This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and

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1 This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues. Other uses, including reproduction and distribution, or selling or licensing copies, or posting to personal, institutional or third party websites are prohibited. In most cases authors are permitted to post their version of the article (e.g. in Word or Tex form) to their personal website or institutional repository. Authors requiring further information regarding Elsevier s archiving and manuscript policies are encouraged to visit:

2 Resuscitation 84 (2013) Contents lists available at SciVerse ScienceDirect Resuscitation jo ur nal homep age: Clinical paper The analysis of efficacy for AutoPulse TM system in flying helicopter Kazuhiko Omori a,, Shunsuke Sato b, Yuka Sumi c, Yoshiaki Inoue c, Ken Okamoto c, Masahiko Uzura a, Hiroshi Tanaka c a Department of Emergency and Disaster Medicine, Juntendo University Shizuoka Hospital, Shizuoka, Japan b Department of Internal Medicine, Juntendo University Shizuoka Hospital, Shizuoka, Japan c Department of Emergency and Disaster Medicine, Juntendo University Urayasu Hospital, Urayasu, Japan a r t i c l e i n f o Article history: Received 28 September 2012 Received in revised form 18 December 2012 Accepted 14 January 2013 Keywords: Cardiopulmonary arrest Cardiopulmonary resuscitation Automated CPR device Load-distributing band CPR device AutoPulse TM Helicopter emergency medical services a b s t r a c t Aim of the study: The helicopter emergency medical service (HEMS) was introduced in Japan in 2001, and some cardiopulmonary arrest (CPA) patients are transported using this service. However, it is difficult to maintain continuous and effective manual cardiopulmonary resuscitation (CPR) in flying helicopters. To overcome this problem, the AutoPulse TM system, automated mechanical CPR devices, was induced. We conducted a retrospective study to clarify the efficacy of AutoPulse TM on CPA patients in flying helicopters. Methods: In total, 92 CPA patients were enrolled in this study. Of these, 43 CPA patients received manual CPR (between April 2004 and June 2008), and 49 patients received AutoPulse TM CPR (between July 2008 and March 2011). We compared the manual CPR group with the AutoPulse TM group using logistic regression analysis and examined the efficacy of AutoPulse TM in flying helicopters. Results: Rates for return of spontaneous circulation (ROSC) and survival to hospital discharge were increased in the AutoPulse TM group compared to the manual CPR group (ROSC, 30.6% [15 patients] vs. 7.0% [3 patients]; survival to hospital discharge, 6.1% [3 patients] vs. 2.3% [1 patient]). In multivariate analysis, the factors associated with ROSC were the use of AutoPulse TM (odds ratio [OR], 7.22; P = 0.005) and patients aged 65 years (OR, 0.31; P = 0.042). Conclusion: The present study demonstrates that the use of AutoPulse TM in flying helicopters was significantly effective for the ROSC in CPA patients. The use of automated chest compression devices such as AutoPulse TM might be recommended at least for CPA patients transported by helicopters Elsevier Ireland Ltd. All rights reserved. 1. Introduction The survival rate of patients suffering from cardiopulmonary arrest (CPA) is related to 5 links of the chain of survival concept: early access, early CPR, early defibrillation, early advanced life support, and integrated post-cardiac arrest care. 1 3 Previous studies have shown that the survival of out-of-hospital cardiac arrest is more closely associated with prehospital factors such as early CPR and early defibrillation than with in-hospital factors. 4 6 Therefore, prehospital emergency care is an important factor in survival. To enable earlier commencement of treatment, helicopters and other aircraft are used in order to carry doctors to the sites of emergency in many countries. The helicopter emergency medical service (HEMS) was introduced in Japan in 2001, and it was referred to as A Spanish translated version of the summary of this article appears as Appendix in the final online version at Corresponding author at: Department of Emergency and Disaster Medicine, Juntendo University Shizuoka Hospital, 1129 Nagaoka, Izunokuni-shi, Shizuoka , Japan. Tel.: ; fax: address: komichiwonasu@hotmail.co.jp (K. Omori). Doctor Heli in Japan in order to emphasize that the doctors move rapidly to patients by a helicopter to provide medical device. By March 2011, 26 helicopters had been deployed in 22 prefectures across Japan. Our hospital is responsible for the eastern region of Shizuoka Prefecture, including the Izu Peninsula (Fig. 1). This region, approximately 4090 km 2 in area with a population of approximately 2 million, is mountainous with only a few hospitals. In order to reduce hospital transport times using ambulances, HEMS was initiated in 2004 with Juntendo University Shizuoka Hospital serving as the base hospital. The journey from the southern tip of the peninsula to the Critical Care Medical Center of our hospital takes a 2 h by ambulance, but only 15 min by helicopter. Currently, most CPA patients are carried using this HEMS. In cases of CPA, continuous manual CPR must be administered during the transport of patients by helicopter. 7 However, this raises several difficulties in terms of effective chest compression. Because the limited space are available in helicopters for medical devices and medical staff, incorrect compression rates or depths and frequent interruptions may occurred during transporting CPA patients by helicopter Therefore, it is difficult to administer continuous and effective CPR inside a helicopter. 12,13 Incorrect chest /$ see front matter 2013 Elsevier Ireland Ltd. All rights reserved.

3 1046 K. Omori et al. / Resuscitation 84 (2013) and an effective payload of 1586 kg. Its cruise range is 550 km with a cruise duration of 2.5 h. It accommodates 7 passengers: a pilot, mechanic, doctor, nurse and patient with room for 2 others AutoPulse TM Fig. 1. Coverage area of our helicopter emergency medical service. NM, nautical mile; EC145, Eurocopter EC145 is a twin-engine light utility helicopter manufactured by Eurocopter; BK117, EC145 is also known as BK117 C2. compression results in poor return of spontaneous circulation (ROSC), and any interruption to chest compression generated blood flow is detrimental To overcome these problems, we introduced the AutoPulse TM system (ZOLL Circulation, Sunnyvale, CA), which is automated mechanical CPR devices. According to the American Heart Association (AHA) Guidelines 2010, AutoPulse TM CPR is classified into Class IIb of the Evidence Levels. 1 Some studies have found improved hemodynamics and ROSC with the use of AutoPulse TM on CPA patients, while others showed a negative neurological outcome. 22 This means that there is insufficient evidence regarding the efficacy of automated chest compression devices. To our knowledge, there are no previous studies analyzing CPR supplemented with an automated chest compression device on CPA patients in helicopters. Therefore, we conducted a retrospective study to establish the efficacy of AutoPulse TM CPR on CPA patients compared with that of manual CPR only during helicopter transport. 2. Methods 2.1. Patients characteristics A total of 205 CPA-related patients between April 2004 and March 2011 were enrolled in the study. Between April 2004 and June 2008, there were 93 CPA-related patients. Among these, we excluded cases involving hopeless resuscitation, transportation by ambulance, and spontaneous circulation return before arrival at the scene. The hopeless resuscitation defined the presence of obvious evidence that clearly indicates irreversible death such as rigor mortis or dependent livido according to Utstein style. 23 The remaining 43 patients constituted the manual CPR group. These CPA patients received manual CPR inside the helicopter during transports, essentially from a doctor and a nurse. Between July 2008 and March 2011, there were 112 CPA-related patients. We again excluded cases involving hopeless resuscitation, transportation by ambulances, no application of AutoPulse TM due to external chest wound and small children. The remaining 49 patients were constituted the AutoPulse TM group (Fig. 2). This study was approved by the Ethics Committee of Juntendo University Shizuoka Hospital in accordance with the Declaration of Helsinki Helicopter: specifications The EC145 (BK117) type helicopter is m long, m wide, and 3.85 m high with a maximum takeoff weight of 3350 kg AutoPulse TM is an automated, portable, battery-powered cardiopulmonary resuscitation device. It contains a control computer, a rechargeable battery and the motors that operate the LifeBand. The LifeBand pulls tight around the chest, determines the patient s chest size and resistance, and proceeds to rhythmically constrict the entire rib cage. The AutoPulse TM weighs 9.71 kg and is 462 mm wide, 84 mm high and 825 mm deep. The helicopter is always equipped with AutoPulse TM. We used AutoPulse TM along with manual CPR after July AutoPulse TM was placed on the helicopter stretcher, and we attached the device to the patient after the patient was placed on the stretcher. Chest compression was continued until ROSC or arrival at the Emergency Room (ER). When CPA patients arrived at the ER, we switched from AutoPulse TM CPR to manual CPR. Manual CPR in the ER was conducted according to the AHA Guidelines Measurements The following measured data was collected according to Utstein style 23 : patients age and gender, etiology of CPA (cardiac/non-cardiac and endogenous/exogenous), witnesses (presence/absence), availability of bystander CPR, time lapse between CPA perception to paramedics arrival, time lapse between paramedics arrival and doctor s arrival, time of manual CPR application, time of AutoPulse TM application, initial cardiac arrest rhythm, result of ROSC, and outcome at the time of patient s release from hospital. Cardiac etiology included presumed cases. Endogenous etiology defined a disease that came from within the human body as opposed to being caused by something externally, such as aortic dissection, pulmonary thromboembolism, pneumonia. Clinical outcome were neurologically assessed according to the Glasgow Pittsburgh Overall Performance Categories. 23, Statistical analysis We conducted statistical analyses using IBM SPSS 13.0 (IBM SPSS, Chicago, IL, USA). In the univariate analysis, the Mann Whitney U-test was used for continuous variables between the 2 groups, and the Chi-squared test was used to compare qualitative data. In the multivariate analysis, logistic regression analysis was performed to identify the factor associated with circulation return. A P-value < 0.05 was considered statistically significant in all analyses. 3. Results 3.1. Patients characteristics The characteristics of 92 patients (manual CPR group, N = 43; AutoPulse TM group, N = 49) are summarized in Table 1. There were no significant differences between the 2 groups. The median age was 65 years in the manual CPR group, and 71 years in the AutoPulse TM group. In the manual CPR group, the etiology of CPA was cardiac in 16 cases and non-cardiac in 27 cases. Among 27 patients with non-cardiac CPA, 7 cases involved an endogenous etiology, and 20 involved an exogenous etiology (14 cases of trauma and 6 cases of drowning) (Table 2). In the AutoPulse TM group, the etiology of CPA was cardiac in 21 cases and non-cardiac in 28 cases.

4 K. Omori et al. / Resuscitation 84 (2013) All cases of CPA that were requested to HEMS N=205 AutoPulse not applied N=15 Multiple trauma N = 5 AutoPulse inoperative N = 4 CPA in a helicopter during transport N = 3 newborns and infants N = 5 Hopeless resuscitation N = 52 Return by an ambulance N = 24 ROSC before arrival N = 20 Subject of this case study N = 92 Manual CPR Group N = 43 AutoPulse Added Group N = 49 Fig. 2. Schematic flowchart of enrolled patients. CPA, cardiopulmonary arrest; HEMS, helicopter emergency medical service; ROSC, return of spontaneous circulation; CPR, cardiopulmonary resuscitation. Among 28 patients with non-cardiac CPA, there were 7 endogenous cases and 21 exogenous cases (12 cases of trauma, 7 cases of drowning, 1 case of suicide, and 1 case of suffocation). Among CPA patients in the manual CPR group, 7.0% (3 of 43) had successful circulation return. In contrast, 30.6% of patients (15 of 49) in the AutoPulse TM group had successful circulation return (P = 0.007). In the manual CPR group, 3 patients had successful circulation return and only 1 patient survived (The Glasgow Pittsburgh Overall Performance Categories 23,24 : OPC1: no or mild neurological disability, 1 case), and was discharged. In the AutoPulse TM group, 15 patients had successful circulation return, and there were 3 survival patients (OPC1, 2 cases; OPC3: severe neurological disability, 1 case), who were discharged. Clinical backgrounds of these survival patients were summarized in Supplementary Table 1. All survivors were characterized by male gender, presence of witness and bystander CPR. Supplementary material related to this article found, in the online version, at Factors associated with ROSC To examine the efficacy of AutoPulse TM, we analyzed factors associated with ROSC. In univariate analysis, the duration of manual CPR application (P = 0.016) and additional use of AutoPulse TM (P = 0.009) were selected as factors associated with ROSC (Table 2). In multivariate analysis, younger age (P = 0.042) and additional use of AutoPulse TM (P = 0.005) were selected as factors associated with ROSC (Table 3). Fig. 3 illustrates the rate for CPA patients who achieved ROSC according to 4 categories including status of age and use of AutoPulse TM. In Particular, 47% of patients aged 65 years had ROSC after use of AutoPulse TM. It appears that AutoPulse TM is more effective in young CPA patients. 4. Discussion The results of the present study demonstrate that use of the AutoPulse TM system in flying helicopters was effective in CPA Table 1 Patients characteristics. Manual CPR AutoPulse TM P value Number of cases Age (years) a 65 (26 92) 71 (15 87) Gender (male/female) b 31/12 38/ Etiology (endogenous/exogenous) b 23/20 28/ Etiology (cardiac/non-cardiac) 16/27 21/ Witnesses (absence/presence) b 12/31 24/ Bystander CPR (absence/presence) b 25/18 25/ Emergency perception-paramedics arrival (min) a 13 (3 31) 14 (0 62) Paramedics-helicopter team arrival (min) a 18 (0 49) 19 (0 54) Manual CPR (min) a 53 (10 87) 41 (0 71) <0.001 AutoPulse TM CPR (min) 15 (3 30) Cardiac arrest rhythm (VF or VT/PEA/asystole) b 3/11/29 4/8/ Circulation return (success/failed) c 3/40 15/ Outcome (survival/death) c 1/42 3/ CPR, cardiopulmonary resuscitation; VF, ventricular fibrillation; VT, ventricular tachycardia; PEA, pulseless electrical activity. a Mann Whitney U test; b Chi-square test. c Fisher s exact test.

5 1048 K. Omori et al. / Resuscitation 84 (2013) Table 2 Etiology of CPA in manual CPR group and AutoPulse TM group. Manual CPR group (N = 43) AutoPulse TM group (N = 49) Total Cardiac etiology Acute myocardial infarction 7 1 Arrhythmia 3 3 Heart failure 2 0 Presumed 4 17 Non-cardiac etiology Endogenous Aortic dissection 3 1 Ruptured aortic aneurysm 1 0 Subarachnoid hemorrhage 1 0 Brain hemorrhage 1 0 Respiratory failure 1 1 Pulmonary thromboembolism 0 1 Gastrointestinal bleeding 0 3 Hypoglycemia 0 1 Exogenous Trauma Blunt Head injury 5 4 Chest injury 2 1 Abdominal injury 2 2 Multiple trauma including thoracic injury 4 1 Multiple trauma that does not include the thoracic injury 1 4 Penetrating 0 0 Drowning Suicide 1 Hanging 0 1 Suffocation CPA, cardiopulmonary arrest; CPR, cardiopulmonary resuscitation. patients. In fact, the number of patients achieved ROSC was significantly increased after introduction of the AutoPulse TM system. Our region of Japan is mountainous, and the provision of emergency medical facilities was not sufficient. HEMS is provided in cases of CPA. However, it has always been very difficult to continue effective CPR in flying helicopters. Because helicopters have such limited space, only 2 medical staff are able to board, and free movement in the helicopter is impossible. Therefore, the person who begins chest compression must continue it alone. Incorrect compression rate or depth, as well as frequent interruptions can occur during the transport of CPA patients by helicopter. 10,11 Therefore, we introduced the AutoPulse TM system in order to resolve Table 3 Univariate analysis and multivariate analysis for factors associated with ROSC. Variable Univariate analysis Multivariate analysis Odds ratio (95%CI) P Odds ratio (95%CI) P Age < (years) 0.41 ( ) ( ) Gender Male 1 Female 0.83 ( ) Etiology Cardiogenic 1 Non-cardiogenic 1.98 ( ) Witnesses Absence 1 Presence 0.76 ( ) Bystander CPR Absence Presence 1.64 ( ) Emergency perception-paramedics arrival < (min) 1.02 ( ) Paramedics-helicopter team arrival < (min) 0.84 ( ) Manual CPR < (min) 0.25 ( ) Cardiac arrest rhythm Asystole 1 PEA 0.84 ( ) 0.81 VF or VT 3.38 ( ) AutoPulse TM No 1 1 Yes 5.89 ( ) ( ) CPR, cardiopulmonary resuscitation; VF, ventricular fibrillation; VT, ventricular tachycardia; PEA, pulseless electrical activity.

6 K. Omori et al. / Resuscitation 84 (2013) flying helicopters is clear, its routine use raises various problems. First, the AutoPulse TM system is designed for adults and cannot be used for pediatric patients. Second, it is necessary to undergo training for appropriate use of AutoPulse TM. Following training, it takes approximately 30 s to attach the AutoPulse TM. Third, a completely charged battery runs for a maximum of 30 min. Finally, the AutoPulse TM system is expensive. 5. Conclusions Fig. 3. The rates for the ROSC according to the status of age and use of AutoPulse TM. It shows that AutoPulse TM is most effective in CPA patients aged 65 years. ROSC, return of spontaneous circulation; CPA, cardiopulmonary arrest. these problems. After the introduction of AutoPulse TM system, the rate of ROSC was significantly increased. This is probably because incorrect chest compression and medical personnel s chest compression workload are reduced, allowing other necessary activities to be carried out. The AHA Guidelines 2010 indicate that load-distributing band CPR such as AutoPulse TM CPR is classified into Class IIb of the Evidence Levels. 1 This means that there is insufficient evidence to support the routine use of AutoPulse TM in CPA patients. Previous studies reported that coronary perfusion pressure, which is considered to be a key survival factor after receiving CPR, 14 is increased after the use of AutoPulse TM. 19,20 In fact, the use of AutoPulse TM in ambulances reportedly improved ROSC rates and survival to hospital discharge in adults with out-of-hospital non-traumatic cardiac arrests. 21 Conversely, another study has reported that the use of AutoPulse TM did not improve in the 4-h survival rates or neurologic outcomes. 22 In our study, ROSC rate was significantly increased in the AutoPulse TM group. However, no statistically significant difference was seen in survival rate. This might be due to limitation by small number of subjects. Thus, further studies including large cohort studies are required to clarify the efficacy for survival of CPA patients. Collectively, no conclusion has been reached on this matter at present. There is much debate about the effectiveness of the AutoPulse TM system itself. Based on our experience, we found that the use of AutoPulse TM in flying helicopters was significantly effective in achieving ROSC, especially in younger patients. In this study, we assessed the use of AutoPulse TM in flying helicopters. HEMS is requested when CPA occurrence is recognized (for example, in a call) or based on the paramedics judgment upon their arrival at the emergency site. If HEMS has been requested, paramedics continue Basic Life Support (BLS) such as cardiopulmonary resuscitation at the site or in the ambulance until the doctor arrives by helicopter. After the doctor arrives at the emergency site, the doctor initiates Advanced Cardiovascular Life Support (ACLS), including tracheal intubation, intravenous catheterization and medication. If paramedics were able to use AutoPulse TM at the emergency site, the rate for ROSC might be improved further. Sternum and rib fractures are often encountered during manual CPR. However, severe injuries such as liver rupture or rib fracture were not observed in the present study. Previous studies also reported no occurrence of severe injury while using AutoPulse TM. 18,20,25 According to the device s manual, some superficial skin abrasion was observed but only when it was used for a long period of time. Thus, the use of AutoPulse TM appears to be safe.finally, although the efficacy and safety of AutoPulse TM in In conclusion, our results demonstrated that the use of AutoPulse TM in flying helicopters was significantly effective among CPA patients: the use of automated chest compression devices such as AutoPulse TM inside helicopters appears to ROSC and survival. However, further studies including larger or prospective randomized studies are required to clarify the efficacy of the AutoPulse TM system. Conflict of interest The authors declared that they do not have anything to disclose regarding funding or conflict of interest with respect to this manuscript. Acknowledgement We are grateful to the emergency doctors of Juntendo University Shizuoka Hospital and the staff of the emergency medical system (Central Helicopter Service Inc., Aichi, Japan). References 1. American Heart Association Guidelines for cardiopulmonary resuscitation and emergency cardiovascular care science. 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