Tetsuo Maeda’s research while affiliated with Kanazawa University and other places

Background In Japan, emergency medical service (EMS) providers are prohibited from field termination-of-resuscitation (TOR) in out-of-hospital cardiac arrest (OHCA) patients. In 2013, we developed a TOR rule for emergency department physicians (Goto’s TOR rule) immediately after hospital arrival. However, this rule is subject to flaws, and there is a need for revision owing to its relatively low specificity for predicting mortality compared with other TOR rules in the emergency department. Therefore, this study aimed to develop and validate a modified Goto’s TOR rule by considering prehospital EMS cardiopulmonary resuscitation (CPR) duration. Methods We analysed the records of 465,657 adult patients with OHCA from the All-Japan Utstein registry from 2016 to 2019 and divided them into two groups: development ( n = 231,363) and validation ( n = 234,294). The primary outcome measures were specificity, false-positive rate (FPR), and positive predictive value (PPV) of the revised TOR rule in the emergency department for predicting 1-month mortality. Results Recursive partitioning analysis for the development group in predicting 1-month mortality revealed that a modified Goto’s TOR rule could be defined if patients with OHCA met the following four criteria: (1) initial asystole, (2) unwitnessed arrest by any laypersons, (3) EMS-CPR duration > 20 min, and (4) no prehospital return of spontaneous circulation (ROSC). The specificity, FPR, and PPV of the rule for predicting 1-month mortality were 99.2% (95% confidence interval [CI], 99.0–99.4%), 0.8% (0.6–1.0%), and 99.8% (99.8–99.9%), respectively. The proportion of patients who fulfilled the rule and the area under the receiver operating curve (AUC) was 27.5% (95% CI 27.3–27.7%) and 0.904 (0.902–0.905), respectively. In the validation group, the specificity, FPR, PPV, proportion of patients who met the rule, and AUC were 99.1% (95% CI 98.9–99.2%), 0.9% (0.8–1.1%), 99.8% (99.8–99.8%), 27.8% (27.6–28.0%), and 0.889 (0.887–0.891), respectively. Conclusion The modified Goto’s TOR rule (which includes the following four criteria: initial asystole, unwitnessed arrest, EMS-CPR duration > 20 min, and no prehospital ROSC) with a > 99% predictor of 1-month mortality is a reliable tool for physicians treating refractory OHCAs immediately after hospital arrival.

Background The International Liaison Committee on Resuscitation recommends that dispatchers provide instructions to perform compression-only cardiopulmonary resuscitation (CPR) to callers responding to adults with out-of-hospital cardiac arrest (OHCA). This study aimed to determine the optimal dispatcher-assisted CPR (DA-CPR) instructions for OHCA. Methods We analysed the records of 24,947 adult patients (aged ≥ 18 years) who received bystander DA-CPR after bystander-witnessed OHCA. Data were obtained from a prospectively recorded Japanese nationwide Utstein-style database for a 2-year period (2016–2017). Patients were divided into compression-only DA-CPR ( n = 22,778) and conventional DA-CPR (with a compression-to-ventilation ratio of 30:2, n = 2169) groups. The primary outcome measure was 1-month neurological intact survival, defined as a cerebral performance category score of 1–2 (CPC 1–2). Results The 1-month CPC 1–2 rate was significantly higher in the conventional DA-CPR group than in the compression-only DA-CPR group (before propensity score (PS) matching, 7.5% [162/2169] versus 5.8% [1309/22778], p < 0.01; after PS matching, 7.5% (162/2169) versus 5.7% (123/2169), p < 0.05). Compared with compression-only DA-CPR, conventional DA-CPR was associated with increased odds of 1-month CPC 1–2 (before PS matching, adjusted odds ratio 1.39, 95% confidence interval [CI] 1.14–1.70, p < 0.01; after PS matching, adjusted odds ratio 1.34, 95% CI 1.00–1.79, p < 0.05). Conclusion Within the limitations of this retrospective observational study, conventional DA-CPR with a compression-to-ventilation ratio of 30:2 was preferable to compression-only DA-CPR as an optimal DA-CPR instruction for coaching callers to perform bystander CPR for adult patients with bystander-witnessed OHCAs.

Aim: Among patients with paediatric out-of-hospital cardiac arrests (OHCAs), most have an initial non-shockable rhythm with poor outcomes. There is a subset who developed shockable rhythms. This study aimed to investigate the association between subsequent shock delivery and outcomes after paediatric OHCAs. Methods: We analysed records of 19,095 children (aged <18 years) with OHCA and initial non-shockable rhythm. Data were obtained from a Japanese nationwide database for 13 years (2005-2017). The primary outcome measure was 1-month neurologically intact survival, defined as cerebral performance category 1-2. Results: Among patients with pulseless electrical activity (PEA, n = 3,326), there was no significant difference between those with subsequent treated shockable rhythm (10.0% [11/109]) and those with sustained non-shockable rhythm (6.0% [192/3,217], p = 0.10) with respect to the neurologically intact survival rate. Among asystole patients (n = 15,769), the neurologically intact survival rate was significantly higher in the subsequent treated shockable rhythm group (4.4% [10/227]) than in the sustained non-shockable rhythm group (0.7% [106/15,542], p < 0.0001). Subsequent treated shockable rhythm with a shock delivery time (time from emergency medical services [EMS]-initiated cardiopulmonary resuscitation [CPR] to shock delivery) ≤9 min was associated with increased odds of neurologically intact survival compared with sustained non-shockable rhythm (PEA, adjusted odds ratio, 2.45 [95% confidence interval, 1.16-5.16], p = 0.018; asystole, 9.77 [4.2-22.5], p < 0.0001). Conclusion: After paediatric OHCAs, subsequent treated shockable rhythm was associated with increased odds of 1-month neurologically intact survival regardless of whether the initial rhythm was PEA or asystole, only when the shock was delivered ≤9 min of EMS-initiated CPR.

Aim: As asphyxial cardiac arrest is more common than cardiac arrest from a primary cardiac event in paediatric cardiac arrest, effective ventilation is important during paediatric cardiopulmonary resuscitation (CPR). We aimed to determine optimal dispatcher-assisted CPR instructions for bystanders after paediatric out-of-hospital cardiac arrest (OHCA). Methods: We analysed the records of 8172 children who received bystander dispatcher-assisted CPR. Data were obtained from an All-Japan Utstein-style registry from 2005 to 2017. Patients were divided into conventional CPR and compression-only CPR groups. The primary study endpoint was 1-month neurologically intact survival, defined as a Cerebral Performance Category score of 1 or 2 (CPC 1-2). Results: The 1-month CPC 1-2 rate was significantly higher in the dispatcher-assisted conventional CPR group than in the dispatcher-assisted compression-only CPR group (before propensity score matching, 5.7% [175/3077] vs. 3.1% [160/5095], p<0.0001, adjusted odds ratio 2.48, 95% confidence interval 1.19-3.22; after propensity score matching, 6.0% [156/2618] vs. 2.6% [69/2618], p<0.0001, adjusted odds ratio 2.42, 95% confidence interval 1.76-3.32). In most subgroup analyses after matching, dispatcher-assisted conventional CPR had a higher CPC 1-2 rate than dispatcher-assisted compression-only CPR; however, CPC 1-2 rates were similar between the two groups for patients with an initial shockable rhythm, those with total prehospital CPR time ≥20 min, those receiving public access defibrillation, advanced airway management, or adrenaline administration. Conclusion: Within the limitations of this retrospective observational study, dispatcher-assisted conventional CPR was preferable to dispatcher-assisted compression-only CPR as optimal CPR instructions for coaching callers to perform bystander CPR.

Background and importance: Bystander cardiopulmonary resuscitation (CPR) and initial shockable rhythm are crucial predictors of survival after out-of-hospital cardiac arrest (OHCA). However, the relationship between dispatcher-assisted CPR (DA-CPR) and initial shockable rhythm is not completely elucidated. Objective: To examine the association of DA-CPR with initial shockable rhythm and outcomes. Design, setting and participants: This nationwide population-based observational study conducted in Japan included 59 688 patients with witnessed OHCA of cardiac origin after excluding those without bystander CPR. Patients were divided into DA-CPR (n = 42 709) and CPR without dispatcher assistance (unassisted CPR, n = 16 979) groups. Outcome measures and analysis: The primary outcome measure was initial shockable rhythm, and secondary outcome measures were 1-month survival and neurologically intact survival. A Cox proportional hazards model adjusted for collapse-to-first-rhythm-analysis time and multivariable logistic regression models were used after propensity score (PS) matching to compare the incidence of initial shockable rhythm and outcomes, respectively. Main results: Among all patients (mean age 76.7 years), the rates of initial shockable rhythm, 1-month survival and neurologically intact survival were 20.8, 10.7 and 7.0%, respectively. The incidence of initial shockable rhythm in the DA-CPR group (20.4%, 3462/16 979) was significantly higher than that in the unassisted CPR group (18.5%, 3133/16 979) after PS matching (P < 0.0001). However, no significant differences were found between the two groups with respect to the incidence of initial shockable rhythm in the Cox proportional hazards model [adjusted hazard ratio of DA-CPR for initial shockable rhythm compared with unassisted CPR, 0.99; 95% confidence interval (CI), 0.97-1.02, P = 0.56]. No significant differences were observed in the survival rates in the two groups after PS matching [10.8% (1833/16 979) vs. 10.3% (1752/16 979), P = 0.16] and neurologically intact survival rates [7.3% (1233/16 979) vs. 6.8% (1161/16 979), P = 0.13]. The multivariable logistic regression model showed no significant differences between the groups with regard to survival (adjusted odds ratio of DA-CPR compared with unassisted CPR: 1.00; 95% CI, 0.89-1.13, P = 0.97) and neurologically intact survival (adjusted odds ratio: 1.12; 95% CI, 0.98-1.29, P = 0.14). Conclusion: DA-CPR after OHCA had the same independent association with the likelihood of initial shockable rhythm and 1-month meaningful outcome as unassisted CPR.

Aim Trends in neurologically intact survival after paediatric out-of-hospital cardiac arrest (OHCA) remain unclear. In the present study, we aimed to determine trends in 1-month neurologically intact survival after paediatric OHCA over time. Methods We reviewed the data of 5461 children (aged < 18 years) who experienced bystander-witnessed OHCA and were included in the nationwide Japanese registry from 2005 to 2017. Patients were divided into three groups according to study period: 2005–2010, 2011–2015, and 2016–2017. We analysed the trends in 1-month neurologically intact survival rates over time. Results The risk-adjusted odds of 1-month neurologically intact survival (odds ratio, 1.86; 95% confidence interval, 1.41–2.44) were significantly improved by 2016–2017 compared with baseline. Similar improvements in 1-month neurologically intact survival rates were observed with both standard bystander cardiopulmonary resuscitation (CPR) with rescue breaths and chest compression-only bystander CPR (P for trend < 0.05 and < 0.001, respectively). In the subgroup analyses by aetiology, the 1-month neurologically intact survival rate in patients with OHCA of non-traumatic origin significantly increased from 11.8%–15.1% to 19.7% (P for trend < 0.001) but not in those with OHCA of traumatic origin (from 4.9% to 3.4% to 4.1%; P for trend = 0.29). Conclusion The 1-month neurologically intact survival rate significantly increased from 2005 to 2017 in Japanese children with bystander-witnessed OHCA, regardless of bystander CPR type; This increase was noted in patients with OHCA of non-traumatic origin but not in those with OHCA of traumatic origin.

Aim Ventricular fibrillation (VF) cardiac arrest may consist of three time-sensitive phases: electrical, circulatory, and metabolic. However, the time boundaries of these phases are unclear. We aimed to determine the time boundaries of the three-phase model for VF cardiac arrest. Methods We reviewed 20,741 out-of-hospital cardiac arrest cases with initial VF and presumed cardiac origin from the All-Japan Utstein-style registry between 2013 and 2017. The study endpoint was 1-month neurologically intact survival. The collapse-to-shock interval was defined as the time from collapse to the first shock delivery by emergency medical service personnel. The patients were divided into the bystander cardiopulmonary resuscitation (CPR, n = 11,606) and non-bystander CPR (n = 9135) groups. Results In the bystander CPR group, the collapse-to-shock times that were associated with increased adjusted 1-month neurologically intact survival, compared with those in the non-bystander CPR group, ranged from 7 min (42.9% [244/4999] vs. 26.0% [119/458], adjusted odds ratio [aOR], 1.95; 95% confidence interval [CI], 1.44–2.63; P < 0.0001) to 17 min (17.1% [70/410] vs. 7.3% [21/288], aOR, 2.82; 95% CI, 1.62–4.91; P = 0.0002). However, the neurologically intact survival rate of the bystander CPR group was statistically insignificant compared with that of the non-bystander CPR group when the collapse-to-shock time was outside this range. Conclusions The time boundaries of the three-phase time-sensitive model for VF cardiac arrest may be defined as follows: electrical phase, from collapse to <7 min; circulatory phase, from 7 to 17 min; and metabolic phase, from >17 min onward.

Background: It remains unclear whether men have more favorable survival outcomes after out-of-hospital cardiac arrest (OHCA) than women. Methods: We reviewed a total of 386,535 patients aged ≥ 18 years with OHCA who were included in the Japanese registry from 2013 to 2016. The study endpoints were the rates of 1-month survival and neurologically intact survival (Cerebral Performance Category Scale score = 1 or 2). Based on age, the reviewed patients were categorized into the following eight groups: < 30, 30-39, 40-49, 50-59, 60-69, 70-79, 80-89, and ≥ 90 years. The survival outcomes in men and women were compared using hierarchical propensity score matching. Results: The crude survival rate was significantly higher in men than in women in five groups: 30-39, 40-49, 50-59, 60-69, and 70-79 years (all P < 0.001). Similarly, the crude neurologically intact survival rate was significantly higher in men than in women in seven groups: < 30, 30-39, 40-49, 50-59, 60-69, 70-79, and 80-89 years (all P < 0.005). However, multivariate logistic regression analysis of each group revealed no significant sex-specific differences in 1-month survival outcomes (all P > 0.02). Moreover, after hierarchical propensity score matching, the survival outcomes did not significantly differ between both sexes (all P > 0.05). Conclusions: No significant sex-specific differences were found in the rates of 1-month survival and neurologically intact survival after OHCA.