Metronome app versus a mentally hummed song to improve the quality of chest compressions

Eva González Martínez, José Ríos Guillermo, Ricard Valero Castell, Carmen Gomar Sancho, Isabel Belda Tortosa, Enrique Jesus Carrero Cardenal


Aim: To compare the usefulness of two strategies for improving chest compression performance: following a mobile phone metronome app versus ‘mentally humming’ a familiar popular song, ‘La Macarena’.

Methods: Controlled study of three clusters of medical student volunteers performing uninterrupted chest compressions for 2 minutes on a manikin. The clusters were assigned to receive no aid for compression timing (controls), to follow a metronome app set to 103 beats per minute, or to time compressions to the silent humming of ‘La Macarena’, a song with the same beat. We recorded demographic variables, delay in starting compressions, and performance quality variables using Resusci Anne Wireless SkillReporter software. The students also answered a satisfaction questionnaire. Data were analysed by intention-to-treat and per-protocol.

Results: We included 164 students. The median (interquartile range) percentage of compressions at the recommended rate of 100–120 cpm was nearly four-fold higher in the app group (91% [87%–94%]) and three-fold higher in the music group (74% [8%–98%]) than in the control group (24% [1%–92%]) (p<0.001). Although the app group had better overall performance scores, they started their compressions later. No group achieved the targeted depth of 5 cm. The guidance method was rated higher in the app group than the music group.

Conclusion: Mentally humming a familiar song with an appropriate beat, such as ‘La Macarena’, facilitates rapid initiation of cardiopulmonary resuscitation and improves the quality of compressions almost as much as following a metronome app.

Palabras Clave

Cardiopulmonary resuscitation; Chest compressions; Mobile applications; Music