岸原 悠貴

<h4>Study objective</h4>Adult evidence for extracorporeal cardiopulmonary resuscitation (ECPR) is substantial, but to our knowledge, comparative studies for pediatric out-of-hospital cardiac arrest (OHCA) are lacking. We compared outcomes of pediatric OHCA with ECPR versus continued cardiopulmonary resuscitation (CPR).<h4>Methods</h4>We conducted a retrospective cohort study of patients <18 years from a multicenter Japanese OHCA registry (2014 to 2022) transported to pediatric ECPR-capable institutions. Exposure was ECPR initiation versus continued CPR among patients at risk for ECPR (no ECPR yet; could receive ECPR later). Outcomes were one-month survival and favorable neurologic outcome (Pediatric Cerebral Performance Category 1 to 3). We applied risk-set matching with time-dependent propensity scores, using full matching with up to 4 controls per case.<h4>Results</h4>Of 799 patients, 27 received ECPR; 1:4 matching yielded 108 at-risk controls. ECPR patients were adolescents (median 14 years), witnessed arrest (70.4%), cardiogenic (74.1%); patient characteristics were similar after matching. In patients receiving ECPR versus controls, 1-month survival was 25.9% (7/27) versus 11.1% (12/108) (risk difference 17.3%; 95% confidence interval [CI], -0.9 to 35.6; risk ratio, 3.56; 95% CI, 1.37 to 9.28) and favorable neurologic outcome was 18.5% (5/27) versus 6.5% (7/108) (risk difference 13.9%; 95% CI, -2.9 to 30.8; risk ratio, 3.78; 95% CI; 1.19 to 11.99).<h4>Conclusions</h4>Compared with continued conventional CPR among at-risk patients, ECPR might be associated with improved patient outcomes after pediatric OHCA, but the precision of estimates was limited, with wide confidence intervals. Interpretation is limited by the residual confounding inherent to an observational design; our findings can inform randomized trials of pediatric ECPR.

<h4>Aim of the study</h4>Short peripheral cannula (SPC)-related phlebitis occurs in 7.5% of critically ill patients, and mechanical irritation from cannula materials is a risk factor. Softer polyurethane cannulas reportedly reduce phlebitis, but the incidence of phlebitis may vary depending on the type of polyurethane. Differences in cannula stiffness may also affect the incidence of phlebitis; however, this relationship is not well understood. This study analyzed intensive care unit (ICU) patient data to compare the incidence of phlebitis across different cannula products, focusing on polyurethane.<h4>Material and methods</h4>This is a post-hoc analysis of the AMOR-VENUS study that involved 23 ICUs in Japan. We included patients aged ≥ 18 years, who were admitted to the ICU with SPCs. The primary outcome was phlebitis, evaluated using hazard ratios (HRs) and 95% confidence intervals (CIs). Based on the market share and differences in synthesis, polyurethanes were categorized into PEU-Vialon^® (BD, USA), SuperCath^® (Medikit, Japan), and other polyurethanes; non-polyurethane materials were also analyzed. Multivariable marginal Cox regression analysis was performed using other polyurethanes as a reference.<h4>Results</h4>In total, 1,355 patients and 3,429 SPCs were evaluated. Among polyurethane cannulas, 1,087 (33.5%) were PEU-Vialon^®, 702 (21.6%) were SuperCath^®, and 276 (8.5%) were other polyurethanes. Among non-polyurethane cannulas, 1,292 (39.8%) were ethylene tetrafluoroethylene (ETFE) cannulas, and 72 (2.2%) used other materials. The highest incidence of phlebitis was observed with SuperCath^® (13.1%). Multivariate analysis revealed an HR of 1.45 (95% CI 0.75-2.8, p = 0.21) for PEU-Vialon^®, 2.60 (95% CI 1.35-5.00, p < 0.01) for SuperCath^®, 2.29 (95% CI 1.19-4.42, p = 0.01) for ETFE, and 2.2 (95% CI 0.46-10.59, p = 0.32) for others.<h4>Conclusions</h4>The incidence of phlebitis varied among polyurethane cannulas. Further research is warranted to determine the causes of these differences.

<h4>Aim of the study</h4>The rupture of delayed formed splenic pseudoaneurysms after pediatric blunt splenic injuries undergoing nonoperative management (NOM) can be life-threatening. We aimed to identify the sub-phenotypes predicting delayed splenic pseudoaneurysm formation following pediatric blunt splenic injury using latent class analysis (LCA).<h4>Material and methods</h4>In this retrospective observational study conducted using a multicenter cohort of pediatric trauma patients, we included pediatric patients (aged ≤16 years) who sustained blunt splenic injuries and underwent NOM from 2008 to 2019. LCA was performed using clinically important variables, and 2-5 sub-phenotypes were identified. The optimal number of sub-phenotypes was determined on the basis of clinical importance and Bayesian information criterion. The association between sub-phenotyping and delayed splenic pseudoaneurysm formation was analyzed using univariate logistic regression analysis with odds ratios (ORs) and 95% confidence intervals (CIs).<h4>Results</h4>The LCA included 434 patients and identified three optimal sub-phenotypes. Contrast extravasation (CE) of initial CT in the spleen was observed in 22 patients (68.8%) in Sub-phenotype 1, 49 patients (25.7%) in Sub-phenotype 2, and 22 patients (10.4%) in Sub-phenotype 3 (p = 0.007). Delayed splenic pseudoaneurysm was observed in 46 patients (10.6%), including seven patients (21.9%) in Sub-phenotype 1, 25 patients (13.1%) in Sub-phenotype 2, and 14 patients (6.6%) in Sub-phenotype 3 (p = 0.01). Logistic regression analysis for delayed splenic pseudoaneurysm formation using Sub-phenotype 3 as the reference revealed an OR (95% CI) of 3.94 (1.45-10.7) in Sub-phenotype 1 and 2.12 (1.07-4.21) in Sub-phenotype 2.<h4>Conclusions</h4>The LCA identified three sub-phenotypes showing statistically significant differences for delayed splenic pseudoaneurysm formation. Our findings suggest that cases with CE on initial CT imaging may be at increased risk of delayed splenic pseudoaneurysm formation.

<h4>Aim</h4>Asphyxial out-of-hospital cardiac arrest (OHCA) is associated with poor outcomes and may have a narrower time window for favourable outcomes compared to cardiac-origin OHCA. However, studies examining cardiopulmonary resuscitation (CPR) duration in OHCA due to asphyxiation are limited. Hence, this study aimed to investigate the relationship between CPR duration and prognosis in patients who experienced OHCA due to asphyxiation.<h4>Methods</h4>This retrospective study used data from the Japanese Association for Acute Medicine's OHCA registry for June 2014 to December 2021. The study population comprised adult patients who received CPR by emergency medical service personnel and achieved return of spontaneous circulation. The primary outcome was one-month survival; the secondary outcome was favourable neurological outcome at one month (cerebral performance category 1 or 2). The influence of CPR duration was examined using logistic regression analysis after adjusting for multiple confounding factors.<h4>Results</h4>The analysis included 2,594 patients of asphyxiation-induced OHCA. The median CPR duration was 26 minutes (interquartile range, 17-35 minutes). At one month, 515 patients (19.9%) survived and 62 (2.4%) achieved favourable neurological outcomes. Increasing CPR duration was associated with lower chances of one-month survival and favorable neurological outcome (aOR per minute: 0.88 and 0.78, respectively; 95% CI: 0.86-0.90 and 0.71-0.85, respectively). The probability of favorable neurological outcome and survival dropped below 1% after 4 and 31 minutes of CPR, respectively.<h4>Conclusions</h4>Prolonged CPR was associated with poor outcomes in patients with asphyxiation-related OHCA and may be futile in these cases.

<h4>Background</h4>Out-of-hospital cardiac arrest (OHCA) has poor survival rates, but extracorporeal cardiopulmonary resuscitation (ECPR) shows promise for selected patients, as a second line of therapy after failure of conventional CPR to obtain return of spontaneous circulation, despite implementation challenges. This study aimed to identify distinct sub-phenotypes among patients with OHCA who undergo ECPR and to investigate their association with clinical outcomes.<h4>Methods</h4>This multi-center, retrospective, observational study used the Japanese Association for Acute Medicine OHCA registry from 83 hospitals that performed ECPR among 91 participating centers between June 2014 and December 2020. We included adult patients with OHCA who received ECPR during cardiac arrest. Three-class latent class analysis (LCA) was employed to identify sub-phenotypes based on 15 variables, including pre- and in-hospital factors. Logistic regression analysis was used to assess the association between sub-phenotypes and 30-day survival and neurological outcomes.<h4>Results</h4>A total of 1528 patients were included. The median low-flow time was 47 min (interquartile rage: 38-58 min). The 30-day survival rate for eligible patients was 20.9%. LCA identified three distinct sub-phenotypes: Standard ECPR Group (n = 702), Delayed ECPR Group (n = 457), and Non-shockable Rhythm Group (n = 369). The variables with high discriminative power in the LCA was low-flow time, followed by pre-hospital shock delivery and initial cardiac rhythm. Thirty-day survival rates varied significantly among the sub-phenotypes (p = 0.001): Standard ECPR Group (26.9%), Delayed ECPR Group (17.1%), and Non-shockable Rhythm Group (14.1%). Favorable neurological outcomes at 30 days also differed significantly (p = 0.004), with the Standard ECPR Group showing the highest rate (12.1%). After adjusting for covariates, both the Delayed ECPR Group (adjusted OR: 0.61, 95% CI 0.44-0.82) and Non-shockable Rhythm Group (adjusted OR: 0.47, 95% CI 0.32-0.68) had significantly lower odds of 30-day survival compared to the Standard ECPR Group.<h4>Conclusions</h4>Three clinically meaningful sub-phenotypes were identified using simple pre-hospital and in-hospital factors, with low-flow time emerging as the most critical discriminating factor. The sub-phenotypes showed significant associations with clinical outcomes and provide a practical framework for ECPR patient stratification. These findings suggest that timing optimization may be as important as rhythm characteristics for ECPR patient selection and support the development of sub-phenotype-specific treatment strategies.