Masaaki Hashimoto’s scientific contributions

Aim: Some out-of-hospital cardiac arrests (OHCAs) are witnessed after emergency calls. This study aimed to confirm the benefit of early emergency calls before patient collapse on survival after OHCAs witnessed by bystanders and/or emergency medical technicians (EMTs). Methods: We analysed 278,310 witnessed OHCAs [EMT-witnessed cases (n = 54,172), bystander-witnessed cases (n = 224,138)] without pre-hospital physician involvement from all Japanese OHCA data prospectively collected between 2006 and 2012. The data were analysed for the correlation between neurologically favourable 1-month survival and the time interval between the emergency call and patient collapse. Results: When emergency calls were placed earlier before patient collapse, the proportion of EMT-witnessed cases and survival rate after OHCAs witnessed by bystanders and EMTs were higher. When analysed only for bystander-witnessed cases, for earlier emergency calls placed before patient collapse, survival rate and incidences of bystander cardiopulmonary resuscitation (CPR) and dispatcher-assisted CPR decreased: 2.9%, 33.6% and 24.4%, respectively, for emergency calls placed >6 min before collapse and 5.5%, 48.8% and 48.5%, respectively, for those placed 1–2 min after collapse. Multivariable logistic regression showed that call-to-collapse interval (adjusted odds ratio; 95% confidence interval) (0.92; 0.90–0.94) and EMT response time after collapse (0.84; 0.82–0.86) were associated with survival after bystander-witnessed OHCAs with emergency calls before collapse. Conclusion: Early emergency calls before patient collapse efficiently increase the proportion of EMT-witnessed cases and promotes survival after witnessed OHCAs. However, early emergency call before collapse may worsen the outcome when the patient's condition deteriorates to cardiac arrest before EMT arrival.

Aim: To investigate the signs, symptoms and incidences of aortic aneurysm/dissection (A/D) that did and did not cause OHCA and were transported by EMTs. Materials and Methods: Fire departments prospectively collected the data for cases with non-traumatic aortic A/D that were transported by EMS during the period of 2011 to 2013. The data included the backgrounds, signs and symptoms of the patients at the scene, backgrounds of the bystanders and 1-month survival. Results: As shown in Fig. 1, of 219 cases transported by Emergency Medical Technicians (EMTs) on their suspicion of aortic A/D, 140 cases were diagnosed with aortic A/D. Of 72,185 cases with endogenous medical emergency, 176 cases transported without EMT’s suspicion of aortic A/D were finally diagnosed with aortic aneurysm/dissection. In total, 316 cases had the aortic A/D. Thus, sensitivity of our regional EMS for non-traumatic aortic AD was 44% (140/316) while positive predictive value was 64% (140/219). The backgrounds of patients are as follows: male gender (51%), median value (25-75%) of age [73 (62-83)], high co-morbidity (88%). The major signs and symptoms obtained by EMTs were characterized by acute onset but mostly non-specific: chest pain (45%), back pain (40%), abdominal pain (14%). Moving severe pain was rarely caught (6%). These symptoms happened without a hard exercise (99%), and detected mainly by family members (41%) and patients themselves (34%). Bilateral blood pressure difference was rarely detected (5%). One-month survival rate was higher in cases transported to major emergency medical hospitals offering a major vascular surgery than those to other hospitals. None of other factors were associated with the survival. Conclusions: The Incidence of aortic A/D in all medical emergencies was extremely low. The survival rate may depend on the level of transported hospital. Clear criteria for “aortic transportation bypass” is required in EMS system.

Aim: To assess the benefit of immediate call-first or CPR-first basic life support (BLS) in promoting a better outcome of out-of-hospital cardiac arrest (OHCA). Methods: From the nation-wide database of 2005 to 2012, we extracted bystander-witnessed OHCAs in which both emergency call and CPR were performed by bystanders on their own initiative (without instruction over telephone) within 6 min of witnessing patient collapse. These cases were categorized into the following four groups; immediate Call+CPR group (N=10,195 ,emergency call and/or CPR within 2 min of witness, call-CPR time interval = 0 or 1 min), immediate Call-First group (N=1,820 , emergency call within 2 min of witness, call-CPR interval = 2[[Unable to Display Character: ‒]]4 min), immediate CPR-First group (N=5,446 , bystander CPR within 2 min of witness, CPR-call interval =2[[Unable to Display Character: ‒]]4 min), the delayed Call/CPR group (N=4,671, the remaining cases). We compared the rates of neurologically favorable survival at 1-month among the four groups for all OHCAs and subgroups of OHCAs. Results: The overall survival rate was highest in Call-First group and lowest in delayed Call/CPR group (Figure). The rate of Call-First group was significantly higher than that of CPR-First group in OHCAs of presumed cardiac etiology (17.2% vs. 14.1%, unadjusted OR; 95% CI, 1.26; 1.05[[Unable to Display Character: ‒]]1.52). The rate of CPR-First group was significantly higher than that of Call-First group in OHCAs of presumed non-cardiac etiology (7.7% vs. 5.0%, 1.59; 1.11[[Unable to Display Character: ‒]]2.33) and young adults/children (age<35y, 32.8% vs. 17.8%, 2.25; 1.33[[Unable to Display Character: ‒]]3.95). Multiple logistic regression analysis confirmed the results of univariate analyses and disclosed that delayed Call/CPR is associated with poor outcomes. Conclusions: The immediate (within 2 min) CPR-first BLS action followed by emergency call without a large (>4 min) delay may be recommended when a single bystander having a fundamental skill to initiate CPR witnesses OHCAs of non-cardiac etiology and young adults/children.

To investigate whether the bystander–patient relationship affects bystander response to out-of-hospital cardiac arrest (OHCA) and patient outcomes depending on the time of day.Methods This population-based observational study in Japan involving 139,265 bystander-witnessed OHCAs (90,426 family members, 10,479 friends/colleagues, and 38,360 others) without prehospital physician involvement was conducted from 2005 to 2009. Factors associated with better bystander response [early emergency call and bystander cardiopulmonary resuscitation (BCPR)] and 1-month neurologically favorable survival were assessed.ResultsThe rates of dispatcher-assisted CPR during daytime (7:00–18:59) and nighttime (19:00–6:59) were highest in family members (45.6% and 46.1%, respectively, for family members; 28.7% and 29.2%, respectively, for friends/colleagues; and 28.1% and 25.3%, respectively, for others). However, the BCPR rates were lowest in family members (35.5% and 37.8%, respectively, for family members; 43.7% and 37.8%, respectively, for friends/colleagues; and 59.3% and 50.0%, respectively, for others). Large delays (≥5 min) in placing emergency calls and initiating BCPR were most frequent in family members. The overall survival rate was lowest (2.7%) for family members and highest (9.1%) for friends/colleagues during daytime. Logistic regression analysis revealed that the effect of bystander relationship on survival was significant only during daytime [adjusted odds ratios (95% CI) for survival from daytime OHCAs with family as reference were 1.51 (1.36–1.68) for friends/colleagues and 1.23 (1.13–1.34) for others].Conclusions Family members are least likely to perform BCPR and OHCAs witnessed by family members are least likely to survive during daytime. Different strategies are required for family-witnessed OHCAs.

Aim: The aim of the study was to determine the quality of basic life support (BLS) in out-of-hospital cardiac arrests (OHCAs) receiving bystander cardiopulmonary resuscitation (CPR) and public automated external defibrillator (AED) application. Methods: From January 2006 to December 2012, data were prospectively collected from OHCA) and impending cardiac arrests treated with and without public AED before emergency medical technician (EMT) arrival. Basic life support actions and outcomes were compared between cases with and without public AED application. Interruptions of CPR were compared between 2 groups of AED users: health care provider (HCP) and non-HCP. Results: Public AEDs were applied in 10 and 273 cases of impending cardiac arrest and non–EMT-witnessed OHCAs, respectively (4.3% of 6407 non–EMT-witnessed OHCAs). Defibrillation was delivered to 33 (13.3%) cases. Public AED application significantly improved the rate of 1-year neurologically favorable survival in bystander CPR–performed cases with shockable initial rhythm but not in those with nonshockable rhythm. Emergency calls were significantly delayed compared with other OHCAs without public AED application (median: 3 and2minutes, respectively; P b .0001). Analysis of AED records obtained from 136 (54.6%) of the 249 cases with AED application revealed significantly lower rate of compressions delivered per minute and significantly greater proportion of CPR pause in the non-HCP group. Time interval between power on and the first electrocardiographic analysis widely varied in both groups and was significantly prolonged in the non-HCP group (P =.0137). Conclusions: Improper BLS responses were common in OHCAs treated with public AEDs. Periodic training for proper BLS is necessary for both HCPs and non-HCPs.

Aims To identify the factors associated with good-quality bystander cardiopulmonary resuscitation (BCPR). Methods Data were prospectively collected from 553 out-of-hospital cardiac arrests (OHCAs) managed with BCPR in the absence of emergency medical technicians (EMT) during 2012. The quality of BCPR was evaluated by EMTs at the scene and was assessed according to the standard recommendations for chest compressions, including proper hand positions, rates and depths. Results Good-quality BCPR was more frequently confirmed in OHCAs that occurred in the central/urban region (56.3% [251/446] vs. 39.3% [42/107], p = 0.0015), had multiple rescuers (31.8% [142/446] vs. 11.2% [12/107], p < 0.0001) and received bystander-initiated BCPR (22.0% [98/446] vs.5.6% [6/107], p < 0.0001). Good-quality BCPR was less frequently performed by family members (46.9% [209/446] vs. 67.3% [72/107], p = 0.0001), elderly bystanders (13.5% [60/446] vs. 28.0% [30/107], p = 0.0005) and in at-home OHCAs (51.1% [228/446] vs. 72.9% [78/107], p < 0.0001). BCPR duration was significantly longer in the good-quality group (median, 8 vs.6 min, p = 0.0015). Multiple logistic regression analysis indicated that multiple rescuers (odds ratio = 2.8, 95% CI: 1.5–5.6), bystander-initiated BCPR (2.7, 1.1–7.3), non-elderly bystanders (1.9, 1.1–3.2), occurrence in the central region (2.1, 1.3–3.3) and duration of BCPR (1.1, 1.0-1.1) were associated with good-quality BCPR. Moreover, good-quality BCPR was initiated earlier after recognition/witness of cardiac arrest compared with poor-quality BCPR (3 vs. 4 min, p = 0.0052). The rate of neurologically favourable survival at one year was 2.7% and 0% in the good-quality and poor-quality groups, respectively (p = 0.1357). Conclusions The presence of multiple rescuers and bystander-initiated CPR are predominantly associated with good-quality BCPR