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Featured researches published by Taku Iwami.


The New England Journal of Medicine | 2010

Nationwide public access defibrillation in Japan

Tetsuhisa Kitamura; Taku Iwami; Takashi Kawamura; Ken Nagao; Hideharu Tanaka; Atsushi Hiraide

BACKGROUND It is unclear whether dissemination of automated external defibrillators (AEDs) in public places can improve the rate of survival among patients who have had an out-of-hospital cardiac arrest. METHODS From January 1, 2005, through December 31, 2007, we conducted a prospective, population-based, observational study involving consecutive patients across Japan who had an out-of-hospital cardiac arrest and in whom resuscitation was attempted by emergency responders. We evaluated the effect of nationwide dissemination of public-access AEDs on the rate of survival after an out-of-hospital cardiac arrest. The primary outcome measure was the 1-month rate of survival with minimal neurologic impairment. A multivariate logistic-regression analysis was performed to assess factors associated with a good neurologic outcome. RESULTS A total of 312,319 adults who had an out-of-hospital cardiac arrest were included in the study; 12,631 of these patients had ventricular fibrillation and had an arrest that was of cardiac origin and that was witnessed by bystanders. In 462 of these patients (3.7%), shocks were administered by laypersons with the use of public-access AEDs, and the proportion increased, from 1.2% to 6.2%, as the number of public-access AEDs increased (P<0.001 for trend). Among all patients who had a bystander-witnessed arrest of cardiac origin and who had ventricular fibrillation, 14.4% were alive at 1 month with minimal neurologic impairment; among patients who received shocks from public-access AEDs, 31.6% were alive at 1 month with minimal neurologic impairment. Early defibrillation, regardless of the type of provider (bystander or emergency-medical-services personnel), was associated with a good neurologic outcome after a cardiac arrest with ventricular fibrillation (adjusted odds ratio per 1-minute increase in the time to administration of shock, 0.91; 95% confidence interval, 0.89 to 0.92; P<0.001). The mean time to shock was reduced from 3.7 to 2.2 minutes, and the annual number of patients per 10 million population who survived with minimal neurologic impairment increased from 2.4 to 8.9 as the number of public-access AEDs increased from fewer than 1 per square kilometer of inhabited area to 4 or more. CONCLUSIONS Nationwide dissemination of public-access AEDs in Japan resulted in earlier administration of shocks by laypersons and in an increase in the 1-month rate of survival with minimal neurologic impairment after an out-of-hospital cardiac arrest.


The Lancet | 2010

Conventional and chest-compression-only cardiopulmonary resuscitation by bystanders for children who have out-of-hospital cardiac arrests: a prospective, nationwide, population-based cohort study

Tetsuhisa Kitamura; Taku Iwami; Takashi Kawamura; Ken Nagao; Hideharu Tanaka; Vinay Nadkarni; Robert A. Berg; Atsushi Hiraide

BACKGROUND The American Heart Association recommends cardiopulmonary resuscitation (CPR) by bystanders with chest compression only for adults who have cardiac arrests, but not for children. We assessed the effect of CPR (conventional with rescue breathing or chest compression only) by bystanders on outcomes after out-of-hospital cardiac arrests in children. METHODS In a nationwide, prospective, population-based, observational study, we enrolled 5170 children aged 17 years and younger who had an out-of-hospital cardiac arrest from Jan 1, 2005, to Dec 31, 2007. Data collected included age, cause, and presence and type of CPR by bystander. The primary endpoint was favourable neurological outcome 1 month after an out-of-hospital cardiac arrest, defined as Glasgow-Pittsburgh cerebral performance category 1 or 2. FINDINGS 3675 (71%) children had arrests of non-cardiac causes and 1495 (29%) cardiac causes. 1551 (30%) received conventional CPR and 888 (17%) compression-only CPR. Data for type of CPR by bystander were not available for 12 children. Children who were given CPR by a bystander had a significantly higher rate of favourable neurological outcome than did those not given CPR (4.5% [110/2439] vs 1.9% [53/2719]; adjusted odds ratio [OR] 2.59, 95% CI 1.81-3.71). In children aged 1-17 years who had arrests of non-cardiac causes, favourable neurological outcome was more common after bystander CPR than no CPR (5.1% [51/1004] vs 1.5% [20/1293]; OR 4.17, 2.37-7.32). However, conventional CPR produced more favourable neurological outcome than did compression-only CPR (7.2% [45/624] vs 1.6% [six of 380]; OR 5.54, 2.52-16.99). In children aged 1-17 years who had arrests of cardiac causes, favourable neurological outcome was more common after bystander CPR than no CPR (9.5% [42/440] vs 4.1% [14/339]; OR 2.21, 1.08-4.54), and did not differ between conventional and compression-only CPR (9.9% [28/282] vs 8.9% [14/158]; OR 1.20, 0.55-2.66). In infants (aged <1 year), outcomes were uniformly poor (1.7% [36/2082] with favourable neurological outcome). INTERPRETATION For children who have out-of-hospital cardiac arrests from non-cardiac causes, conventional CPR (with rescue breathing) by bystander is the preferable approach to resuscitation. For arrests of cardiac causes, either conventional or compression-only CPR is similarly effective. FUNDING Fire and Disaster Management Agency and the Ministry of Education, Culture, Sports, Science and Technology (Japan).


Circulation | 2007

Effectiveness of Bystander-Initiated Cardiac-Only Resuscitation for Patients With Out-of-Hospital Cardiac Arrest

Taku Iwami; Takashi Kawamura; Atsushi Hiraide; Robert A. Berg; Yasuyuki Hayashi; Tatsuya Nishiuchi; Kentaro Kajino; Naohiro Yonemoto; Hidekazu Yukioka; Hisashi Sugimoto; Hiroyuki Kakuchi; Kazuhiro Sase; Hiroyuki Yokoyama; Hiroshi Nonogi

Background— Previous animal and clinical studies suggest that bystander-initiated cardiac-only resuscitation may be superior to conventional cardiopulmonary resuscitation (CPR) for out-of-hospital cardiac arrests. Our hypothesis was that both cardiac-only bystander resuscitation and conventional bystander CPR would improve outcomes from out-of-hospital cardiac arrests of ≤15 minutes’ duration, whereas the addition of rescue breathing would improve outcomes for cardiac arrests lasting >15 minutes. Methods and Results— We carried out a prospective, population-based, observational study involving consecutive patients with emergency responder resuscitation attempts from May 1, 1998, through April 30, 2003. The primary outcome measure was 1-year survival with favorable neurological outcome. Multivariable logistic regression analysis was performed to evaluate the relationship between type of CPR and outcomes. Among the 4902 witnessed cardiac arrests, 783 received conventional CPR, and 544 received cardiac-only resuscitation. Excluding very-long-duration cardiac arrests (>15 minutes), the cardiac-only resuscitation yielded a higher rate of 1-year survival with favorable neurological outcome than no bystander CPR (4.3% versus 2.5%; odds ratio, 1.72; 95% CI, 1.01 to 2.95), and conventional CPR showed similar effectiveness (4.1%; odds ratio, 1.57; 95% CI, 0.95 to 2.60). For the very-long-duration arrests, neurologically favorable 1-year survival was greater in the conventional CPR group, but there were few survivors regardless of the type of bystander CPR (0.3% [2 of 624], 0% [0 of 92], and 2.2% [3 of 139] in the no bystander CPR, cardiac-only CPR, and conventional CPR groups, respectively; P<0.05). Conclusions— Bystander-initiated cardiac-only resuscitation and conventional CPR are similarly effective for most adult out-of-hospital cardiac arrests. For very prolonged cardiac arrests, the addition of rescue breathing may be of some help.


Circulation | 2009

Continuous Improvements in “Chain of Survival” Increased Survival After Out-of-Hospital Cardiac Arrests A Large-Scale Population-Based Study

Taku Iwami; Graham Nichol; Atsushi Hiraide; Yasuyuki Hayashi; Tatsuya Nishiuchi; Kentaro Kajino; Hiroshi Morita; Hidekazu Yukioka; Hisashi Ikeuchi; Hisashi Sugimoto; Hiroshi Nonogi; Takashi Kawamura

Background— The impact of ongoing efforts to improve the “chain of survival” for out-of-hospital cardiac arrest (OHCA) is unclear. The objective of this study was to evaluate the incremental effect of changes in prehospital emergency care on survival after OHCA. Methods and Results— This prospective, population-based observational study involved consecutive patients with OHCA from May 1998 through December 2006. The primary outcome measure was 1-month survival with favorable neurological outcome. Multiple logistic regression analysis was used to assess factors that were potentially associated with better neurological outcome. Among 42 873 resuscitation-attempted adult OHCAs, 8782 bystander-witnessed arrests of presumed cardiac origin were analyzed. The median time interval from collapse to call for medical help, first cardiopulmonary resuscitation, and first shock shortened from 4 (interquartile range [IQR] 2 to 11) to 2 (IQR 1 to 5) minutes, from 9 (IQR 5 to 13) to 7 (IQR 3 to 11) minutes, and from 19 (IQR 13 to 22) to 9 (IQR 7 to 12) minutes, respectively. Neurologically intact 1-month survival after witnessed ventricular fibrillation increased from 6% (6/96) to 16% (49/297; P<0.001). Among all witnessed OHCAs, earlier cardiopulmonary resuscitation (odds ratio per minute 0.89, 95% confidence interval 0.85 to 0.93) and earlier intubation (odds ratio per minute 0.96, 95% confidence interval 0.94 to 0.99) were associated with better neurological outcome. For ventricular fibrillation, only earlier shock was associated with better outcome (odds ratio 0.84, 95% confidence interval 0.80 to 0.88). Conclusions— Data from a large, population-based cohort demonstrate a continuous increase in OHCA survival with improvement in the chain of survival. The incremental benefit of early advanced care on OHCA survival is also suggested.


Circulation | 2012

Nationwide Improvements in Survival From Out-of-Hospital Cardiac Arrest in Japan

Tetsuhisa Kitamura; Taku Iwami; Takashi Kawamura; Masahiko Nitta; Ken Nagao; Hiroshi Nonogi; Naohiro Yonemoto; Takeshi Kimura

Background—Little is known about the nationwide trend in the survival of out-of-hospital cardiac arrest (OHCA) in Japan and the differences in incidence and survival by age group and origin of arrest. Methods and Results—A nationwide, prospective, population-based observation covering the whole population of Japan and involving consecutive OHCA patients with resuscitation attempts was conducted from January 2005 to December 2009. The main outcome measure was 1-month survival with favorable neurological outcome. The nationwide trends in OHCA incidence and outcome by age and origin of arrest were assessed. Multiple logistic regression analysis for bystander-witnessed OHCA was used to adjust for factors that were potentially associated with favorable neurological outcome. During 5 years, 547 153 overall OHCAs and 169 360 bystander-witnessed OHCAs were enrolled. The annual incidence significantly increased among overall OHCAs and bystander-witnessed OHCAs. Neurologically favorable survival significantly increased from 1.6% (1676/102 737) in 2005 to 2.8% (3280/115 250) in 2009 (P<0.001), from 2.1% (638/30 556) to 4.3% (1558/36 361) (P<0.001), and from 9.8% (437/4461) to 20.6% (1215/5906) (P<0.001) among overall OHCA, bystander-witnessed OHCA, and bystander-witnessed ventricular fibrillation OHCA, respectively. Public-access automated external defibrillator use, either bystander-initiated chest compression–only cardiopulmonary resuscitation or conventional cardiopulmonary resuscitation, and earlier emergency medical services response time were associated with a better neurological outcome. Favorable neurological outcome among adult OHCA subjects significantly improved, but the outcome among younger children and very elderly subjects did not improve and was poor irrespective of origin of OHCA. Conclusions—Nationwide improvements of favorable neurological outcome from OHCA were observed in Japan and differed by age group and origin of OHCA.


Pediatrics | 2011

Age-Specific Differences in Outcomes After Out-of-Hospital Cardiac Arrests

Masahiko Nitta; Taku Iwami; Tetsuhisa Kitamura; Vinay Nadkarni; Robert A. Berg; Naoki Shimizu; Kunio Ohta; Tatsuya Nishiuchi; Yasuyuki Hayashi; Atsushi Hiraide; Hiroshi Tamai; Masanao Kobayashi; Hiroshi Morita

OBJECTIVE: We assessed out-of-hospital cardiac arrests (OHCAs) for various pediatric age groups. METHODS: This prospective, population-based, observational study included all emergency medical service-treated OHCAs in Osaka, Japan, between 1999 and 2006 (excluding 2004). Patients were grouped as adults (>17 years), infants (<1 year), younger children (1–4 years), older children (5–12 years), and adolescents (13–17 years). The primary outcome measure was 1-month survival with favorable neurologic outcome. RESULTS: Of 950 pediatric OHCAs, resuscitations were attempted for 875 patients (92%; 347 infants, 203 younger children, 135 older children, and 190 adolescents). The overall incidence of nontraumatic pediatric OHCAs was 7.3 cases per 100 000 person-years, compared with 64.7 cases per 100 000 person-years for adults and 65.5 cases per 100 000 person-years for infants. Most infant OHCAs occurred in homes (93%) and were not witnessed (90%). Adolescent OHCAs often occurred outside the home (45%), were witnessed by bystanders (37%), and had shockable rhythms (18%). One-month survival was more common after nontraumatic pediatric OHCAs than adult OHCAs (8% [56 of 740 patients] vs 5% [1677 of 33 091 patients]; adjusted odds ratio: 2.26 [95% confidence interval: 1.63–3.13]). One-month survival with favorable neurologic outcome was more common among children than adults (3% [21 of 740 patients] vs 2% [648 of 33 091 patients]; adjusted odds ratio: 2.46 [95% confidence interval: 1.45–4.18]). Rates of 1-month survival with favorable neurologic outcome were 1% for infants, 2% for younger children, 2% for older children, and 11% for adolescents. CONCLUSION: Survival and favorable neurologic outcome at 1 month were more common after pediatric OHCAs than adult OHCAs.


Resuscitation | 2010

Impact of transport to critical care medical centers on outcomes after out-of-hospital cardiac arrest ,

Kentaro Kajino; Taku Iwami; Mohamud Daya; Tatsuya Nishiuchi; Yasuyuki Hayashi; Tetsuhisa Kitamura; Taro Irisawa; Tomohiko Sakai; Yasuyuki Kuwagata; Atushi Hiraide; Masashi Kishi; Shigeru Yamayoshi

BACKGROUND Post-resuscitation care has emerged as an important predictor of survival from out-of-hospital cardiac arrest (OHCA). In Japan, selected hospitals are certified as Critical Care Medical Centers (CCMCs) based on their ability and expertise. HYPOTHESIS Outcome after OHCA is better in patients transported to a CCMC compared a non-critical care hospital (NCCH). MATERIALS AND METHODS Adults with OHCA of presumed cardiac etiology, treated by emergency medical services systems, and transported in Osaka from January 1, 2005 to December 31, 2007 were registered using a prospective Utstein style population cohort database. Primary outcome measure was 1 month neurologically favorable survival (CPC< or =2). Outcomes of patients transported to CCMC were compared with patients transported to NCCH using multiple logistic regressions and stratified on the basis of stratified field ROSC. RESULTS 10,383 cases were transported. Of these, 2881 were transported to CCMC and 7502 to NCCH. Neurologically favorable 1-month survival was greater in the CCMC group [6.7% versus 2.8%, P<0.001]. Among patients who were transported to hospital without field ROSC, neurologically favorable outcome was greater in the CCMC group than the NCCH group [1.7% versus 0.5%; adjusted odds ratio (OR), 3.39; 95% confidence interval (CI), 2.17-5.29; P<0.001]. In the presence of field ROSC, survival was similar between the groups [43% versus 41%; adjusted OR, 1.09; 95% CI, 0.82-1.45; P=0.554]. CONCLUSIONS Survival after OHCA of presumed cardiac etiology transported to CCMCs was better than those transported to NCCHs. For OHCA patients without field ROSC, transport to a CCMC was an independent predictor for a good neurological outcome.


Circulation | 2012

Chest Compression-Only Cardiopulmonary Resuscitation for Out-of-Hospital Cardiac Arrest With Public-Access Defibrillation A Nationwide Cohort Study

Taku Iwami; Tetsuhisa Kitamura; Takashi Kawamura; Hideo Mitamura; Ken Nagao; Morimasa Takayama; Yoshihiko Seino; Hideharu Tanaka; Hiroshi Nonogi; Naohiro Yonemoto; Takeshi Kimura

Background—It remains unclear which is more effective to increase survival after out-of-hospital cardiac arrest in those with public-access defibrillation, bystander-initiated chest compression–only cardiopulmonary resuscitation (CPR) or conventional CPR with rescue breathing. Methods and Results—A nationwide, prospective, population-based observational study covering the whole population of Japan and involving consecutive out-of-hospital cardiac arrest patients with resuscitation attempts has been conducted since 2005. We enrolled all out-of-hospital cardiac arrests of presumed cardiac origin that were witnessed and received shocks with public-access automated external defibrillation (AEDs) by bystanders from January 1, 2005, to December 31, 2009. The main outcome measure was neurologically favorable 1-month survival. We compared outcomes by type of bystander-initiated CPR (chest compression–only CPR and conventional CPR with compressions and rescue breathing). Multivariable logistic regression was used to assess the relationship between the type of CPR and a better neurological outcome. During the 5 years, 1376 bystander-witnessed out-of-hospital cardiac arrests of cardiac origin in individuals who received CPR and shocks with public-access AEDs by bystanders were registered. Among them, 506 (36.8%) received chest compression–only CPR and 870 (63.2%) received conventional CPR. The chest compression–only CPR group (40.7%, 206 of 506) had a significantly higher rate of 1-month survival with favorable neurological outcome than the conventional CPR group (32.9%, 286 of 870; adjusted odds ratio, 1.33; 95% confidence interval, 1.03–1.70). Conclusions—Compression-only CPR is more effective than conventional CPR for patients in whom out-of-hospital cardiac arrest is witnessed and shocked with public-access defibrillation. Compression-only CPR is the most likely scenario in which lay rescuers can witness a sudden collapse and use public-access AEDs.


Circulation | 2010

Bystander-Initiated Rescue Breathing for Out-of-Hospital Cardiac Arrests of Noncardiac Origin

Tetsuhisa Kitamura; Taku Iwami; Takashi Kawamura; Ken Nagao; Hideharu Tanaka; Atsushi Hiraide

Background— Although chest compression–only cardiopulmonary resuscitation (CPR) is effective for adult out-of-hospital cardiac arrest (OHCA) of cardiac origin, it remains uncertain whether bystander-initiated rescue breathing has an incremental benefit for OHCA of noncardiac origin. Methods and Results— A nationwide, prospective, population-based, observational study covering the whole population of Japan and involving consecutive OHCA patients with emergency responder resuscitation attempts was conducted from January 2005 through December 2007. The primary outcome was neurologically intact 1-month survival. Multiple logistic regression analysis was used to assess the contribution of bystander-initiated CPR to better neurological outcomes. Among a total of 43 246 bystander-witnessed OHCAs of noncardiac origin, 8878 (20.5%) received chest compression–only CPR, and 7474 (17.3%) received conventional CPR with rescue breathing. The conventional CPR group (1.8%) had a higher rate of better neurological outcome than both the no CPR group (1.4%; odds ratio, 1.58; 95% confidence interval, 1.28 to 1.96) and the compression-only CPR group (1.5%; odds ratio, 1.32; 95% confidence interval, 1.03 to 1.69). However, the compression-only CPR group did not produce better neurological outcome than the no CPR group (odds ratio, 1.19; 95% confidence interval, 0.96 to 1.47). The number of OHCAs needed to treat with conventional CPR versus compression-only CPR to save a life with favorable neurological outcome after OHCA was 290. Conclusions— This nationwide observational study indicates that rescue breathing has an incremental benefit for OHCAs of noncardiac origin, but the impact on the overall survival after OHCA was small.


Critical Care | 2011

Comparison of supraglottic airway versus endotracheal intubation for the pre-hospital treatment of out-of-hospital cardiac arrest

Kentaro Kajino; Taku Iwami; Tetsuhisa Kitamura; Mohamud Daya; Marcus Eng Hock Ong; Tatsuya Nishiuchi; Yasuyuki Hayashi; Tomohiko Sakai; Takeshi Shimazu; Atsushi Hiraide; Masashi Kishi; Shigeru Yamayoshi

IntroductionBoth supraglottic airway devices (SGA) and endotracheal intubation (ETI) have been used by emergency life-saving technicians (ELST) in Japan to treat out-of-hospital cardiac arrests (OHCAs). Despite traditional emphasis on airway management during cardiac arrest, its impact on survival from OHCA and time dependent effectiveness remains unclear.MethodsAll adults with witnessed, non-traumatic OHCA, from 1 January 2005 to 31 December 2008, treated by the emergency medical services (EMS) with an advanced airway in Osaka, Japan were studied in a prospective Utstein-style population cohort database. The primary outcome measure was one-month survival with neurologically favorable outcome. The association between type of advanced airway (ETI/SGA), timing of device placement and neurological outcome was assessed by multiple logistic regression.ResultsOf 7,517 witnessed non-traumatic OHCAs, 5,377 cases were treated with advanced airways. Of these, 1,679 were ETI while 3,698 were SGA. Favorable neurological outcome was similar between ETI and SGA (3.6% versus 3.6%, P = 0.95). The time interval from collapse to ETI placement was significantly longer than for SGA (17.2 minutes versus 15.8 minutes, P < 0.001). From multivariate analysis, early placement of an advanced airway was significantly associated with better neurological outcome (Adjusted Odds Ratio (AOR) for one minute delay, 0.91, 95% confidence interval (CI) 0.88 to 0.95). ETI was not a significant predictor (AOR 0.71, 95% CI 0.39 to 1.30) but the presence of an ETI certified ELST (AOR, 1.86, 95% CI 1.04 to 3.34) was a significant predictor for favorable neurological outcome.ConclusionsThere was no difference in neurologically favorable outcome from witnessed OHCA for ETI versus SGA. Early airway management with advanced airway regardless of type and rhythm was associated with improved outcomes.

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