This review found that good evidence existed to support use of cardiopulmonary resuscitation (CPR) feedback/prompt devices during CPR training to improve skill acquisition and retention. The existence of a number of studies that reported no intervention effects in conjunction with an inadequate assessment of study quality means that the conclusions should be treated with caution.
To assess use of cardiopulmonary resuscitation (CPR) real-time feedback/prompt devices during training and actual resuscitation attempts.
MEDLINE (1950 to Dec 2008), EMBASE (1988 to Dec 2008), PsycINFO (1988 to Dec 2008), Cochrane Database of Systematic Reviews (search dates not provided) were searched. American Heart Association Resuscitation Endnote library was searched (search dates not provided). Search terms were reported. Bibliographies of narrative reviews were handsearched for additional material.
Studies that compared use of a CPR feedback/prompt device compared with no device to improve CPR skill acquisition, retention or real-life performance were eligible for inclusion in the review. Eligible participants were lay persons and health providers. Audio and visual CPR feedback were eligible for inclusion.
Outcomes of interest were: compressions depth, rate and error rates (or percentage performed correctly); and ventilation rate, volume and error rates.
Devices used were: metronomes; skill meters; voice advisory manikins (VAM); Q-CPR system; public awareness resuscitator (PAR); and pressure-sensing devices CPREzy and CPR Plus. Devices varied in their ability to monitor compression rates and depths, ventilation volume and inflation rate, hand position, CPR performance, feedback and mode of feedback. A variety of participants were included: medical students, non-clinical hospital staff, nurses, lay persons and health care staff.
Two reviewers independently selected studies for inclusion in the review. Articles about which there were disagreements were included in the review.
Assessment of study quality
The authors stated that they assessed quality and rated studies as poor, fair or good. Criteria used for this classification were not reported in the review.
Studies were graded using the hierarchy of study design described by International Liaison Committee on Resuscitation (LOE) in which LOE 1 came from randomised controlled trials, LOE 2 from nonrandomised studies with a concurrent control, LOE 3 from studies with retrospective controls, LOE 4 from studies with no control group and LOE 5 from studies not directly related to the specific patient or population. Manikin studies were rated as evidence level 5 irrespective of study design.
The authors did not state how many reviewers performed the validity assessment.
Percentages of patients or continuous measures were extracted for each treatment group together with levels of statistical significance of treatment differences. Studies were classified as supportive, neutral or opposing (regarding benefits of the CPR feedback/prompt device).
The authors did not state how many reviewers performed data extraction.
Methods of synthesis
Studies were synthesised narratively by outcome. Differences between studies were discussed in the text and presented in tables.
Results of the review
Thirty-two studies were included in the review (total number of participants unclear). Twenty-six studies were rated 5 for level of evidence (manikin or animal), four studies were rated 3 (retrospective controls) and two studies were rated 2 (non-randomised cross-over).
Impact of CPR feedback/prompt device on skill acquisition during training on manikins:
Eight studies (total participants=985), all with level of evidence of 5. Four studies showed improved compression depths after feedback (n=455) and three showed no effect (n=480). Three studies reported improved compression rates with the intervention (n=404) and five showed no effect (n=581). One study found increased error rates for compressions (n=156), one found reduced error rates (n=50) and two found no effect (n=437). Three studies found improved ventilation rates (n=245) and one found no effect (n=65). Two studies found reduced ventilation volumes after feedback (n=195) and one showed no effect (n=164). Four studies found reduced error rates for compressions (n=576), one showed increased rates (n=50) and one showed no effect (n=164).
Impact of CPR feedback/prompt device on skill retention after training on manikins:
Four studies (total participants=474), all had level of evidence of 5. Two studies showed improved retention of compression depth (n=267) and two showed no effect (n=207). One study improved compression rates (n=65) and three showed no effect (n=409). One study found improved error rate for compressions (n=164). One study found improved retention of ventilation rate (n=43) and one found no effect (n=65). One study found reduced ventilation volumes after feedback (n=43) and one showed no effect (n=164). One study found improved error rate for compressions (n=65) and two showed no effect (n=366).
Impact of CPR feedback/prompt devices during skill performance on manikins:
Eighteen studies (total participants=1,350), all had level of evidence of 5. Eight out of 13 studies showed improved compression depth (n=634), one showed decreased depth (n=80) and four found no effect (n=228). Six out of 14 studies showed improved rates of compression (n=415), six found no effect (n=519) and two showed a reduced variability in rate (n=97). Six studies showed increased percentage of correct compression (n=472) and three found no effect (n=290). Two studies showed improved ventilation rates (n=232) and three reported no effect (n=99). One study reported reduced ventilation volumes (n=152), two reported no effect (80) and one reported attenuated decline (n=114). Seven studies reported increased percentage of correct ventilation (n=450).
Impact of CPR feedback/prompt devices during skill performance, human studies on manikins:
Six studies (total participants not stated, four studies had level of evidence of 3 and two studies had level of evidence of 2.
For use of metronomes, two studies measured improved chest compression rates and end-tidal carbon dioxide after metronome use. One study found improved hands-off time and improved proportion of intubation attempts that took less than 20 seconds. One study found that improved CPR was associated with improved patient survival.
For use of Q-CPR system, one hospital study found that compression and ventilation rates were less variable after feedback, but there was no effect on CPR variables, return of spontaneous circulation and hospital discharge. One pre-hospital study found increased compression depth, increased percentage of adequate compressions and decreased compression rates.
Limitations: There was a risk of over estimating compression depths if CPR was performed on a compressible surface (one study). There was a risk of having hands caught in the feedback device (one study). Mechanical work was required to provide compression forces in pressure-sensing devices (one study).
Good evidence existed to support use of CPR feedback/prompt devices during CPR training to improve CPR skill acquisition and retention. Further studies were needed to to determine if devices improved patient outcomes.
This review addressed a clear research question with clear inclusion criteria. The search strategy included some relevant sources. It was unclear whether there were language restrictions and so there may have been language bias. There was no search for unpublished material, so relevant trials may have been missed and publication bias could not be ruled out. Although the authors graded the level of evidence and stated that they assessed study quality, no details of quality criteria were reported and this made it difficult to judge the reliability of the studies. Some steps were taken to minimise errors and bias. Study details were not presented clearly and it was difficult to determine whether presented values were for the experiment or the control. A narrative synthesis was appropriate in view of the heterogeneity of outcomes, method used to measure outcome, devices used and study design. The authors' conclusions focused on the positive outcomes and ignored the large number of studies that found no effects. This, in conjunction with an inadequate assessment of study quality, means that the conclusions should be treated with caution.
Implications of the review for practice and research
Practice: The authors stated that it may be beneficial to use CPR feedback/prompt devices in clinical practice as an overall strategy to improve the quality of CPR.
Research: The authors stated that further studies were needed to determine if devices improved patient outcomes. The accuracy of devices to measure compression depth should be calibrated to account for the support surface (floor or mattress).
Dr Perkins was supported by the Dept. Health National Institute of Health Research (DH NIHR) Clinical Scientist Scheme and the review was supported in part by the DH NIHR and Research for Patient Benefit Programme.
Yeung J, Meeks R, Edelson D, Gao F, Soar J, Perkins GD. The use of CPR feedback/prompt devices during training and CPR performance: a systematic review. Resuscitation 2009; 80(7): 743-751. [PubMed: 19477574]
Subject indexing assigned by NLM
Cardiopulmonary Resuscitation /education; Clinical Competence; Cues; Humans; Knowledge of Results (Psychology)
Database entry date
This is a critical abstract of a systematic review that meets the criteria for inclusion on DARE. Each critical abstract contains a brief summary of the review methods, results and conclusions followed by a detailed critical assessment on the reliability of the review and the conclusions drawn.