岸原 悠貴

<h4>Objective</h4>Out-of-hospital cardiac arrest (OHCA) due to blunt trauma has extremely poor outcomes and may have a shorter tolerable no-flow duration than nontraumatic OHCA. This study aimed to characterize the association between no-flow duration and prognosis in adults with witnessed blunt traumatic OHCA using dynamic probability curves.<h4>Methods</h4>This nationwide, population-based, retrospective cohort study used the All-Japan Utstein Registry from January 1, 2010, through December 31, 2023. Adults with witnessed OHCA due to blunt trauma were included. No-flow time was defined as the interval from witnessed cardiac arrest to initiation of CPR by emergency medical services personnel. The primary outcome was 30-day favorable neurological outcome (Cerebral Performance Category 1 or 2), and the secondary outcome was 30-day survival. Dynamic probability curves with pointwise 95% confidence intervals (CIs) were estimated using the exact Clopper-Pearson method, and no-flow thresholds below 1% were estimated with bootstrap 95% CIs.<h4>Results</h4>Among 1,795,502 registry patients, 14,334 met the eligibility criteria. Median age was 66 years, 9451 patients (65.9%) were male, and median no-flow time was 10 min. Thirty-day favorable neurological outcome occurred in 73 patients (0.5%), and 264 patients (1.8%) survived to 30 days. The no-flow thresholds below 1% with 95% CIs were 0 (0-0) minutes for 30-day favorable neurological outcome and 6 (4-8) minutes for 30-day survival.<h4>Conclusions</h4>Adults with witnessed OHCA due to blunt trauma, the no-flow duration compatible with a chance of 30-day favorable neurological outcome was extremely short, and overall prognosis was poor.

<h4>Objectives</h4>While advanced airway management (AAM) is commonly performed for children with out-of-hospital cardiac arrest (OHCA), the benefit and optimal timing of AAM remains unclear. To determine whether earlier prehospital AAM is associated with patient outcomes compared with later or no AAM in children with OHCA.<h4>Methods</h4>Retrospective cohort study of pediatric patients (aged <18 years) with nontraumatic OHCA treated by emergency medical services (EMS), using the Resuscitation Outcomes Consortium Epidemiologic Registry-Cardiac Arrest at 10 sites in the United States and Canada from April 2011 to June 2015. The exposures are early prehospital AAM (defined as successful AAM within 10 minutes of EMS arrival) and any successful prehospital AAM (endotracheal intubation or supraglottic airway placement). The primary outcome was survival to hospital discharge. Children who received successful prehospital AAM at each minute after EMS arrival were matched, using time-dependent propensity scores, to children at risk of AAM in the same minute.<h4>Results</h4>Among 954 eligible pediatric patients (median [IQR] age, 1 [0 to 11] years), 521 (54.6%) received prehospital AAM, and 433 (45.4%) did not. Overall, 91 (9.5%) survived to discharge. In the propensity score-matched cohort (922 matched cases), successful AAM ≤10 minutes was associated with higher likelihood of survival to hospital discharge (risk ratio [RR], 1.93; 95% CI, 1.01-3.70) compared with children at risk of receiving AAM. In contrast, when successful prehospital AAM was considered regardless of timing, any successful AAM was not associated with survival (RR, 1.35; 95% CI, 0.75-2.43).<h4>Conclusions</h4>In this North American cohort of pediatric OHCA, earlier AAM (successful AAM within 10 minutes) was associated with survival to hospital discharge. However, successful prehospital AAM at any time was not associated with survival to hospital discharge. These findings suggest that performing AAM earlier in the resuscitation may have a potential benefit for children with OHCA.

<h4>Aim of the study</h4>This study sought to determine whether prehospital administration of amiodarone improves outcomes among adult patients with out-of-hospital cardiac arrest (OHCA) presenting with ventricular fibrillation (VF) or pulseless ventricular tachycardia (VT). The analysis accounted for time-dependent confounding and resuscitation time bias using real-world registry data.<h4>Material and methods</h4>We conducted a multicenter, retrospective cohort study using a nationwide Japanese OHCA database, including adult nontraumatic shockable rhythms. The exposure was prehospital amiodarone administration at a given time, and the comparator was no amiodarone at the same time point. The comparison reflects amiodarone administration at that time versus no amiodarone, not 'amiodarone versus never-amiodarone'. The primary and secondary endpoints were favorable neurological status and survival at 30 days. Patients were matched 1:3 using time-dependent propensity score matching, followed by generalized estimating equations to address intrahospital clustering. Sensitivity analyses included covariates with standardized mean differences greater than 0.25 after matching. Associations were expressed as risk ratios (RRs) with 95% confidence intervals (CIs).<h4>Results</h4>Among 9,909 eligible patients, 56 (0.6%) remained after matching, including 19 (0.2%) who received amiodarone at the index time point. Median (IQR) age was 65 (52-76) years, and 81.8% were male. The median interval from first medical contact to drug administration was 27 (22-32) minutes. In models adjusted for timing variables and hospital clustering, amiodarone was not significantly related to favorable neurological recovery (RR, 0.45 [95% CI, 0.14-1.47]) or survival (RR, 0.74 [95% CI, 0.31-1.73]). Sensitivity analyses yielded consistent findings, though survival model convergence was limited.<h4>Conclusions</h4>Prehospital administration of amiodarone in adult OHCA patients with shockable rhythms was not associated with improved neurological or survival outcomes. However, these findings should be interpreted with caution, and further studies are warranted to confirm and extend these observations.

<h4>Background</h4>The association between hospital case volume and outcomes following out-of-hospital cardiac arrest (OHCA) remains controversial. Prior investigations in Japan categorized hospitals into discrete volume groups and did not demonstrate consistent volume-outcome relationships. This study examined the relationship between annual hospital OHCA case volume and short-term outcomes by modeling case volume as a continuous variable to capture potential nonlinear effects.<h4>Methods</h4>This retrospective observational study analyzed data from the Japan Association for Acute Medicine OHCA registry from 2014 to 2021. Adult patients (aged ≥18 years) with non-traumatic OHCA were included. Annual hospital OHCA case volume was treated as a continuous variable. The primary outcome was 1-month favorable neurological status (cerebral performance category 1-2). The secondary outcome was 1-month survival. Associations were evaluated using multilevel generalized additive models with spline functions, adjusting for prespecified confounders and accounting for within-hospital clustering.<h4>Results</h4>A total of 66,768 patients were included. Favorable neurological status at 1 month occurred in 2.9% and 1-month survival was 6.0%. Spline analyses across the full spectrum of hospital case volume demonstrated minimal variation in adjusted outcome probabilities. No statistically significant associations were observed between case volume and favorable neurological status (p = 0.06) or survival (p = 0.29).<h4>Conclusions</h4>When modeled as a continuous variable, annual hospital case volume was not independently associated with short-term neurological or survival outcomes following OHCA. These findings indicate that hospital case volume alone may be insufficient as a standalone metric of institutional performance in the management of OHCA.