岸原 悠貴

<jats:sec id="ab-zoi260866-4"> <jats:title>Importance</jats:title> <jats:p>The burden of cardiogenic out-of-hospital cardiac arrest (OHCA) among older adults is increasing. No-flow time is a key determinant of prognosis, and the aging brain may be increasingly vulnerable to ischemic injury during this interval.</jats:p> </jats:sec> <jats:sec id="ab-zoi260866-5"> <jats:title>Objective</jats:title> <jats:p>To delineate the association between no-flow duration and outcomes in older adults with cardiogenic OHCA using dynamic probability curves.</jats:p> </jats:sec> <jats:sec id="ab-zoi260866-6"> <jats:title>Design, Setting, and Participants</jats:title> <jats:p>This nationwide, population-based, multicenter retrospective observational cohort study used data from the All-Japan Utstein Registry from January 1, 2010, through December 31, 2023. Participants included adults 65 years or older with witnessed cardiogenic OHCAs treated within Japan’s nationwide emergency medical service (EMS) system. Data were analyzed from December 1, 2025, to July 7, 2026.</jats:p> </jats:sec> <jats:sec id="ab-zoi260866-7"> <jats:title>Exposure</jats:title> <jats:p>No-flow time, defined as the interval from witnessed arrest to initiation of cardiopulmonary resuscitation by EMS clinicians.</jats:p> </jats:sec> <jats:sec id="ab-zoi260866-8"> <jats:title>Main Outcomes and Measures</jats:title> <jats:p>The primary outcome was 30-day favorable neurologic outcome, defined as cerebral performance category of 1 or 2. Age-stratified dynamic probability curves were constructed for patients aged 65 to 74 years, 75 to 84 years, 85 to 94 years, and 95 years or older to describe the time-dependent likelihood of outcome according to no-flow duration. For each age group, the no-flow time at which the estimated probability fell below 1% with 95% CIs was identified.</jats:p> </jats:sec> <jats:sec id="ab-zoi260866-9"> <jats:title>Results</jats:title> <jats:p>Among 1 795 502 registry cases, 259 851 patients met the inclusion criteria. The median patient age was 82 (IQR, 75-88) years, 148 018 (57.0%) were male, and the median no-flow time was 11 (IQR, 8-15) minutes. Overall, 8711 patients (3.4%) achieved a 30-day favorable neurologic outcome. In all patients 65 years or older, the no-flow times at which the estimated probability of favorable neurologic outcome fell below 1% was 11 (95% CI, 11-11) minutes. Corresponding thresholds for favorable neurologic outcome was 14 (95% CI, 14-14) minutes for those aged 65 to 74 years, 11 (95% CI, 10-11) minutes for those aged 75 to 84 years, 2 (IQR, 0-4) minutes for those aged 85 to 94 years, and 0 (95% CI, 0-0) minutes for those 95 years or older.</jats:p> </jats:sec> <jats:sec id="ab-zoi260866-10"> <jats:title>Conclusions and Relevance</jats:title> <jats:p>In this cohort study of older adults with cardiogenic OHCA, the no-flow time window compatible with an estimated probability of at least 1% for favorable neurologic outcome became progressively shorter with advancing age. These findings may inform resuscitation decision-making in aging populations.</jats:p> </jats:sec>

<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.