for the Japanese Circulation Society Resuscitation Science Study GroupNonogi, Naohiro Yonemoto and Takeshi Kimura

Tetsuhisa Kitamura, Taku Iwami, Takashi Kawamura, Masahiko Nitta, Ken Nagao, HiroshiNationwide Improvements in Survival From Out-of-Hospital Cardiac Arrest in Japan

Print ISSN: 0009-7322. Online ISSN: 1524-4539 Copyright © 2012 American Heart Association, Inc. All rights reserved.

is published by the American Heart Association, 7272 Greenville Avenue, Dallas, TX 75231Circulation doi: 10.1161/CIRCULATIONAHA.112.109496

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Nationwide Improvements in Survival From Out-of-HospitalCardiac Arrest in Japan

Tetsuhisa Kitamura, MD, MSc, DrPH; Taku Iwami, MD, MPH, PhD; Takashi Kawamura, MD, PhD;Masahiko Nitta, MD, PhD; Ken Nagao, MD, PhD; Hiroshi Nonogi, MD, PhD;

Naohiro Yonemoto, DrPH; Takeshi Kimura, MD, PhD; for the Japanese Circulation SocietyResuscitation Science Study Group

Background—Little is known about the nationwide trend in the survival of out-of-hospital cardiac arrest (OHCA) in Japanand 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 Japanand involving consecutive OHCA patients with resuscitation attempts was conducted from January 2005 to December2009. The main outcome measure was 1-month survival with favorable neurological outcome. The nationwide trendsin OHCA incidence and outcome by age and origin of arrest were assessed. Multiple logistic regression analysis forbystander-witnessed OHCA was used to adjust for factors that were potentially associated with favorable neurologicaloutcome. During 5 years, 547 153 overall OHCAs and 169 360 bystander-witnessed OHCAs were enrolled. The annualincidence significantly increased among overall OHCAs and bystander-witnessed OHCAs. Neurologically favorablesurvival significantly increased from 1.6% (1676/102 737) in 2005 to 2.8% (3280/115 250) in 2009 (P�0.001), from2.1% (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, respec-tively. Public-access automated external defibrillator use, either bystander-initiated chest compression–only cardiopul-monary resuscitation or conventional cardiopulmonary resuscitation, and earlier emergency medical services responsetime were associated with a better neurological outcome. Favorable neurological outcome among adult OHCA subjectssignificantly improved, but the outcome among younger children and very elderly subjects did not improve and was poorirrespective of origin of OHCA.

Conclusions—Nationwide improvements of favorable neurological outcome from OHCA were observed in Japan anddiffered by age group and origin of OHCA. (Circulation. 2012;126:2834-2843.)

Key Words: cardiac arrest � cardiopulmonary resuscitation � death, sudden � epidemiology

Sudden cardiac arrest is one of the leading causes of deathand has been an important public health problem in the

industrialized world.1,2 Approximately 300 000 cardiac ar-rests in the United States and 100 000 in Japan occur annuallyin out-of-hospital settings, and survival from out-of-hospitalcardiac arrest (OHCA) is still low.3,4

Clinical Perspective on p 2843

Recently, after improvements in the chain of survival,including the development of a public-access defibrillationsystem and revisions to cardiopulmonary resuscitation (CPR)guidelines, survival from OHCA has been improving in somecommunities.5–10 However, the temporal improvement of

OHCA survival after dissemination of public-access defibril-lation and CPR and changes of CPR guidelines was reportedon the basis of data in relatively small geographic areas, andlittle is known about the nationwide improvement in survivalfrom OHCA. In addition, most studies evaluated overallincidence and survival among adult OHCA patients with acardiac origin, and the differences by age group and origin ofcardiac arrest are poorly understood.

In Japan, the Fire and Disaster Management Agency4

launched a prospective, nationwide, population-based cohortstudy of OHCA patients since January 2005 and collected�540 000 overall OHCAs and 170 000 bystander-witnessedOHCAs from January 1, 2005, to December 31, 2009. The

Received April 2, 2012; accepted September 13, 2012.From the Kyoto University Health Service, Kyoto (T. Kitamura, T.I., T. Kawamura); Department of Emergency Medicine, Osaka Medical College,

Takatsuki (M.N.); Department of Cardiology, Cardiopulmonary Resuscitation and Emergency Cardiovascular Care, Nihon University Surugadai Hospital,Tokyo (K.N.); Division of Cardiovascular Care Unit, Department of Cardiovascular Medicine, National Cerebral and Cardiovascular Center, Osaka(H.N.); Department of Epidemiology and Biostatistics, National Center of Neurology and Psychiatry, Tokyo (N.Y.); and Department of CardiovascularMedicine, Kyoto University Graduate School of Medicine, Kyoto (T. Kimura), Japan.

Correspondence to Taku Iwami, MD, PhD, Kyoto University Health Service, Yoshida Honmachi, Sakyo-ku, Kyoto 606-8501, Japan. E-mailiwamit@e-mail.jp

© 2012 American Heart Association, Inc.

Circulation is available at http://circ.ahajournals.org DOI: 10.1161/CIRCULATIONAHA.112.109496

2834 at Osaka University on December 10, 2012http://circ.ahajournals.org/Downloaded from

purpose of this study was to assess the nationwide trend in theincidence and outcome of these OHCA patients in Japan byusing the national Utstein-style registry. Furthermore, weassessed the trends in OHCA after dividing bystander-witnessed OHCA patients by age group and origin of OHCA.

MethodsStudy Design and SettingThe All-Japan Utstein Registry of the Fire and Disaster ManagementAgency is a prospective, nationwide, population-based registrysystem of OHCA based on the Utstein style.11,12 This observationalstudy registered all patients with OHCA of cardiac and noncardiacorigins in whom resuscitation was attempted and who were thentransported to medical institutions from January 1, 2005, throughDecember 31, 2009. The study protocol for analyses was approvedby the Ethics Committee of the National Cerebral and Cardiovascu-lar Center.

Cardiac arrest was defined as the cessation of cardiac mechanicalactivity as confirmed by the absence of signs of circulation.11,12 Thearrest was presumed to be of cardiac origin unless it was caused bycerebrovascular diseases; respiratory diseases; malignant tumors;external causes including trauma, hanging, drowning, drug overdose,and asphyxia; or any other noncardiac causes. These diagnoses ofcardiac or noncardiac origin were clinically determined by thephysicians in charge in collaboration with the emergency medicalservices (EMS) personnel.

EMS Systems in JapanJapan has an area of �378 000 km2, including both urban and ruralcommunities, and its population was 127 million inhabitants in 2009.There were 803 fire stations with dispatch centers in 2009, and theirEMS systems are almost uniform.4 The free emergency telephonenumber 119 is used to call for an ambulance from anywhere in Japan.Emergency services are provided 24 hours every day. An ambulanceis dispatched from the nearest fire station when called. Eachambulance has 3 emergency providers including at least 1 emergencylife-saving technician, a highly trained prehospital emergency careprovider. Emergency life-saving technicians were allowed to insertan intravenous line and an adjunct airway and to use semiautomatedexternal defibrillators for OHCA patients. Specially trained emer-gency life-saving technicians have been permitted to insert trachealtubes and to administer intravenous epinephrine since July 2006.Citizen use of an automated external defibrillator (AED) has beenlegally permitted since July 2004 in Japan. EMS providers were notpermitted to terminate resuscitation in the field. Therefore, mostpatients with OHCA who were treated by EMS personnel weretransported to a hospital and registered in this All-Japan UtsteinRegistry, excluding those with decapitation, incineration, decompo-sition, rigor mortis, or dependent cyanosis.

All EMS providers had been performing and teaching CPRaccording to the Japanese CPR guidelines based on the 2000American Heart Association guidelines until September 2006 and the2005 guidelines thereafter.13–16 In Japan, �1.6 million citizens peryear participated in the conventional CPR training programs, con-sisting of chest compressions, mouth-to-mouth ventilation, and AEDuse, offered mainly by local fire departments.4 Chest compression–only CPR had not been taught as the recommended technique in anyresuscitation training program during the study period, but it wasfirst recommended as acceptable for those who were not able to ordid not wish to perform rescue breathing in the 2005 CPR guide-lines.13 The emergency telephone dispatchers in Japan are basicallytrained and ordered to give CPR instructions with conventional CPRbefore EMS arrival. However, it is permitted to encourage bystand-ers to provide chest compression–only CPR if it is difficult for themto administer rescue breathing.14 Details of the EMS system in Japanwere described previously.5

Data Collection and Quality ControlData were prospectively collected with the use of a form based on theUtstein-style reporting guidelines for OHCA, including age, sex,origin of cardiac arrest, type of bystander witness status, firstdocumented rhythm, time course of resuscitation, type of bystander-initiated CPR, public-access AEDs, type of advanced airway man-agement, intravenous fluids, epinephrine, and year, as well asprehospital return of spontaneous circulation, 1-month survival, andneurological status 1 month after the event. A series of EMS times ofcall receipt, vehicle arrival at the scene, contact with patients,initiation of CPR, defibrillation by EMS, and hospital arrival wererecorded with the clock of each EMS system. When bystandersdelivered shocks using public-access AEDs, the patient’s firstrecorded rhythm was regarded as ventricular fibrillation (VF). Bothbystander-initiated chest compression–only and conventional CPRwith compressions and rescue breathing were considered bystanderCPR. The times of collapse, initiation of public-access AED shocks,and initiation and type of bystander CPR were obtained by EMSinterview with the bystander before EMS personnel left the scene.

All survivors were evaluated 1 month after the event by the EMSpersonnel in charge. Neurological outcome was determined by afollow-up interview 1 month after successful resuscitation with theuse of the cerebral performance category scale, as follows: category1, good cerebral performance; category 2, moderate cerebral disabil-ity; category 3, severe cerebral disability; category 4, coma orvegetative state; and category 5, death.11,12 The primary outcomemeasure was 1-month survival with favorable neurological outcome,defined as cerebral performance category 1 or 2.11,12

The data form was completed by the EMS personnel in coopera-tion with the physicians in charge of the patients, and the data wereintegrated into the registry system on the Fire and Disaster Manage-ment Agency database server, then logically checked by the com-puter system. If the data form was incomplete, the Fire and DisasterManagement Agency returned it to the respective fire station for datacompletion.

Statistical AnalysisFirst, we assessed the trends in the incidence and outcome of overallOHCA in Japan. Next, analyses were conducted for all bystander-witnessed OHCA patients with cardiac and noncardiac origins inwhom resuscitation was attempted. We assessed the trend in theproportion of favorable neurological outcome in overall bystander-witnessed OHCA and also according to age group and origin ofcardiac arrest. On the basis of the preceding studies,17–19 age wasdivided into the following groups: �1 year and 1 to 4, 5 to 12, 13 to17, 18 to 35, 36 to 64, 65 to 79, 80 to 90, and �90 years. The annualincidences per 100 000 persons were calculated with the use ofestimated Japanese population data in each year,20 and their trendswere calculated with Poisson regression models. Trends in categor-ical values and numeric values were tested with logistic regressionmodels and linear tests for trend, respectively. Multivariable analysisfor bystander-witnessed OHCA was used to assess factors associatedwith 1-month survival with favorable neurological outcome with theuse of logistic regression models; odds ratios (ORs) and their 95%confidence intervals (CIs) were calculated. Potential confoundingfactors based on biological plausibility and previous studies wereincluded in the multivariable analysis. These variables included age(�1 year and 1–4, 5–12, 13–17, 18–35, 36–64, 65–79, 80–90, or�90 years); sex (male, female); cause of cardiac arrest (cardiac,noncardiac); type of bystander witness status (family members,others); first documented rhythm (VF, non-VF); public-access AEDuse (yes, no); type of bystander-initiated CPR (compression-only,conventional, or none); intravenous fluids and epinephrine adminis-tration (yes, no); advanced airway management (yes, no); EMSresponse time (from call to contact with patients by EMS); and yearof arrest (in 1-year increments). All statistical analyses were per-formed with the use of SPSS statistical package version 16.0J (SPSS,Inc, Chicago, IL). All tests were 2-tailed, and P values of �0.05were considered statistically significant.

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The authors had full access to and take full responsibility for theintegrity of the data. All authors have read and agree to themanuscript as written.

ResultsDuring these 5 years, a total of 547 153 OHCA patients wereconfirmed, excluding 65 without information on age (Figure1). Of 539 758 OHCA patients with resuscitation attempts,174 068 were witnessed by bystanders, 43 098 were wit-nessed by EMS, 320 257 were not witnessed, and 2335 hadunknown witness status. With the exclusion of patientswithout information on first documented rhythm (n�4326)and bystander CPR (n�382), 169 360 patients were eligiblefor our analyses. The proportion of prehospital return ofspontaneous circulation among these patients was 10.0%,1-month survival was 7.6%, and 1-month survival withfavorable neurological outcome was 3.3%.

Patient and EMS characteristics of 169 360 patients withbystander-witnessed OHCAs in Japan are noted in Table 1.The proportion of OHCAs that were of cardiac origin was56.1%. Male patients accounted for 61.4%. Mean age was72.3 years, and the proportion of OHCA patients aged �1year and 1 to 4, 5 to 12, 13 to 17, 18 to 35, 36 to 64, 65 to 79,80 to 89, and �90 years was 0.4%, 0.3%, 0.3%, 0.4%, 3.4%,21.2%, 33.8%, 28.1%, and 12.2%, respectively. OHCApatients were more likely to be witnessed by a family member(64.4%), followed by friend, colleague, passerby, and other.VF as first documented rhythm was 15.4%. The proportionsof OHCA patients who were delivered shocks by public-access AEDs and received bystander-initiated CPR were1.0% and 42.8% (25.8% chest compression–only CPR and

17.0% conventional CPR), respectively. Mean EMS responsetime and hospital arrival time were 8.6 and 31.9 minutes,respectively.

The annual incidence rates per 100 000 persons werecalculated over time, and the overall incidence rate of547 153 confirmed OHCAs increased from 80.7 in 2005 to90.4 in 2009 (P�0.001). The incidence rate of overallbystander-witnessed OHCAs significantly increased from24.0 in 2005 to 28.5 in 2009 (from 13.6 to 16.0 for those ofcardiac origin and from 10.4 to 12.5 for those of noncardiacorigin) (Table 2). The incidence rate did not decrease regard-less of age and origin except for OHCA of noncardiac originamong younger children. The incidence rate increased to agreat extent among elderly OHCA patients with both cardiacorigin aged 80 to 89 years (from 85.4 in 2005 to 91.9 in 2009;P�0.001) and �90 years (from 173.8 in 2005 to 196.7 in2009; P�0.001) and noncardiac origin aged 80 to 89 years(from 66.8 in 2005 to 74.2 in 2009; P�0.001) and �90 years(from 136.9 in 2005 to 159.4 in 2009; P�0.001).

Table 3 shows temporal trends in patient and EMS charac-teristics of bystander-witnessed OHCAs during the study period.VF as the first documented rhythm significantly increased from14.6% to 16.2%. The proportion of those who were shockedwith public-access AEDs (from 0.2% in 2005 to 1.8% in 2009),received bystander-initiated CPR (from 36.6% to 48.4%), re-ceived epinephrine administration (from 0.0% to 15.5%), orreceived endotracheal intubation (from 3.4% to 9.5%) alsoincreased significantly during the study period. Mean EMSresponse time (from 8.5 minutes in 2005 to 8.9 minutes in 2009)and hospital arrival time (from 30.9 minutes in 2005 to 32.6minutes in 2009) were prolonged significantly.

Confirmed cardiac arrestsn = 547,153

Arrests witnessed by bystandersn = 174,068

Resuscitation attemptedn = 539,758

Arrests witnessed by EMS n = 43,098Arrests not witnessed n = 320,257Unknown n = 2335

No resuscitation n = 7395

Age unknown n = 65

Eligible patientsn = 169,360

Prehospital ROSCn = 17,020 (10.0%)

One-month survivaln = 12,861 (7.6%)

Favorable neurological outcomen = 5645 (3.3%)

All out-of-hospital cardiac arrests from 2005 to 2009 in Japan

n = 547,218

Population at risk in Japann = 127,767,994

First documented rhythm unknown n = 4326Bystander CPR unknown n = 382

Figure 1. Study flow of out-of-hospital cardiacarrest patients with an abridged Utstein tem-plate from January 1, 2005, to December 31,2009. EMS indicates emergency medical ser-vices; CPR, cardiopulmonary resuscitation; andROSC, return of spontaneous circulation.

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Among 547 153 overall OHCA patients, 1-month survivalwith favorable neurological outcome increased from 1.6%(1676/102 737) in 2005 to 2.8% (3280/115 250) in 2009(P�0.001). Figure 2 shows temporal trends in 1-monthsurvival with favorable neurological outcome among allbystander-witnessed arrests and VF arrests. The proportion ofthose with neurologically favorable outcomes increased sig-nificantly from 2.1% (638/30 556) in 2005 to 4.3% (1558/36 361) in 2009 (adjusted OR for 1-year increment, 1.21;95% CI, 1.18–1.21) (Figure 2A). With regard to bystander-witnessed VF arrests, the proportion increased significantlyfrom 9.8% (437/4461) in 2005 to 20.6% (1215/5906) in 2009(adjusted OR for 1-year increment, 1.28; 95% CI, 1.25–1.31)(Figure 2B). In non-VF arrests, the proportion increasedsignificantly from 0.8% (201/26 095) in 2005 to 1.1% (343/30 455) in 2009 (adjusted OR for 1-year increment, 1.13;95% CI, 1.08–1.17).

In the multivariate analysis (Table 4), compared with olderadults aged 36 to 64 years, adolescents aged 13 to 17 yearshad a significantly better neurological outcome (adjusted OR,2.03; 95% CI, 1.54–2.66). The elderly groups aged �65years had a significantly worse outcome than the older adultgroup. VF as first documented rhythm (adjusted OR, 10.06;95% CI, 9.35–10.82), public-access AED use (adjusted OR,2.07; 95% CI, 1.82–2.35), either bystander-initiated chestcompression–only CPR (adjusted OR, 1.42; 95% CI, 1.33–1.52) or conventional CPR (adjusted OR, 1.55; 95% CI,1.43–1.68), and earlier EMS response time (adjusted OR for1-minute increase, 0.91; 95% CI, 0.91–0.92) were associatedwith a better neurological outcome. Epinephrine administra-tion (adjusted OR, 0.48; 95% CI, 0.41–0.56) and advancedairway management (adjusted OR, 0.44; 95% CI, 0.41–0.47)were associated with a worse outcome.

The temporal trends in favorable neurological outcome ofbystander-witnessed OHCAs by age group and origin of arrestare shown in Table 5. Among OHCA patients with cardiacorigin, 1-month survival with favorable neurological outcomesignificantly increased among adults aged 18 to 35 years(adjusted OR for 1-year increment, 1.37; 95% CI, 1.23–1.52), 36to 64 years (adjusted OR, 1.19; 95% CI, 1.15–1.24), 65 to 79years (adjusted OR, 1.26; 95% CI, 1.21–1.31), and 80 to 89years (adjusted OR, 1.15; 95% CI, 1.06–1.25) and tended toincrease among children aged �1 year and 1 to 4, 5 to 12, and13 to 17 years, whereas it did not change among the elderly aged�90 years. Among those with noncardiac origin, the trend wasalmost the same as for those with cardiac origin.

DiscussionFrom this large, prospective nationwide registry of OHCA,we demonstrated that 1-month survival with favorable neu-rological outcome from OHCA significantly increased duringthe study period in Japan. In addition, we demonstrated thatthe temporal changes in incidences and outcomes weredifferent by age group and origin of OHCA. Although thepreceding studies showed incidences and outcomes ofOHCA, little attention was paid to the differences in patientage and OHCA origin. Our nationwide registry of OHCAcovering 127 million enabled us to assess the differences

Table 1. Patient and EMS Characteristics of Patients WithBystander-Witnessed Out-of-Hospital Cardiac Arrest in Japan

Total(n�169 360)

Year, n (%)

2005 30 556 (18.0)

2006 32 951 (19.5)

2007 33 728 (19.9)

2008 35 764 (21.1)

2009 36 361 (21.5)

Origin, n (%)

Cardiac 95 005 (56.1)

Noncardiac 74 355 (43.9)

External cause 28 988 (17.1)

Respiratory disease 11 631 (6.9)

Cerebrovascular disease 7710 (4.6)

Malignant tumor 6682 (3.9)

Other 19 344 (11.4)

Male, n (%) 103 978 (61.4)

Age, y, mean (SD) 72.3 (17.5)

Age group, n (%)

�1 y 616 (0.4)

1–4 y 469 (0.3)

5–12 y 458 (0.3)

13–17 y 661 (0.4)

18–35 y 5685 (3.4)

36–64 y 35 947 (21.2)

65–79 y 57 236 (33.8)

80–89 y 47 658 (28.1)

�90 y 20 630 (12.2)

Type of bystander witness status, n (%)

Family member 109 008 (64.4)

Friend 7183 (4.2)

Colleague 5804 (3.4)

Passerby 8720 (5.1)

Other 38 645 (22.8)

First documented rhythm, n (%)

Ventricular fibrillation 26 086 (15.4)

Pulseless electric activity 56 286 (33.2)

Asystole 86 988 (51.4)

Shock by public-access AEDs, n (%) 1699 (1.0)

Type of bystander-initiated CPR, n (%)

None 96 781 (57.1)

Chest compression–only CPR 43 769 (25.8)

Conventional CPR with rescue breathing 28 810 (17.0)

Intravenous fluid, n (%) 39 274 (23.2)

Epinephrine, n (%) 13 281 (7.8)

Advanced airway management, n (%)

None 88 161 (52.1)

Laryngeal mask airway 15 620 (9.2)

Esophageal obturator airway 52 512 (31.0)

Endotracheal intubation 13 067 (7.7)

EMS response time (call to contact with patients),min, mean (SD)

8.6 (4.2)

Hospital arrival time (call to hospital arrival), min,mean (SD)

31.9 (11.8)

EMS indicates emergency medical services; AED, automated externaldefibrillator; and CPR, cardiopulmonary resuscitation.

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among these patients and provided helpful information toestablish age- and origin-specific approaches.

This study successfully demonstrated improved outcomesamong OHCA patients in Japan. Although some previouscommunity-based studies6,7 showed improvements in out-comes after OHCA, they covered small areas. Few studies

have investigated a nationwide improvement in survival fromOHCA. Japan has a uniform prehospital EMS protocol andhas improved the EMS system, with its population-basedOHCA registry covering the whole country.4–6 In the Swed-ish national registry of OHCA, 1-month survival frombystander-witnessed OHCA increased from 5.8% to 8.2%

Table 2. Incidence Rates of Bystander-Witnessed Out-of-Hospital Cardiac Arrest in JapanOver Time

Incidence per 100 000 Persons

2005 2006 2007 2008 2009 P for Trend

Overall 24.0 25.8 26.4 28.0 28.5 �0.001

Cardiac origin 13.6 14.4 14.7 15.7 16.0 �0.001

Age �1 y 3.6 1.8 6.5 10.2 2.8 0.001

Age 1–4 y 0.7 0.6 0.5 0.5 0.5 0.417

Age 5–12 y 0.3 0.3 0.3 0.3 0.3 0.901

Age 13–17 y 0.7 0.7 0.9 0.8 0.9 0.180

Age 18–35 y 1.2 1.4 1.5 1.3 1.4 0.281

Age 36–64 y 8.2 8.2 8.2 8.6 8.5 0.017

Age 65–79 y 32.9 34.0 32.3 33.4 33.0 0.724

Age 80–89 y 85.4 87.8 87.1 92.5 91.9 �0.001

Age �90 y 173.8 181.7 185.8 193.0 196.7 �0.001

Noncardiac origin 10.4 11.4 11.7 12.3 12.5 �0.001

Age �1 y 4.7 4.8 10.1 7.6 4.6 0.282

Age 1–4 y 1.7 1.9 1.6 1.3 1.3 0.028

Age 5–12 y 0.9 0.4 0.8 0.7 0.8 0.721

Age 13–17 y 1.2 1.5 1.3 1.3 1.6 0.227

Age 18–35 y 2.4 2.7 2.5 2.6 2.6 0.561

Age 36–64 y 5.6 6.0 6.1 6.0 6.0 0.005

Age 65–79 y 22.8 23.4 23.2 24.0 23.5 0.103

Age 80–89 y 66.8 72.2 72.1 73.8 74.2 �0.001

Age �90 y 136.9 150.9 154.9 161.2 159.4 �0.001

Table 3. Patient and EMS Characteristics of Patients With Bystander-Witnessed Out-of-Hospital Cardiac Arrest in Japan Over Time

2005(n�30 556)

2006(n�32 951)

2007(n�33 728)

2008(n�35 764)

2009(n�36 361)

P forTrend

Cardiac origin, n (%) 17 344 (56.8) 18 446 (56.0) 18 728 (55.5) 20 088 (56.2) 20 399 (56.1) 0.238

Age, y, mean (SD) 71.4 (17.6) 71.9 (17.4) 72.1 (17.9) 72.7 (17.6) 73.2 (17.2) �0.001

Male, n (%) 19 082 (62.4) 20 406 (61.9) 20 642 (61.2) 21 813 (61.0) 22 035 (60.6) �0.001

Arrests witnessed by non–family members, n (%) 9968 (32.6) 11 274 (34.2) 12 114 (35.9) 13 400 (37.5) 13 596 (37.4) �0.001

Ventricular fibrillation, n (%) 4461 (14.6) 5008 (15.2) 5134 (15.2) 5577 (15.6) 5906 (16.2) �0.001

Shocks by public-access AEDs, n (%) 55 (0.2) 161 (0.5) 317 (0.9) 494 (1.4) 672 (1.8) �0.001

Bystander-initiated CPR, n (%) 11 172 (36.6) 12 972 (39.3) 14 664 (43.5) 16 169 (45.2) 17 602 (48.4) �0.001

Chest compression–only CPR 5314 (17.4) 6672 (20.2) 8725 (25.9) 10 680 (29.9) 12 378 (34.0)

Conventional CPR with rescue breathing 5858 (19.2) 6300 (19.1) 5939 (17.6) 5489 (15.3) 5224 (14.4)

Intravenous fluid, n (%) 3343 (10.9) 6213 (18.9) 8402 (24.9) 10 090 (28.2) 11 226 (30.9) �0.001

Epinephrine, n (%) 0 (0.0) 789 (2.4) 2622 (7.8) 4233 (11.8) 5637 (15.5) �0.001

Endotracheal intubation, n (%) 1037 (3.4) 2396 (7.3) 2919 (8.7) 3249 (9.1) 3466 (9.5) �0.001

EMS response time (call to contact withpatients), min, mean (SD)

8.5 (4.3) 8.5 (4.3) 8.5 (4.1) 8.7 (4.1) 8.9 (4.2) �0.001

Hospital arrival time (call to hospital arrival),min, mean (SD)

30.9 (11.7) 31.7 (11.8) 31.9 (11.7) 32.1 (11.9) 32.6 (11.8) �0.001

EMS indicates emergency medical services; AED, automated external defibrillator; and CPR, cardiopulmonary resuscitation.

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during 14-year observation, although it was not significant.8

This study showing a 2-fold increment of favorable neuro-logical outcome from OHCA during only a 5-year studyprovides considerable helpful information for other countriesand areas.

Various factors are associated with improving outcomesafter bystander-witnessed OHCA. The multivariate analysisof this study, which clearly demonstrates the effectiveness ofbystander CPR regardless of CPR type and public-accessAEDs, suggests that the increment of CPR and public-accessAED use by bystanders would be the most important factorsthat resulted in this remarkable improvement. Japan had a2-fold increase of bystander-initiated CPR during the last 10years,4,6,21 and public-access AEDs have been widely devel-oped.5,22 The recent increase of bystander CPR is due in partto the change in CPR guidelines that accept chest compres-sion–only CPR.9,10,21 This study demonstrating both nation-wide improvement in survival after OHCA and the effective-ness of either chest compression–only CPR or conventionalCPR also reinforces the importance of systematic and strate-gic dissemination of CPR by the use of chest compression–only CPR to increase survival after OHCA.

The proportion of advanced life support (ALS) measuresby EMS personnel, such as epinephrine administration andendotracheal intubation, also increased during the studyperiod. However, unlike basic life support provided by layrescuers, ALS measures were not associated with betteroutcome. Indeed, they seemed to be associated with a worseoutcome, as some previous observational studies have sug-gested.23,24 However, importantly, we consider that thereshould be an inversion phenomenon of cause and effect, andit would be difficult to assess the effect of ALS measures inthis observational study because EMS personnel in Japancould provide ALS measures only for OHCA patients whodid not respond to basic life support. Recently, some studiessuggested that earlier epinephrine administration and earlierendotracheal intubation contributed to improving outcomesafter OHCA.25,26 Further elaborate studies that consider thetiming of the procedure or the patient’s rhythm are needed toconfirm the effect of ALS measures.

Our study underscored the nationwide improvement insurvival from OHCA over the short term in Japan, but it wasstill low. To further improve survival from OHCA, thedissemination of CPR training (especially chest compres-sion–only CPR training), including public-access AED usefor the general public, should be particularly encouraged, asthe new 2010 International Liaison Committee on Resuscita-tion consensus and the new national CPR guidelines empha-sized,1,2,27 because the proportions of bystander CPR andpublic-access AED use were only 50% and 1%, respectively.The Japan Circulation Society also started to recommendchest compression–only CPR training for lay rescuers toincrease CPR and AED use since 2010.28

During the study period, the incidence of either overallOHCA or bystander-witnessed OHCA increased gradually,but the change was different by age group. Although theincidence of pediatric and adult OHCAs remained almoststable, the incidence of OHCA in very elderly subjectsincreased to a great extent. Although the reasons for theincrement in OHCA incidence were unclear, the rapid agingof society might be one of the possible explanations for thisphenomenon. In fact, the proportion of elderly population inJapan increased from 20.2% in 2005 to 22.7% in 2009 (anincrement of �3 million elderly).20 In addition, the increaseof witnessed arrests of the elderly might be due to the changein social conditions, such as more elderly subjects starting tolive in care facilities where they are more likely to bewitnessed.

Although some reports demonstrated a reduction in theincidence of cardiovascular events, including sudden cardiacdeath, in prehospital settings in areas where primary andsecondary preventions worked effectively,29–31 the trends inOHCA incidence varied by community.32–34 In this study,OHCA incidence did not decrease regardless of age andorigin except for OHCA of noncardiac origin in youngerchildren. Further efforts to prevent sudden cardiac arrest areneeded, as the new CPR guidelines recommended,1,2,27 andthe preventive approach and evaluation should be conductedon the basis of age and origin.

Furthermore, the poor outcome without improvementamong very elderly patients was an important issue. The

0

5

10

15

20

2005 2006 2007 2008 2009

(%)

Year

Adjusted OR for one-increment of year 1.21 (1.18-1.23)

2.1(638/30,556)

2.6(867/32,951)

3.7(1232/33,728)

3.8(1350/35,764)

4.3(1558/36,361)

0

5

10

15

20

2005 2006 2007 2008 2009

(%)

Year

Adjusted OR for one-increment of year 1.28 (1.25-1.31)

9.8(437/4461)

12.2(613/5008)

17.9(918/5134)

18.3(1023/5577)

20.6(1215/5906)

A

B

Figure 2. Temporal trend in the proportion of 1-month survivalwith favorable neurological outcome in all bystander-witnessedarrests (A) and ventricular fibrillation arrests (B) during the studyperiod. Odds ratios (ORs) were adjusted for age, sex, cause ofcardiac arrest, type of bystander-witnessed status, first docu-mented rhythm, public-access automated external defibrillatoruse, type of bystander-initiated cardiopulmonary resuscitation,intravenous fluids and epinephrine, advanced airway manage-ment, and emergency medical services response time.

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Table 4. Factors Associated With 1-Month Survival With Favorable Neurological Outcome After Bystander-Witnessed Out-of-HospitalCardiac Arrest in Japan

Survival OR

% No./Total No. Crude 95% CI Adjusted 95% CI

Age group

�1 y 4.4 27/616 0.58 0.40–0.86 1.11 0.73–1.69

1–4 y 1.9 9/469 0.25 0.13–0.48 0.79 0.40–1.56

5–12 y 6.8 31/458 0.93 0.64–1.34 1.43 0.94–2.18

13–17 y 13.9 92/661 2.06 1.65–2.58 2.03 1.54–2.66

18–35 y 6.4 361/5685 0.86 0.77–0.97 1.12 0.98–1.27

36–64 y 7.3 2615/35 947 Reference Reference

65–79 y 3.3 1871/57 236 0.43 0.41–0.46 0.65 0.61–0.69

80–89 y 1.1 538/47 658 0.15 0.13–0.16 0.31 0.28–0.34

�90 y 0.5 101/20 630 0.06 0.05–0.08 0.15 0.12–0.19

Origin

Cardiac cause 5.0 4725/95 005 Reference Reference

Noncardiac cause 1.2 920/74 355 0.24 0.22–0.26 0.61 0.56–0.66

Gender

Male 4.1 4292/103 978 Reference Reference

Female 2.1 1353/65 382 0.49 0.46–0.52 1.07 1.00–1.15

Type of bystander-witnessed status

Family member 2.6 2806/109 008 Reference Reference

Other 4.7 2839/60 352 1.87 1.77–1.97 1.19 1.12–1.27

First documented rhythm

VF 16.1 4206/26 086 18.95 17.82–20.15 10.06 9.35–10.82

Non-VF 1.0 1439/143 274 Reference Reference

Public-access AEDs

No 3.0 5112/167 661 Reference Reference

Yes 31.4 533/1699 14.54 13.07–16.16 2.07 1.82–2.35

Type of bystander-initiated CPR

None 2.5 2438/96 781 Reference Reference

Chest compression–only CPR 4.2 1837/43 769 1.70 1.59–1.80 1.42 1.33–1.52

Conventional CPR with rescue breathing 4.8 1370/28 810 1.93 1.81–2.07 1.55 1.43–1.68

Intravenous fluid

No 3.5 4553/130 086 Reference Reference

Yes 2.8 1092/39 274 0.79 0.74–0.84 0.99 0.91–1.08

Epinephrine

No 3.5 5383/156 079 Reference Reference

Yes 2.0 262/13 281 0.56 0.50–0.64 0.48 0.41–0.56

Advanced airway management

No 4.6 4082/88 161 Reference Reference

Yes 1.9 1563/81 199 0.40 0.38–0.43 0.44 0.41–0.47

EMS response time (for 1-min increment) 0.91 0.91–0.92 0.91 0.91–0.92

Year (for 1-y increment) 1.19 1.17–1.21 1.21 1.18–1.23

2005 2.1 638/30 556

2006 2.6 867/32 951

2007 3.7 1232/33 728

2008 3.8 1350/35 764

2009 4.3 1558/36 361

OR indicates odds ratio; CI, confidence interval; VF, ventricular fibrillation; AED, automated external defibrillator; CPR, cardiopulmonary resuscitation; and EMS,emergency medical services. ORs were adjusted for age, sex, cause of cardiac arrest, type of bystander-witnessed status, first documented rhythm, public-accessAED use, type of bystander-initiated CPR, intravenous fluids and epinephrine, advanced airway management, EMS response time, and year.

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increasing number of the elderly population is becoming animportant social and medical problem in industrialized coun-tries.35 The implementation of the termination of resuscitationrule and advance directives has been discussed only to alimited degree in Japan. To make effective use of limitedmedical resources and allow the elderly to die a peacefuldeath, identifying unrecoverable patients and performingtermination of resuscitation 36,37 at the scene, as well as usingadvance directives, should be considered. Further study iswarranted for detailed proposals on these issues.

The present study also showed that the proportion of thosewith favorable neurological outcome from OHCA in adoles-cents was high, whereas that in younger children was poor.The causes of pediatric OHCAs differed markedly by agegroup.19,38 This suggests the necessity of age-specific mea-sures to improve survival from pediatric OHCA, as reportedpreviously.19 In addition to age-specific approaches, moreefforts should focus on prevention of pediatric OHCAsbecause many of them are preventable.1,2,27

Furthermore, this study demonstrated that although favor-able neurological outcome among adult patients with OHCAof noncardiac origin increased year by year, the absolutesurvival was low. Because �40% of adult OHCAs are ofnoncardiac origin, further efforts, including ALS techniques,origin-specific treatments, and preventive approaches, as thenew Japanese CPR guidelines recommended,27 are needed todecrease mortality in those with OHCAs of noncardiac origin.

To improve survival after OHCA, further efforts arewarranted not only to strengthen prehospital EMS proceduresbut also to establish in-hospital therapies and age- andorigin-specific approaches. For these purposes, collection andassessment of these comprehensive prehospital and in-hospital data would contribute to improving the OHCAoutcome.

LimitationsThis study has some inherent limitations, however. First, ourdata do not address the potential variability in postarrest care(hemodynamic support, induced hypothermia, and coronaryinterventional therapies), although the development of thesetreatments can be other possible explanations for the improv-ing outcome. Second, there might be unmeasured confound-ing factors that might have influenced outcomes. Third, thisstudy had only a short-term 5-year observation period.Therefore, long-term observation is also needed to assess thechanges in survival from OHCA in Japan. Finally, as with allepidemiological studies, data integrity, validity, and ascer-tainment bias are potential limitations. The use of uniformdata collection based on Utstein-style guidelines for reportingcardiac arrest, large sample size, and a population-baseddesign to cover all known OHCAs in Japan were intended tominimize these potential sources of bias.

ConclusionsFrom this national registry of OHCA, we demonstratednationwide improvement of 1-month survival with favorable

Table 5. One-Month Survival With Favorable Neurological Outcome of Patients With Bystander-Witnessed Out-of-Hospital CardiacArrest in Japan by Origin and Age Over Time

Total 2005 2006 2007 2008 2009

Adjusted ORs(95% CI) for

1-Year Increment

Cardiac origin

All 5.0 (4725/95 005) 3.1 (530/17 344) 3.8 (703/18 446) 5.5 (1036/18 728) 5.7 (1144/20 088) 6.4 (1312/20 399) 1.22 (1.19–1.25)

Age �1 y 5.9 (16/270) 2.6 (1/38) 5.3 (1/19) 7.0 (5/71) 7.1 (8/112) 3.3 (1/30) 1.17 (0.64–2.19)

Age 1–4 y 1.6 (2/124) 0.0 (0/30) 4.0 (1/25) 0.0 (0/23) 0.0 (0/23) 4.3 (1/23) NA

Age 5–12 y 14.0 (18/129) 3.8 (1/26) 3.7 (1/27) 30.8 (8/26) 16.0 (4/25) 16.0 (4/25) 1.71 (0.92–3.13)

Age 13–17 y 31.6 (77/244) 28.9 (13/45) 21.4 (9/42) 27.8 (15/54) 32.7 (16/49) 44.4 (24/54) 1.19 (0.92–1.53)

Age 18–35 y 15.7 (313/1991) 7.6 (28/370) 9.4 (40/426) 18.8 (81/432) 15.7 (60/381) 27.2 (104/382) 1.37 (1.23–1.52)

Age 36–64 y 11.2 (2344/20 998) 6.8 (279/4101) 8.3 (344/4155) 12.3 (509/4133) 13.6 (589/4334) 14.6 (623/4275) 1.19 (1.15–1.24)

Age 65–79 y 4.6 (1538/33 551) 2.6 (164/6367) 3.6 (246/6740) 4.9 (322/6562) 5.2 (361/6924) 6.4 (445/6958) 1.26 (1.21–1.31)

Age 80–89 y 1.4 (356/26 366) 0.9 (42/4494) 1.0 (48/4917) 1.4 (72/5155) 1.7 (96/5766) 1.6 (98/6034) 1.15 (1.06–1.25)

Age �90 y 0.5 (61/11 332) 0.1 (2/1873) 0.6 (13/2095) 1.1 (24/2272) 0.4 (10/2474) 0.5 (12/2618) 1.04 (0.86–1.26)

Noncardiac origin

All 1.2 (920/74 355) 0.8 (108/13 212) 1.1 (164/14 505) 1.3 (196/15 000) 1.3 (206/15 676) 1.5 (246/15 962) 1.16 (1.11–1.22)

Age �1 y 3.2 (11/346) 0.0 (0/50) 5.8 (3/52) 0.9 (1/110) 3.6 (3/84) 8.0 (4/50) 1.50 (0.82–2.77)

Age 1–4 y 2.0 (7/345) 2.6 (2/76) 1.2 (1/85) 2.8 (2/71) 1.8 (1/56) 1.8 (1/57) 1.06 (0.53–2.10)

Age 5–12 y 4.0 (13/329) 1.2 (1/83) 2.6 (1/39) 5.6 (4/72) 3.3 (2/61) 6.8 (5/74) 1.55 (0.93–2.86)

Age 13–17 y 3.6 (15/417) 2.8 (2/72) 4.3 (4/94) 2.5 (2/80) 2.6 (2/77) 5.3 (5/94) 1.10 (0.68–1.79)

Age 18–35 y 1.3 (48/3694) 0.5 (4/728) 0.9 (7/801) 1.5 (11/723) 1.5 (11/742) 2.1 (15/700) 1.51 (1.29–1.91)

Age 36–64 y 1.8 (271/14 949) 1.1 (30/2800) 1.8 (53/3003) 2.0 (60/3071) 1.7 (53/3032) 2.5 (75/3043) 1.17 (1.06–1.28)

Age 65–79 y 1.4 (333/23 685) 1.0 (46/4414) 1.1 (51/4651) 1.4 (66/4709) 1.8 (91/4960) 1.6 (79/4951) 1.14 (1.05–1.24)

Age 80–89 y 0.9 (182/21 292) 0.6 (20/3514) 0.8 (34/4040) 0.9 (40/4269) 0.8 (39/4597) 1.0 (49/4872) 1.11 (0.99–1.24)

Age �90 y 0.4 (40/9298) 0.2 (3/1475) 0.6 (10/1740) 0.5 (10/1895) 0.2 (4/2067) 0.6 (13/2121) 1.13 (0.89–1.44)

Values (other than odds ratios �ORs� and confidence intervals �CIs�) are percentages (No./total No.). NA indicates not analyzed. ORs were adjusted for age, sex,cause of cardiac arrest, type of bystander-witnessed status, first documented rhythm, public-access automated external defibrillator use, type of bystander-initiatedcardiopulmonary resuscitation, intravenous fluids and epinephrine, advanced airway management, emergency medical services response time, and year.

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neurological outcome from OHCA in Japan and the impact ofdifference by age and origin. An age- and origin-basedapproach and evaluation to reduce the mortality of suddencardiac arrest are needed.

AcknowledgmentsWe are greatly indebted to all of the EMS personnel and concernedphysicians in Japan and to the Fire and Disaster ManagementAgency and Institute for Fire Safety and Disaster Preparedness ofJapan for their generous cooperation in establishing and maintainingthe Utstein database. We also thank Kosuke Kiyohara and KayoTanigawa for their statistical support.

DisclosuresNone.

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CLINICAL PERSPECTIVESudden cardiac arrest is one of the leading causes of death and has been an important public health problem in theindustrialized world. However, survival from out-of-hospital cardiac arrest (OHCA) is still low, and few studies haveinvestigated a nationwide improvement in survival from OHCA. This Japanese nationwide, prospective, population-basedstudy of OHCA analyzed approximately a half million OHCAs from 2005 through 2009 and clearly demonstrated an�2-fold increment of 1-month survival with favorable neurological outcome after OHCA. The multivariate analysisshowed the effectiveness of bystander cardiopulmonary resuscitation (CPR) regardless of the type of CPR andpublic-access automated external defibrillators. When these data and rapid dissemination of bystander CPR andpublic-access automated external defibrillators in Japan were taken into account, the increment of CPR and public-accessautomated external defibrillator use by bystanders are the most important factors that resulted in this remarkableimprovement. This study demonstrating both nationwide improvement in survival after OHCA and the effectiveness ofeither chest compression–only CPR or conventional CPR reinforces the importance of systematic and strategicdissemination of CPR training by use of chest compression–only CPR to increase survival after OHCA because survivalis still poor, and the proportion of bystander CPR and public-access automated external defibrillator use was still only 50%and 1%, respectively. This study also showed differences in incidence, characteristics, and temporal trends in outcomes ofOHCA according to age group. To improve survival after OHCA, an age- and origin-based approach and evaluation toreduce the mortality of sudden cardiac arrest are needed.

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ct-12012年11月22日

201211

2005

2.1（638/30,556）

2.6（867/32,951）

3.7（1,232/33,728） 3.8

（1,350/35,764）

4.3（1,558/36,361）

2006 2007 2008 2009 （年）

20

15

10

5

0

１年経過するごとの補正後オッズ比1.21（95％信頼区間1.18 ～1.23）

（％）目撃者がいた院外心停止患者

2005

9.8（437/4,461）

12.2（613/5,008）

17.9（918/5,134）

18.3（1,023/5,577）

20.6（1,215/5,906）

2006 2007 2008 2009（年）

20

15

10

5

0

１年経過するごとの補正後オッズ比1.28（95％信頼区間1.25 ～1.31）

目撃者がいたVF症例

（％）

（図１，２ともCirculation 2012: ○: ○～○）

■図 1 神経学的に良好な状態での1カ月生存率の経年的変化（院外心停止全例）

■図 2 神経学的に良好な状態での１カ月生存率の 経年的変化（VF症例）

　院外心停止患者の生存率の経年変化について，初めて国家レベルでの評価ができたことは意義深いと考えている。社会復帰可能な状態での１カ月生存率が２倍に増加した要因は，目撃者によるCRPおよび公共のAED使用が増加したことと考えられる。ただ，生存率は今なお低く，また，目撃者がいたCRPの実施が約50％，公共のAED使用は１％にすぎなかった。今後，より簡便な胸骨圧迫のみによるCPRを推奨し，公共で最適な場所へのAED設置を推進していけば，その効果が結果に表われていくのではないか。　今後重視すべき対策としては，１カ月後の転帰が不良だった小児や高齢者への取り組みが挙げられる。小児については，目撃者によるCPRを確実に実施した上で，速やかに病院に搬送し，高度な救命措置を実施することが重要だろう。一方，今後ますます増加していく高齢者人口への対応としては，救命できる高齢心停止患者を同定するとともに，日本独自の‘蘇生中止基準’の検討が求められる段階にあるのではないかと考えている。

京都大学環境安全保健機構健康科学センター

（現・大阪大学病院未来医療センター）

北村　哲久氏

たが，転帰改善への貢献は明らかではなかった。また，覚知（患者から消防への119番電話）から接触，病院到着までの時間が有意に延長していた。いわゆる“患者のたらい回し”の影響の１つと推察されるが，北村氏は「搬送件数の膨大により救急隊が疲弊する中，１カ月生存率が２倍に増加したことは高く評価されるべき」としている。

*神経学的に良好な状態（社会復帰可能な状態）：神経学的予後の指標である脳機能カテゴリーCPC（Cerebral Performance Categories）でカテゴリー１（機能良好），２（中等度障害）を社会復帰可能な状態と定義

生存率が1.2倍/年ずつ増加

　北村氏らは，総務省消防庁による日本全国の院外心停止患者の統計データを用い，2005～09年に救急蘇生が試みられ，目撃者がいた院外心停止全患者を対象に，神経学的に良好な状態（社会復帰可能な状態）＊での１カ月生存率を前向きに解析した。さらに，年齢および心停止の原因による生存率の違いも検討した。日本の人口約１億2,700万人のうち，５年間で蘇生が試みられた院外心停止患者は54万7,218人であり，そのうち目撃者がいた同患者でデータがそろっている16万9,360人が解析対象となった。　その結果，神経学的に良好な状態での１カ月生存率が全体で3.3％だった。経年的に見ると，2005年の2.1％から1.21倍/年ずつ増加，2009年の生存率は4.3％と，５年間で約２倍に増加した（図 1）。また，心室細動（VF）症例では，神経学的に良好な状態での１カ月生存率が2005年の9.8％から1.28倍/年ずつ増加し，2009年には20.6％に増加（図 2）。市民もしくは救急隊により電気ショックが実施されれば，５人に１人は社会復帰できる時代となっていることが分かった。

予後不良な幼児と超高齢者が今後の課題

　多変量解析から神経学的に良好な状態での１カ月生存に関連する因子を分析したところ，36～64歳と比べて13～17歳がオッズ比2.03，VFは

10.06，公共の自動体外式除細動器（AED）使用は2.07，胸骨圧迫のみの心肺蘇生（CPR）は1.42，従来の人工呼吸を併用するCPRは1.55であった。さらに心原性・非心原性に分け，年齢群別で経年的に分析したところ，心原性・非心原性ともに１～４歳および90歳以上で改善が見られず，非心原性の方が予後不良であった。　なお，10万人当たりの院外心停止発生率は心原性・非心原性にかかわらず増加傾向で，市民目撃あり患者全体で2005年の24.0人が2009年には28.5人と有意に増加していた。ただし，年齢別に見ると，心原性・非心原性ともに若年者や成人ではほとんど変化がなく，80歳以上の高齢者で有意な増加が認められた。日本における院外心停止患者数は毎年約5,000人ずつ増えており，増加の要因は５年間で20.2％から22.7％に増加した65歳以上の高齢者人口（約300万人）の影響が大きいと推測された。　その他，解析対象者におけるAEDの使用は，全体では１％と頻度としては低率だったが，55人（2005年）から672人（2009年）に有意に増加してきている。目撃者のいたCPRは，胸骨圧迫のみ，あるいは従来の人工呼吸を併用するCPRがそれぞれ25.8％，17.0％に施行され，経年的には従来のCPRからより簡易な胸骨圧迫のみのCPRへの移行が顕著だった。　二次救命措置（エピネフリン投与や高度気道確保）については，措置件数は有意に増加してい

日本国内の院外心停止患者生存率が５年で２倍に　院外心停止は，米国で年間約30万人，日本では約10万人発生しているとされ，その救命率向上が大きな課題となっている。しかし，心停止発生後の転帰を国レベルで評価した報告は今までなかった。京都大学環境安全保健機構附属健康科学センターの北村哲久氏（現・大阪大学病院未来医療センター）らは，2005～09年に日本全域で救急蘇生が試みられた院外心停止全患者の予後を前向きに検討し，神経学的に良好な状態（社会復帰可能な状態）での１カ月生存率が５年間で２倍に増加したことをCirculation 2012; ○: ○に報告した。

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