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Interventions to improve the quality of bystander cardiopulmonary resuscitation: A systematic review

  • Kuan-Yu Chen ,

    Contributed equally to this work with: Kuan-Yu Chen, Ying-Chih Ko

    Roles Conceptualization, Data curation, Formal analysis, Investigation, Methodology, Software, Writing – original draft

    Affiliation College of Medicine, National Taiwan University, Taipei, Taiwan

  • Ying-Chih Ko ,

    Contributed equally to this work with: Kuan-Yu Chen, Ying-Chih Ko

    Roles Investigation, Methodology

    Affiliation Department of Emergency Medicine, National Taiwan University Hospital, Taipei, Taiwan

  • Ming-Ju Hsieh ,

    Roles Conceptualization, Data curation, Formal analysis, Investigation, Methodology, Resources, Software, Writing – original draft, (MHM); (MH)

    ‡ These authors also contributed equally to this work.

    Affiliation Department of Emergency Medicine, National Taiwan University Hospital, Taipei, Taiwan

  • Wen-Chu Chiang,

    Roles Conceptualization, Resources, Software, Writing – review & editing

    Affiliation Department of Emergency Medicine, National Taiwan University Hospital Yun-Lin Branch, Yun-Lin County, Taiwan

  • Matthew Huei-Ming Ma

    Roles Conceptualization, Funding acquisition, Methodology, Resources, Software, Writing – review & editing, (MHM); (MH)

    ‡ These authors also contributed equally to this work.

    Affiliations College of Medicine, National Taiwan University, Taipei, Taiwan, Department of Emergency Medicine, National Taiwan University Hospital Yun-Lin Branch, Yun-Lin County, Taiwan



Performing high-quality bystander cardiopulmonary resuscitation (CPR) improves the clinical outcomes of victims with sudden cardiac arrest. Thus far, no systematic review has been performed to identify interventions associated with improved bystander CPR quality.


We searched Ovid MEDLINE, Ovid EMBASE, EBSCO CINAHL, Ovid PsycInfo, Thomson Reuters SCI-EXPANDED, and the Cochrane Central Register of Controlled Trials to retrieve studies published from 1 January 1966 to 5 October 2018 associated with interventions that could improve the quality of bystander CPR. Data regarding participant characteristics, interventions, and design and outcomes of included studies were extracted.


Of the initially identified 2,703 studies, 42 were included. Of these, 32 were randomized controlled trials. Participants included adults, high school students, and university students with non-medical professional majors. Interventions improving bystander CPR quality included telephone dispatcher-assisted CPR (DA-CPR) with simplified or more concrete instructions, compression-only CPR, and other on-scene interventions, such as four-hand CPR for elderly rescuers, kneel on opposite sides for two-person CPR, and CPR with heels for a tired rescuer. Devices providing real-time feedback and mobile devices containing CPR applications or software were also found to be beneficial in improving the quality of bystander CPR. However, using mobile devices for improving CPR quality or for assisting DA-CPR might cause rescuers to delay starting CPR.


To further improve the clinical outcomes of victims with cardiac arrest, these effective interventions may be included in the guidelines for bystander CPR.


Sudden cardiac arrest (SCA) poses a significant threat to our community in the industrialized world and is responsible for 420,000 and 275,000 deaths per year in the US and Europe, respectively [1,2]. It has been proved that bystander cardiopulmonary resuscitation (CPR) improves the survival rate of victims with SCA [3]. Therefore, numerous strategies have been implemented to increase the rate of bystander CPR. For example, many CPR training courses have been held to enable more laypersons to perform CPR because wider dissemination of CPR training might ultimately increase the rate of bystander CPR. Additionally, dispatcher-assisted CPR programs had also been shown to increase bystander CPR rates and the clinical outcomes of victims with SCA [4,5], and were recommended to be integrated into the system of care for prehospital cardiac arrest [68]. In addition to improving the rate of performing bystander CPR, the quality of CPR is also vital for the outcome of victims with SCA. High-quality CPR is associated with survival to emergency department arrival [9], survival to hospital admission [10], survival to hospital discharge [11,12], and favourable functional outcome [12]. To further improve the outcomes of victims with SCA, it is necessary to explore which interventions can improve the quality of bystander CPR. Therefore, the aim of our study was to perform a systematic review to identify interventions that could improve the quality of bystander CPR.

Materials and methods

Population, intervention, comparator and outcome question

We conducted a systematic review by using a predetermined protocol and reported it according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-analyses) guidelines [13]. The Population, Intervention, Comparator, Outcome (PICO) question of our study was: for laypersons who perform bystander CPR either in a real resuscitation situation or in a simulation setting (P), what interventions or methods except education (I), compared with no such interventions or methods (C), improved the quality of CPR (O)?

Eligibility criteria

To answer our PICO question, the inclusion criteria for our systematic review were as follows: (1) studies addressing the question “can the intervention improve the quality of bystander CPR?”; (2) studies that were randomized controlled trials (RCTs), quasi-experimental studies, before-and-after interventional studies, crossover studies, and prospective/retrospective observational studies; (3) studies that were published after 1966; (4) original articles, articles in press or short communications; (5) studies in which the participants were laypersons; (6) studies in which the setting was a real resuscitation situation or a simulation setting; (7) studies in which the outcome measures had at least one CPR quality parameter (the CPR quality parameters considered in this study were described below: chest compression depth, chest compression rate, number of chest compression, chest recoil, interruption time during CPR, ventilation volume, time to first compression/ventilation, and correct hand positioning); (8) studies focusing on the correlation between the intervention and bystander CPR quality; and (9) studies written in English.

The exclusion criteria were as follows: (1) conference abstracts or articles, reviews, editorials, erratum, letters, case studies, and case reports; (2) non-human studies; (3) studies in which the participants included both laypersons and non-laypersons; (4) studies that provided survival outcomes instead of CPR quality data, which were required for this review.

The layperson in our study was defined as an individual who did not work at a hospital. Therefore, we did not include studies whose participants were doctors, dentists, nurses, emergency medical technicians, and pharmacists. We also excluded studies in which the participants were students who majored in medical, nursing or associated medical professionals. In addition, studies in which participants whose duty is to save lives, such as lifeguards and first responders in a public place, were also excluded.

Information sources

We searched Ovid MEDLINE, Ovid EMBASE, EBSCO CINAHL, Ovid PsycInfo, Thomson Reuters SCI-EXPANDED, and the Cochrane Central Register of Controlled Trials (CENTRAL) to acquire studies, which could answer our PICO question. The time range was set from 1966 because 1966 was the year when the American Heart Association (AHA) published the first guidelines for CPR [14]. The last time we searched was 5 October, 2018. We also checked the reference lists of studies included for additional relevant articles.


Our search strategy consisted of three key concepts, including cardiac arrest, bystander/layperson, and the quality of CPR. Analogous terms for each were also used. A full search strategy is provided in S1 Table in Supplementary materials.

Study selection

Two reviewers (KYC and MJH) performed the database searching and screened out papers that were potentially relevant by reviewing titles and abstracts independently.

The article would receive full-text assessment if one of the reviewers determined that it was needed. If two reviewers had different opinions during the process of determining which article ought to be included in the final analysis, they reached an agreement after full discussion.

Data collection process and data items

After identifying the final papers included, we collected the data, using a standard data extraction form specifically adapted for this review. Extracted data included author(s), publication year, nation, identity of the participants, date of enrolment, study design, study group, outcome, evaluation methods, and funding sources.

The outcomes among studies varied considerably. The AHA 2015 guidelines recommended high-quality CPR required adequate chest compression depth (50–60 mm), adequate chest compression rate (100–120/min), full chest wall recoil, minimal pauses in chest compressions, correct hand position during compressions, and avoidance of hyperventilation [6]. In order to focus on the essential parameters of CPR quality which the guidelines recommended, we only extracted data on compression depth, chest compression rate, number of chest compressions, chest recoil, time of interruption, ventilation, time to first compression/ventilation, and correct hand positioning.

Risk of bias for individual studies

We used two tools to assess studies included. We used the “Cochrane Collaboration’s tool for assessing risk of bias” to assess the quality of studies for randomized controlled studies [15] and Newcastle-Ottawa Scale (NOS) for non-randomized controlled studies [16].


Study selection

After the initial database searching, a total of 4,524 records were retrieved. After removing 1,821 duplicates, 2,703 articles were screened by reviewing the titles and abstracts. We then found 152 potentially relevant articles. After we reviewed the full text of these articles and reached an agreement between the two reviewers, 42 articles were finally included in our study [1758]. The reasons for exclusion included papers that were not in English (9), review articles (19), those included participants who were not laypersons (37), publication types that do not meet the inclusion criteria (26), and those articles with outcomes which were not CPR quality parameters considered in this study (19). The flow diagram of the articles included is shown in Fig 1. The different study designs, interventions and types of data presentations in included articles precluded further meta-analysis. For example, the authors tried to evaluate whether changing some instructional content of telephone dispatcher-assisted CPR would improve bystander CPR quality in some included studies, but those changes were different among studies [22,26,27,3335,37,40,41,52]. In other studies, the authors tried to compare the effect of compression-only CPR with that of conventional CPR on bystander CPR quality, but they presented different types of outcome data [18,25,32]. Therefore, a narrative review was performed instead.

Fig 1. Flow diagram of included studies.

From: Moher D, Liberati A, Tetzlaff J, Altman DG, The PRISMA Group (2009). Preferred Reporting Iterns for Systematic Reviews and Meta-Analyses: The PRISMA Statement. PLoS Med 6(6): e1000097. doi:10.1371/journal.pmed1000097. For more information, visit

Characteristics and risk of bias of included studies

The characteristics and outcomes of studies included are shown in Table 1. More detailed information about characteristics and outcomes of included studies are also shown in S2 and S3 Tables in Supplementary materials. Among 42 studies included, 32 were RCTs, 6 studies [18,36,45,54,55,57] were randomized crossover controlled trials and 4 studies [24,48,49,53] were non-randomized studies. There were 13 studies conducted in North America [18,2224,34,35,37,40,44,49,52,53,58], 19 in Europe [17,2527,2931,33,38,39,4143,45,46,48,51,55,57], and 10 in the Asia-Pacific region [1921,28,32,36,47,50,54,56]. The years of publication ranged from 1989 to 2018. Twelve studies only included participants who did not receive any CPR training previously [17,21,23,25,36,39,43,44,45,50,51,56]. The methods to evaluate CPR quality included on-scene evaluation by evaluators, observation of the video by evaluators after studies were completed, or the data acquired from the manikins with software, which could record the CPR performance of the participants.

Table 1. The characteristics and outcomes of included studies.

All RCTs had a high risk of bias in blinding of the participants and personnel. Blinding of outcome assessment was rated high risk in 13 studies because the measurement included video recording review [17,18,20,23,2729,33,39,43,5052]. Among non-RCT studies, 3 studies earned full points of 9 [24,49,53]. Tables 2 and 3 show the risk of bias for included studies.

Table 3. Quality assessment using Newcastle-Ottawa Scale.

Results of the individual studies

We grouped the interventions of studies included into three groups: (A) modifications to dispatcher-assisted CPR (DA-CPR), (B) Different methods to perform CPR, and (C) additional aids to bystander CPR. The summary of interventions in studies included is shown in Table 4.

Table 4. Summary of interventions for the quality of bystander cardiopulmonary resuscitation in the included studies.

(A) Modifications to dispatcher-assisted CPR.

There were seventeen studies where the intervention was related to modifications to DA-CPR [17,2022,2628,3335,37,3941,46,50,52]. The interventions are described below.

Modified telephone DA-CPR instructions. There were ten studies that employed interventions of modified telephone DA-CPR instructions [22,26,27,3335,37,40,41,52]. Among them, seven studies found that the interventions improved the quality of CPR or shorten time to start chest compressions [27,33,34,37,40,41,52]. These interventions included adding instructions with speakerphone activation, removing obstacles, and continuous instruction during CPR [27], simplified compressions-only CPR instructions [34,40], instruction to “push hard as you can” for adult with cardiac arrest [37], modified instruction using arm and nipple line [41], eliminating the instruction to remove the victim’s clothing [52], and a novel instructional protocol with changing instructional content of hand position, compression depth and compression rate at the same time [33].

The other three studies showed no significant improvement in the quality of CPR, including the added instruction of “put the phone down” [22], repeated or intensified wording to remind or emphasize the importance of chest compression depth [26], and for paediatric CPR using “push as hard as you can.” [35]

Video-assisted DA-CPR. Six studies discussed whether video-assisted DA-CPR improved CPR quality when compared to telephone DA-CPR [17,20,28,39,46,50]. Among those, five studies used video-conferencing DA-CPR [17,20,28,39,46] and one study asked the participants to watch a video on cellular phone when performing CPR [50]. The comparison between video-assisted and telephone DA-CPR for different components of CPR quality in studies is shown in Table 5.

Table 5. The comparison between video-assisted and telephone DA-CPR for different components of CPR quality in 6 studies.

The conclusions of five studies were in favor of video-assisted DA-CPR [17,20,28,39,50]. Only one study demonstrated video communication was unlikely to improve telephone CPR significantly [46]. However, three studies showed that video-conferencing DA-CPR has increased time to first chest compression/rescuer breathing when compared to audio-assisted DA-CPR [20,28,39]. The other two studies had the opposite result, showing that video-conferencing DA-CPR did not have significantly longer time to first chest compression [17,46]. One study in which the participants watched a video on cellular phone during CPR had a shorter time starting chest compression when compared with audio-assisted DA-CPR [50]. Among the six studies, video-assisted DA-CPR is superior to, at least equivalent to telephone DA-CPR on the performance of correct chest compression depth, correct chest compression rate and correct hand position (Table 5).

Playing metronome sounds to the rescuer. In one study, metronome sounds were played to the rescuers through their mobile phone when performing DA-CPR, and it showed no improvement in the overall CPR quality even though it improved the chest compression rates [21], but was associated more with shallow compressions than the conventional telephone dispatcher-assisted compression-only CPR. Another study showed the rescuers receiving emergency medical dispatchers’ instructions with metronome assistance performed better with correct compression rate than those receiving instructions without metronome assistance [58]. However, the compression depth tended to be shallower under metronome assistance.

(B) Different methods of performing CPR.

There were nine studies comparing different methods of performing CPR [18,24,25,30,32,36,42,44,47].

Compression-only CPR vs. conventional CPR. There were five studies comparing the quality of CPR between compression-only CPR and conventional CPR with compression: breath ratio as 30:2 [18,25,32,42,44]. All of these studies showed that compression-only CPR had better CPR quality than the conventional CPR since compression-only CPR got more chest compressions, less hands-off time, and less time to first compression. However, two studies pointed out that chest compressions with appropriate depth decreased more rapidly in groups with compression-only CPR than those with conventional CPR due to increased physical fatigue [18,32]. A study performed in Japan even found that appropriate chest compression depth decreased significantly one minute after starting compression-only CPR [32]. On the other hand, two studies performed in the UK and Norway showed no difference in CPR-related exhaustion between the compression-only CPR group and the conventional CPR group during the 10-minute test [25,42], and one study performed in the United States also revealed no difference in perceived fatigue in both groups after performing CPR for 3-minutes [44].

Dominant vs. non-dominant hands. One study explored whether there were any differences in CPR quality when laypersons compressed the victim’s chest with their dominant or non-dominant hand against the chest wall [36]. This study demonstrated that, although there was a trend towards increased incidence of correct chest compressions when the dominant hand was positioned in contact with the sternum, it did not have statistical significance for a 5-minute-long CPR session.

Opposite sides vs. the same side. One study compared CPR quality between two rescuers being on the same side and being on the opposite sides in a two-rescuer situation [47]. The study showed that changing compression from the opposite sides reduced hands-off time compared to changing on the same side in prehospital hands-only CPR provided by two bystanders. The other parameters such as CPR quality were similar between the two groups.

Four hands vs. two hands. One study compared the quality of four-hand CPR to that of a two-hand CPR [30]. The study showed that four-hand chest compression during the simulated DA-CPR significantly improved the chest compression depth without affecting the compression rate among older female rescuers.

Heels vs. hands. One study compared the quality of CPR when chest compressions were applied with heels or hands [24]. The study results showed significantly more compressions meeting guidelines and fewer compressions without adequate depth in the heel group. The study concluded that heel compressions were useful in situations where a lone rescuer could not get down on the floor, could not compress the chest to adequate depth because of an infirmity or lack of weight, or when the rescuer became too tired to continue manual compressions.

(C) Additional aids to bystander CPR.

There were twelve studies related to additional aids to bystander CPR [19,23,29,31,38,42,43,45,48,49,51,53].

Telephone DA-CPR. There were five studies including telephone DA-CPR intervention [23,29,31,48,49]. Three of them were RCTs [23,29,31]. All of them demonstrated telephone DA-CPR improved the overall quality of CPR. One study showed that dispatcher-assisted compression-only CPR had better CPR quality than dispatcher-assisted conventional 30:2 CPR [31]. Another non-RCT showed that participants with CPR training before receiving telephone instructions had better CPR performance than those without CPR training before receiving the same telephone instructions [49].

Simple basic life support flowchart. One study demonstrated that the quality of bystander CPR could be improved significantly by a simple basic life support (BLS) flowchart offered to the rescuer [51].

Assistance via mobile phone. One study demonstrated that the BLS software program on a mobile phone, which had a metronome function, contributed to a better overall performance [43]. Nevertheless, participants with the mobile program took a longer time to call the dispatch centre and to start chest compressions. Another study showed that the newly-developed CPR support application (app) for smartphones resulted in an increased number of total chest compressions performed [19]. However, the participants with the new app delayed starting compressions or ventilations.

Assistance via real-time feedback device. Certain kinds of real-time feedback devices for CPR performance improved the quality of bystander CPR in seven studies. One study showed that the group with visual real-time feedback from PC Skillreporter performed more compressions and had a higher rate of chest compression with less hands-off time when compared with those without such feedback [42]. One study revealed that the group with visual real-time feedback from CPR meter, a device put between the victim’s chest and the rescuer’s hands when performing CPR, significantly improved chest compression quality [45]. Another study showed that, with feedback on compression rate from the test device, the rescuer could perform higher quality of CPR with higher compression rate and without compromising compression depth [38]. The other 4 studies also found that real-time feedback devices improved the quality of bystander CPR in a simulation setting [5457].

Usage of M730 (a pneumatically powered transport ventilator). One study showed that M730 ventilator yielded better ventilation quality than bag-valve mask, resulting in lower delivered airway flow rate, lower airway pressure and lower volume of gas entering the stomach per breath [53].


Our review showed that telephone DA-CPR seemed to improve the overall quality of bystander CPR. Further studies revealed that telephone DA-CPR with simplified or more concrete instructional protocols might further improve the quality of bystander CPR. It suggested that more efforts might be needed in the future not only for dispatchers to identify patients with cardiac arrest and instruct the bystander to perform CPR, but also to build up an effective instructional protocol to let bystanders perform high-quality CPR. Including effective on-scene interventions into instructional protocols, such as four-hand CPR for elderly rescuers, kneel on opposite sides for two-person CPR, and CPR with heels for a tired rescuer, could improve the overall quality of CPR. In addition, it had been shown that, among participants who received the same telephone instruction, the participants receiving CPR training before had better CPR performance than those without receiving any CPR training [49]. It seemed that prior CPR education and telephone DA-CPR had a synergistic effect on the quality of bystander CPR. Therefore, to improve the survival of victims with SCA by improving the quality of bystander CPR, the importance of CPR education and the effective strategy of telephone DA-CPR should be emphasized to the community. More people who receive CPR training would improve the overall quality of bystander CPR. It could translate into better outcomes for patients with out-of-hospital cardiac arrest if an effective, evidence-based protocol of telephone DA-CPR is implemented in the community.

Although dispatcher-used video devices, including mobile phones, can be used to communicate with bystanders to improve some parameters of CPR quality, it is crucial to make the rescuer to perform CPR as fast as possible. Some studies revealed that video-assisted DA-CPR had more time starting chest compression or rescue breathing than audio-assisted DA-CPR. The increased non-flow time might compromise the clinical outcomes of patients with SCA. Further studies on video-assisted DA-CPR are needed to overcome this problem.

It is also worth noting that additional assistance from electronic devices has been shown to improve the quality of bystander CPR. Various electronic devices with apps and software are currently being developed. These devices could provide readily available instructions, sensing and feedback, which might improve the quality of bystander CPR. However, using such mobile devices also caused rescuers to delay starting chest compressions or ventilations in some studies [19,43]. An app or software on mobile devices with clear and easy-to-understand content that can be activated easily is helpful for rescuers to start CPR quickly.

Our study also revealed that compression-only CPR had better CPR quality and less time spent starting chest compression compared with conventional CPR. It has been shown that, by skipping the breathing part, compression-only CPR not only increased the compression rate of bystander CPR, but also improved the clinical outcomes of adult victims [59]. Additionally, one study showed that the quality of dispatcher-assisted compression-only CPR was better than that of dispatcher-assisted conventional CPR [31]. It was also recommended that dispatchers should provide compression-only CPR instructions to callers for adults with suspected out-of-hospital cardiac arrest by the guidelines of International Liaison Committee of Resuscitation, European Resuscitation Council and American Heart Association [68]. However, some studies pointed out the possibility of compression-only CPR exhausting the first rescuer quickly and compromising the quality of CPR before the medical personnel arrived [32,60]. In our review, there were different results among studies about whether compression-only CPR exhausted rescuers more quickly. One study showed that the quality of chest compressions rapidly declined in compression-only CPR when compared with performing conventional CPR for only one minute [32]. Another study involving elderly volunteers also showed that the conventional CPR group had significantly more adequate depth of chest compressions than the compression-only CPR group one minute after starting CPR [60]. However, other studies revealed no differences between the two methods [25,42,44]. The different results hinted that compression-only CPR might cause rescuers with less muscle strength, low body weight or older age to become fatigued quickly [61]. These types of rescuers may change their roles sooner than every 2 minutes to maintain the quality of chest compressions during compression-only CPR if there are two or more bystanders at the scene.

In our study, we only included studies whose participants were laypersons. Although medical personnel might also be at the scene of the event of a cardiac arrest and perform bystander CPR, most of the cardiac arrest events happened outside health care institutions, and it is reasonable to assume that bystander CPR was performed by laypersons in most cases. Hence, we only selected laypersons in our study. In addition, the interventions found to be effective in improving the quality of CPR performed by laypersons could reasonably be speculated to improve of the quality of CPR performed by the medical personnel.

From our review, strategies to improve the quality of bystander CPR were proposed as follows. Telephone DA-CPR with effective, evidence-based instructions to instruct callers to perform chest compression-only CPR for adults with SCA may be implemented first. If only one rescuer performs CPR on the scene and feels tired, CPR with heels may be suggested. If more than one rescuer performs CPR, a second rescuer is suggested on the opposite side of the first rescuer. The rescuers with less muscle strength, low body weight or older age may change their roles sooner than every 2 minutes. Four-hand CPR may be suggested to elderly rescuers. Real-time feedback devices are considered to be used during CPR if available. Easy-to-understand information about how to perform high-quality CPR via mobile devices may be provided to rescuers immediately. Finally, before dispatchers use video devices, such as mobile phones, to communicate to rescuers, a simplified communication protocol to minimize time to start resuscitation should be designed and proved effective first.

In our study, we did not perform meta-analysis due to high inconsistencies among included studies in study designs, interventions and types of data presentations. Therefore, our study cannot report any conclusive results and can only give a clue about that what interventions might be helpful in improving bystander CPR quality. Further evaluation will be needed before an intervention is implemented in a community.


There were some limitations in our study. First, during our search for studies on interventions which could improve the quality of bystander CPR, we could not find a study performed in a real-life resuscitation situation. Whether such interventions associated with higher quality of bystander CPR could be translated to better victims’ outcomes remained unknown. However, several studies have already shown that high-quality CPR could be translated to good outcomes for the victims [912]. Second, the inconsistencies in CPR quality measurement among studies were high. There were different parameters that were recorded in studies included, and how the researchers measured CPR quality was also different. In addition, there were inherent biases when the instructors assessed CPR performance when using video recordings or checklists by visual assessment [62]. Yet, we extracted the most commonly recognized parameters in CPR quality measurement [63]. Finally, we found that all of studies included had a high risk of bias in the blinding of participants and personnel while performing risk of bias assessment. Because the participants knew the interventions they were performing during evaluation, it might have affected their self-confidence somewhat, influencing CPR performance. This might be another cause for some bias.


In our systematic review, telephone DA-CPR with simplified or more concrete instructional protocols was shown to improve the quality of bystander CPR. Compression-only CPR and other on-scene interventions also seemed to improve CPR quality. Devices providing real-time feedback and mobile devices containing a CPR app or software were also found to be beneficial to CPR quality. However, using mobile devices for improving CPR quality or for assisting DA-CPR might cause rescuers to spend more time starting CPR. Additional efforts are needed to build up an effective protocol to organize these interventions to improve bystander CPR quality, further improving the clinical outcomes of cardiac arrest victims.

Supporting information

S2 Table. Detailed characteristics of included studies.


S3 Table. Detailed outcomes of the included studies.


S4 Table. The PRISMA checklist of our study.



We acknowledge the statistical assistance provided by the Taiwan Clinical Trial Bioinformatics and Statistical Center, Training Center, and Pharmacogenomics Laboratory; and the Department of Medical Research of National Taiwan University Hospital.


  1. 1. Go AS, Mozaffarian D, Roger VL, Benjamin EJ, Berry JD, Blaha MJ, et al. Heart disease and stroke statistics—2014 update: a report from the American Heart Association. Circulation 2014;129:e28–292. pmid:24352519
  2. 2. Atwood C, Eisenberg MS, Herlitz J, Rea TD. Incidence of EMS-treated out-of-hospital cardiac arrest in Europe. Resuscitation 2005;67:75–80. pmid:16199289
  3. 3. Van Hoeyweghen RJ, Bossaert LL, Mullie A, Calle P, Martens P, Buylaert WA, et al. Quality and efficiency of bystander CPR. Belgian Cerebral Resuscitation Study Group. Resuscitation 1993;26:47–52. pmid:8210731
  4. 4. Rea TD, Eisenberg MS, Culley LL, Becker L. Dispatcher-assisted cardiopulmonary resuscitation and survival in cardiac arrest. Circulation 2001;104:2513–6. pmid:11714643
  5. 5. Stiell I, Nichol G, Wells G, De Maio V, Nesbitt L, Blackburn J, et al. Health-related quality of life is better for cardiac arrest survivors who received citizen cardiopulmonary resuscitation. Circulation 2003;108:1939–44. pmid:14530198
  6. 6. Perkins GD, Travers AH, Berg RA, Castren M, Considine J, Escalante R, et al. Part 3: Adult basic life support and automated external defibrillation: 2015 International Consensus on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science with Treatment Recommendations. Resuscitation 2015;95:e43–69. pmid:26477428
  7. 7. Monsieurs KG, Nolan JP, Bossaert LL, Greif R, Maconochie IK, Nikolaou NI, et al. European Resuscitation Council Guidelines for Resuscitation 2015: Section 1. Executive summary. Resuscitation 2015;95:1–80. pmid:26477410
  8. 8. Kronick SL, Kurz MC, Lin S, Edelson DP, Berg RA, Billi JE, et al. Part 4: Systems of Care and Continuous Quality Improvement: 2015 American Heart Association Guidelines Update for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care. Circulation 2015;132:S397–413. pmid:26472992
  9. 9. Bohn A, Weber TP, Wecker S, Harding U, Osada N, Van Aken H, et al. The addition of voice prompts to audiovisual feedback and debriefing does not modify CPR quality or outcomes in out of hospital cardiac arrest—a prospective, randomized trial. Resuscitation 2011;82:257–62. pmid:21146279
  10. 10. Kramer-Johansen J, Myklebust H, Wik L, Fellows B, Svensson L, Sørebø H, et al. Quality of out-of-hospital cardiopulmonary resuscitation with real time automated feedback: a prospective interventional study. Resuscitation 2006;71:283–92. pmid:17070980
  11. 11. Stiell IG, Brown SP, Nichol G, Cheskes S, Vaillancourt C, Callaway CW, et al. What is the optimal chest compression depth during out-of-hospital cardiac arrest resuscitation of adult patients? Circulation 2014;130:1962–70. pmid:25252721
  12. 12. Vadeboncoeur T, Stolz U, Panchal A, Silver A, Venuti M, Tobin J, et al. Chest compression depth and survival in out-of-hospital cardiac arrest. Resuscitation 2014;85:182–8. pmid:24125742
  13. 13. Moher D, Liberati A, Tetzlaff J, Altman DG; PRISMA Group. Preferred reporting items for systematic reviews and meta-analyses: the PRISMA statement. BMJ 2009;339:b2535. pmid:19622551
  14. 14. Cardiopulmonary resuscitation: Statement by the ad hoc committee on cardiopulmonary resuscitation of the division of medical sciences, national academy of sciences—national research council. JAMA 1966;198:372–9.
  15. 15. Deeks JJ, Higgins JPT, Altman DG. Assessing risk of bias in included studies. In: Higgins JPT, Green S, editors. Cochrane handbook for systematic reviews of interventions. Chichester, UK: John Wiley & Sons; 2009.
  16. 16. Stang A. Critical evaluation of the Newcastle-Ottawa scale for the assessment of the quality of nonrandomized studies in meta-analyses. Eur J Epidemiol 2010;25:603–5. pmid:20652370
  17. 17. Atkinson PR, Bingham J, McNicholl BP, Loane MA, Wootton R. Telemedicine and cardiopulmonary resuscitation: the value of video-link and telephone instruction to a mock bystander. J Telemed Telecare 1999;5:242–5. pmid:10829375
  18. 18. Liu S, Vaillancourt C, Kasaboski A, Taljaard M. Bystander fatigue and CPR quality by older bystanders: a randomized crossover trial comparing continuous chest compressions and 30:2 compressions to ventilations. CJEM 2016;18:461–8. pmid:27650514
  19. 19. Sakai T, Kitamura T, Nishiyama C, Murakami Y, Ando M, Kawamura T, et al. Cardiopulmonary resuscitation support application on a smartphone—randomized controlled trial. Circ J 2015;79:1052–7. pmid:25740350
  20. 20. Yang CW, Wang HC, Chiang WC, Hsu CW, Chang WT, Yen ZS, et al. Interactive video instruction improves the quality of dispatcher-assisted chest compression-only cardiopulmonary resuscitation in simulated cardiac arrests. Crit Care Med 2009;37:490–5. pmid:19114904
  21. 21. Park SO, Hong CK, Shin DH, Lee JH, Hwang SY. Efficacy of metronome sound guidance via a phone speaker during dispatcher-assisted compression-only cardiopulmonary resuscitation by an untrained layperson: a randomised controlled simulation study using a manikin. Emerg Med J 2013;30:657–61. pmid:23018287
  22. 22. Brown TB, Saini D, Pepper T, Mirza M, Nandigam HK, Kaza N, et al. Instructions to "put the phone down" do not improve the quality of bystander initiated dispatcher-assisted cardiopulmonary resuscitation. Resuscitation 2008;76:249–55. pmid:17804145
  23. 23. Merchant RM, Abella BS, Abotsi EJ, Smith TM, Long JA, Trudeau ME, et al. Cell phone cardiopulmonary resuscitation: audio instructions when needed by lay rescuers: a randomized, controlled trial. Ann Emerg Med 2010;55:538–43. pmid:20202719
  24. 24. Trenkamp RH, Perez FJ. Heel compressions quadruple the number of bystanders who can perform chest compressions for 10 minutes. Am J Emerg Med 2015;33:1449–53. pmid:26298049
  25. 25. Woollard M, Smith A, Whitfield R, Chamberlain D, West R, Newcombe R, et al. To blow or not to blow: a randomised controlled trial of compression-only and standard telephone CPR instructions in simulated cardiac arrest. Resuscitation 2003;59:123–31. pmid:14580743
  26. 26. van Tulder R, Roth D, Krammel M, Laggner R, Heidinger B, Kienbacher C, et al. Effects of repetitive or intensified instructions in telephone assisted, bystander cardiopulmonary resuscitation: an investigator-blinded, 4-armed, randomized, factorial simulation trial. Resuscitation 2014;85:112–8. pmid:24012684
  27. 27. Birkenes TS, Myklebust H, Neset A, Kramer-Johansen J. Quality of CPR performed by trained bystanders with optimized pre-arrival instructions. Resuscitation 2014;85:124–30. pmid:24096105
  28. 28. Yang CW, Wang HC, Chiang WC, Chang WT, Yen ZS, Chen SY, et al. Impact of adding video communication to dispatch instructions on the quality of rescue breathing in simulated cardiac arrests—a randomized controlled study. Resuscitation 2008;78:327–32. pmid:18583016
  29. 29. Ghuysen A, Collas D, Stipulante S, Donneau AF, Hartstein G, Hosmans T, et al. Dispatcher-assisted telephone cardiopulmonary resuscitation using a French-language compression-only protocol in volunteers with or without prior life support training: A randomized trial. Resuscitation 2011;82:57–63. pmid:21036454
  30. 30. Krikscionaitiene A, Dambrauskas Z, Barron T, Vaitkaitiene E, Vaitkaitis D. Are two or four hands needed for elderly female bystanders to achieve the required chest compression depth during dispatcher-assisted CPR: a randomized controlled trial. Scand J Trauma Resusc Emerg Med 2016;24:47. pmid:27067836
  31. 31. Spelten O, Warnecke T, Wetsch WA, Schier R, Böttiger BW, Hinkelbein J. Dispatcher-assisted compression-only cardiopulmonary resuscitation provides best quality cardiopulmonary resuscitation by laypersons: A randomised controlled single-blinded manikin trial. Eur J Anaesthesiol 2016;33:575–80. pmid:26908002
  32. 32. Nishiyama C, Iwami T, Kawamura T, Ando M, Yonemoto N, Hiraide A, et al. Quality of chest compressions during continuous CPR; comparison between chest compression-only CPR and conventional CPR. Resuscitation 2010;81:1152–5. pmid:20732607
  33. 33. Rasmussen SE, Nebsbjerg MA, Krogh LQ, Bjørnshave K, Krogh K, Povlsen JA, et al. A novel protocol for dispatcher assisted CPR improves CPR quality and motivation among rescuers-A randomized controlled simulation study. Resuscitation 2017;110:74–80. pmid:27658651
  34. 34. Dias JA, Brown TB, Saini D, Shah RC, Cofield SS, Waterbor JW, et al. Simplified dispatch-assisted CPR instructions outperform standard protocol. Resuscitation 2007;72:108–14. pmid:17123687
  35. 35. Rodriguez SA, Sutton RM, Berg MD, Nishisaki A, Maltese M, Meaney PA, et al. Simplified dispatcher instructions improve bystander chest compression quality during simulated pediatric resuscitation. Resuscitation 2014;85:119–23. pmid:24036408
  36. 36. Nikandish R, Shahbazi S, Golabi S, Beygi N. Role of dominant versus non-dominant hand position during uninterrupted chest compression CPR by novice rescuers: a randomized double-blind crossover study. Resuscitation 2008;76:256–60. pmid:17822829
  37. 37. Mirza M, Brown TB, Saini D, Pepper TL, Nandigam HK, Kaza N, et al. Instructions to "push as hard as you can" improve average chest compression depth in dispatcher-assisted cardiopulmonary resuscitation. Resuscitation 2008;79:97–102. pmid:18635306
  38. 38. Torney H, O’Hare P, Davis L, Delafont B, Bond R, McReynolds H, et al. A usability study of a critical man-machine interface: can layperson responders perform optimal compression rates when using a public access defibrillator with automated real-time feedback during cardiopulmonary resuscitation? IEEE T Hum-Mach Syst 2016;46:749–54.
  39. 39. Stipulante S, Delfosse AS, Donneau AF, Hartsein G, Haus S, D’Orio V, et al. Interactive videoconferencing versus audio telephone calls for dispatcher-assisted cardiopulmonary resuscitation using the ALERT algorithm: a randomized trial. Eur J Emerg Med 2016;23:418–24. pmid:26485693
  40. 40. Painter I, Chavez DE, Ike BR, Yip MP, Tu SP, Bradley SM, et al. Changes to DA-CPR instructions: can we reduce time to first compression and improve quality of bystander CPR? Resuscitation 2014;85:1169–73. pmid:24864063
  41. 41. Birkenes TS, Myklebust H, Kramer-Johansen J. New pre-arrival instructions can avoid abdominal hand placement for chest compressions. Scand J Trauma Resusc Emerg Med 2013;21:47. pmid:23799963
  42. 42. Neset A, Birkenes TS, Myklebust H, Mykletun RJ, Odegaard S, Kramer-Johansen J. A randomized trial of the capability of elderly lay persons to perform chest compression only CPR versus standard 30:2 CPR. Resuscitation 2010;81:887–92. pmid:20418006
  43. 43. Paal P, Pircher I, Baur T, Gruber E, Strasak AM, Herff H, et al. Mobile phone-assisted basic life support augmented with a metronome. J Emerg Med 2012;43:472–7. pmid:22257600
  44. 44. Williams JG, Brice JH, De Maio VJ, Jalbuena T. A simulation trial of traditional dispatcher-assisted CPR versus compressions—only dispatcher-assisted CPR. Prehosp Emerg Care 2006;10:247–53. pmid:16531384
  45. 45. Buléon C, Parienti JJ, Halbout L, Arrot X, De Facq Régent H, Chelarescu D, et al. Improvement in chest compression quality using a feedback device (CPRmeter): a simulation randomized crossover study. Am J Emerg Med 2013;31:1457–61. pmid:24035507
  46. 46. Bolle SR, Scholl J, Gilbert M. Can video mobile phones improve CPR quality when used for dispatcher assistance during simulated cardiac arrest? Acta Anaesthesiol Scand 2009;53:116–20. pmid:19032569
  47. 47. Kim YH, Lee JH, Lee DW, Cho KW, Kang MJ, Kim YW, et al. Differences in hands-off time according to the position of a second rescuer when switching compression in pre-hospital cardiopulmonary resuscitation provided by two bystanders: a randomized, controlled, parallel study. J Korean Med Sci 2015;30:1347–53. pmid:26339178
  48. 48. Birkenes TS, Myklebust H, Neset A, Olasveengen TM, Kramer-Johansen J. Video analysis of dispatcher-rescuer teamwork-Effects on CPR technique and performance. Resuscitation 2012;83:494–9. pmid:21982923
  49. 49. Kellermann AL, Hackman BB, Somes G. Dispatcher-assisted cardiopulmonary resuscitation. Validation of efficacy. Circulation 1989;80:1231–9. pmid:2805260
  50. 50. Lee JS, Jeon WC, Ahn JH, Cho YJ, Jung YS, Kim GW. The effect of a cellular-phone video demonstration to improve the quality of dispatcher-assisted chest compression-only cardiopulmonary resuscitation as compared with audio coaching. Resuscitation 2011;82:64–8. pmid:21036457
  51. 51. Rössler B, Ziegler M, Hüpfl M, Fleischhackl R, Krychtiuk KA, Schebesta K. Can a flowchart improve the quality of bystander cardiopulmonary resuscitation? Resuscitation 2013;84:982–6. pmid:23306815
  52. 52. Eisenberg Chavez D, Meischke H, Painter I, Rea TD. Should dispatchers instruct lay bystanders to undress patients before performing CPR? A randomized simulation study. Resuscitation 2013;84:979–81. pmid:23261884
  53. 53. Hurst V 4th, West S, Austin P, Branson R, Beck G. Comparison of ventilation and chest compression performance by bystanders using the Impact Model 730 ventilator and a conventional bag valve with mask in a model of adult cardiopulmonary arrest. Resuscitation 2007;73:123–30. pmid:17175090
  54. 54. White AE, Ng HX, Ng WY, Ng EK, Fook-Chong S, Kua PH, et al. Measuring the effectiveness of a novel CPRcard feedback device during simulated chest compressions by non-healthcare workers. Singapore Med J 2017;58:438–45. pmid:28741006
  55. 55. Wutzler A, von Ulmenstein S, Bannehr M, Völk K, Förster J, Storm C, et al. Improvement of lay rescuer chest compressions with a novel audiovisual feedback device: A randomized trial. Med Klin Intensivmed Notfmed 2018;113:124–30. pmid:28378150
  56. 56. Liu Y, Huang Z, Li H, Zheng G, Ling Q, Tang W, et al. CPR feedback/prompt device improves the quality of hands-only CPR performed in manikin by laypersons following the 2015 AHA guidelines. Am J Emerg Med 2018;36:1980–5. pmid:29525478
  57. 57. Eaton G, Renshaw J, Gregory P, Kilner T. Can the British Heart Foundation PocketCPR application improve the performance of chest compressions during bystander resuscitation: A randomised crossover manikin study. Health Informatics J 2018;24:14–23. pmid:27402135
  58. 58. Scott G, Barron T, Gardett I, Broadbent M, Downs H, Devey L, et al. Can a Software-Based Metronome Tool Enhance Compression Rate in a Realistic 911 Call Scenario Without Adversely Impacting Compression Depth for Dispatcher-Assisted CPR? Prehosp Disaster Med 2018;33:399–405. pmid:30033904
  59. 59. Cabrini L, Biondi-Zoccai G, Landoni G, Greco M, Vinciguerra F, Greco T, et al. Bystander-initiated chest compression-only CPR is better than standard CPR in out-of-hospital cardiac arrest. HSR Proc Intensive Care Cardiovasc Anesth 2010;2:279–85. pmid:23439400
  60. 60. Heidenreich JW, Bonner A, Sanders AB. Rescuer fatigue in the elderly: standard vs. hands-only CPR. J Emerg Med 2012;42:88–92. pmid:20634016
  61. 61. López-González A, Sánchez-López M, Garcia-Hermoso A, López-Tendero J, Rabanales-Sotos J, Martínez-Vizcaíno V. Muscular fitness as a mediator of quality cardiopulmonary resuscitation. Am J Emerg Med 2016;34:1845–9. pmid:27344099
  62. 62. Jones A, Lin Y, Nettel-Aguirre A, Gilfoyle E, Cheng A. Visual assessment of CPR quality during pediatric cardiac arrest: does point of view matter? Resuscitation 2015;90:50–5. pmid:25727057
  63. 63. Neumar RW, Shuster M, Callaway CW, Gent LM, Atkins DL, Bhanji F, et al. Part 1: Executive Summary: 2015 American Heart Association Guidelines Update for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care. Circulation 2015;132:S315–67. pmid:26472989