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).