Introduction

Hyperventilation negatively impacts CPR hemodynamics and outcomes, yet pediatric providers often exceed guideline-recommended ventilation rates. This study aimed to develop a metronome using human factors engineering to improve ventilation during CPR. Researchers hypothesized that the metronome would achieve a System Usability Score (SUS) >70 and maintain target ventilation rates in >70% of CPR epochs, supporting a PICU pilot trial.

Method

Multidisciplinary PICU clinicians provided feedback through surveys and participatory design sessions to optimize metronome features (audio, visual, etc.). High-fidelity simulation usability testing was conducted with 30 clinicians. The final prototype incorporated a bell sound and a scrolling vertical bar to indicate target ventilation rates (10/min for adults, 20/min for older children, 30/min for infants). Ventilation rates were measured during 30-second CPR epochs, with rates within ±2 breaths/min considered within target. Descriptive statistics summarized performance.

Results

Among 107 survey respondents, the ventilation metronome was deemed appropriate, acceptable, and feasible. The final prototype features a bell sound for enhanced audibility in noisy settings and a scrolling timed vertical bar, offering guideline-recommended CPR ventilation rates (10/min for adults, 20/min for older children, 30/min for infants). In usability testing (3 groups, 30 clinicians), the median System Usability Score (SUS) was 92.5 (IQR 89.4–93.1; max 100), with no recorded errors. During 36 simulated CPR epochs using the metronome, 34 (94%) maintained ventilation rates within ±2 breaths/min of the target.

Conclusion

By applying human factors engineering and implementation science, we developed a novel digital audio-visual ventilation rate metronome with high usability and superior accuracy in achieving target CPR ventilation rates. Compared to previously reported pediatric cardiac arrest data, the metronome significantly improved adherence to guideline-recommended rates. It has been implemented in a PICU pilot, with ongoing data collection to assess its impact on real-world CPR ventilation delivery.

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