Elsevier

Resuscitation

Volume 71, Issue 3, December 2006, Pages 283-292
Resuscitation

Clinical paper
Quality of out-of-hospital cardiopulmonary resuscitation with real time automated feedback: A prospective interventional study

https://doi.org/10.1016/j.resuscitation.2006.05.011Get rights and content

Summary

Aims

To compare quality of CPR during out-of-hospital cardiac arrest with and without automated feedback.

Materials and methods

Consecutive adult, out-of-hospital cardiac arrests of all causes were studied. One hundred and seventy-six episodes (March 2002–October 2003) without feedback were compared to 108 episodes (October 2003–September 2004) where automatic feedback on CPR was given. Automated verbal and visual feedback was based on measured quality with a prototype defibrillator. Quality of CPR was the main outcome measure and survival was reported as specified in the protocol.

Results

Average compression depth increased from (mean ± S.D.) 34 ± 9 to 38 ± 6 mm (mean difference (95% CI) 4 (2, 6), P < 0.001), and median percentage of compressions with adequate depth (38–51 mm) increased from 24% to 53% (P < 0.001, Mann–Whitney U-test) with feedback. Mean compression rate decreased from 121 ± 18 to 109 ± 12 min−1 (difference −12 (−16, −9), P = 0.001). There were no changes in the mean number of ventilations per minute; 11 ± 5 min−1 versus 11 ± 4 min−1 (difference 0 (−1, 1), P = 0.8) or the fraction of time without chest compressions; 0.48 ± 0.18 versus 0.45 ± 0.17 (difference −0.03 (−0.08, 0.01), P = 0.08). With intention to treat analysis 7/241 control patients were discharged alive (2.9%) versus 5/117 with feedback (4.3%) (OR 1.5 (95% CI; 0.8, 3), P = 0.2). In a logistic regression analysis of all cases, witnessed arrest (OR 4.2 (95% CI; 1.6, 11), P = 0.004) and average compression depth (per mm increase) (OR 1.05 (95% CI; 1.01, 1.09), P = 0.02) were associated with rate of hospital admission.

Conclusions

Automatic feedback improved CPR quality in this prospective non-randomised study of out-of-hospital cardiac arrest. Increased compression depth was associated with increased short-term survival.

Trial registration

ClinicalTrials.gov (NCT00138996), http://www.clinicaltrials.gov/.

Introduction

Cardiopulmonary resuscitation (CPR) defined as chest compressions and ventilations are important for survival after cardiac arrest,1 and quality of CPR influences outcome during basic life support.2, 3, 4

We have reported recently that quality of CPR during advanced life support (ALS) out-of-hospital did not adhere to the international guidelines,5, 6 when measured with new technology incorporated in standard defibrillators.7 Chest compressions were not given 48% of the time without spontaneous circulation, and only mean 28% (median 24%) of the chest compressions had a depth of 38–51 mm (guidelines recommendation).7

Others have reported similar findings with the same equipment in in-hospital arrests,8 and the results correspond with those found with other methods of quality measurements during out-of-hospital arrest in first responders and paramedics.9, 10, 11

Automated verbal feedback consistently has been reported to improve quality of CPR during manikin training,12, 13 with faster recovery of CPR skills when tested 6 and 12 months later.14, 15 Our recent publication on quality of CPR during ALS was a planned baseline-period before studying similar feedback via the defibrillator during CPR on patients. The hypothesis was that addition of such feedback would reactivate CPR skills and improve quality.

Section snippets

Methods

Except for the feedback system and statistical comparisons between the two groups without and with feedback, all details of the methods in this study have been reported in our recent publication,7 and a condensed version is therefore presented here.

Results

The annual statistics and demographic data for the three emergency medical service systems have been described previously.7 Two hundred and forty-three episodes were collected in the baseline period and 120 in the feedback period. Two patients during baseline and three with feedback did not receive CPR and were excluded leaving a total of 241 and 117, respectively. For quality of CPR analysis 65 additional patients were excluded from baseline (27%) and 9 (8%) from feedback. This was due to

Discussion

In this prospective, clinical trial chest compression depth and rate improved during a period with automatic verbal and visual feedback on CPR quality compared to the time period immediately before feedback was introduced. A limitation is that the study was sequential, not randomised. This was done on purpose to avoid possible spill-over effects to the control group of feedback-induced increased awareness of quality problems. This spill-over was anticipated to be a problem even if cluster

Conclusion

Quality of CPR improved with automated feedback. Changing feedback priority caused a parallel change in quality. Among all cases, increased chest compression depth was associated with increased short-term survival in a logistic regression model.

Conflict of interest statements

Authors Kramer-Johansen, Fellows, Svensson, and Sørebø have no conflicts of interest to declare. Myklebust is a full time employee on a fixed salary at Laerdal Medical, Stavanger.

Wik is on an advisory board for Medtronic Medical. Steen is a member of the board of directors for Laerdal Medical and The Norwegian Air Ambulance.

Acknowledgements

We thank all the participating paramedics and nurses for their enthusiasm, criticism and invaluable effort. We especially want to thank the local instructors: Jan Ottem, and Lars Didrik Flingtorp (Division of Prehospital Medicine, Ullevål University Hospital, Oslo, Norway), Helena Borovszky, RN, and Lars Säfsten, RN (Stockholm Ambulance Service, Stockholm, Sweden) Andrew Nord and Allan Bromley (London Ambulance Service NHS Trust, London, UK). The helpfulness and technical skills of Ståle

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A Spanish translated version of the summary of this article appears as Appendix in the online version at doi:10.1016/j.resuscitation.2006.05.011.

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