Effects of repetitive or intensified instructions in telephone assisted, bystander cardiopulmonary resuscitation: An investigator-blinded, 4-armed, randomized, factorial simulation trial

doi:10.1016/j.resuscitation.2013.08.010

Resuscitation

Volume 85, Issue 1, January 2014, Pages 112-118

https://doi.org/10.1016/j.resuscitation.2013.08.010 Get rights and content

Abstract

Background

Compression depth is frequently suboptimal in cardiopulmonary resuscitation (CPR). We investigated effects of intensified wording and/or repetitive target depth instructions on compression depth in telephone-assisted, protocol driven, bystander CPR on a simulation manikin.

Methods

Thirty-two volunteers performed 10 min of compression only-CPR in a prospective, investigator-blinded, 4-armed, factorial setting. Participants were randomized either to standard wording (“push down firmly 5 cm”), intensified wording (“it is very important to push down 5 cm every time”) or standard or intensified wording repeated every 20 s. Three dispatchers were randomized to give these instructions. Primary outcome was relative compression depth (absolute compression depth minus leaning depth). Secondary outcomes were absolute distance, hands-off times as well as BORG-scale and nine-hole peg test (NHPT), pulse rate and blood pressure to reflect physical exertion. We applied a random effects linear regression model.

Results

Relative compression depth was 35 ± 10 mm (standard) versus 31 ± 11 mm (intensified wording) versus 25 ± 8 mm (repeated standard) and 31 ± 14 mm (repeated intensified wording).

Adjusted for design, body mass index and female sex, intensified wording and repetition led to decreased compression depth of 13 (95%CI −25to −1) mm (p = 0.04) and 9 (95%CI −21 to 3) mm (p = 0.13), respectively. Secondary outcomes regarding intensified wording showed significant differences for absolute distance (43 ± 2 versus 20 (95%CI 3–37) mm; p = 0.01) and hands-off times (60 ± 40 versus 157 (95%CI 63–251) s; p = 0.04).

Conclusion

In protocol driven, telephone-assisted, bystander CPR, intensified wording and/or repetitive target depth instruction will not improve compression depth compared to the standard instruction.

Introduction

Telephone-assisted, bystander cardiopulmonary resuscitation (CPR) has received more and more attention in resuscitation research since it has been recognized as the anchor link of the chain of survival.¹ The importance has been underlined by a scientific statement of the American Heart Association (AHA)² and also by the European Resuscitation Council (ERC) guidelines 2010 on CPR³ encouraging dispatchers to provide verbal prompts for bystanders faced with a cardiac arrest victim. Several studies have shown the benefit of the so-called dispatch assisted life support on outcome of out-of hospital cardiac arrest (OOHCA).4, 5, 6 However, quality of chest compressions remains of specific concern as favourable (neurological) outcome is essentially linked to compression depth.⁷ Therefore, considerable research is undertaken to improve compression depth not only in telephone CPR.

Currently, for protocol driven telephone-assisted, bystander CPR the medical priority dispatch system (MPDS^®) provided by the International Academy of Emergency Dispatch (IAED – Salt Lake City, UT, USA) is used in 2855 dispatch centres of 43 countries worldwide. According to the AHA guideline on CPR it advises to “push down firmly 5 cm”.

By now, it is unknown whether this or another phrase is appropriate to transport the essential information to achieve adequate compression depth. The current study was set out to evaluate the effectiveness of an intensified wording and/or repetitive target depth instruction in a simulated, telephone-assisted, compression-only, bystander CPR. We hypothesized that an intensified wording and/or the continuously repeated target depth instruction results in an improved compression depth compared to the standard instruction set.

Section snippets

Trial design

The study was planned as a prospective, investigator-blinded, randomized, 4-armed, factorial trial (www.controlled-trials.com/ISRCTN85521420). The ethical committee of the Medical University Vienna approved the protocol.

Participants

The study was conducted at a central shopping mall in Vienna, on July 17, 2012. Visitors of the shopping mall were asked to participate voluntarily. Volunteers at the age or older than 18 years of age were eligible for randomization, if they had no advanced life support

Results

In total, 69 visitors of the shopping mall were asked to participate voluntarily. Finally, 35 visitors spontaneously agreed to take part. A participant flow chart is provided in Fig. 1 Baseline information of each group is provided in Table 1.

To each of the 4 groups 8 participants were allocated to. In six participants observation times were censored for exhaustion. For these participants the latest available outcomes were used. BORG values of the last observation were carried forward (LOC) to

Discussion

The current study provides evidence that the strategy of repeating the target depth every 20 s and/or using an intensified wording for compression depth instruction did not improve compression depth and worsened compression depth significantly. Also, the repetition of the target depth instruction did not improve quality of CPR.

This is an important finding because blood flow/pressure or cardiac output are linearly related to compression depth.15, 16, 17 Furthermore, an increase of 5 mm in

Limitations

Although this was a manikin based simulation study we tried to create a realistic scenario for untrained bystanders by simulating an emergency call with professional emergency dispatchers. Certainly, the nature of a real life emergency situation simulating a bystander CPR is impossible to achieve. Results are therefore not necessarily applicable to real life situation. Additionally, our study sample differs from archetypical bystanders as we recruited generally young and healthy subjects. The

Generalizability

Although simulation studies are not directly applicable to clinical practice we assume that the results give a good idea of bystander's CPR performance in real life telephone-assisted, bystander CPR.

Conclusion

In protocol driven, telephone-assisted, bystander CPR, intensified wording and/or repetitive target depth instruction will not improve compression depth compared to standard instruction.

Trial registration

http://www.controlled-trials.com/ISRCTN85521420/.

Funding

The current study was funded by the Austrian Association of Emergency and Disaster Medicine (www.notarzt.at) and supported by RORACO which provided the Laerdal^® Resusci Anne Simulator manikin. NOTRUF NOE provided the certified dispatchers. The Municipal Ambulance Service, Vienna, provided the LIFEPAK^® 12.

Authors’ contributions

R.v.T., D.R., H.N., R.L., C.H., W.S. and H.H. designed the study. R.v.T., D.R., M.K., R.L., B.H., C.K., H.N., C.C., C.H., F.S., W.S. and H.H. critically revised the study protocol. R.v.T., D.R., M.K., R.L., B.H., C.K., H.N., C.H., W.S. and H.H. participated in data acquisition. All authors participated in analysis and interpretation of the data. R.v.T. drafted the manuscript. R.v.T., D.R., M.K., R.L., B.H., C.K., H.N., C.C., C.H., F.S., W.S. and H.H. critically revised the manuscript for

Conflict of interest statement

The authors have no conflicts of interests.

Acknowledgements

We thank all voluntary participants and all involved personnel at the Lugner City shopping mall, Vienna, NOTRUF NOE, RORACO and the Vienna Municipal Ambulance Service.

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‘We're going to do CPR’: A linguistic study of the words used to initiate dispatcher-assisted CPR and their association with caller agreement
2018, Resuscitation
Citation Excerpt :
There is significant room for improvement in uptake of DA-CPR instructions by callers. Two important foci of research on DA-CPR during emergency calls have been: the delays and barriers to bystanders performing CPR [3–13] and the specific protocol for DA-CPR [14–20]. Whether callers agree to attempt CPR is an issue which is distinct from, though closely connected to, whether bystander-CPR occurs.
Background: In emergency ambulance calls for out-of-hospital cardiac arrest (OHCA), dispatcher-assisted cardiopulmonary resuscitation (CPR) plays a crucial role in patient survival. We examined whether the language used by dispatchers to initiate CPR had an impact on callers’ agreement to perform CPR.
Methods: We analysed 424 emergency calls relating to cases of paramedic-confirmed OHCA where OHCA was recognised by the dispatcher, the caller was with the patient, and resuscitation was attempted by paramedics. We investigated the linguistic choices used by dispatchers to initiate CPR, and the impact of those choices on caller agreement to perform CPR.
Results: Overall, CPR occurred in 85% of calls. Caller agreement was low (43%) when dispatchers used terms of willingness (“do you want to do CPR?”). Caller agreement was high (97% and 84% respectively) when dispatchers talked about CPR in terms of futurity (“we are going to do CPR”) or obligation (“we need to do CPR”). In 38% (25/66) of calls where the caller initially declined CPR, the dispatcher eventually secured their agreement by making several attempts at initiating CPR.
Conclusion: There is potential for increased agreement to perform CPR if dispatchers are trained to initiate CPR with words of futurity and/or obligation.
A novel protocol for dispatcher assisted CPR improves CPR quality and motivation among rescuers—A randomized controlled simulation study
2017, Resuscitation
Citation Excerpt :
Based on real life experiences from dispatchers at the Prehospital Medical Services in Central Denmark Region encouragements were provided on average about every 90th seconds and thus provided with a similar rate in the study. The novel protocol was designed based on previous research9–11,13–20,25–29 and pilot studies. Elements reported to improve CPR performance were included (Supplemental material, Table 2).
Emergency dispatchers use protocols to instruct bystanders in cardiopulmonary resuscitation (CPR). Studies changing one element in the dispatcher’s protocol report improved CPR quality. Whether several changes interact is unknown and the effect of combining multiple changes previously reported to improve CPR quality into one protocol remains to be investigated. We hypothesize that a novel dispatch protocol, combining multiple beneficial elements improves CPR quality compared with a standard protocol.
A novel dispatch protocol was designed including wording on chest compressions, using a metronome, regular encouragements and a 10-s rest each minute. In a simulated cardiac arrest scenario, laypersons were randomized to perform single-rescuer CPR guided with the novel or the standard protocol. Primary outcome: a composite endpoint of time to first compression, hand position, compression depth and rate and hands-off time (maximum score: 22 points). Afterwards participants answered a questionnaire evaluating the dispatcher assistance.
The novel protocol (n = 61) improved CPR quality score compared with the standard protocol (n = 64) (mean (SD): 18.6 (1.4)) points vs. 17.5 (1.7) points, p < 0.001. The novel protocol resulted in deeper chest compressions (mean (SD): 58 (12) mm vs. 52 (13) mm, p = 0.02) and improved rate of correct hand position (61% vs. 36%, p = 0.01) compared with the standard protocol. In both protocols hands-off time was short. The novel protocol improved motivation among rescuers compared with the standard protocol (p = 0.002).
Participants guided with a standard dispatch protocol performed high quality CPR. A novel bundle of care protocol improved CPR quality score and motivation among rescuers.
Communication and protocol compliance and their relation to the quality of cardiopulmonary resuscitation (CPR): A mixed-methods study of simulated telephone-assisted CPR
2015, International Emergency Nursing
Citation Excerpt :
Previous studies have evaluated the results of the given instructions, but no studies have been found that have the purpose of evaluating compliance with T-CPR protocols by EMD and laypersons, as well as the quality of performed CPR. Previous T-CPR simulation studies showed disappointing results for chest compression depth and frequency (Cheung et al., 2007; Deakin et al., 2007; Van Tulder et al., 2014). The aim of our investigation was to describe compliance with the T-CPR protocol, the performance of the laypersons in a simulated T-CPR situation, and the communication between laypersons and EMDs during these actions.
In the event of a cardiac arrest, emergency medical dispatchers (EMDs) play a critical role by providing telephone-assisted cardiopulmonary resuscitation (T-CPR) to laypersons. The aim of our investigation was to describe compliance with the T-CPR protocol, the performance of the laypersons in a simulated T-CPR situation, and the communication between laypersons and EMDs during these actions.
We conducted a retrospective observational study by analysing 20 recorded video and audio files. In a simulation, EMDs provided laypersons with instructions following T-CPR protocols. These were then analysed using a mixed method with convergent parallel design.
If the EMDs complied with the T-CPR protocol, the laypersons performed the correct procedures in 71% of the actions. The single most challenging instruction of the T-CPR protocol, for both EMDs and laypersons, was airway control. Mean values for compression depth and frequency did not reach established guideline goals for CPR.
Proper application of T-CPR protocols by EMDs resulted in better performance by laypersons in CPR. The most problematic task for EMDs as well for laypersons was airway management. The study results did not establish that the quality of communication between EMDs and laypersons performing CPR in a cardiac arrest situation led to statistically different outcomes, as measured by the quality and effectiveness of the CPR delivered.
The capability of professional- and lay-rescuers to estimate the chest compression-depth target: A short, randomized experiment
2015, Resuscitation
Citation Excerpt :
After that, a high proportion of lay-rescuers will then have no more contact with this important issue. Our finding is in line with several publications indicating limited quality of CPR in lay-rescuers.7,8,16–22 Significant underestimation of chest compression depth by lay-rescuers as it has been shown in this study is also an important finding because blood flow/pressure and cardiac output are linearly related to compression depth.3,23,24
In CPR, sufficient compression depth is essential. The American Heart Association (“at least 5 cm”, AHA-R) and the European Resuscitation Council (“at least 5 cm, but not to exceed 6 cm”, ERC-R) recommendations differ, and both are hardly achieved. This study aims to investigate the effects of differing target depth instructions on compression depth performances of professional and lay-rescuers.
110 professional-rescuers and 110 lay-rescuers were randomized (1:1, 4 groups) to estimate the AHA-R or ERC-R on a paper sheet (given horizontal axis) using a pencil and to perform chest compressions according to AHA-R or ERC-R on a manikin. Distance estimation and compression depth were the outcome variables.
Professional-rescuers estimated the distance according to AHA-R in 19/55 (34.5%) and to ERC-R in 20/55 (36.4%) cases (p = 0.84). Professional-rescuers achieved correct compression depth according to AHA-R in 39/55 (70.9%) and to ERC-R in 36/55 (65.4%) cases (p = 0.97).
Lay-rescuers estimated the distance correctly according to AHA-R in 18/55 (32.7%) and to ERC-R in 20/55 (36.4%) cases (p = 0.59). Lay-rescuers yielded correct compression depth according to AHA-R in 39/55 (70.9%) and to ERC-R in 26/55 (47.3%) cases (p = 0.02).
Professional and lay-rescuers have severe difficulties in correctly estimating distance on a sheet of paper. Professional-rescuers are able to yield AHA-R and ERC-R targets likewise. In lay-rescuers AHA-R was associated with significantly higher success rates. The inability to estimate distance could explain the failure to appropriately perform chest compressions. For teaching lay-rescuers, the AHA-R with no upper limit of compression depth might be preferable.
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^☆: A Spanish translated version of the summary of this article appears as Appendix in the final online version at http://dx.doi.org/10.1016/j.resuscitation.2013.08.010.

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Simulation and educationEffects of repetitive or intensified instructions in telephone assisted, bystander cardiopulmonary resuscitation: An investigator-blinded, 4-armed, randomized, factorial simulation trial☆

Abstract

Background

Methods

Results

Conclusion

Introduction

Section snippets

Trial design

Participants

Results

Discussion

Limitations

Generalizability

Conclusion

Trial registration

Funding

Authors’ contributions

Conflict of interest statement

Acknowledgements

Resuscitation

Resuscitation

Resuscitation

Resuscitation

Resuscitation

Ann Emerg Med

Ann Emerg Med

Resuscitation

Resuscitation

Resuscitation

Resuscitation

Resuscitation

Resuscitation

Resuscitation

Simulation and education
Effects of repetitive or intensified instructions in telephone assisted, bystander cardiopulmonary resuscitation: An investigator-blinded, 4-armed, randomized, factorial simulation trial☆