Two- and Three-Dimensional Modeling and Simulations of Grain Growth Behavior in Dual-Phase Steel Using Monte Carlo and Machine Learning.

Dual-phase (DP) steel has been widely used in automotive steel plates with a balance of excellent strength and ductility. Grain refinement in DP steel is important to improve the properties further; however, the factors affecting grain growth need to be well understood. The remaining problem is that acquiring data through experiments is still time-consuming and difficult to evaluate quantitatively. With the development of materials informatics in recent years, material development time and costs are expected to be significantly reduced through experimentation, simulation, and machine learning. In this study, grain growth behavior in DP steel was studied using two-dimensional (2D) and three-dimensional (3D) Monte Carlo modeling and simulation to estimate the effect of some key parameters. Grain growth can be suppressed when the grain boundary energy is greater than the phase boundary energy. When the volume fractions of the matrix and the second phase were equal, the suppression of grain growth became obvious. The long-distance diffuse frequency can promote grain growth significantly. The simulation results allow us to better understand the factors affecting grain growth behavior in DP steel. Machine learning was performed to conduct a sensitivity analysis of the affecting parameters and estimate the magnitude of each parameter's effects on grain growth in the model. Combining MC simulation and machine learning will provide one promising research strategy to gain deeper insights into grain growth behaviors in metallic materials and accelerate the research process.

Evaluation of Austenite-Ferrite Phase Transformation in Carbon Steel Using Bayesian Optimized Cellular Automaton Simulation.

Austenite-ferrite phase transformation is a crucial metallurgical tool to tailor the properties of steels required for particular applications. Extensive simulation and modeling studies have been conducted to evaluate the phase transformation behaviors; however, some fundamental physical parameters still need to be optimized for better understanding. In this study, the austenite-ferrite phase transformation was evaluated in carbon steels with three carbon concentrations during isothermal annealing at various temperatures using a developed cellular automaton simulation model combined with Bayesian optimization. The simulation results show that the incubation period for nucleation is an essential factor that needs to be considered during austenite-ferrite phase transformation simulation. The incubation period constant is mainly affected by carbon concentration and the optimized values have been obtained as 10-24, 10-19, and 10-21 corresponding to carbon concentrations of 0.2 wt%, 0.35 wt%, and 0.5 wt%, respectively. The average ferrite grain size after phase transformation completion could decrease with the decreasing initial austenite grain size. Some other parameters were also analyzed in detail. The developed cellular automaton simulation model combined with Bayesian optimization in this study could conduct an in-depth exploration of critical and optimal parameters and provide deeper insights into understanding the fundamental physical characteristics during austenite-ferrite phase transformation.

Big-Volume SliceGAN for Improving a Synthetic 3D Microstructure Image of Additive-Manufactured TYPE 316L Steel.

A modified SliceGAN architecture was proposed to generate a high-quality synthetic three-dimensional (3D) microstructure image of TYPE 316L material manufactured through additive methods. The quality of the resulting 3D image was evaluated using an auto-correlation function, and it was discovered that maintaining a high resolution while doubling the training image size was crucial in creating a more realistic synthetic 3D image. To meet this requirement, modified 3D image generator and critic architecture was developed within the SliceGAN framework.

Cholesterol and breast cancer risk: a cohort study using health insurance claims and health checkup databases.

PURPOSE: This study aimed to investigate the association between serum cholesterol and triglyceride levels and breast cancer risk in Japanese women. METHODS: We retrospectively evaluated the association between the levels of low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), and triglycerides (TGs) and the incidence of breast cancer in a cohort study by using the health insurance claims and health checkup data from a database provided by JMDC Inc. We included 956,390 women who were insured between April 2008 and June 2019, identified breast cancer cases by using validated definitions, and estimated the risk of breast cancer by using multivariable Cox proportional hazards regression models adjusted for potential confounders. RESULTS: During the 2,832,277 person-years observation period (median 2.4 years), 6284 participants were diagnosed with breast cancer. There was marginally significant association between LDL-C and breast cancer risk when comparing the highest and lowest quintiles and at the clinical cutoff values for diagnosing hyperlipidemia. HDL-C was not associated with breast cancer. However, when stratified by age groups (< 50 and ≥ 50), HDL-C was inversely associated with breast cancer risk in women over 50 years old. TG was not associated with breast cancer risk. CONCLUSION: In this population, there was a modest association of LDL-C at the clinical cutoff values for diagnosing hyperlipidemia (140 mg/mL), and there were no associations of HDL-C and TG with breast cancer risk.

Novel Algorithm for the Estimation of Cancer Incidence Using Claims Data in Japan: A Feasibility Study.

PURPOSE: We developed algorithms to identify patients with newly diagnosed cancer from a Japanese claims database to identify the patients with newly diagnosed cancer of the sample population, which were compared with the nationwide cancer incidence in Japan to assess the validity of the novel algorithms. METHODS: We developed two algorithms to identify patients with stomach, lung, colorectal, breast, and cervical cancers: diagnosis only (algorithm 1), and combining diagnosis, treatments, and medicines (algorithm 2). Patients with newly diagnosed cancer were identified from an anonymized commercial claims database (JMDC Claims Database) in 2017 with two inclusions/exclusion criteria: selecting all patients with cancer (extract 1) and excluding patients who had received cancer treatments in 2015 or 2016 (extract 2). We estimated the cancer incidence of the five cancer sites and compared it with the Japan National Cancer Registry incidence (calculated standardized incidence ratio with 95% CIs). RESULTS: The number of patients with newly diagnosed cancer ranged from 219 to 17,840 by the sites, algorithms, and exclusion criteria. Standardized incidence ratios were significantly higher in the JMDC Claims Database than in the national registry data for extract 1 and algorithm 1, extract 1 and algorithm 2, and extract 2 and algorithm 1. In extract 2 and algorithm 2, colorectal cancer in male and stomach, lung, and cervical cancers in females showed similar cancer incidence in the JMDC and national registry data. CONCLUSION: The novel algorithms are effective for extracting information about patients with cancer from claims data by using the combined information on diagnosis, procedures, and medicines (algorithm 2), with 2-year cancer-treatment history as an exclusion criterion (extract 2).

Factors Associated With Impeding the Reintegration of Incest Survivors: A Qualitative Study in Selected Safe Homes in Nepal.

BACKGROUND: Incest is a globally prevalent phenomenon and is defined as sexual relations between closely related family members. Despite being a criminal offense irrespective to the gender and age incest is a prevalent issue in Nepal. Incest survivors are sheltered in safe homes for specific periods and reintegrated into their families following their healing. This research aims to explore the challenges and issues involved in the reintegration of incest survivors and investigate how the interconnected perceptions of families and individuals relate to the incest survivors' successful reintegration. METHODS: This qualitative study was conducted in three districts of Nepal. Fourteen incest survivors, five service providers from safe homes, and 22 community members were purposefully and theoretically selected. Semi-structured interviews were carried out to collect the study data, which were subsequently coded and analyzed using a grounded theory approach. RESULTS: The results indicate the importance of the reintegration of incest survivors, as staying in a safe home may not offer a long-term solution for these individuals. However, reintegration is challenging without acceptance and support from the survivors' families and communities, the survivors' readiness to reintegrate, and agreement from the survivors' safe homes. Factors found to influence the unsuccessful reintegration of survivors included family fragmentation, socio-economic status, family resistance, the survivor-perpetrator relationship, survivors' interests, fears, and the possibility of repeated incidents, harmful social norms and cultural practices, community intervention, and negative perceptions. CONCLUSION: This study found that factors associated with impeding the reintegration of incest survivors are found in survivors, their families, and their communities. Creating harmonious family systems, providing education on gender equality, empowering women to fight against all sorts of abuse, and governmental assurances on the implementation of legal aid, human rights, ratified conventions on child rights and women's rights may help prevention of incest, and address the reintegration challenges of incest victims.

Development of gamma-ray-induced positron age-momentum correlation measurement.

In conventional positron annihilation spectroscopy using radioisotopes, source contributions are unavoidable since positrons annihilate in the material covering the radioisotopes. Part of the positrons annihilate within the radioisotopes even when radioisotopes are deposited directly on a sample. Gamma-ray-induced positron annihilation spectroscopy makes it possible to measure only the spectra of a sample without source contributions since positrons are directly generated inside the sample from the gamma rays by pair production and annihilate inside the same sample. In this study, a new positron age-momentum correlation measurement system using ultrashort pulsed gamma rays is developed. The gamma rays with an energy of 6.6 MeV are generated by the inverse Thomson scattering of laser photons by high-energy electrons and are irradiated to the sample. The laser pulse can fully control the timing of gamma-ray generation. This characteristic and the use of a digital oscilloscope with a 12-bit vertical resolution enable us to develop a simple measurement system. Time-resolved momentum distributions for stainless steel with no defects and deformed interstitial free steel show the explicit differences reflecting the type of defect; for BaF2 single crystals, the results have been interpreted by considering the formation of positronium.

Effect of Cold-Rolling Directions on Recrystallization Texture Evolution of Pure Iron.

The influence of cold-rolling directions on the recrystallization texture evolution of pure iron was examined. As-received pure iron sheets were cold-rolled under two different conditions (specimens A and B). Specimen A was cold-rolled in the vertical direction against the cold-rolling direction of the as-received sheet. Specimen B was cold-rolled in the vertical direction against the cold-rolling direction of the as-received sheet, and then in the cold-rolling direction of the as-received sheet. Cold-rolled specimens were heated to each desired temperature before being quenched in water to room temperature (298 ± 2 K). Both cold-rolled specimens showed the development of γ-fiber and {100}<011> orientation. Additionally, γ-fiber formed comparatively more in cold-rolled specimen A, while α-fiber developed comparatively more in cold-rolled specimen B. Strain distribution in cold-rolled specimen A was presumably inhomogeneous, whereas that in cold-rolled specimen B was rather uniform at the macro-scale. The formation of γ-fiber was confirmed in annealed specimen A. In annealed specimen B, however, the recrystallization texture tended to be random, and the formation of α-fiber was observed. Furthermore, the formation of Goss orientation in both annealed specimens was established. Recrystallized ferrite grains with Goss orientation nucleated in high strain regions of cold-rolled specimen. These findings show that by devising the cold-rolling direction, it is possible to discover new types of recrystallization textures.

Three-Dimensional Analysis of Ferrite Grains Recrystallized in Low-Carbon Steel during Annealing.

We performed a three-dimensional (3D) analysis of ferrite grains recrystallized in low-carbon steel during annealing. Cold-rolled specimens were heated to 723 K and held for various periods. The 3D morphology of ferrite grains recrystallized during the annealing process was investigated. The progress of recovery in low-carbon steel was more inhibited than that in pure iron. However, ferrite recrystallization in low-carbon steel was more rapid than that in pure iron. The Avrami exponent was inconsistent with the 3D morphology of the recrystallized ferrite grains in pure iron but consistent with that of the grains in low-carbon steel. Thus, the Avrami exponent depends on the recovery and recrystallization behaviors. Furthermore, the recrystallized ferrite grain growth was virtually 2D. Three types of recrystallized ferrite grains were observed: recrystallized ferrite grains elongated along the transverse or rolling direction; plate-shaped recrystallized ferrite grains grown in the transverse and rolling directions; fine and equiaxed recrystallized ferrite grains. These results suggest that the recrystallized ferrite grains did not grow in the normal direction. Thus, we concluded that the 3D morphology of recrystallized ferrite grains depends on the kinetics of recrystallization and the initial microstructure before recrystallization.

Quantitative Analysis of the Recovery Process in Pure Iron Using X-ray Diffraction Line Profile Analysis.

We conducted quantitative analysis of the recovery process during pure iron annealing using the modified Williamson-Hall and Warren-Averbach methods. We prepared four types of specimens with different dislocation substructures. By increasing the annealing temperature, we confirmed a decrease in dislocation density. In particular, screw-dislocation density substantially decreased in the early stage of the recovery process, while edge-dislocation density gradually decreased as annealing temperature increased. Moreover, changes in hardness during the recovery process mainly depended on edge-dislocation density. Increases in annealing temperature weakly affected the dislocation arrangement parameter and crystallite size. Recovery-process modeling demonstrated that the decrease in screw-dislocation density during the recovery process was mainly dominated by glide and/or cross-slip with dislocation core diffusion. In contrast, the decrease in edge-dislocation density during the recovery process was governed by a climbing motion with both dislocation core diffusion and lattice self-diffusion. From the above results, we succeeded in quantitatively distinguishing between edge- and screw-dislocation density during the recovery process, which are difficult to distinguish using transmission electron microscope and electron backscatter diffraction.

Additional medical costs associated with ventilator-associated pneumonia in an intensive care unit in Japan.

BACKGROUND: Additional health care costs associated with ventilator-associated pneumonia (VAP) vary widely per country; none of which have been explored in Japan. Thus, we aimed to examine the economic and clinical effects of VAP in Japan. METHODS: This was a retrospective matched case-control study of 22 patients with VAP who were treated in the intensive care unit of Yokohama Rosai Hospital between January 2012 and December 2018. Twenty-two matched controls were selected based on 5 variables (ie, sex, age, diagnosis and surgical procedure, underlying disease with or without advanced malignant tumor, and best motor response). The additional health care costs incurred owing to VAP were calculated from the difference between the mean costs of VAP and control cases. RESULTS: VAP incurred an additional cost of approximately United States Dollars (USD) 34,884 per case. The length of hospitalization itself was the major factor contributing to additional medical costs, generating a difference of 9,824 USD. DISCUSSION: VAP not only worsens patient outcomes but also generates significant additional medical costs. Patients who had developed VAP required more medical resources such as the performance of a tracheostomy. CONCLUSIONS: VAP incurs a higher mean total hospital medical cost. Thus, appropriate infection control strategies should be implemented.

Fruit and Vegetable Intake and Stomach Cancer among Male Adults: A Case-Control Study in Northern Viet Nam.

OBJECTIVE: This study investigated the association between fruit and vegetable intake and stomach cancer, with considering the impacts of Helicobacter pylori (H. pylori) infection and tobacco smoking. METHODS: A case-control study featuring 80 male incident stomach-cancer cases and 146 male controls was conducted in a general hospital in Viet Nam. A semi-quantitative food frequency and demographic lifestyle questionnaire were used; and venous blood samples were collected to determine H. pylori status by IgG ELISA. The respective associations between fruit and vegetable intake and stomach cancer were examined using unconditional logistic regression analysis with adjustments for possible cofactors. RESULTS: Fruit intake and stomach cancer showed a weak inverse association when this became non-significant after adjusting for H. pylori infection (OR = 0.50, 95%CI: 0.22-1.12, p trend = 0.094). Stratifying by H. pylori status returned a negative trend for fruit intake and stomach cancer among H. pylori-negative participants (OR = 0.21, 95%CI: 0.06-0.69, p trend = 0.010), but no significant interaction for H. pylori-positive participants (OR = 0.76, 95%CI: 0.21-2.68, p trend = 0.670). Vegetable intake and stomach cancer showed no association, regardless of H. pylori status. Compared to ever-smokers with low intake, never-smokers with high vegetable (OR = 0.25, 95% CI: 0.06-0.95) and fruit intake (OR = 0.20, 95%CI: 0.06-0.65) showed the lowest odds of stomach cancer. CONCLUSIONS: Fruit, but not vegetable, intake showed a weak inverse association with stomach cancer. H. pylori infection and tobacco-smoking status may influence the protective effects of fruit and vegetable intake on stomach cancer.
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Acute Renal Failure, Ketoacidosis, and Urogenital Tract Infections with SGLT2 Inhibitors: Signal Detection Using a Japanese Spontaneous Reporting Database.

BACKGROUND: Sodium-glucose cotransporter-2 (SGLT2) inhibitors are a class of oral anti-hyperglycemic agents that have been available on the market in Japan since 2014. Although safety information has accumulated alongside the clinical use, the warnings issued by each country based on adverse events associated with the drug are different and examination of the safety of the drug is insufficient. OBJECTIVE: This study examined the safety of SGLT2 inhibitors by using a Japanese spontaneous reporting database and focusing on the cautions issued in each country and the disparities within existing research into the occurrence of the adverse events of acute renal failure (ARF), ketoacidosis, and urogenital tract infections (UTIs). PATIENTS AND METHODS: We analyzed data recorded on the Japanese Adverse Drug Event Report database (JADER) between April 2014 and February 2019. We calculated the reporting odds ratio (ROR) and 95% confidence interval (CI) with sex and age as adjustment factors. RESULTS: JADER contained 366,501 cases with the adverse events of interest; 4322 involved SGLT2 inhibitors. The ROR for SGLT2 inhibitors was calculated as 1.0 (95% CI 0.9-1.2) for ARF, 72.2 (95% CI 59.3-87.8) for ketoacidosis, and 14.0 (95% CI 11.0-17.8) for UTIs. Analysis of only subjects receiving treatment for diabetes showed a similar trend. CONCLUSION: The results suggested a correlation between SGLT2 inhibitors and the onset of ketoacidosis and UTIs, but not between SGLT2 inhibitors and ARF. Further verification of the safety of SGLT2 inhibitors, through continued risk assessments and large-scale clinical studies, are necessary.

An impact analysis of the implementation of health technology assessment for new treatment of orphan diseases in Japan.

Objectives: In Japan, a cost-effectiveness evaluation (CEE) for pricing was introduced in April 2019 and potentially covers orphan drugs (ODs) within its scope. The purpose of this study was to explore a reasonable approach to evaluate the utility of health technology assessment (HTA) for ODs in Japan. Methods: We extracted ODs that were approved in Japan from 2009 to 2018, and investigated their appraisals in the United Kingdom, Canada, and Australia, where HTA and different frameworks on ODs have been implemented. Results: Overall, 76 ODs were identified, with high recommendation rates in the three countries (80.6%-90.9%). The major reason for negative recommendation was uncertainty regarding clinical effectiveness, with actual decisions varying across countries. This indicates difficulties in setting an objective evaluation for the uncertainty of clinical effectiveness. The results of the CEE were mainly used to adjust prices. Conclusion: As Japan's CEE is expected to be used only for price adjustment after reimbursement is secured, the approach seems to be similar to the other countries. However, pre-launch clinical data are limited and the peak sales of ODs vary in Japan. Therefore, the careful introduction of CEE and multifaceted measures referring to the policies for ODs in other countries should be considered.

Development and Use of a Cancer Research Funding Database: Promoting Strategic Global Cancer Research Using the International Cancer Research Partnership Database.

The International Cancer Research Partnership (ICRP) has developed a cancer research funding database since its establishment, with data gathered from the participating funnding organizations. We estimated and compared the total amount of cancer research funding from governmental organizations in the USA, the UK and Japan using ICRP and publicly available databases. We also discussed use of the ICRP database as a tool to consider the cancer research funding allocation at a national level.

Characteristics and outcomes of pediatric out-of-hospital cardiac arrest by scholastic age category.

OBJECTIVES: There is a paucity of data examining nationwide population-based incidences and outcomes of pediatric out-of-hospital cardiac arrest. The objective of this study is to describe the detailed characteristics of pediatric out-of-hospital cardiac arrest by scholastic age category and to evaluate the impact of bystander cardiopulmonary resuscitation and public access-automated external defibrillators on the 1-month survival and favorable neurological status of pediatric out-of-hospital cardiac arrest patients. DESIGN: A nationwide, population-based, observational study. SETTING: Nationwide emergency medical system in Japan. PATIENTS: Out-of-hospital cardiac arrest patients aged ≤ 18 yr. MEASUREMENTS AND MAIN RESULTS: We identified 7,624 pediatric out-of-hospital cardiac arrest patients (≤ 18 yr old) from a nationwide population-based out-of-hospital cardiac arrest database in Japan from 2005 to 2008 and stratified them into five categories by scholastic age. The overall rates of 1-month survival and favorable neurological outcomes were 11.0% and 5.1%, respectively. Bystander cardiopulmonary resuscitation resulted in a significant improvement in both 1-month survival (odds ratio 2.81; 95% confidence interval 2.30-3.44) and favorable neurological outcomes (odds ratio 4.55; 95% confidence interval 3.35-6.18). Performing public access-automated external defibrillators had a significant effect on the 1-month survival rate (odds ratio 3.51; 95% confidence interval 1.81-6.81) and favorable neurological outcomes (odds ratio 5.13; 95% confidence interval 2.64-9.96). CONCLUSIONS: This study demonstrated that bystander cardiopulmonary resuscitation and public access-automated external defibrillators had a significant impact on the outcomes of pediatric out-of-hospital cardiac arrest. The improved survival associated with bystander cardiopulmonary resuscitation and public access-automated external defibrillators are clinically important and are of major public health importance for school-aged out-of-hospital cardiac arrest patients.

Comparison of neurological outcome between tracheal intubation and supraglottic airway device insertion of out-of-hospital cardiac arrest patients: a nationwide, population-based, observational study.

BACKGROUND: The effect of prehospital use of supraglottic airway devices as an alternative to tracheal intubation on long-term outcomes of patients with out-of-hospital cardiac arrest is unclear. STUDY OBJECTIVES: We compared the neurological outcomes of patients who underwent supraglottic airway device insertion with those who underwent tracheal intubation. METHODS: We conducted a nationwide population-based observational study using a national database containing all out-of-hospital cardiac arrest cases in Japan over a 3-year period (2005-2007). The rates of neurologically favorable 1-month survival (primary outcome) and of 1-month survival and return of spontaneous circulation before hospital arrival (secondary outcomes) were examined. Multiple logistic regression analyses were performed to adjust for potential confounders. Advanced airway devices were used in 138,248 of 318,141 patients, including an endotracheal tube (ETT) in 16,054 patients (12%), a laryngeal mask airway (LMA) in 34,125 patients (25%), and an esophageal obturator airway (EOA) in 88,069 patients (63%). RESULTS: The overall rate of neurologically favorable 1-month survival was 1.03% (1426/137,880). The rates of neurologically favorable 1-month survival were 1.14% (183/16,028) in the ETT group, 0.98% (333/34,059) in the LMA group, and 1.04% (910/87,793) in the EOA group. Compared with the ETT group, the rates were significantly lower in the LMA group (adjusted odds ratio 0.77, 95% confidence interval [CI] 0.64-0.94) and EOA group (adjusted odds ratio 0.81, 95% CI 0.68-0.96). CONCLUSIONS: Prehospital use of supraglottic airway devices was associated with slightly, but significantly, poorer neurological outcomes compared with tracheal intubation, but neurological outcomes remained poor overall.

Monophasic versus biphasic defibrillation for pediatric out-of-hospital cardiac arrest patients: a nationwide population-based study in Japan.

INTRODUCTION: Conventional monophasic defibrillators for out-of-hospital cardiac-arrest patients have been replaced with biphasic defibrillators. However, the advantage of biphasic over monophasic defibrillation for pediatric out-of-hospital cardiac-arrest patients remains unknown. This study aimed to compare the survival outcomes of pediatric out-of-hospital cardiac-arrest patients who underwent monophasic defibrillation with those who underwent biphasic defibrillation. METHODS: This prospective, nationwide, population-based observational study included pediatric out-of-hospital cardiac-arrest patients from January 1, 2005, to December 31, 2009. The primary outcome measure was survival at 1 month with minimal neurologic impairment. The secondary outcome measures were survival at 1 month and the return of spontaneous circulation before hospital arrival. Multivariable logistic regression analysis was performed to identify the independent association between defibrillator type (monophasic or biphasic) and outcomes. RESULTS: Among 5,628 pediatric out-of-hospital cardiac-arrest patients (1 through 17 years old), 430 who received defibrillation shock with monophasic or biphasic defibrillator were analyzed. The number of patients who received defibrillation shock with monophasic defibrillator was 127 (30%), and 303 (70%) received defibrillation shock with biphasic defibrillator. The survival rates at 1 month with minimal neurologic impairment were 17.5% and 24.4%, the survival rates at 1 month were 32.3% and 35.6%, and the rates of return of spontaneous circulation before hospital arrival were 24.4% and 27.4% in the monophasic and biphasic defibrillator groups, respectively. Hierarchic logistic regression analyses by using generalized estimation equations found no significant difference between the two groups in terms of 1-month survival with minimal neurologic impairment (odds ratio (OR), 1.57; 95% confidence interval (CI), 0.87 to 2.83; P = 0.14) and 1-month survival (OR, 1.38; 95% CI, 0.87 to 2.18; P = 0.17). CONCLUSIONS: The present nationwide population-based observational study could not confirm an advantage of biphasic over monophasic defibrillators for pediatric OHCA patients.

Elderly out-of-hospital cardiac arrest has worse outcomes with a family bystander than a non-family bystander.

BACKGROUND: A growing elderly population along with advances in equipment and approaches for pre-hospital resuscitation necessitates up-to-date information when developing policies to improve elderly out-of-hospital cardiac arrest (OHCA) outcomes. We examined the effects of bystander type (family or non-family) intervention on 1-month outcomes of witnessed elderly OHCA patients. METHODS: Data from a total of 85,588 witnessed OHCA events in patients aged ≥65 years, which occurred from 2005 to 2008, were obtained from a nationwide population-based database. Patients were stratified into three age categories (65-74, 75-84, ≥85 years), and the effects of bystander type (family or non-family) on initial cardiac rhythm, rate of bystander cardiopulmonary resuscitation (CPR), and 1-month outcomes were assessed. RESULTS: The overall survival rate was 6.9% (65-74 years: 9.8%, 75-84 years: 6.9%, ≥85 years: 4.6%). Initial VF/VT was recorded in 11.1% of cases with a family bystander and 12.9% of cases with a non-family bystander. The rate of bystander CPR was constant across the age categories in patients with a family bystander and increased with advancing age categories in patients with a non-family bystander. Patients having a non-family bystander were associated with significantly higher 1-month rates of survival (OR: 1.26; 95% CI: 1.19-1.33) and favorable neurological status (OR: 1.47; 95% CI: 1.34-1.60). CONCLUSIONS: Elderly patient OHCA events witnessed by a family bystander were associated with worse 1-month outcomes than those witnessed by a non-family bystander. Healthcare providers should consider targeting potential family bystanders for CPR education to increase the rate and quality of bystander CPR.

Comparison of outcomes after use of biphasic or monophasic defibrillators among out-of-hospital cardiac arrest patients: a nationwide population-based observational study.

BACKGROUND: The use and popularity of the biphasic waveform defibrillator as a replacement for the monophasic waveform defibrillator are increasing, but it is unclear whether this can improve the rate of survival among out-of-hospital cardiac arrest patients. This study aimed to verify the hypothesis that the outcome of out-of-hospital cardiac arrest patients who received defibrillation shock with the biphasic waveform defibrillator was better than that of patients who received defibrillation shock with the monophasic defibrillator. METHODS AND RESULTS: This prospective, nationwide, population-based, observational study included 21 172 out-of-hospital cardiac arrest patients with initial ventricular fibrillation or pulseless ventricular tachycardia from January 1, 2005, through December 31, 2007. Defibrillation shock was performed by monophasic defibrillator on 8224 (39%) patients and by biphasic defibrillator on 12 948 (61%) patients. The rate of survival at 1 month with minimal neurological impairment was 11.6% (951/8192) in the monophasic defibrillator group and 12.8% (1653/12 928) in the biphasic defibrillator group. Hierarchical logistic regression analysis using a generalized estimation equation showed no significant difference between the biphasic and monophasic groups in 1-month survival with minimal neurological impairment (adjusted odds ratio, 1.07; 95% confidence interval, 0.91-1.26; P=0.42). Confirmatory propensity score analyses showed similar results. CONCLUSIONS: Although monophasic defibrillators are being replaced by biphasic defibrillators, our nationwide population-based observational study failed to demonstrate a statistically significant association between defibrillation waveform and 1-month survival rate with minimal neurological impairment.