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. 2025 Jan 6:21:100867.
doi: 10.1016/j.resplu.2025.100867. eCollection 2025 Jan.

Release velocity ImprovemenT with a new Metronome guIding chest COmpressions: The RITMICO simulation study

Maria Luce Caputo  1   2   3 , Giuliana Monachino  4 , Ruggero Cresta  2 , Alessia Currao  5   6 , Enrico Baldi  5   6   7 , Simone Savastano  5   6 , Andrea Cortegiani  8   9 , Mariachiara Ippolito  8   9 , Sara Accetta  8 , Alessandra Gargano  9 , Camilla Metelmann  10 , Bibiana Metelmann  10 , Carlos Ramon Hölzing  10 , Julian Ganter  11 , Michael Patrick Müller  12 , Claudio Benvenuti  2 , Stefania Tomola  13 , Pierangelo Pinetti  13 , Pier Luigi Ingrassia  13 , Francesca Dalia Faraci  4 , Angelo Auricchio  1   2
Affiliations

Release velocity ImprovemenT with a new Metronome guIding chest COmpressions: The RITMICO simulation study

Maria Luce Caputo et al. Resusc Plus. .

Abstract

Background and trial design: Outcomes of out-of-hospital cardiac arrest vary significantly, often due to the quality of cardiopulmonary resuscitation (CPR) provided. Automated real-time feedback devices have been explored to enhance CPR skills, but few devices currently ensure proper chest recoil. This study aimed to assess whether a double-click metronome could improve chest compressions (CC) metrics and particularly CC release velocity (CCRV) during CPR manikin simulation.

Methods: We developed and tested a double-click metronome for CPR, where the first click signals the compression and the second click marks the end of chest release. We performed a multicenter non-blinded, randomized, controlled trial including volunteers with different levels of CPR expertise. Three CC metrics-depth, rate, and CCRV-were measured using an automated external defibrillator equipped with pads for CPR quality analysis.

Results: 503 volunteers participated in the study, with 54% being male and a mean age of 34 ± 12 years. The median CCRV and CC depth achieved with the double-click metronome were significantly higher compared to the standard metronome (median difference 6 mm/s, IQR-15.2, 28.5, +1.5%, p < 0.001; median difference 0.1 cm, +2.5%, IQR -0.1, 0.4, p < 0.001). The double-click metronome led to significant improvements in CC depth and CCRV across all volunteer categories, with the greater effect observed in first responders and in non-specialized healthcare personnel.

Conclusions: Compared to a standard metronome, the double-click metronome significantly enhances CPR quality. If further validated in real resuscitations, this new audio prompt could be a valuable tool for integration into devices designed for out-of-hospital cardiac arrest resuscitation, as well as a training tool to improve CPR quality.

Keywords: Audio prompt; CPR quality; Cardiopulmonary resuscitation; Out-of-hospital cardiac arrest.

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Conflict of interest statement

The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: “AC is an associate member of the ILCOR Education Implementation and Team (EIT) Task force. MPM is chair of Regions of Lifesavers non-profit first responder organisation, shareholder of SmartResQ Aps, and member of the executive committee of the German Resuscitation Council (GRC). All other authors have no conflict of interest to declare.”.

Figures

None
Graphical abstract
Fig. 1
Fig. 1
Flowchart of the study protocol.
Fig. 2
Fig. 2
Violin plots representing the distribution of the median values of the three parameters (chest release velocity, chest compression depth and rate) resulting with the standard (blue) and the double-click (orange) metronome. In each boxplot the mean, median, 25th and 75th quantiles are reported. The shaded green area represents the valid range for the corresponding metric. An asterisk is reported on top of the orange violin plot if the difference between the double-click and the standard metronome was found to be statistically significant (p < 0.05 with one-sided Wilcoxon signed-ranks test). (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)
See this image and copyright information in PMC

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