A comparison of two designs for earcons conveying pulse oximetry information.

We performed a randomised controlled trial comparing two kinds of earcons that could provide intermittent pulse oximetry information about a patient's oxygen saturation (SpO) and heart rate (HR). Timbre-earcons represented SpO levels with different levels of timbre, and pitch-earcons with different levels of pitch. Both kinds of earcons represented HR with tremolo. Participants using pitch-earcons identified SpO levels alone, and both SpO plus HR levels, significantly better than participants using timbre-earcons: p < .001 in both cases. However, there was no difference between earcon conditions in how effectively HR was identified, p = .422. For both kinds of earcons, identification of SpO levels was more compromised by simultaneous changes in HR than identification of HR levels was compromised by simultaneous changes in SpO, suggesting asymmetric integrality. Overall, pitch-earcons may provide a better intermittent auditory pulse oximetry display than timbre-earcons, especially for clinical contexts when quiet is needed.