Extracorporeal cardiopulmonary resuscitation in hypothermic cardiac arrest: A secondary analysis of multicenter extracorporeal cardiopulmonary resuscitation registry data in Japan.

Aim: Extracorporeal cardiopulmonary resuscitation (ECPR) is used to resuscitate patients with cardiac arrest; however, its effect in treating hypothermic cardiac arrest has not been well studied. Therefore, in this study, we aimed to examine the characteristics and outcomes of patients with hypothermic cardiac arrest who underwent ECPR, using a multicenter out-of-hospital cardiac arrest (OHCA) registry in Japan. Methods: Baseline characteristics of patients with hypothermic OHCA and body temperature below 32 °C were assessed. Logistic regression analysis was performed to identify factors associated with in-hospital mortality and neurological outcomes in these patients. Outcomes of hypothermic and cardiogenic OHCA cases were compared using propensity-score matching to investigate differences among subgroups. Results: We included 2,157 patients, with 102 and 1,646 in the hypothermic and cardiogenic groups, respectively. Higher age and longer low-flow time were independent risk factors for mortality, and higher age was an independent risk factor for unfavorable neurological outcomes in the hypothermic OHCA group.Eighty matched pairs were selected during propensity-score matching, and the mortality rate was lower in the hypothermic group than in the cardiogenic group (46.2% vs. 77.5%; p < 0.01). Unfavorable neurological outcome rate was lower in the hypothermic group than in the cardiogenic group (62.5% vs. 87.5%; p < 0.01). Conclusions: Increased age and prolonged low-flow time were identified as negative prognostic factors in patients with hypothermic OHCA who underwent ECPR. These patients showed lower mortality and unfavorable neurological outcome rates than patients with cardiogenic OHCA, suggesting that ECPR is a promising strategy for treating hypothermic OHCA.

Differences in outcomes of patients with out-of-hospital cardiac arrest treated with extracorporeal cardiopulmonary resuscitation between day-time and night-time.

Although patients who underwent night-time resuscitation for out-of-hospital cardiac arrest (OHCA) had worse clinical outcomes than those who underwent day-time resuscitation, the differences between the outcomes of patients with OHCA who underwent extracorporeal cardiopulmonary resuscitation (ECPR) in the day-time and night-time remain unclear. We analyzed data from the Study of Advanced Life Support for Ventricular Fibrillation with Extracorporeal Circulation in Japan. Patients were categorized according to whether they received treatment during the day-time or night-time. The primary outcomes were survival to hospital discharge and favorable neurological outcome at discharge, and the secondary outcomes were estimated low-flow time, implementation time of ECPR, and complications due to ECPR. A multivariate logistic regression model adjusted for confounders was used for comparison. Among the 1644 patients, the night-time patients had a significantly longer ECMO implementation time and estimated low-flow time than the day-time patients, along with a significantly higher number of complications than the day-time patients. However, the survival and neurologically favorable survival rates did not differ significantly between the groups. Thus, although patients who underwent ECPR at night had an increased risk of longer implementation time and complications, their clinical outcomes did not differ from those who underwent day-time ECPR.

Fatal SARS-CoV-2 Infection among Children, Japan, January-September 20221.

To determine the characteristics of pediatric patients 0-19 years of age who died after onset of SARS-CoV-2 infection in Japan during January 1-September 30, 2022, we reviewed multiple sources. We identified 62 cases, collected detailed information from medical records and death certificates, and conducted interviews, resulting in 53 patients with detailed information for our study. Among 46 patients with internal causes of death (i.e., not external causes such as trauma), 15% were <1 year of age, 59% had no underlying disease, and 88% eligible for vaccination were unvaccinated. Nonrespiratory symptoms were more common than respiratory symptoms. Out-of-hospital cardiac arrest affected 46% of patients, and time from symptom onset to death was <7 days for 77%. Main suspected causes of death were central nervous system abnormalities (35%) and cardiac abnormalities (20%). We recommend careful follow-up of pediatric patients after SARS-CoV-2 infection during the first week after symptom onset, regardless of underlying diseases.

Door-to-Needle Time for Extracorporeal Cardiopulmonary Resuscitation and Neurological Outcomes in Out-of-Hospital Cardiac Arrest: A Nationwide Study.

BACKGROUND: Extracorporeal cardiopulmonary resuscitation (ECPR) is an option for refractory cardiac arrest, and immediate initiation after indication is recommended. However, the practical goals of ECPR preparation (such as the door-to-needle time) remain unclear. This study aimed to elucidate the association between the door-to-needle time and neurological outcomes of out-of-hospital cardiac arrest. METHODS AND RESULTS: This is a post hoc analysis of a nationwide multicenter study on out-of-hospital cardiac arrest treated with ECPR at 36 institutions between 2013 and 2018 (SAVE-J [Study of Advanced Cardiac Life Support for Ventricular Fibrillation with Extracorporeal Circulation in Japan] II study). Adult patients without hypothermia (≥32 °C) in whom circulation was not returned at ECPR initiation were included. The probability of favorable neurological function at 30 days (defined as Cerebral Performance Category ≤2) was estimated using a generalized estimating equations model, in which institutional, patient, and treatment characteristics were adjusted. Estimated probabilities were then calculated according to the door-to-needle time with 3-minute increments, and a clinical threshold was assumed. Among 1298 patients eligible for this study, 136 (10.6%) had favorable neurological function. The estimated probability of favorable outcomes was highest in patients with 1 to 3 minutes of door-to-needle time (12.9% [11.4%-14.3%]) and remained at 9% to 10% until 27 to 30 minutes. Then, the probability dropped gradually with each 3-minute delay. A 30-minute threshold was assumed, and shorter door-to-extracorporeal membrane oxygenation/low-flow time and fewer adverse events related to cannulation were observed in patients with door-to-needle time <30 minutes. CONCLUSIONS: The probability of favorable functions after out-of-hospital cardiac arrest decreased as the door-to-needle time for ECPR was prolonged, with a rapid decline after 27 to 30 minutes. REGISTRATION: URL: https://center6.umin.ac.jp/cgi-open-bin/ctr/ctr_view.cgi?recptno=R000041577; Unique identifier: UMIN000036490.

Low-flow time and outcomes in hypothermic cardiac arrest patients treated with extracorporeal cardiopulmonary resuscitation: a secondary analysis of a multi-center retrospective cohort study.

BACKGROUND: In out-of-hospital cardiac arrest (OHCA) patients with extracorporeal cardiopulmonary resuscitation (ECPR), the association between low-flow time and outcomes in accidental hypothermia (AH) patients compared to those of patients without AH has not been fully investigated. METHODS: This was a secondary analysis of the retrospective multicenter registry in Japan. We enrolled patients aged ≥ 18 years who had been admitted to the emergency department for OHCA and had undergone ECPR between January, 2013 and December, 2018. AH was defined as an arrival body temperature below 32 °C. The primary outcome was survival to discharge. Cubic spline analyses were performed to assess the non-linear associations between low-flow time and outcomes stratified by the presence of AH. We also analyzed the interaction between low-flow time and the presence of AH. RESULTS: Of 1252 eligible patients, 105 (8.4%) and 1147 (91.6%) were in the AH and non-AH groups, respectively. Median low-flow time was 60 (47-79) min in the AH group and 51 (42-62) min in the non-AH group. The survival discharge rates in the AH and non-AH groups were 44.8% and 25.4%, respectively. The cubic spline analyses showed that survival discharge rate remained constant regardless of low-flow time in the AH group. Conversely, a decreasing trend was identified in the survival discharge rate with longer low-flow time in the non-AH group. The interaction analysis revealed a significant interaction between low-flow time and AH in survival discharge rate (p for interaction = 0.048). CONCLUSIONS: OHCA patients with arrival body temperature < 32 °C who had received ECPR had relatively good survival outcomes regardless of low-flow time, in contrast to those of patients without AH.

Impact of center volume on in-hospital mortality in adult patients with out­of­hospital cardiac arrest resuscitated using extracorporeal cardiopulmonary resuscitation: a secondary analysis of the SAVE-J II study.

Recently, patients with out-of-hospital cardiac arrest (OHCA) refractory to conventional resuscitation have started undergoing extracorporeal cardiopulmonary resuscitation (ECPR). However, the mortality rate of these patients remains high. This study aimed to clarify whether a center ECPR volume was associated with the survival rates of adult patients with OHCA resuscitated using ECPR. This was a secondary analysis of a retrospective multicenter registry study, the SAVE-J II study, involving 36 participating institutions in Japan. Centers were divided into three groups according to the tertiles of the annual average number of patients undergoing ECPR: high-volume (≥ 21 sessions per year), medium-volume (11-20 sessions per year), or low-volume (< 11 sessions per year). The primary outcome was survival rate at the time of discharge. Patient characteristics and outcomes were compared among the three groups. Moreover, a multivariable-adjusted logistic regression model was applied to study the impact of center ECPR volume. A total of 1740 patients were included in this study. The center ECPR volume was strongly associated with survival rate at the time of discharge; furthermore, survival rate was best in high-volume compared with medium- and low-volume centers (33.4%, 24.1%, and 26.8%, respectively; P = 0.001). After adjusting for patient characteristics, undergoing ECPR at high-volume centers was associated with an increased likelihood of survival compared to middle- (adjusted odds ratio 0.657; P = 0.003) and low-volume centers (adjusted odds ratio 0.983; P = 0.006). The annual number of ECPR sessions was associated with favorable survival rates and lower complication rates of the ECPR procedure.Clinical trial registration: https://center6.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000041577 (unique identifier: UMIN000036490).

Fluid balance during acute phase extracorporeal cardiopulmonary resuscitation and outcomes in OHCA patients: a retrospective multicenter cohort study.

OBJECTIVE: The association between fluid balance and outcomes in patients who underwent out-of-hospital cardiac arrest (OHCA) and received extracorporeal cardiopulmonary resuscitation (ECPR) remains unknown. We aimed to examine the above relationship during the first 24 h following intensive care unit (ICU) admission. METHODS: We performed a secondary analysis of the SAVE-J II study, a retrospective multicenter study involving OHCA patients aged ≥ 18 years treated with ECPR between 2013 and 2018 and who received fluid therapy following ICU admission. Fluid balance was calculated based on intravenous fluid administration, blood transfusion, and urine output. The primary outcome was in-hospital mortality. The secondary outcomes included unfavorable outcome (cerebral performance category scores of 3-5 at discharge), acute kidney injury (AKI), and need for renal replacement therapy (RRT). RESULTS: Overall, 959 patients met our inclusion criteria. In-hospital mortality was 63.6%, and the proportion of unfavorable outcome at discharge was 82.0%. The median fluid balance in the first 24 h following ICU admission was 3673 mL. Multivariable analysis revealed that fluid balance was significantly associated with in-hospital mortality (odds ratio (OR), 1.04; 95% confidence interval (CI), 1.02-1.06; p < 0.001), unfavorable outcome (OR, 1.03; 95% CI, 1.01-1.06; p = 0.005), AKI (OR, 1.04; 95% CI, 1.02-1.05; p < 0.001), and RRT (OR, 1.05; 95% CI, 1.03-1.07; p < 0.001). CONCLUSIONS: Excessive positive fluid balance in the first day following ICU admission was associated with in-hospital mortality, unfavorable outcome, AKI, and RRT in ECPR patients. Further investigation is warranted.

A Seasonal Variation of Clinical and Neurological Outcomes in Patients with Out-of-Hospital Cardiac Arrest Treated with Extracorporeal Cardiopulmonary Resuscitation: A Secondary Data Analysis of the SaveJ II Study.

The prognosis for patients with out-of-hospital cardiac arrest (OHCA) has been reported to be worse in the cold season. On the other hand, it is unclear whether a similar trend exists in OHCA patients who are treated with extracorporeal cardiopulmonary resuscitation (ECPR). This study was a retrospective multicenter registry study. We examined the association between ECPR and season. We compared the prognosis in four seasonal groups according to the day of occurrence. Multivariable logistic regression analysis was performed for the assessment of clinical and neurological outcomes. A total of 2024 patients with OHCA who received ECRP were included. There were no significant differences in in-hospital mortality (p = 0.649) and in the rate of favorable neurological outcome (p = 0.144). In the multivariable logistic regression, the seasonal factor was not significantly associated with worse in-hospital mortality (p = 0.855) and favorable neurological outcomes (p = 0.807). In this study, there was no seasonal variation in OHCA patients with ECPR.

Association between pupillary examinations and prognosis in patients with out-of-hospital cardiac arrest who underwent extracorporeal cardiopulmonary resuscitation: a retrospective multicentre cohort study.

BACKGROUND: In some cases of patients with out-of-hospital cardiac arrest (OHCA) who underwent extracorporeal cardiopulmonary resuscitation (ECPR), negative pupillary light reflex (PLR) and mydriasis upon hospital arrival serve as common early indicator of poor prognosis. However, in certain patients with poor prognoses inferred by pupil findings upon hospital arrival, pupillary findings improve before and after the establishment of ECPR. The association between these changes in pupillary findings and prognosis remains unclear. This study aimed to clarify the association of pupillary examinations before and after the establishment of ECPR in patients with OHCA showing poor pupillary findings upon hospital arrival with their outcomes. To this end, we analysed retrospective multicentre registry data involving 36 institutions in Japan, including all adult patients with OHCA who underwent ECPR between January 2013 and December 2018. We selected patients with poor prognosis inferred by pupillary examinations, negative pupillary light reflex (PLR) and pupil mydriasis, upon hospital arrival. The primary outcome was favourable neurological outcome, defined as Cerebral Performance Category 1 or 2 at hospital discharge. Multivariable logistic regression analysis was performed to evaluate the association between favourable neurological outcome and pupillary examination after establishing ECPR. RESULTS: Out of the 2,157 patients enrolled in the SAVE-J II study, 723 were analysed. Among the patients analysed, 74 (10.2%) demonstrated favourable neurological outcome at hospital discharge. Multivariable analysis revealed that a positive PLR at ICU admission (odds ration [OR] = 11.3, 95% confidence intervals [CI] = 5.17-24.7) was significantly associated with favourable neurological outcome. However, normal pupil diameter at ICU admission (OR = 1.10, 95%CI = 0.52-2.32) was not significantly associated with favourable neurological outcome. CONCLUSION: Among the patients with OHCA who underwent ECPR and showed poor pupillary examination findings upon hospital arrival, 10.2% had favourable neurological outcome at hospital discharge. A positive PLR after the establishment of ECPR was significantly associated with favourable neurological outcome.

Impact of Lactate Clearance on Clinical and Neurological Outcomes of Patients With Out-of-Hospital Cardiac Arrest Treated With Extracorporeal Cardiopulmonary Resuscitation: A Secondary Data Analysis.

OBJECTIVES: Serial evaluations of lactate concentration may be more useful in predicting outcomes in patients with out-of-hospital cardiac arrest (OHCA) than a single measurement. This study aimed to evaluate the impact of lactate clearance (LC) on clinical and neurologic outcomes in patients with OHCA who underwent extracorporeal cardiopulmonary resuscitation (ECPR). DESIGN: Retrospective multicenter observational study. SETTING: Patients with OHCA receiving ECPR at 36 hospitals in Japan between January 1, 2013, and December 31, 2018. PATIENTS: This study evaluated 1227 patients, with lactate initial assessed upon emergency department admission and lactate second measured subsequently. To adjust for the disparity in the time between lactate measurements, the modified 6-hour LC was defined as follows: ([lactate initial -lactate second ]/lactate initial ) × 100 × (6/the duration between the initial and second measurements [hr]). The patients were divided into four groups according to the modified 6-hour LC with an equivalent number of patients among LC quartiles: Q1 (LC < 18.8), Q2 (18.8 < LC < 59.9), Q3 (60.0 < LC < 101.2), and Q4 (101.2 < LC). INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: The 30-day survival rates increased as the 6-hour LC increased (Q1, 21.2%; Q2, 36.8%; Q3, 41.4%; Q4, 53.6%; p for trend < 0.001). In the multivariate analysis, the modified 6-hour LC was significantly associated with a 30-day survival rate (adjusted odds ratio [AOR], 1.003; 95% CI, 1.001-1.005; p < 0.001) and favorable neurologic outcome (AOR, 1.002; 95% CI, 1.000-1.004; p = 0.027). CONCLUSIONS: In patients with OHCA who underwent ECPR, an increase in the modified 6-hour LC was associated with favorable clinical and neurologic outcome. Thus, LC can be a criterion to assess whether ECPR should be continued.

Overview and future prospects of out-of-hospital cardiac arrest registries in Japan.

Aim: Out-of-hospital cardiac arrest (OHCA) is a life-threatening emergency with high mortality. The "chain of survival" is critical to improving patient outcomes. To develop and enhance this chain of survival, measuring and monitoring the resuscitation processes and outcomes are essential for quality assurance. In Japan, several OHCA registries have successfully been implemented at both local and national levels. We aimed to review and summarise the conception, strengths, and challenges of OHCA registries in Japan. Method and results: The following representing registries in Japan were reviewed: the All-Japan Utstein registry, the Utstein Osaka Project/the Osaka-CRITICAL study, the SOS-KANTO study, the JAAM-OHCA study, and the SAVE-J II study. The All-Japan Utstein registry, operated by the Fire and Disaster Management Agency of Japan and one of the largest nationwide population-based registries in the world, collects data concerning all patients with OHCA in Japan, excluding in-hospital data. Other research- and hospital-based registries collect detailed out-of-hospital and in-hospital data. The Osaka-CRITICAL study and the SOS-KANTO study are organized at regional levels, and hospitals in the Osaka prefecture and in the Kanto area participate in these registries. The JAAM-OHCA study is managed by the Japanese Association of Acute Medicine and includes 107 hospitals throughout Japan. The Save-J II study focuses on patients with OHCA treated with extracorporeal cardiopulmonary resuscitation. Conclusion: Each OHCA registry has its own philosophy, strengths, perspectives, and challenges; however, all have been successful in contributing to the improvement of emergency medical service (EMS) systems through the quality improvement process. These registries are expected to be further utilized to enhance EMS systems and improve outcomes for patients with OHCA, while also contributing to the field of resuscitation science.

Factors associated with favourable neurological outcomes following cardiopulmonary resuscitation for out-of-hospital cardiac arrest: A retrospective multi-centre cohort study.

Aim: To investigate the factors associated with favourable neurological outcomes in adult patients undergoing extracorporeal cardiopulmonary resuscitation (ECPR) for out-of-hospital cardiac arrest (OHCA). Methods: This retrospective observational study used secondary analysis of the SAVE-J II multicentre registry data from 36 institutions in Japan. Between 2013 and 2018, 2157 patients with OHCA who underwent ECPR were enrolled in SAVE-J II. A total of 1823 patients met the study inclusion criteria. Adult patients (aged ≥ 18 years) with OHCA, who underwent ECPR before admission to the intensive care unit, were included in our secondary analysis. The primary outcome was a favourable neurological outcome at hospital discharge, defined as a Cerebral Performance Category score of 1 or 2. We used a multivariate logistic regression model to examine the association between factors measured at the incident scene or upon hospital arrival and favourable neurological outcomes. Results: Multivariable analysis revealed that shockable rhythm at the scene [odds ratio (OR); 2.11; 95% confidence interval (CI), 1.16-3.95] and upon hospital arrival (OR 2.59; 95% CI 1.60-4.30), bystander CPR (OR 1.63; 95% CI 1.03-1.88), body movement during resuscitation (OR 7.10; 95% CI 1.79-32.90), gasping (OR 4.33; 95% CI 2.57-7.28), pupillary reflex on arrival (OR 2.93; 95% CI 1.73-4.95), and male sex (OR 0.43; 95% CI 0.24-0.75) significantly correlated with neurological outcomes. Conclusions: Shockable rhythm, bystander CPR, body movement during resuscitation, gasping, pupillary reflex, and sex were associated with favourable neurological outcomes in patients with OHCA treated with ECPR.

Optimal chest compression for cardiac arrest until the establishment of ECPR: Secondary analysis of the SAVE-J II study.

INTRODUCTION: The widespread incorporation of extracorporeal cardiopulmonary resuscitation (ECPR) for out-of-hospital cardiac arrest requires the delivery of effective and high-quality chest compressions prior to the initiation of ECPR. The aim of this study was to evaluate and compare the effectiveness of mechanical and manual chest compressions until the initiation of ECPR. METHODS: This study was a secondary analysis of the Japanese retrospective multicenter registry "Study of Advanced Life Support for Ventricular Fibrillation by Extracorporeal Circulation II (SAVE-J II)". Patients were divided into two groups, one receiving mechanical chest compressions and the other receiving manual chest compressions. The primary outcome measure was mortality at hospital discharge, while the secondary outcome was the cerebral performance category (CPC) score at discharge. RESULTS: Of the 2157 patients enrolled in the SAVE-J II trial, 453 patients (329 in the manual compression group and 124 in the mechanical compression group) were included in the final analysis. Univariate analysis showed a significantly higher mortality rate at hospital discharge in the mechanical compression group compared to the manual compression group (odds ratio [95% CI] = 2.32 [1.34-4.02], p = 0.0026). Multivariate analysis showed that mechanical chest compressions were an independent factor associated with increased mortality at hospital discharge (adjusted odds ratio [95% CI] = 2.00 [1.11-3.58], p = 0.02). There was no statistically significant difference in CPC between the two groups. CONCLUSION: For patients with out-of-hospital cardiopulmonary arrest who require ECPR, extreme caution should be used when performing mechanical chest compressions.

Prophylactic distal perfusion catheter and survival in patients with out-of-hospital cardiac arrest: Secondary analysis of the SAVE-J II study.

PURPOSE: The effect of a prophylactic distal perfusion catheter (DPC) after extracorporeal cardiopulmonary resuscitation (ECPR) in patients with out-of-hospital cardiac arrest (OHCA) remains unclear. Therefore, we aimed to clarify the association between prophylactic DPC and prognosis in patients with OHCA undergoing ECPR. MATERIALS AND METHODS: A secondary analysis of the Study of Advanced Life Support for Ventricular Fibrillation with Extracorporeal Circulation in Japan (SAVE-J II) database was performed to compare groups of patients with and without prophylactic DPCs. A multivariate analysis of survival at discharge was performed using factors that were significant in the two-arm comparison. RESULTS: A total of 2044 patients were included in the analysis after excluding those who met the exclusion criteria. Survival at discharge was observed in 548 (26.9%) patients. In total, 100 (4.9%) patients developed limb ischemia, among whom 14 (0.7%) required therapeutic intervention. Multivariate analysis showed that prophylactic DPC did not result in a significant difference in survival at discharge (odds ratio: 0.898 [0.652-1.236], p = 0.509). CONCLUSIONS: The implementation of prophylactic DPC after ECPR for patients with OHCA may not contribute to survival at discharge.

Risk factors for bleeding complications in patients undergoing extracorporeal cardiopulmonary resuscitation following out-of-hospital cardiac arrest: a secondary analysis of the SAVE-J II study.

BACKGROUND: Bleeding is the most common complication in out-of-hospital cardiac arrest (OHCA) patients receiving extracorporeal cardiopulmonary resuscitation (ECPR). No studies comprehensively described the incidence rate, timing of onset, risk factors, and treatment of bleeding complications in OHCA patients receiving ECPR in a multicenter setting with a large database. This study aimed to analyze the risk factors of bleeding during the first day of admission and to comprehensively describe details of bleeding during hospitalization in patients with OHCA receiving ECPR in the SAVE-J II study database. METHODS: This study was a secondary analysis of the SAVE-J II study, which is a multicenter retrospective registry study from 36 participating institutions in Japan in 2013-2018. Adult OHCA patients who received ECPR were included. The primary outcome was the risk factor of bleeding complications during the first day of admission. The secondary outcomes were the details of bleeding complications and clinical outcomes. RESULTS: A total of 1,632 patients were included. Among these, 361 patients (22.1%) had bleeding complications during hospital stay, which most commonly occurred in cannulation sites (14.3%), followed by bleeding in the retroperitoneum (2.8%), gastrointestinal tract (2.2%), upper airway (1.2%), and mediastinum (1.1%). These bleeding complications developed within two days of admission, and 21.9% of patients required interventional radiology (IVR) or/and surgical interventions for hemostasis. The survival rate at discharge of the bleeding group was 27.4%, and the rate of favorable neurological outcome at discharge was 14.1%. Multivariable logistic regression analysis showed that the platelet count (< 10 × 104/µL vs > 10 × 104/µL) was significantly associated with bleeding complications during the first day of admission (adjusted odds ratio [OR]: 1.865 [1.252-2.777], p = 0.002). CONCLUSIONS: In a large ECPR registry database in Japan, up to 22.1% of patients experienced bleeding complications requiring blood transfusion, IVR, or surgical intervention for hemostasis. The initial platelet count was a significant risk factor of early bleeding complications. It is necessary to lower the occurrence of bleeding complications from ECPR, and this study provided an additional standard value for future studies to improve its safety.

The role of torsional stress in the development of subchondral insufficiency fracture of the femoral head: A finite element model analysis.

BACKGROUND: Subchondral insufficiency fracture of the femoral head generally occurs without evidence of trauma or with a history of minor trauma. Insufficient bone quality is considered one cause; however, the detailed mechanism of fracture development at the subchondral area (SA) is not understood. The aim of this study was to clarify the directions of force that cause subchondral fracture using finite element model analysis. METHODS: Two types of finite element models were generated from the CT data of femurs obtained from three individuals without osteoporosis (normal models) and another three with osteoporosis (osteoporosis models). Three directions of force, including compressive, shearing, and torsional, were applied to the femoral head. The distribution of von Mises stress (Mises stress) was evaluated at the SA, principal compressive trabeculae (PC), and principal tensile trabeculae. RESULTS: Under compressive force, the mean Mises stress value was greatest at the PC in both the normal and osteoporosis models. Under shearing force, the mean Mises stress value tended to be greatest at the SA in the normal model and at the PC in the osteoporosis model. Under torsional force, the mean Mises stress value was greatest at the SA in both types of models. CONCLUSIONS: The torsional force showed the greatest Mises stress at the SA in both the normal and osteoporosis models, suggesting the importance of torsion as a possible force responsible for subchondral insufficiency fracture development.

Side-to-side variability in the femoral neck anteversion angle: A study of the Japanese population with osteonecrosis of the femoral head.

BACKGROUND: Side-to-side variability in the femoral neck anteversion angle (FA) reportedly varies from 0.0° to 17.3°. To investigate the side-to-side variability in the FA and the relationship between the FA and the morphology of the acetabulum in the Japanese population, we performed a three-dimensional computed tomography (CT)-based study involving patients with osteonecrosis of the femoral head (ONFH). METHODS: CT data were obtained from 170 nondysplastic hips of 85 patients with ONFH. The FA and acetabular coverage parameters, including the acetabular anteversion angle, acetabular inclination angle, and acetabular sector angle in the anterior, superior, and posterior directions, were measured using three-dimensional CT. The distribution of the side-to-side variability in the FA was evaluated separately for each of the five degrees. RESULTS: The mean side-to-side variability in the FA was 6.7° ± 5.3° (range, 0.2°-26.2°). The distribution of the side-to-side variability in the FA was 0.0°-5.0° in 41 patients (48.2%), 5.1°-10.0° in 25 patients (29.4%), 10.1°-15.0° in 13 patients (15.3%), 15.1°-20.0° in 4 patients (4.7%), and >20.1° in 2 patients (2.4%). There was a weak negative correlation between the FA and anterior acetabular sector angle (r = -0.282, P < 0.001) and a very weak positive correlation between the FA and acetabular anteversion angle (r = 0.181, P < 0.018). CONCLUSIONS: The mean side-to-side variability in the FA was 6.7° ± 5.3° (range, 0.2°-26.2°) in Japanese nondysplastic hips, and about 20% of the patients had a side-to-side variability of >10°.

Etiology-Based Prognosis of Extracorporeal CPR Recipients After Out-of-Hospital Cardiac Arrest: A Retrospective Multicenter Cohort Study.

BACKGROUND: A better understanding of the relative contributions of various factors to patient outcomes is essential for optimal patient selection for extracorporeal CPR (ECPR) therapy for patients with out-of-hospital cardiac arrest (OHCA). However, evidence on the prognostic comparison based on the etiologies of cardiac arrest is limited. RESEARCH QUESTION: What is the etiology-based prognosis of patients undergoing ECPR for OHCA? STUDY DESIGN AND METHODS: This retrospective multicenter registry study involved 36 institutions in Japan and included all adult patients with OHCA who underwent ECPR between January 2013 and December 2018. The primary etiology for OHCA was determined retrospectively from all hospital-based data at each institution. We performed a multivariable logistic regression model to determine the association between etiology of cardiac arrest and two outcomes: favorable neurologic outcome and survival at hospital discharge. RESULTS: We identified 1,781 eligible patients, of whom 1,405 (78.9%) had cardiac arrest because of cardiac causes. Multivariable logistic regression analysis for favorable neurologic outcome showed that accidental hypothermia (adjusted OR, 5.12; 95% CI, 2.98-8.80; P < .001) was associated with a significantly higher rate of favorable neurologic outcome than cardiac causes. Multivariable logistic regression analysis for survival showed that accidental hypothermia (adjusted OR, 5.19; 95% CI, 3.15-8.56; P < .001) had significantly higher rates of survival than cardiac causes. Acute aortic dissection/aneurysm (adjusted OR, 0.07; 95% CI, 0.02-0.28; P < .001) and primary cerebral disorders (adjusted OR, 0.12; 95% CI, 0.03-0.50; P = .004) had significantly lower rates of survival than cardiac causes. INTERPRETATION: In this retrospective multicenter cohort study, although most patients with OHCA underwent ECPR for cardiac causes, accidental hypothermia was associated with favorable neurologic outcome and survival; in contrast, acute aortic dissection/aneurysm and primary cerebral disorders were associated with nonsurvival compared with cardiac causes.

Prognostic Significance of Signs of Life in Out-of-Hospital Cardiac Arrest Patients Undergoing Extracorporeal Cardiopulmonary Resuscitation.

OBJECTIVES: Signs of life (SOLs) during cardiac arrest (gasping, pupillary light reaction, or any form of body movement) are suggested to be associated with favorable neurologic outcomes in out-of-hospital cardiac arrest (OHCA). While data has demonstrated that extracorporeal cardiopulmonary resuscitation (ECPR) can improve outcomes in cases of refractory cardiac arrest, it is expected that other contributing factors lead to positive outcomes. This study aimed to investigate whether SOL on arrival is associated with neurologic outcomes in patients with OHCA who have undergone ECPR. DESIGN: Retrospective multicenter registry study. SETTING: Thirty-six facilities participating in the Study of Advanced life support for Ventricular fibrillation with Extracorporeal circulation in Japan II (SAVE-J II). PATIENTS: Consecutive patients older than 18 years old who were admitted to the Emergency Department with OHCA between January 1, 2013, and December 31, 2018, and received ECPR. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Patients were classified into two groups according to the presence or absence of SOL on arrival. The primary outcome was a favorable neurologic outcome (Cerebral Performance Category 1 or 2) at discharge. Of the 2157 patients registered in the SAVE-J II database, 1395 met the inclusion criteria, and 250 (17.9%) had SOL upon arrival. Patients with SOL had more favorable neurologic outcomes than those without SOL (38.0% vs. 8.1%; p < 0.001). Multivariate analysis showed that SOL on arrival was independently associated with favorable neurologic outcomes (odds ratio, 5.65 [95% CI, 3.97-8.03]; p < 0.001). CONCLUSIONS: SOL on arrival was associated with favorable neurologic outcomes in patients with OHCA undergoing ECPR. In patients considered for ECPR, the presence of SOL on arrival can assist the decision to perform ECPR.