Conflict of Interest Declaration
The ILCOR Continuous Evidence Evaluation process is guided by a rigorous ILCOR Conflict of Interest policy. The following Task Force members and other authors were recused from the discussion as they declared a conflict of interest: (none applicable)
The following Task Force members and other authors declared an intellectual conflict of interest and this was acknowledged and managed by the Task Force Chairs and Conflict of Interest committees: (none applicable)
CoSTR Citation
Brooks S, Considine J, Avis S, , Castren M, Chung C, Considine J, Duff J, Grief R, Kudenchuck P, Mancini MB, Nishiyama C, Perkins GD, Ristagno G, Semeraro F, Smith C, Smyth M, Morley P, Olasveengen TM - on behalf of the International Liaison Committee on Resuscitation Basic and Education Implementation and Teams Task Forces. Feedback for CPR quality in Adults and Children Consensus on Science with Treatment Recommendations [Internet] Brussels, Belgium: International Liaison Committee on Resuscitation (ILCOR) Basic Life Support Task Force, 2020 Jan 23rd. Available from: http://ilcor.org
Methodological Preamble
The continuous evidence evaluation process for the production of Consensus on Science with Treatment Recommendations (CoSTR) started with a systematic review of basic life support conducted by Steven Brooks and Julie Considine with involvement of clinical content experts. Evidence for adult literature was sought and considered by the Basic Life Support Adult Task Force and Education Implementation and Teams Task Force. These data were taken into account when formulating the Treatment Recommendations.
PICOST
The PICOST (Population, Intervention, Comparator, Outcome, Study Designs and Timeframe)
Population: Adults and children who are in cardiac arrest in any setting
Intervention: Real-time feedback and prompt devices regarding the mechanics of CPR quality (e.g. rate and depth of compressions and/or ventilations)
Comparators: No real-time feedback
Outcomes: Survival to hospital discharge with good neurological outcome and survival to hospital discharge were ranked as critical outcomes. Return of spontaneous circulation (ROSC), bystander CPR rates, time to first compressions, time to first shock, and CPR quality was ranked as important outcomes.
Study Designs: Randomized controlled trials (RCTs) and non-randomized studies (non-randomized controlled trials, interrupted time series, controlled before-and-after studies, cohort studies) are eligible for inclusion. Studies involving manikins only, the use of CPR quality data for monitoring quality of care (e.g. debriefing or quality assurance programs) were excluded from this review.
Timeframe: All years and all languages were included as long as there was an English abstract; unpublished studies (e.g., conference abstracts, trial protocols) were excluded. Literature search updated to Sept, 2019.
In most cases bias was assessed per comparison rather than per outcome, since there were no meaningful differences in bias across outcomes.
Consensus on Science
Three discrete forms of real-time feedback were identified: 1) audiovisual feedback that provided visual feedback and corrective audio prompts; 2) audio feedback that indicated adequate chest compression depth and release but did not offer corrective instructions; and 3) metronome guidance for chest compression rate. Due to a high degree of clinical heterogeneity across studies with respect to the type of devices used, the mechanism of CPR quality measurement, the mode of feedback, patient types, locations (e.g. in-hospital and out-of-hospital), and baseline (control group) CPR quality, we did not conduct a meta-analysis for any of the outcomes.
Real-time audiovisual feedback
For the critical outcome of survival with favorable neurological outcome we identified low-certainty evidence (downgraded for very serious risk of bias) testing audiovisual feedback from one cluster RCT [Hostler 2011 342] enrolling 1586 patients which showed no benefit from real-time feedback compared to no real-time feedback; (RR, 1.02; 95%CI, 0.76–1.36; P = 0.9; absolute risk reduction (ARR), 0.19%; 95% CI, −3.18% to 2.82%, or 2 more patients/1000 survived with the intervention (95% CI, 24 fewer patients/1000 to 36 more patients/1000 survived with the intervention)) and very-low-certainty evidence (downgraded for very serious risk of bias) from 4 observational studies testing real-time audiovisual feedback in 1,100 adult cardiac arrests. [Couper 2015 2321; Sainio 2013 50; Bobrow 2013 47; Riyapan 2019 245] These studies did not show any benefit from real-time feedback on survival with favorable neurological outcome at 6 months (ARR 5.75%; 95% CI, −18.51% to 3.85%), [Sainio 2013 50], 30 days (2/16 vs. 0/16; P = 0.14)[Riyapan 2019 245] or at discharge (adjusted odds ratio 0.92 (95% CI, 0.37–2.30), P=0.86).[Couper 2015 2321] The forth study tested audiovisual feedback after scenario based training in a before-and-after study of 484 adult out-of-hospital cardiac arrest patients which showed no benefit from real-time feedback in unadjusted analysis but increased survival in adjusted analysis (unadjusted OR of 1.76 (95% CI 0.88 to 3.52) and adjusted OR 2.69 (95% CI 1.04 to 6.94), adjusting for witnessed arrest, provision of therapeutic hypothermia, age, and minimally interrupted cardiac resuscitation protocol compliance). [Bobrow 2013 47]
For the critical outcome of survival to hospital discharge we identified low certainty evidence (downgraded for serious risk of bias) testing audiovisual feedback from one cluster RCT [Hostler 2011 342] enrolling 1586 patients which showed no benefit from real-time feedback compared to no real-time feedback; (RR, 0.91; 95%CI, 0.69–1.19; P = 0.5; ARR -1.16%; 95% CI, −4.37% to 2.02%, or 9 fewer patients/1000 survived with the intervention (95% CI, 31 fewer patients/1000 to 19 more patients/1000 survived with the intervention)) and very low certainty evidence (downgraded for serious risk of bias) from six observational studies representing 1592 patients: five in adults [Couper 2015 2321; Sainio 2015 50; Bobrow 2013 47; Abella 2007 54; Kramer-Johansen 2006 283] and one in children [Sutton 2014 70]. There was no difference in outcome between real-time feedback vs. no feedback among 400 adult patients with in-hospital cardiac arrest (adjusted OR 0.90; 95% CI 0.39–2.06, P= 0.80), [Couper 2015 2321] 187 cardiac arrest patients treated by a physician staffed helicopter emergency medical service (ARR -0.91 95% CI -11.18-12.33),[Sainio 2013 50] 483 adults with out-of-hospital cardiac arrest treated after concurrent implementation of scenario based training (ARR 5.23 95% CI -0.49-10.89),[Bobrow 2013 47] 159 adults with in-hospital cardiac arrest (ARR -0.18 95% CI -11.46-8.64),[Abella 2007 54], 358 adults with out-of-hospital cardiac arrest (ARR 1.37 95% CI -2.47-6.91)[Kramer-Johansen 2006 283] and 8 children (1-7 years) with in-hospital cardiac arrest (1/4 vs. 1/4).[Sutton 2014 70].
For the critical outcome of survival to 30 days we identified very low certainty evidence (downgraded for serious risk of bias) testing audiovisual feedback from one observational study [Agerskov 2017 1345] enrolling 196 patients which showed no benefit from the use of real-time feedback compared to no real-time feedback before ambulance arrival ARR -0.84 95% CI -13.88-14.82, P =0.9.
For the critical outcome of survival to 24 hours we identified low certainty evidence (downgraded for risk of bias) testing CPR audiovisual feedback from one cluster RCT [Hostler 2011 342] representing 1586 patients which showed no benefit from real-time feedback compared to no real-time feedback; (RR, 0.96; 95%CI, 0.82–1.13; P = 0.6; ARR -1.09%; 95% CI, −3.35% to 5.50%, or 4 fewer patients/1000 survived with the intervention (95% CI, 18 fewer patients/1000 to 13 more patients/1000 survived with the intervention)) and very low certainty evidence (downgraded for very serious risk of bias) from two observational studies [Riyapan 2019 245; Sainio 2013 50] representing 219 patients. There was no difference in outcome between real-time feedback vs. no feedback among 32 adults with out-of-hospital cardiac arrest treated in the emergency department (2/16 vs. 0/16)[Riyapan 2019 245] or 187 cardiac arrest patients treated by a physician staffed helicopter emergency medical service (ARR 13.13 95% CI -0.66-28.02).[Sainio 2013 50]
For the critical outcome of return of spontaneous circulation (ROSC) we identified low certainty evidence (downgraded for very serious risk of bias) testing CPR audiovisual feedback from one cluster RCT [Hostler 2011 342] representing 1586 patients which showed no benefit from real-time feedback compared to no real-time feedback; (RR, 1.01; 95%CI, 0.91–1.13; P = 0.9; ARR -0.45%; 95% CI, −5.33% to 4.43%, or 1 more patient/1000 survived with the intervention (95% CI, 9 fewer patients/1000 to 13 more patients/1000 survived with the intervention)) and very low certainty evidence (downgraded for very serious risk of bias) from nine observational studies representing 2263 patients: seven in adults [Riyapan 2019 245; Couper 2015 p2321; Sainio 2015 50; Bobrow 2013 47; Lukas 2012 1212; Abella 2007 54; Kramer-Johansen 2006 p283, ] and one in children [Sutton 2014 p70]. There was no difference in outcome between real-time feedback vs. no feedback among 32 adults with out-of-hospital cardiac arrest treated in the emergency department (9/16 vs. 10/16),[Riyapan 2019 245]400 adult patients with in-hospital cardiac arrest (adjusted OR 0.62; 95% CI 0.31–1.22, P= 0.49), [Couper 2015 2321] 483 adults with out-of-hospital cardiac arrest treated after concurrent implementation of scenario based training (ARR -3.17 95% CI -10.73-4.35),[Bobrow 2013 47] 638 or 319 matched pairs of out-of-hospital cardiac arrest patients (ARR -4.39 95% CI -3.35-12.06),[Lukas 2012 1212] 159 adults with in-hospital cardiac arrest (ARR 4.55 95% CI -11.59-19.90),[Abella 2007 54], 358 adults with out-of-hospital cardiac arrest (ARR 5.65 95% CI -2.89-15.09)[Kramer-Johansen 2006 283], 196 patients treated with or without real-time feedback before ambulance arrival ARR 1.11 95% CI -15.56-13.69, P =0.9, and 8 children (1-7 years) with in-hospital cardiac arrest (3/4 vs. 1/4).[Sutton 2014 70]In one study of 187 cardiac arrest patients treated by a physician staffed helicopter emergency medical service higher ROSC rates were observed among patients receiving CPR with real-time feedback compared to those receiving CPR without real-time feedback (ARR 17.55 95% CI 1.79-32.46).[Sainio 2013 50]
For the important outcome of chest compression rate, we identified moderate-quality evidence from 1 randomized study [Hostler 2011 342] representing 1586 patients, and very-low-quality evidence (downgraded due to serious risk of bias) from 6 observational studies: 5 in adults [Riyapan, 2019, 245; Couper, 2015 2312; Bobrow 2013 47; Abella 2007 54; Kramer-Johansen 2006 283] representing 1433 patients, and 1 in children [Sutton 2014 70] representing 8 patients. The cluster RCT [Hostler 2011 342] found a significant difference of −4.7/min (95% CI, −6.4 to −3.0/min) when feedback was used . One observational study [Abella 2007 54] showed no difference in chest compression rates with and without feedback, and, again, all compression rates were close to international recommendations of 100/min. The other 4 observational studies [Riyapan, 2019, 245; Couper, 2015, 2312; Bobrow 2013 47; Kramer-Johansen 2006 283] showed lower compression rates in the group with CPR feedback with differences ranging from –23 to –11 compressions per minute. The control groups mean compression rates in these 4 studies showing a reduction in rates associated with feedback devices ranged from 121-136 compressions per minute. The pediatric study [Sutton 2014 70] found a median difference of −10/min with feedback, and, again, the chest compression rate in the control group exceeded 120/min. The use of CPR feedback devices may be effective in limiting compression rates that are too fast.
For the important outcome of chest compression depth, we identified moderate-quality evidence from 1 randomized study [Hostler 2011 342] representing 1586 patients, and very-low-quality evidence(downgraded for serious risk of bias) from 6 observational studies: 5 in adults [Riyapan, 2019, 245; Couper, 2015, 2312; Bobrow 2013 47; Abella 2007 54; Kramer-Johansen 2006 283] representing 1433 patients and 1 in children [Sutton 2014 70] representing 8 patients. The cluster RCT [Hostler 2011 342] found a significant +1.6 mm (95% CI, 0.5–2.7) (cluster adjusted) difference in chest compression depth with feedback. However, this is of questionable clinical significance, and the average compression depths in both arms were less than international recommendations of 5 cm (2 inches) in adults (3.96 cm [1.55 inches] and 3.87 cm [1.52 inches]). One observational study [Abella 2007 54] showed no difference in chest compression depth with and without feedback, and all compression rates were close to, but less than, international recommendations of 5 cm (2 inches) in adult patients (4.4 and 4.3 cm or 1.7 inches). Three observational studies [Riyapan, 2019, 245; Bobrow 2013 47; Kramer-Johansen 2006 283] showed significantly deeper chest compressions in the groups with CPR feedback: Bobrow et al [Bobrow 2013 47] found a 1.06 cm (0.42 inches) increase with feedback (5.46 versus 4.52 cm, or 2.15 versus 1.78 inches) (mean difference, 0.97 cm; 95% CI, 0.71–1.19 cm); Riyapan [Riyapan, 2019, 245] observed that feedback was associated with a 0.9 cm increase in depth (increase from a mean of 38.8±11.5 mm to 48.0±9.2mm, p< 0.018); Kramer-Johansen et al. [Kramer-Johansen 2006 283] observed a more modest (increase from 3.4 to 3.88 cm, or [from 1.3 to 1.5 inches]) (mean difference, 0.4 cm; 95% CI, 0.2–0.6). The pediatric study [Sutton 2014 70] found no median difference in compression depth. The effect of CPR feedback devices on depth was variable across studies, but a consistent, clinically important effect is not apparent.
For the important outcome of chest compression fraction, we identified moderate-quality evidence from 1 randomized study [Hostler 2011 342] representing 1586 adults and very-low-quality evidence (downgraded due to serious risk of bias) from 5 observational studies in adults [Kramer-Johansen 2006 283,Abella 2007 54,Bobrow 2014 47 [Riyapan, 2019, 245; Couper, 2015, 2312; Bobrow 2013 47; Abella 2007 54; Kramer-Johansen 2006 283] and 1 in children.[Sutton 2014 70] The randomized study found a cluster adjusted difference of +2% (66% versus 64%; P=0.016) when CPR prompt devices were used. Although statistically significant, such a small difference has questionable clinical significance. The results from the adult observational studies were variable. Two studies reported statistically significant increases in CPR fraction associated with feedback [Couper 2015 2312; Abella 2007 54; and 3 studies did not observe a statistically or clinically important difference [Riyapan, 2019, 245; Bobrow 2013 47; Kramer-Johansen 2006 283]. The Couper study [Couper, 2015, 2312] demonstrated an increase in compression fraction from 78% (8%) to 82% (7%), p= 0.003. This increase is of questionable clinical significance. The Bobrow study [Bobrow, 2013, 47] was an outlier, demonstrating an increase in chest compression fraction from 66 % (95% CI 64 to 68) to 84% (95% CI 82 to 85), Absolute difference: 18% (95% CI 15 to 20). Two major caveats with this study include a concern that the observed difference may have not been related to the feedback device intervention and use of an imputed data set. This study was a before-after study with two interventions: audio-visual feedback and an intensive case-based training program for paramedics. An imputed dataset was used for the CPR quality metric analysis. The sample size of the pediatric study [Sutton 2014 70] was too small to enable inferential statistical analysis. Overall, the evidence does not indicate a strong signal for clinically significant differences in CPR fraction associated with the use of audiovisual feedback in the patient and provider populations studied.
For the important outcome of ventilation rate, we identified moderate-quality evidence from 1 randomized study [Hostler 2011 342] representing 1586 adults and very-low-quality evidence (downgraded due to serious risk of bias) from 3 observational studies in adults [Bobrow 2013 47; Abella 2007 54; Kramer-Johansen 2006 283] representing 1,001 patients. None of the studies showed a significant difference in ventilation rate with and without CPR feedback.
Real-time audio feedback
For the critical outcome of survival to hospital discharge we identified very low certainty evidence (downgraded for very serious risk of bias)testing a stand-alone (non-AED), hand-held CPR audio feedback related to compression depth and release from one RCT [Goharani 2019 5] representing 900 in-hospital cardiac arrest patients which showed benefit from real-time feedback compared to no real-time feedback; (RR, 1.90; 95%CI, 1.60–2.25; P < 0.001; ARR 25.56%; 95% CI, 19.22% to 31.60%, or 91 more patient/1000 survived with the intervention (95% CI, 61 more patients/1000 to 126 more patients/1000 survived with the intervention)).
For the critical outcome of return of spontaneous circulation (ROSC) we identified low certainty evidence (downgraded for very serious risk of bias) for testing CPR audio feedback related to compression depth and release from two RCTs [Goharani 2019 5; Vahedian-Azimi 2016 147] representing 980 patients. Both RCTs showed that the use of chest compression depth and release audio feedback increased ROSC (RR, 1.57; 95%CI, 1.38–1.78; P < 0.001; ARR 24.22%; 95% CI, 17.79% to 30.36%, or 58 more patient/1000 survived with the intervention (95% CI, 38 more patients/1000 to 79 more patients/1000 survived with the intervention)) [Goharani 2019 5] and (RR, 2.07; 95%CI, 1.20–3.29; P < 0.001; ARR 37.50%; 95% CI, 15.70% to 54.68%, or 108 more patient/1000 survived with the intervention (95% CI, 20 more patients/1000 to 232 more patients/1000 survived with the intervention)) [Vahedian-Azimi 2016 147].
Metronome rate guidance
For the critical outcome of survival to 30 days we identified very low certainty evidence (downgraded for very serious risk of bias) testing use of a metronome to guide chest compression rate during CPR prior to ambulance arrival from one observational study [Agerskov 2017 1345] representing 196 patients which showed no benefit from use of metronome vs. no use of metronome (ARR 1.66 95% CI -17.71-14.86, (P = 0.8) For the critical outcome of survival to 7 days we identified very low certainty evidence (downgraded for very serious risk of bias) testing use of a metronome to guide chest compression rate during CPR from one observational study [Chiang 2005 297] representing 30 patients which showed no benefit from use of metronome vs. no use of metronome (3/17 vs. 2/13, P=0.9).
For the critical outcome of return of spontaneous circulation (ROSC) we identified very low certainty evidence (downgraded for very serious risk of bias) from 2 observational studies of adult out-of-hospital cardiac arrests. One study showed no benefit when a metronome was used prior to ambulance arrival ARR 4.97 95% CI -21.11-11.76, (P = 0.6) [Agerskov 2017 1345] and the other showed no benefit from the use of metronome prior to ambulance arrival (7/13 vs. 8/17, P = 0.7),[Chiang 2005 297]
Treatment Recommendations
We suggest against routine implementation of real-time CPR feedback devices as a stand-alone measure to improve resuscitation outcome, or in isolation from more comprehensive quality improvement initiatives (weak recommendation, very low quality of evidence).
In systems currently using real-time CPR feedback devices, we suggest the devices may continue to be used given that there is no evidence suggesting significant harm (weak recommendation, very low quality of evidence).
Justification and Evidence to Decision Framework Highlights
The focused scope of this question was on the use of CPR feedback devices alone and excluded studies where the technology was used with system wide quality improvement initiatives or post event debriefing. High quality CPR is important to patient outcomes and the task force recognizes the importance of monitoring CPR quality. Monitoring CPR quality may take many forms: this systematic review focused solely on real-time CPR feedback devices so does not negate the importance of a CPR quality improvement program. In making this recommendation, we place a higher value on resource allocation and cost effectiveness than widespread implementation of a technology with uncertain effectiveness.
The task force recognized that most devices which provide real-time feedback during real cardiac arrests can also be used support CPR training with manikins, debriefing after cardiac arrest events with CPR quality data and longitudinal programmatic CPR quality assurance. There was significant debate amongst task force members on whether to recommend for or against the use of these devices for real-time feedback on the basis of available data. The task force acknowledged that most studies identified did not demonstrate a clinically or statistically significant association between real-time feedback and improved patient outcomes. However, no studies identified significant harm and some demonstrated clinically important improvements in outcomes. Most notable was the addition of the Goharani study [Goharani 2019 5] to the evidence base considered in 2020, which was an RCT of 900 in-patient cardiac arrests from Iran. This study demonstrated a +25.6% absolute increase in survival to hospital discharge with audio feedback on compression depth and recoil (54% vs 28.4%, p<0.001). Several observational studies demonstrated improvements in favorable neurologic outcome which were not statistically significant, and statistically significant improvements in various aspects of CPR quality including CPR rate and CPR fraction.
The 2020 task force placed value on the fact that ILCOR has made recommendations for optimal CPR on the basis of chest compression metrics which can be measured with CPR feedback devices. The task force acknowledged that implementing high quality CPR in hospital and EMS systems would be difficult a reliable way to measure CPR quality in those systems. Measuring and monitoring the quality of health care provided is regarded essential for any high quality health care system. Most CPR quality measurement devices also have real-time feedback capability.
So, in the context of some very low certainty evidence suggesting benefit of real-time feedback identified by our literature review, supportive recommendations for the delivery of CPR with particular metrics, supportive treatment recommendations for the use of devices for quality assurance and education from the EIT task force, and a lack of evidence suggesting harm, we made a weak recommendation in support of these devices for real-time feedback.
Knowledge Gaps
Current knowledge gaps include but are not limited to:
- What is the effect of feedback devices on patient outcomes when used by lay people with AEDs?
- What is the effect of real-time feedback devices in “low performing services” with baseline CPR metrics which are below recommended values, as an alternative to conventional training strategies?
- What are the most effective parameters to feedback to users (i.e. measures of brain or other tissue perfusion, ECG characteristics, other physiologic measurements?
- What are the most effective modalities for feedback to be provided to users?
Attachments
Evidence-to-Decision Table: BLS-361 Feedback CPR devices Et D
References
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