Can metronomes improve CPR quality?

September 8, 2013

February 26, 2014

Dr C. J. W. Targett, ED Specialty Doctor (Hinchingbrooke Healthcare NHS Trust)

Prof T. Harris, Hinchingbrooke Healthcare NHS Trust

In [patients receiving external chest compressions in ED] is [a metronome better than no audible prompt] at [maintaining the quality of chest compressions delivered]?

During a long resuscitation in the emergency department, you have to repeatedly remind the members of staff performing chest compressions to keep up a good rate. You recall that during previous cardiac arrests, the quality and rate of external cardiac compressions differs between operators. You wonder if a metronome could help providers by defining a set rate and so improve cardiopulmonary resuscitation (CPR) quality.

Ovid MEDLINE(R) 1946 to November Week 3 2013: (Exp Cardiopulmonary Resuscitation/ OR cardiopulmonary resuscitation.af. OR cardiopulmonary.af. OR resuscitation.af. OR cpr.af.) AND metronome.af. Results limited to English language, adults and studies in humans. 17 records 0 new relevancies

The Cochrane Library Issue 12 of 12, December 2013: metronome:ti,ab,kw (Word variations have been searched) AND MeSH descriptor: [Cardiopulmonary Resuscitation] explode all trees 6 results 0 unique data.

Seventeen papers were found, of which 11 appeared relevant from reviewing the abstract; subsequently, two were dismissed. A further 21 papers were identified by reference in the original 11 papers; subsequently eight were dismissed leaving a total of 21 relevant papers which are summarised in the following table.

The role of cardiopulmonary resuscitation, using closed-chest compressions and assisted or expired air ventilation, is to maintain cardiopulmonary perfusion while identifying then treating reversible causes of cardiopulmonary arrest. High-quality closed-chest compression (chest compression rate and depth) has been associated with increased survival. A large number of small studies suggest that using auditory feedback devices, such as metronomes, improve the rates of chest compression to rates closer to those recommended by the resuscitation council guidelines (100–120 compressions per minute for adults). For this reason resuscitation guidelines recommend mechanical devices to support rescuers providing chest compressions.<br><br>Metronomes are an option on some monitor/defibrillators. We focussed on the use of metronomes to guide closed-chest compressions as these are cheap, can be used from smart phone apps, and are placed on some defibrillators. We have identified some studies published subsequent to the publication of the most recent resuscitation guidelines. This is important, as the rate and depth of closed-chest compressions have changed during range time of the cited studies (eg, ALS 5th Edition: rate 100/min, depth 4–5 cm, ALS 6th Edition: rate 100–120/min, depth 5–6 cm) (Chung et al 2012, 2013). These studies add to the evidence that metronomes may assist in optimising chest compressions to optimum rates suggested by the guidelines. These studies involve a diverse range of participants from lay, medical student, nursing and medical backgrounds. The findings are consistent across all groups with metronome use being associated with faster, regular compressions. However, the increase in compression rate is offset by a fall in compression depth in some studies, particularly in non-medical participants. One study has specifically explored this and suggested that faster rates were associated with a reduction in the quality and depth of chest compressions (Hurst et al 2011). This is backed up by some evidence of a reduction in compression depth (Oh et al 2008, Chung et al 2012, Park et al 2013). The majority of studies have been performed in simulated clinical situations using manikins. Data from these studies may not translate to clinical scenarios. However, limited clinical observational data suggests similar findings do occur in the clinical arena. A high proportion of studies have been performed using the CPREzy device. No randomised clinical trials have been performed. However, given the consistency of evidence and the low risk of the intervention, a clinical randomised trial would be difficult to justify.

The use of metronomes to guide the rate at which external chest compressions are delivered is associated with improved rates closer to those recommended in the current resuscitation guidelines.

1. Park SO, Hong CK, Shin DH et al.. Efficacy of metronome sound guidance via a phone speaker during dispatcher-assisted compression-only cardiopulmonary resuscitation by an untrained layperson: a randomised controlled simulation study u
2. You JS, Chung SP, Chang CH et al.. Effects of flashlight guidance on chest compression performance in cardiopulmonary resuscitation in a noisy environment.
3. Lukas RP, Engel P, Wecker S et al.. Cardiopulmonary resuscitation guidance improves medical students' adherence to guidelines in simulated cardiac arrest: A prospective, randomised, cross-over study.
4. Chung TN, Kim SW, You JS et al.. The specific effect of metronome guidance on the quality of one-person cardiopulmonary resuscitation and rescuer fatigue
5. Chung TN, Bae J, Kim EC et al,. Induction of a shorter compression phase is correlated with a deeper chest compression during metronome-guided cardiopulmonary resuscitation: a manikin study.
6. Hafner JW, Sturgell JL, Matlock DL, et al.. “Stayin’ alive”: a novel mental metronome to maintain compression rates in simulated cardiac arrests.
7. Paal P, Pircher I, Baur T et al.. Mobile phone-assisted basic life support augmented with a metronome.
8. Hurst VW 4th, Whittam SW, Austin PN et al.. Cardiopulmonary resuscitation during spaceflight: examining the role of timing devices.
9. Kern KB, Stickney RE, Gallison L, Smith RE.. Metronome improves compression and ventilation rates during CPR on a manikin in a randomized trial.
10. Havel C, Schreiber W, Trimmel H et al.. Quality of closed chest compression on a manikin in ambulance vehicles and flying helicopters with a real time automated feedback.
11. Jäntti H, Silfvast T, Turpeinen A et al.. Influence of chest compression rate guidance on the quality of cardiopulmonary resuscitation performed on manikins.
12. Fletcher D, Galloway R, Chamberlain D et al.. Basics in advanced life support: a role for download audit and metronomes.
13. Oh JH, Lee SJ, Kim SE et al.. Effects of audio tone guidance on performance of CPR in simulated cardiac arrest with an advanced airway.
14. Beckers SK, Skorning MH, Fries M et al.. CPREzy improves performance of external chest compressions in simulated cardiac arrest.
15. Noordergraaf GJ, Drinkwaard BW, van Berkom PF, et al.. The quality of chest compressions by trained personnel: the effect of feedback, via the CPREzy, in a randomized controlled trial using a manikin model.
16. Perkins GD, Augré C, Rogers H et al.. CPREzy: an evaluation during simulated cardiac arrest on a hospital bed.
17. Chiang WC, Chen WJ, Chen SY, et al.. Better adherence to the guidelines during cardiopulmonary resuscitation through the provision of audio-prompts.
18. Williamson LJ, Larsen PD, Tzeng YC et al.. Effect of automatic external defibrillator audio prompts on cardiopulmonary resuscitation performance.
19. Boyle AJ, Wilson AM, Connelly K et al.. Improvement in timing and effectiveness of external cardiac compressions with a new non-invasive device: the CPR-Ezy.
20. Wik L, Thowsen J, Steen PA.. An automated voice advisory manikin system for training in basic life support without an instructor. A novel approach to CPR training.
21. Kern KB, Sanders AB, Raife J et al.. A study of chest compression rates during cardiopulmonary resuscitation in humans. The importance of rate-directed chest compressions.