo tournaments compared with control days in the Tokyo metropolis between 2005 and 2014. Further studies are needed to verify these initial findings on sumo tournaments and cardiovascular events.

Interaction of defibrillation waveform with the time to defibrillation or the number of defibrillation attempts on survival from out-of-hospital cardiac arrest.

AIM: Early biphasic defibrillation is effective in out-of-hospital cardiac arrest (OHCA) cases. In the resuscitation of patients with OHCA, it is not clear how the defibrillation waveform interacts with the time to defibrillation to influence patient survival. The second, and any subsequent, shocks need to be administered by an on-line physician in Japan. Thus, we investigated the interaction between the defibrillation waveform and time to or the number of defibrillation on resuscitation outcomes. METHODS: This prospective observational study used data for all OHCAs that occurred between 2005 and 2014 in Japan. To investigate the interaction effect between the defibrillation waveform and the time to defibrillation or the number of defibrillations on the return to spontaneous circulation (ROSC), 1-month survival, and cerebral performance category (CPC) (1, 2), we assessed the modifying effects of the defibrillation waveform and the time to or the number of defibrillation on additive scale (i.e., the relative excessive risk due to interaction, RERI) and multiplicative scale (i.e., ratio of odds ratios (ORs)). RESULTS: In total, 71,566 cases met the inclusion criteria. For the measure of interaction between the defibrillation waveform and the time to defibrillation, ratio of ORs for ROSC was 0.84 (0.75-0.94), implying that the effect of time to first defibrillation on ROSC was negatively modified by defibrillation waveform. For the interaction between the defibrillation waveform and the number of defibrillations, RERI and ratio of ORs for CPC (1, 2) was -0.25 (-0.47 to -0.06) and 0.79 (0.67-0.93), respectively. It is implied that the effect of number of defibrillation on CPC (1, 2) was negatively modified by defibrillation waveform. CONCLUSIONS: An increased number of defibrillations was associated with a decreased ROSC in the case of biphasic and monophasic defibrillation, while an increased number of defibrillations was related to an increased 1-month survival rate and CPC (1, 2) only in the case of biphasic defibrillation. When two or more defibrillations were performed, a biphasic waveform was more effective in terms of long-term survival than a monophasic waveform.

Dispatcher-assisted bystander cardiopulmonary resuscitation and survival in out-of-hospital cardiac arrest.

INTRODUCTION: Bystander cardiopulmonary resuscitation (CPR) is critical to the survival of patients with out-of-hospital cardiac arrest (OHCA). However, it is unknown whether bystander CPR with or without dispatcher assistance is more effective or why. Thus, we evaluated the association between dispatcher-assisted bystander CPR (vs. bystander CPR without dispatcher assistance) and survival of patients with OHCA. METHODS: This is a retrospective, nonrandomized, observational study using national registry data for all OHCAs. We performed a propensity analysis. Patients with OHCA of cardiac origin were 18-100 years of age and received bystander chest compression in Japan between 2005 and 2014. Outcome measures were bystander rescue breathing, return of spontaneous circulation (ROSC) before hospital arrival, and survival and Cerebral Performance Category (CPC) 1 or 2 at 1 month after the event. RESULTS: During the study period, 1,176,351 OHCAs occurred, and 87,400 cases met the inclusion criteria. Among propensity-matched patients, a negative association was observed between dispatcher-assisted bystander CPR and outcome measures in a fully-adjusted model [odds ratio (OR) (95% CI) for ROSC = 0.87 (0.78-0.97), P < 0.05; OR (95% CI) for 1-month survival = 0.81 (0.65-1.00), P < 0.05; OR (95% CI) for CPC 1 or 2 = 0.64 (0.43-0.93), P < 0.05]. OR of survival for dispatcher-assisted bystander CPR tended to decrease as the emergency medical services response time increased. CONCLUSIONS: Survival benefit was less for dispatcher-assisted bystander CPR with dispatcher assistance than without dispatcher assistance. Low quality is hypothesized to be the cause of the reduced benefit.

Factors associated with the outcome of out-of-hospital cardiopulmonary arrest among people over 80 years old in Japan.

AIM: To determine if termination of resuscitation should be considered for older individuals, we sought to identify factors associated with clinical outcome following out-of-hospital cardiac arrest (OHCA) in people ≥80 years old and over. METHODS: A prospective, population-based, observational study was conducted for ≥80-year-old individuals who experienced out-of-hospital cardiac arrest and to whom resuscitation was provided by emergency responders between January 1, 2005 and December 31, 2012 (n=377,577). The primary endpoint was 1-month survival. Signal detection analysis was applied to estimate predictive factors among 17 variables. RESULTS: Among all out-of-hospital cardiac arrest cases, 59.4% were of cardiac origin, and 1-month survival rate was 3.3%. Following signal detection analysis, cases of both cardiac and non-cardiac origin were categorized into three subgroups defined by return of spontaneous circulation (ROSC) and epinephrine use. One-month survival ranged between 1.2 and 41.0% for the three subgroups of cardiac origin and between 2.0 and 41.1% for the three subgroups of non-cardiac origin. CONCLUSIONS: ROSC was the most significant predictor of 1-month survival among patients with cardiac and non-cardiac OHCA who were ≥80 years old. Absence of ROSC might be an important factor to the termination of resuscitation rule for OHCA in individuals who are ≥80years old.

Resuscitation outcomes of reproductive-age females who experienced out-of-hospital cardiac arrest.

BACKGROUND: Although some studies have shown that women in their reproductive years have better resuscitation outcomes of out-of-hospital cardiac arrest (OHCA), conflicting results and methodological problems have also been noted. Thus, we evaluated the resuscitation outcomes of OHCA of females by age. METHODS: This was a prospective observational study using registry data from all OHCA cases between 2005 and 2012 in Japan. The subjects were females aged 18-110 years who suffered an out-of-hospital cardiac arrest. Logistic regression analyses were performed using total and propensity-matched patients. RESULTS: There were 381,123 OHCA cases that met the inclusion criteria. Among propensity-matched patients, females aged 18-49 and 50-60 years of age had similar rates of return of spontaneous circulation before hospital arrival and 1-month survival (all p>0.60). In contrast, females aged 18-49 years of age had significantly lower rates of 1-month survival with minimal neurological impairment than did females aged 50-60 years of age (after adjusting for selected variables: Cerebral Performance Category scale 1 or 2 (CPC (1, 2)), OR=0.45, p=0.020; Overall Performance Category scale 1 or 2 (OPC (1, 2)): OR=0.42, p= 0.014; after adjustment for all variables: CPC (1, 2), OR=0.27, p= 0.008; OPC (1, 2), OR=0.29, p=0.009). CONCLUSION: Women of reproductive age did not show improved resuscitation outcomes in OHCA. Additionally, women in their reproductive years showed worse neurological outcomes one month after the event, which may be explained by the negative effects of estrogen. These findings need to be verified in further studies.

Age × Gender Interaction Effect on Resuscitation Outcomes in Patients With Out-of-Hospital Cardiac Arrest.

Although an interaction between gender and age has been shown to influence resuscitation outcomes in patients with out-of-hospital cardiac arrest (OHCA), this interaction has not been investigated in Asian populations. In this prospective, observational study, data from all cases of OHCA in Japan between 2005 and 2012 were obtained from the Japanese National Registry. We determined the relative excess risk due to interaction and the ratio of odds ratios (ORs) to assess the interaction effect of gender and age on the incidence of return of spontaneous circulation (ROSC) before hospital arrival, 1-month survival, and neurologically intact survival 1 month after OHCA. Male gender was associated with decreased ROSC and lower 1-month survival rates in patients with OHCA of presumed cardiac origin. Older age was associated with lower 1-month and neurologically intact survival rates in male patients with OHCA of presumed cardiac and noncardiac origin and with increased ROSC in male patients with OHCA of presumed cardiac origin. The relative excess risk due to interaction for ROSC in patients with OHCA of presumed cardiac origin was statistically significant (OR 0.19, 95% confidence interval [CI] 0.06 to 0.32). The ratio of ORs for ROSC was statistically significant in patients with OHCA of presumed cardiac origin (OR 1.25, 95% CI 1.05 to 1.47) and of noncardiac origin (OR 0.40, 95% CI 0.17 to 0.92). In conclusion, the interaction effect between age and gender on ROSC was positive in OHCA cases of presumed cardiac origin and negative in those of noncardiac origin.