- Email: [email protected]
Effectiveness of the new ‘Mobile AED Map’ to find and retrieve an AED: A randomised controlled trial
Resuscitation 82 (2011) 69–73
Contents lists available at ScienceDirect
Resuscitation journal homepage: www.elsevier.com/locate/resuscitation
Simulation and education
Effectiveness of the new ‘Mobile AED Map’ to find and retrieve an AED: A randomised controlled trial夽,夽夽 Tomohiko Sakai a , Taku Iwami b,∗ , Tetsuhisa Kitamura b , Chika Nishiyama c , Takashi Kawamura b , Kentaro Kajino d , Hiroshi Tanaka e , Seishiro Marukawa f , Osamu Tasaki a , Tadahiko Shiozaki a , Hiroshi Ogura a , Yasuyuki Kuwagata a , Takeshi Shimazu a a
Department of Traumatology and Acute Critical Medicine, Osaka University Graduate School of Medicine, 2-15 Yamada-Oka, Suita, Osaka 565-0871, Japan Kyoto University Health Service, Yoshida-Honmachi, Sakyo-ku, Kyoto 606-8501, Japan c Kyoto Prefectural University of Medicine School of Nursing, 410 Nakagoryo-cho, Kamigyou-ku, Kyoto 602-0857, Japan d Emergency and Critical Care Medical Center, Osaka Police Hospital, 10-31 Kitayama-cho, Tennoji-ku, Osaka 543-0035, Japan e Department of Emergency and Critical Care Medicine, Juntendo University, Urayasu Hospital, 2-1-1 Tomioka, Urayasu 279-0021, Japan f Emergency Medical Center, Iseikai Hospital, 6-2-25 Sugawara, Higashi-Yodogawa-ku, Osaka 533-0022, Japan b
a r t i c l e
i n f o
Article history: Received 7 July 2010 Received in revised form 24 August 2010 Accepted 12 September 2010 Keywords: Automated external defibrillator (AED) Cardiac arrest Cardiopulmonary resuscitation (CPR) Out-of-hospital CPR Sudden cardiac death Randomised controlled trial
a b s t r a c t Background: Although early shock with an automated external defibrillator (AED) is one of the several key elements to save out-of-hospital cardiac arrest (OHCA) victims, it is not always easy to find and retrieve a nearby AED in emergency settings. We developed a cell phone web system, the Mobile AED Map, displaying nearby AEDs located anywhere. The simulation trial in the present study aims to compare the time and travel distance required to access an AED and retrieve it with and without the Mobile AED Map. Methods: Design: Randomised controlled trial. Setting: Two fields where it was estimated to take 2 min (120–170 m) to access the nearest AED. Participants were randomly assigned to either the Mobile AED Map group or the control group. We provided each participant in both groups with an OHCA scenario, and measured the time and travel distance to find and retrieve a nearby AED. Results: Forty-three volunteers were enrolled and completed the protocol. The time to access and retrieve an AED was not significantly different between the Mobile AED Map group (400 ± 238 s) and the control group (407 ± 256 s, p = 0.92). The travel distance was significantly shorter in the Mobile AED Map group (606 m vs. 891 m, p = 0.019). Trial field conditions affected the results differently. Conclusions: Although the new Mobile AED Map reduced the travel distance to access and retrieve the AED, it failed to shorten the time. Further technological improvements of the system are needed to increase its usefulness in emergency settings (UMIN000002043). © 2010 Elsevier Ireland Ltd. All rights reserved.
Increasing survival after out-of-hospital cardiac arrest (OHCA) is strongly associated with early defibrillation.1–3 Public access defibrillation (PAD) is, therefore, one of several key elements to save OHCA victims, and, indeed, its effectiveness in various settings has been elucidated.4–9 In Japan, the PAD programme was started in July 2004, and automated external defibrillators (AEDs) have been disseminated with amazing rapidity.10,11 A nationwide, prospective, population-based, observational study covering the whole
夽 A Spanish translated version of the abstract of this article appears as Appendix in the final online version at doi:10.1016/j.resuscitation.2010.09.466. 夽夽 Clinical Trial Registration Information: http://www.umin.ac.jp/ctr/index.htm (UMIN000002043). ∗ Corresponding author. Tel.: +81 75 753 2401; fax: +81 75 753 2424. E-mail address: [email protected] (T. Iwami). 0300-9572/$ – see front matter © 2010 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.resuscitation.2010.09.466
population of Japan showed that survival after OHCA increased as public access AEDs increased.12 Although the PAD concept, that is, early defibrillation by lay rescuers with public-access AEDs, is widely accepted, there are studies showing the difficulties for people in general to use AEDs on the scene.13–15 Thus, the placement of AEDs and information given to the general public of AED locations are as important as the actual cardiopulmonary resuscitation (CPR) training with AED. We established an Internet service informing people of the location of AEDs (AED Map) and have provided information on registered AEDs through the website since 2007. Recently, we developed a new AED Map that is accessible even by cellphones (Mobile AED Map) for emergency use. This study uses a simulation trial to compare the time and travel distance to find and retrieve an AED with or without the Mobile AED Map.
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T. Sakai et al. / Resuscitation 82 (2011) 69–73
1. Methods
1.4. Randomisation
1.1. Study design This study, which was designed as an open, prospective, individual, randomised controlled trial, was carried out in February 2009.
Participants were randomly assigned to either the Mobile AED Map group or the control group stratified by sex and age (age <40 or ≥40 years) using permuted blocks and a computer-generated randomisation list drawn up by a statistician. The allocation was opened to the participants at the trial site.
1.2. AED Map system
1.5. Interventions
The AED Map is a free-access web map showing information on the locations of registered AEDs (http://osakaaed.jp/maps). Registration of AEDs is carried out by the Osaka Life Support Association, a non-profit organisation, using letter, e-mail or telephone in cooperation with the Osaka prefectural government. The AED Map provides not only the geographic location of each AED but also information on the name and nature of the facility with the AED installation map below in text form. The Mobile AED Map indicates the mobile phone’s location using the global positioning system (GPS) function of cellphones and indicates nearby AEDs on the cellphone display. It takes several seconds before the GPS function pinpoints the mobile phone’s location and displays the map on the screen. For backup, the locations of the nearest four other AEDs within 500 m are displayed. The monitor range can be changed to 100, 200, 500, 1000 and 1500 m by the user. Text information about the nearest AED, including distance from the user and the name, business hours and telephone number of the facility is also displayed (Fig. 1).
The following scenario was presented to each participant: “Someone has collapsed in front of you. He does not respond at all. I (instructor) will call 119 and perform cardiopulmonary resuscitation. So, please find and retrieve an AED as soon as possible!” Participants assigned to the Mobile AED Map group were told to use the Mobile AED Map to find a nearby AED using a flip-design cell telephone (N-02A; NTTDOCOMO, Inc., Tokyo, Japan). The control group members had to find an AED without the Mobile AED Map. Two campuses of Kyoto University were selected as the trial fields. The main campus (http://www.kyotou.ac.jp/en/access/campus/main.htm) had seven AEDs in an area of 0.16 km2 (field A), and the north campus (http://www.kyotou.ac.jp/en/access/campus/north.htm) had eight AEDs in 0.16 km2 (field B), in February 2009. The starting point was specified in each field as it was estimated to take about 2 min (120–170 m) to reach the nearest AED. Fig. 2 shows the geographical relationships of the located AEDs and the starting point of this simulation. To mask the study field and the AED locations in the field, the study participants were taken by a chartered bus to a waiting room near each starting point after assignment. The Mobile AED Map group was shown how to use the Mobile AED Map, and they carefully familiarised themselves with system operation for some time before moving to the trial site. The trial was carried out person by person, and each examinee was blinded to the performances of the others. After the trial, the control group members were also instructed on the use of the Mobile AED Map. All participants received a prepaid card of 5000 yen as token thanks for their participation.
1.3. Study participants Participants were recruited via local billboards and Internet advertisements as well as by word of mouth from the current participants. People of age 20 years or more living in Japan and having a cellphone accessible to the Internet were included. Those who had any difficulties in their movements and were familiar with Kyoto University, where the trial was conducted, were excluded.
1.6. Data collection The time from the starting point to the AED, and from the AED to the starting point and the participants’ actions, including their travel routes, were recorded in an original report form by two investigators following the participants with a stopwatch. In field B, the Mobile AED Map operation time, that is, the time from starting to use a cellphone to recognising the direction of the nearest AED was also recorded. Travel distance was calculated by the two investigators by tracing the participant’s route on the map soon after the simulation. 1.7. Questionnaire After the trials, all participants were debriefed to identify their difficulties in accessing the AED and the most useful information to find the AED. A five-point Likert-scale questionnaire and an openended questionnaire were used to obtain the information. 1.8. Outcome measures
Fig. 1. Cellphone display of Mobile AED Map.
The primary outcome was the overall time to find and retrieve a nearby AED to the starting point in two trial fields. Secondary outcomes included their time fractions (starting point to AED and AED to starting point), travel distances (overall, starting point to AED and AED to starting point) and the participant’s impressions about the AED search with or without the Mobile AED Map.
T. Sakai et al. / Resuscitation 82 (2011) 69–73
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Fig. 2. AED locations in the study fields.
1.9. Statistical analysis
2. Results
We estimated that an AED Map user would find and retrieve an AED within 240 s, and a control group member would do so in 360 s, based on a previous report.16 Based on 0.8 power to detect a significant difference (p = 0.05, two-sided), 17 participants were required for each study group. To compensate for possible absences, we planned to enrol 20 participants per group. Baseline characteristics and outcomes were compared between groups using unpaired t-test for numerical variables and the chi-square test for categorical variables. Data are presented as means ± standard deviations (SDs). The participants’ impressions of the AED search were recorded and categorised. All of the tests were two-tailed and a p value of <0.05 was considered statistically significant. All statistical analyses were performed using Statistical Package for Social Sciences (SPSS) statistical package version 16.0J (SPSS, Inc., Chicago, IL, USA).
2.1. Flow and baseline characteristics of participants A total of 44 participants applied for this trial in January and February in 2009. All of them proved eligible and were randomly assigned to either the Mobile AED Map group (22) or the control group (22). One from the control group did not attend the trial due to urgent business, and 21 participants in the control group and 22 in the Mobile AED Map group completed the study protocol (Fig. 3). Baseline characteristics of the participants are shown in Table 1. The mean age was 28 years in both groups, and there were no significant differences in sex ratio, previous AED training, family history of sudden cardiac death and occupation between the groups. Twenty-six participants were students and six were healthcare providers, including nurses and emergency medical-service workers.
1.10. Ethical considerations
2.2. Time and travel distance to find and retrieve an AED
All procedures were conducted according to the Declaration of Helsinki. Participants submitted their written informed consent prior to participation. This study was approved by the Ethics Committee of Kyoto University Graduate School of Medicine, and was registered in the UMIN Clinical Trials Registry (UMIN000002043).
The time and travel distance to find and retrieve an AED are shown in Table 2. The mean overall time required to find and retrieve a nearby AED was 400 ± 238 s (range, 182–1052 s) in the Mobile AED Map group, and 407 ± 256 s (range, 92–1067 s) in the control group. The mean overall time was similar between the
Table 1 Baseline characteristics of participants.
Age, year, mean ± SD Men, n (%) Previous AED training, n (%) Family history of sudden cardiac death, n (%) Occupation, n (%) Student Health care provider Other SD, standard deviation; AED, automated external defibrillator.
Mobile AED Map group (n = 22)
Control group (n = 21)
p value
27.7 ± 10.4 14 (63.6) 17(77.3) 3 (13.6)
27.5 ± 10.9 13 (61.9) 16 (76.2) 2 (9.5)
0.94 0.91 0.94 0.67
14 (63.6) 3 (13.6) 5 (22.7)
12 (57.1) 3 (14.3) 6 (28.6)
0.90
0.007 0.019 0.01
Assessed for eligibility (n=44)
863.2 ± 336.2 539.8 ± 194.4 323.4 ± 158.9
Randomized (n=44) 392.9 ± 221.7 288.2 ± 154.6 104.7 ± 75.3 –
Control group (n = 11)
0.163 0.298 0.061
T. Sakai et al. / Resuscitation 82 (2011) 69–73
p value
72
Mobile AED Map group (n=22)
Control group (n=22)
Mobile AED Map group (n = 11)
0.499 0.138 0.281
0.309 0.508 0.27
Control group (n = 10)
422.4 ± 299.9 284.6 ± 179.8 137.8 ± 166.9
921.8 ± 558.6 612.5 ± 377.4 309.3 ± 289.0
Mobile AED Map group (n = 11)
510.9 ± 289.0 435.7 ± 256.4 75.2 ± 52.4 Not measured
705.1 ± 382.3 506.6 ± 342.0 198.5 ± 88.0
p value
0.922 0.422 0.07
0.019 0.079 0.022
Evaluated (n=22)
Evaluated (n=21)
505.6 ± 201.8 322.3 ± 205.5 184.3 ± 31.5
groups (p = 0.92). The mean time (334 ± 213 s) to reach an AED in the Mobile AED Map group was rather longer (287 ± 163 s) than in the control group (p = 0.42), while the mean time to return to the starting point was somewhat shorter in the Mobile AED Map group (66 ± 42 s) compared with the control group (121 ± 125 s, p = 0.07). However, the inter-group difference in time to find an AED varied with the trial field. The operation time of the Mobile AED Map measured in field B was 77 ± 30 s (range, 35–133 s). The overall travel distance to find and retrieve an AED was 606 ± 315 m (range, 306–1480 m) in the Mobile AED Map group and significantly shorter than 891 ± 445 m (range, 318–1873 m) in the control group (p = 0.019). Both travel distances from starting point to AED and from AED to starting point tended to be shorter in the Mobile AED Map group than in the control group. These measurements were similar, irrespective of the trial field. 2.3. Post-trial feedback In the post-trial inquiry, 86% (18/21) in the control group answered that they felt some difficulties in finding the AED, whereas 50% (11/22) of the Mobile AED Map group did not; 22.7% (5/22) answered that it was even easy (Table 3). In the Mobile AED Map group, 55% (12/22) answered that the Mobile AED Map had provided the most useful information to find an AED. 3. Discussion
AED, automated external defibrillator; SD, standard deviation.
891.1 ± 444.8 574.4 ± 290.5 316.7 ± 224.2 ± 315.1 ± 291.1 ± 64.9
± 238.2 ± 213.4 ± 42.2
407.0 ± 255.5 286.5 ± 162.8 120.5 ± 125.1
288.2 231.6 56.6 77.3
± ± ± ±
91.3 83.7 28.3 30.8
Fig. 3. Participant flow.
Travel time, s, mean ± SD Overall 399.6 Starting point to AED 333.6 AED to starting point 65.9 Operation time Travel distance, m, mean ± SD Overall 605.8 Starting point to AED 414.5 AED to starting point 191.4
Mobile AED Map group (n = 22)
Total
Table 2 Time and travel distance to find and retrieve an AED.
Control group (n = 21)
p value
Field B Field A
Absent from trial (n=1)
We developed a new technology to find a nearby AED using a cellphone, the Mobile AED Map, and evaluated their efficacy by a randomised controlled trial. In this trial, the travel distance to find and retrieve an AED was significantly shortened by using the new Map, suggesting that such a new system can indeed support lay rescuers in emergency settings. Table 3 Participants’ impressions about the trial. Mobile AED Map group (n = 22) Difficulty to find AED Very easy, n (%) 2 (9.1) Easy, n (%) 3 (13.6) Equivocal, n (%) 6 (27.3) Difficult, n (%) 10 (45.5) Very difficult, n (%) 1 (4.5) Most useful information to find AED Mobile AED Map, n (%) 12 (54.5) Information from local people, n (%) 4 (18.2) Notice of AED at building entrance, n (%) 4 (18.2) Guide map of facility itself, n (%) 1 (4.5) Nothing, n (%) 1 (4.5)
Control group (n = 21) 0 (0.0) 2 (9.5) 1 (4.8) 10 (47.6) 8 (38.1) 0 (0.0) 10 (47.6) 10 (47.6) 0 (0.0) 1 (4.8)
T. Sakai et al. / Resuscitation 82 (2011) 69–73
Although the travel distance was shortened, the new system failed to significantly decrease the time to find and retrieve an AED, probably due to the time needed to operate the system and to display the user’s location on the screen. In field B where the location of buildings and the user’s position could be easily specified, the overall time was shorter in the Mobile AED Map group. Even in this easier setting, it took about 80 s until the user knew where he/she was and began to move. In addition to the difficulty in operating the system, the complexity of buildings in field A may have made it more difficult for examinees to recognise their location. Time to defibrillation is the most important factor in saving the lives of OHCA patients.1–3 Thus, we should make further efforts to shorten the time with new technologies such as a navigation system with a digital compass or a one-touch operation system. It took up to 7 min to find and retrieve an AED only 150 m from the scene. This suggests the difficulty for lay rescuers to find an AED without any guiding tool in an emergency setting. Unfamiliarity with the field might be another reason for the longer time to find the AED, even in the Mobile AED Map group. Nearly half of the control group and one-fifth of the Mobile AED Map group answered that the notice of an AED at the building entrance was the most useful information in finding the AED. Not only the new technology, but also improvements in basic information regarding AED locations including useful on-the-spot information at building entrances are required. Alerting people, in general, to become aware of AEDs at ordinary times is also important. The effectiveness of the Mobile AED Map depends on the proportion of registered AEDs to distributed AEDs. To increase the effectiveness of the Mobile AED Map, most AEDs must be duly registered. However, the Mobile AED Map will be ineffective if the proportion of registered AEDs to the distributed AEDs is low. If an AED near the emergency site is not registered, the lay rescuer is forced to find a registered AED further away. Thus, registered AED information must be managed with great care and accuracy. The Mobile AED Map would have further potential to encourage public awareness of bystander-CPR, if AEDs were positioned in public spaces.17 Providing information through cellphones on AED locations might increase not only AED awareness but also positive attitudes towards bystander-CPR and PAD. 4. Study limitations This study has some inherent limitations. One is that the experiment was carried out only in a limited situation. AEDs are actually located in various places in various densities, and with all kinds of guidance information. Although we conducted the trial in two fields, our findings cannot be generalised. A simulation test, no matter how well conducted, is not an actual event for participants; hence, there is an obvious limitation. In the present study, the participants of the Mobile AED Map group had received training in the system just prior to the present investigation; but it was not in connection with an actual real-life event. Hence, their awareness of the genuine usefulness of the AED Map would not be the same as in an actual life-saving event. That is the obvious limitation. 5. Conclusion Although the new Mobile AED Map reduced the travel distance to access and retrieve an AED, it failed to shorten the time. Further improvements of the system are warranted to increase its usefulness in emergency settings. Conflict of interest statement None.
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Sources of funding This study was supported by Health and Labour Sciences Research Grants (H21-Shinkin-ippan-001) from the Japanese Ministry of Health, Labour and Welfare. Acknowledgements Our sincere thanks to Masae Shimabukuro, Yasuyuki Shinkai, Rika Shirai, Maiko Kiyose, Aki Iwamura, Yasuhisa Nakatani, Erika Oki and Eri Yamabe from the Trauma and Acute Critical Care Center of Osaka University Hospital for the data collection. We thank Miho Kyoriki for taking the time from their working schedules to help our study, and are grateful to Kayo Tanigawa, Tomoko Souda, Tomoko Nishimura, Hye Soon Son and Yuriko Kajiura for managerial support. We also thank Masahiko Ando for assisting with the randomisation of the participants and Tsutomu Ohmae for coordination with the faculties concerned at Kyoto University. We are also indebted to Fukuda Denshi Kinki Hanbai Co., Ltd., Laerdal Medical Japan KK., Medtronic Japan Co., Ltd. and Nihon Kohden Kansai Co. for assisting with the registry of AEDs on the AED Map and to members of the non-profit organisation Osaka Life Support Association for registering and managing the AED Map. References 1. Stiell IG, Wells GA, Field B, et al. Advanced cardiac life support in out-of-hospital cardiac arrest. N Engl J Med 2004;351:647–56. 2. Nishiuchi T, Hayashino Y, Fukuhara S, et al. Survival rate and factors associated with 1-month survival of witnessed out-of-hospital cardiac arrest of cardiac origin with ventricular fibrillation and pulseless ventricular tachycardia: the Utstein Osaka project. Resuscitation 2008;78:307–13. 3. Iwami T, Nichol G, Hiraide A, et al. Continuous improvements in “chain of survival” increased survival after out-of-hospital cardiac arrests: a large-scale population-based study. Circulation 2009;119:728–34. 4. Capucci A, Aschieri D, Piepoli MF, Bardy GH, Iconomu E, Arvedi M. Tripling survival from sudden cardiac arrest via early defibrillation without traditional education in cardiopulmonary resuscitation. Circulation 2002;106:1065– 70. 5. Drezner JA, Rao AL, Heistand J, Bloomingdale MK, Harmon KG. Effectiveness of emergency response planning for sudden cardiac arrest in United States high schools with automated external defibrillators. Circulation 2009;120:518– 25. 6. Caffrey SL, Willoughby PJ, Pepe PE, Becker LB. Public use of automated external defibrillators. N Engl J Med 2002;347:1242–7. 7. Rho RW, Page RL. The automated external defibrillator. J Cardiovasc Electrophysiol 2007;18:896–9. 8. Culley LL, Rea TD, Murray JA, et al. Public access defibrillation in out-ofhospital cardiac arrest: a community-based study. Circulation 2004;109:1859– 63. 9. Marenco JP, Wang PJ, Link MS, Homoud MK, Estes 3rd NA. Improving survival from sudden cardiac arrest: the role of the automated external defibrillator. JAMA 2001;285:1193–200. 10. Tanigawa K, Tanaka K. Emergency medical service systems in Japan: past, present, and future. Resuscitation 2006;69:365–70. 11. Mitamura H. Public access defibrillation: advances from Japan. Nat Clin Pract Cardiovasc Med 2008;5:690–2. 12. Kitamura T, Iwami T, Kawamura T, et al. Nationwide public-access defibrillation in Japan. N Engl J Med 2010;362:994–1004. 13. Gundry JW, Comess KA, DeRook FA, Jorgenson D, Bardy GH. Comparison of naive sixth-grade children with trained professionals in the use of an automated external defibrillator. Circulation 1999;100:1703–7. 14. Mattei LC, McKay U, Lepper MW, Soar J. Do nurses and physiotherapists require training to use an automated external defibrillator? Resuscitation 2002;53:277–80. 15. Starr LM, American College of Occupational and Environmental Medicine. Automated external defibrillation in the occupational setting. J Occup Environ Med 2002;44:2–7. 16. Report on a study on social system development to improve survival from emergency cardiovascular disease using automated external defibrillator (Marukawa’s report) [In Japanese; Accessed 05.07.10, at http://kouroukakenkyukyusosei.info/wpm/archivepdf/19/2 1 f.pdf]. 17. Kuramoto N, Morimoto T, Kubota Y, et al. Public perception of and willingness to perform bystander CPR in Japan. Resuscitation 2008;79:475– 81.
Contents lists available at ScienceDirect
Resuscitation journal homepage: www.elsevier.com/locate/resuscitation
Simulation and education
Effectiveness of the new ‘Mobile AED Map’ to find and retrieve an AED: A randomised controlled trial夽,夽夽 Tomohiko Sakai a , Taku Iwami b,∗ , Tetsuhisa Kitamura b , Chika Nishiyama c , Takashi Kawamura b , Kentaro Kajino d , Hiroshi Tanaka e , Seishiro Marukawa f , Osamu Tasaki a , Tadahiko Shiozaki a , Hiroshi Ogura a , Yasuyuki Kuwagata a , Takeshi Shimazu a a
Department of Traumatology and Acute Critical Medicine, Osaka University Graduate School of Medicine, 2-15 Yamada-Oka, Suita, Osaka 565-0871, Japan Kyoto University Health Service, Yoshida-Honmachi, Sakyo-ku, Kyoto 606-8501, Japan c Kyoto Prefectural University of Medicine School of Nursing, 410 Nakagoryo-cho, Kamigyou-ku, Kyoto 602-0857, Japan d Emergency and Critical Care Medical Center, Osaka Police Hospital, 10-31 Kitayama-cho, Tennoji-ku, Osaka 543-0035, Japan e Department of Emergency and Critical Care Medicine, Juntendo University, Urayasu Hospital, 2-1-1 Tomioka, Urayasu 279-0021, Japan f Emergency Medical Center, Iseikai Hospital, 6-2-25 Sugawara, Higashi-Yodogawa-ku, Osaka 533-0022, Japan b
a r t i c l e
i n f o
Article history: Received 7 July 2010 Received in revised form 24 August 2010 Accepted 12 September 2010 Keywords: Automated external defibrillator (AED) Cardiac arrest Cardiopulmonary resuscitation (CPR) Out-of-hospital CPR Sudden cardiac death Randomised controlled trial
a b s t r a c t Background: Although early shock with an automated external defibrillator (AED) is one of the several key elements to save out-of-hospital cardiac arrest (OHCA) victims, it is not always easy to find and retrieve a nearby AED in emergency settings. We developed a cell phone web system, the Mobile AED Map, displaying nearby AEDs located anywhere. The simulation trial in the present study aims to compare the time and travel distance required to access an AED and retrieve it with and without the Mobile AED Map. Methods: Design: Randomised controlled trial. Setting: Two fields where it was estimated to take 2 min (120–170 m) to access the nearest AED. Participants were randomly assigned to either the Mobile AED Map group or the control group. We provided each participant in both groups with an OHCA scenario, and measured the time and travel distance to find and retrieve a nearby AED. Results: Forty-three volunteers were enrolled and completed the protocol. The time to access and retrieve an AED was not significantly different between the Mobile AED Map group (400 ± 238 s) and the control group (407 ± 256 s, p = 0.92). The travel distance was significantly shorter in the Mobile AED Map group (606 m vs. 891 m, p = 0.019). Trial field conditions affected the results differently. Conclusions: Although the new Mobile AED Map reduced the travel distance to access and retrieve the AED, it failed to shorten the time. Further technological improvements of the system are needed to increase its usefulness in emergency settings (UMIN000002043). © 2010 Elsevier Ireland Ltd. All rights reserved.
Increasing survival after out-of-hospital cardiac arrest (OHCA) is strongly associated with early defibrillation.1–3 Public access defibrillation (PAD) is, therefore, one of several key elements to save OHCA victims, and, indeed, its effectiveness in various settings has been elucidated.4–9 In Japan, the PAD programme was started in July 2004, and automated external defibrillators (AEDs) have been disseminated with amazing rapidity.10,11 A nationwide, prospective, population-based, observational study covering the whole
夽 A Spanish translated version of the abstract of this article appears as Appendix in the final online version at doi:10.1016/j.resuscitation.2010.09.466. 夽夽 Clinical Trial Registration Information: http://www.umin.ac.jp/ctr/index.htm (UMIN000002043). ∗ Corresponding author. Tel.: +81 75 753 2401; fax: +81 75 753 2424. E-mail address: [email protected] (T. Iwami). 0300-9572/$ – see front matter © 2010 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.resuscitation.2010.09.466
population of Japan showed that survival after OHCA increased as public access AEDs increased.12 Although the PAD concept, that is, early defibrillation by lay rescuers with public-access AEDs, is widely accepted, there are studies showing the difficulties for people in general to use AEDs on the scene.13–15 Thus, the placement of AEDs and information given to the general public of AED locations are as important as the actual cardiopulmonary resuscitation (CPR) training with AED. We established an Internet service informing people of the location of AEDs (AED Map) and have provided information on registered AEDs through the website since 2007. Recently, we developed a new AED Map that is accessible even by cellphones (Mobile AED Map) for emergency use. This study uses a simulation trial to compare the time and travel distance to find and retrieve an AED with or without the Mobile AED Map.
70
T. Sakai et al. / Resuscitation 82 (2011) 69–73
1. Methods
1.4. Randomisation
1.1. Study design This study, which was designed as an open, prospective, individual, randomised controlled trial, was carried out in February 2009.
Participants were randomly assigned to either the Mobile AED Map group or the control group stratified by sex and age (age <40 or ≥40 years) using permuted blocks and a computer-generated randomisation list drawn up by a statistician. The allocation was opened to the participants at the trial site.
1.2. AED Map system
1.5. Interventions
The AED Map is a free-access web map showing information on the locations of registered AEDs (http://osakaaed.jp/maps). Registration of AEDs is carried out by the Osaka Life Support Association, a non-profit organisation, using letter, e-mail or telephone in cooperation with the Osaka prefectural government. The AED Map provides not only the geographic location of each AED but also information on the name and nature of the facility with the AED installation map below in text form. The Mobile AED Map indicates the mobile phone’s location using the global positioning system (GPS) function of cellphones and indicates nearby AEDs on the cellphone display. It takes several seconds before the GPS function pinpoints the mobile phone’s location and displays the map on the screen. For backup, the locations of the nearest four other AEDs within 500 m are displayed. The monitor range can be changed to 100, 200, 500, 1000 and 1500 m by the user. Text information about the nearest AED, including distance from the user and the name, business hours and telephone number of the facility is also displayed (Fig. 1).
The following scenario was presented to each participant: “Someone has collapsed in front of you. He does not respond at all. I (instructor) will call 119 and perform cardiopulmonary resuscitation. So, please find and retrieve an AED as soon as possible!” Participants assigned to the Mobile AED Map group were told to use the Mobile AED Map to find a nearby AED using a flip-design cell telephone (N-02A; NTTDOCOMO, Inc., Tokyo, Japan). The control group members had to find an AED without the Mobile AED Map. Two campuses of Kyoto University were selected as the trial fields. The main campus (http://www.kyotou.ac.jp/en/access/campus/main.htm) had seven AEDs in an area of 0.16 km2 (field A), and the north campus (http://www.kyotou.ac.jp/en/access/campus/north.htm) had eight AEDs in 0.16 km2 (field B), in February 2009. The starting point was specified in each field as it was estimated to take about 2 min (120–170 m) to reach the nearest AED. Fig. 2 shows the geographical relationships of the located AEDs and the starting point of this simulation. To mask the study field and the AED locations in the field, the study participants were taken by a chartered bus to a waiting room near each starting point after assignment. The Mobile AED Map group was shown how to use the Mobile AED Map, and they carefully familiarised themselves with system operation for some time before moving to the trial site. The trial was carried out person by person, and each examinee was blinded to the performances of the others. After the trial, the control group members were also instructed on the use of the Mobile AED Map. All participants received a prepaid card of 5000 yen as token thanks for their participation.
1.3. Study participants Participants were recruited via local billboards and Internet advertisements as well as by word of mouth from the current participants. People of age 20 years or more living in Japan and having a cellphone accessible to the Internet were included. Those who had any difficulties in their movements and were familiar with Kyoto University, where the trial was conducted, were excluded.
1.6. Data collection The time from the starting point to the AED, and from the AED to the starting point and the participants’ actions, including their travel routes, were recorded in an original report form by two investigators following the participants with a stopwatch. In field B, the Mobile AED Map operation time, that is, the time from starting to use a cellphone to recognising the direction of the nearest AED was also recorded. Travel distance was calculated by the two investigators by tracing the participant’s route on the map soon after the simulation. 1.7. Questionnaire After the trials, all participants were debriefed to identify their difficulties in accessing the AED and the most useful information to find the AED. A five-point Likert-scale questionnaire and an openended questionnaire were used to obtain the information. 1.8. Outcome measures
Fig. 1. Cellphone display of Mobile AED Map.
The primary outcome was the overall time to find and retrieve a nearby AED to the starting point in two trial fields. Secondary outcomes included their time fractions (starting point to AED and AED to starting point), travel distances (overall, starting point to AED and AED to starting point) and the participant’s impressions about the AED search with or without the Mobile AED Map.
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Fig. 2. AED locations in the study fields.
1.9. Statistical analysis
2. Results
We estimated that an AED Map user would find and retrieve an AED within 240 s, and a control group member would do so in 360 s, based on a previous report.16 Based on 0.8 power to detect a significant difference (p = 0.05, two-sided), 17 participants were required for each study group. To compensate for possible absences, we planned to enrol 20 participants per group. Baseline characteristics and outcomes were compared between groups using unpaired t-test for numerical variables and the chi-square test for categorical variables. Data are presented as means ± standard deviations (SDs). The participants’ impressions of the AED search were recorded and categorised. All of the tests were two-tailed and a p value of <0.05 was considered statistically significant. All statistical analyses were performed using Statistical Package for Social Sciences (SPSS) statistical package version 16.0J (SPSS, Inc., Chicago, IL, USA).
2.1. Flow and baseline characteristics of participants A total of 44 participants applied for this trial in January and February in 2009. All of them proved eligible and were randomly assigned to either the Mobile AED Map group (22) or the control group (22). One from the control group did not attend the trial due to urgent business, and 21 participants in the control group and 22 in the Mobile AED Map group completed the study protocol (Fig. 3). Baseline characteristics of the participants are shown in Table 1. The mean age was 28 years in both groups, and there were no significant differences in sex ratio, previous AED training, family history of sudden cardiac death and occupation between the groups. Twenty-six participants were students and six were healthcare providers, including nurses and emergency medical-service workers.
1.10. Ethical considerations
2.2. Time and travel distance to find and retrieve an AED
All procedures were conducted according to the Declaration of Helsinki. Participants submitted their written informed consent prior to participation. This study was approved by the Ethics Committee of Kyoto University Graduate School of Medicine, and was registered in the UMIN Clinical Trials Registry (UMIN000002043).
The time and travel distance to find and retrieve an AED are shown in Table 2. The mean overall time required to find and retrieve a nearby AED was 400 ± 238 s (range, 182–1052 s) in the Mobile AED Map group, and 407 ± 256 s (range, 92–1067 s) in the control group. The mean overall time was similar between the
Table 1 Baseline characteristics of participants.
Age, year, mean ± SD Men, n (%) Previous AED training, n (%) Family history of sudden cardiac death, n (%) Occupation, n (%) Student Health care provider Other SD, standard deviation; AED, automated external defibrillator.
Mobile AED Map group (n = 22)
Control group (n = 21)
p value
27.7 ± 10.4 14 (63.6) 17(77.3) 3 (13.6)
27.5 ± 10.9 13 (61.9) 16 (76.2) 2 (9.5)
0.94 0.91 0.94 0.67
14 (63.6) 3 (13.6) 5 (22.7)
12 (57.1) 3 (14.3) 6 (28.6)
0.90
0.007 0.019 0.01
Assessed for eligibility (n=44)
863.2 ± 336.2 539.8 ± 194.4 323.4 ± 158.9
Randomized (n=44) 392.9 ± 221.7 288.2 ± 154.6 104.7 ± 75.3 –
Control group (n = 11)
0.163 0.298 0.061
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p value
72
Mobile AED Map group (n=22)
Control group (n=22)
Mobile AED Map group (n = 11)
0.499 0.138 0.281
0.309 0.508 0.27
Control group (n = 10)
422.4 ± 299.9 284.6 ± 179.8 137.8 ± 166.9
921.8 ± 558.6 612.5 ± 377.4 309.3 ± 289.0
Mobile AED Map group (n = 11)
510.9 ± 289.0 435.7 ± 256.4 75.2 ± 52.4 Not measured
705.1 ± 382.3 506.6 ± 342.0 198.5 ± 88.0
p value
0.922 0.422 0.07
0.019 0.079 0.022
Evaluated (n=22)
Evaluated (n=21)
505.6 ± 201.8 322.3 ± 205.5 184.3 ± 31.5
groups (p = 0.92). The mean time (334 ± 213 s) to reach an AED in the Mobile AED Map group was rather longer (287 ± 163 s) than in the control group (p = 0.42), while the mean time to return to the starting point was somewhat shorter in the Mobile AED Map group (66 ± 42 s) compared with the control group (121 ± 125 s, p = 0.07). However, the inter-group difference in time to find an AED varied with the trial field. The operation time of the Mobile AED Map measured in field B was 77 ± 30 s (range, 35–133 s). The overall travel distance to find and retrieve an AED was 606 ± 315 m (range, 306–1480 m) in the Mobile AED Map group and significantly shorter than 891 ± 445 m (range, 318–1873 m) in the control group (p = 0.019). Both travel distances from starting point to AED and from AED to starting point tended to be shorter in the Mobile AED Map group than in the control group. These measurements were similar, irrespective of the trial field. 2.3. Post-trial feedback In the post-trial inquiry, 86% (18/21) in the control group answered that they felt some difficulties in finding the AED, whereas 50% (11/22) of the Mobile AED Map group did not; 22.7% (5/22) answered that it was even easy (Table 3). In the Mobile AED Map group, 55% (12/22) answered that the Mobile AED Map had provided the most useful information to find an AED. 3. Discussion
AED, automated external defibrillator; SD, standard deviation.
891.1 ± 444.8 574.4 ± 290.5 316.7 ± 224.2 ± 315.1 ± 291.1 ± 64.9
± 238.2 ± 213.4 ± 42.2
407.0 ± 255.5 286.5 ± 162.8 120.5 ± 125.1
288.2 231.6 56.6 77.3
± ± ± ±
91.3 83.7 28.3 30.8
Fig. 3. Participant flow.
Travel time, s, mean ± SD Overall 399.6 Starting point to AED 333.6 AED to starting point 65.9 Operation time Travel distance, m, mean ± SD Overall 605.8 Starting point to AED 414.5 AED to starting point 191.4
Mobile AED Map group (n = 22)
Total
Table 2 Time and travel distance to find and retrieve an AED.
Control group (n = 21)
p value
Field B Field A
Absent from trial (n=1)
We developed a new technology to find a nearby AED using a cellphone, the Mobile AED Map, and evaluated their efficacy by a randomised controlled trial. In this trial, the travel distance to find and retrieve an AED was significantly shortened by using the new Map, suggesting that such a new system can indeed support lay rescuers in emergency settings. Table 3 Participants’ impressions about the trial. Mobile AED Map group (n = 22) Difficulty to find AED Very easy, n (%) 2 (9.1) Easy, n (%) 3 (13.6) Equivocal, n (%) 6 (27.3) Difficult, n (%) 10 (45.5) Very difficult, n (%) 1 (4.5) Most useful information to find AED Mobile AED Map, n (%) 12 (54.5) Information from local people, n (%) 4 (18.2) Notice of AED at building entrance, n (%) 4 (18.2) Guide map of facility itself, n (%) 1 (4.5) Nothing, n (%) 1 (4.5)
Control group (n = 21) 0 (0.0) 2 (9.5) 1 (4.8) 10 (47.6) 8 (38.1) 0 (0.0) 10 (47.6) 10 (47.6) 0 (0.0) 1 (4.8)
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Although the travel distance was shortened, the new system failed to significantly decrease the time to find and retrieve an AED, probably due to the time needed to operate the system and to display the user’s location on the screen. In field B where the location of buildings and the user’s position could be easily specified, the overall time was shorter in the Mobile AED Map group. Even in this easier setting, it took about 80 s until the user knew where he/she was and began to move. In addition to the difficulty in operating the system, the complexity of buildings in field A may have made it more difficult for examinees to recognise their location. Time to defibrillation is the most important factor in saving the lives of OHCA patients.1–3 Thus, we should make further efforts to shorten the time with new technologies such as a navigation system with a digital compass or a one-touch operation system. It took up to 7 min to find and retrieve an AED only 150 m from the scene. This suggests the difficulty for lay rescuers to find an AED without any guiding tool in an emergency setting. Unfamiliarity with the field might be another reason for the longer time to find the AED, even in the Mobile AED Map group. Nearly half of the control group and one-fifth of the Mobile AED Map group answered that the notice of an AED at the building entrance was the most useful information in finding the AED. Not only the new technology, but also improvements in basic information regarding AED locations including useful on-the-spot information at building entrances are required. Alerting people, in general, to become aware of AEDs at ordinary times is also important. The effectiveness of the Mobile AED Map depends on the proportion of registered AEDs to distributed AEDs. To increase the effectiveness of the Mobile AED Map, most AEDs must be duly registered. However, the Mobile AED Map will be ineffective if the proportion of registered AEDs to the distributed AEDs is low. If an AED near the emergency site is not registered, the lay rescuer is forced to find a registered AED further away. Thus, registered AED information must be managed with great care and accuracy. The Mobile AED Map would have further potential to encourage public awareness of bystander-CPR, if AEDs were positioned in public spaces.17 Providing information through cellphones on AED locations might increase not only AED awareness but also positive attitudes towards bystander-CPR and PAD. 4. Study limitations This study has some inherent limitations. One is that the experiment was carried out only in a limited situation. AEDs are actually located in various places in various densities, and with all kinds of guidance information. Although we conducted the trial in two fields, our findings cannot be generalised. A simulation test, no matter how well conducted, is not an actual event for participants; hence, there is an obvious limitation. In the present study, the participants of the Mobile AED Map group had received training in the system just prior to the present investigation; but it was not in connection with an actual real-life event. Hence, their awareness of the genuine usefulness of the AED Map would not be the same as in an actual life-saving event. That is the obvious limitation. 5. Conclusion Although the new Mobile AED Map reduced the travel distance to access and retrieve an AED, it failed to shorten the time. Further improvements of the system are warranted to increase its usefulness in emergency settings. Conflict of interest statement None.
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Sources of funding This study was supported by Health and Labour Sciences Research Grants (H21-Shinkin-ippan-001) from the Japanese Ministry of Health, Labour and Welfare. Acknowledgements Our sincere thanks to Masae Shimabukuro, Yasuyuki Shinkai, Rika Shirai, Maiko Kiyose, Aki Iwamura, Yasuhisa Nakatani, Erika Oki and Eri Yamabe from the Trauma and Acute Critical Care Center of Osaka University Hospital for the data collection. We thank Miho Kyoriki for taking the time from their working schedules to help our study, and are grateful to Kayo Tanigawa, Tomoko Souda, Tomoko Nishimura, Hye Soon Son and Yuriko Kajiura for managerial support. We also thank Masahiko Ando for assisting with the randomisation of the participants and Tsutomu Ohmae for coordination with the faculties concerned at Kyoto University. We are also indebted to Fukuda Denshi Kinki Hanbai Co., Ltd., Laerdal Medical Japan KK., Medtronic Japan Co., Ltd. and Nihon Kohden Kansai Co. for assisting with the registry of AEDs on the AED Map and to members of the non-profit organisation Osaka Life Support Association for registering and managing the AED Map. References 1. Stiell IG, Wells GA, Field B, et al. Advanced cardiac life support in out-of-hospital cardiac arrest. N Engl J Med 2004;351:647–56. 2. Nishiuchi T, Hayashino Y, Fukuhara S, et al. Survival rate and factors associated with 1-month survival of witnessed out-of-hospital cardiac arrest of cardiac origin with ventricular fibrillation and pulseless ventricular tachycardia: the Utstein Osaka project. Resuscitation 2008;78:307–13. 3. Iwami T, Nichol G, Hiraide A, et al. Continuous improvements in “chain of survival” increased survival after out-of-hospital cardiac arrests: a large-scale population-based study. Circulation 2009;119:728–34. 4. Capucci A, Aschieri D, Piepoli MF, Bardy GH, Iconomu E, Arvedi M. Tripling survival from sudden cardiac arrest via early defibrillation without traditional education in cardiopulmonary resuscitation. Circulation 2002;106:1065– 70. 5. Drezner JA, Rao AL, Heistand J, Bloomingdale MK, Harmon KG. Effectiveness of emergency response planning for sudden cardiac arrest in United States high schools with automated external defibrillators. Circulation 2009;120:518– 25. 6. Caffrey SL, Willoughby PJ, Pepe PE, Becker LB. Public use of automated external defibrillators. N Engl J Med 2002;347:1242–7. 7. Rho RW, Page RL. The automated external defibrillator. J Cardiovasc Electrophysiol 2007;18:896–9. 8. Culley LL, Rea TD, Murray JA, et al. Public access defibrillation in out-ofhospital cardiac arrest: a community-based study. Circulation 2004;109:1859– 63. 9. Marenco JP, Wang PJ, Link MS, Homoud MK, Estes 3rd NA. Improving survival from sudden cardiac arrest: the role of the automated external defibrillator. JAMA 2001;285:1193–200. 10. Tanigawa K, Tanaka K. Emergency medical service systems in Japan: past, present, and future. Resuscitation 2006;69:365–70. 11. Mitamura H. Public access defibrillation: advances from Japan. Nat Clin Pract Cardiovasc Med 2008;5:690–2. 12. Kitamura T, Iwami T, Kawamura T, et al. Nationwide public-access defibrillation in Japan. N Engl J Med 2010;362:994–1004. 13. Gundry JW, Comess KA, DeRook FA, Jorgenson D, Bardy GH. Comparison of naive sixth-grade children with trained professionals in the use of an automated external defibrillator. Circulation 1999;100:1703–7. 14. Mattei LC, McKay U, Lepper MW, Soar J. Do nurses and physiotherapists require training to use an automated external defibrillator? Resuscitation 2002;53:277–80. 15. Starr LM, American College of Occupational and Environmental Medicine. Automated external defibrillation in the occupational setting. J Occup Environ Med 2002;44:2–7. 16. Report on a study on social system development to improve survival from emergency cardiovascular disease using automated external defibrillator (Marukawa’s report) [In Japanese; Accessed 05.07.10, at http://kouroukakenkyukyusosei.info/wpm/archivepdf/19/2 1 f.pdf]. 17. Kuramoto N, Morimoto T, Kubota Y, et al. Public perception of and willingness to perform bystander CPR in Japan. Resuscitation 2008;79:475– 81.