Client: Masimo

Case Study: Critical Alarm Sound Development

The second longer-term project with Masimo has involved working specifically on the critical alarm sounds. The work is on-going having started in late 2017. The alarm sounds are used to communicate critical events or significant physiological changes during patient monitoring – for example a significant change in pulse rate or blood oxygen level. Importantly, all critical alarm sounds should conform to guidelines within the IEC-60601-1-8 Standard, a global standard which applies to all medical devices, setting out clear guidelines for basic safety and essential performance requirements.

Currently, Masimo uses one critical alarm sound (named as the General Alarm) for any high priority events. This can include physiological changes or a technical error with the device or sensor. Although effective in gaining one’s attention due to it’s perceived high volume, studies have shown the existing alarm to be widely disliked amongst clinicians, whilst causing excessive stress to the patient. Research has also shown that a perceived high volume does not necessarily make the sound more effective. What is also clear is the fact that medical devices now have the capability to play any type of sound (beyond the abstract monophonic tones we typically hear). This enables us to create much more harmonically-rich sounds, and push the pre-conditioned expectations of what a medical alarm should sound like.  

Initial work has involved replacing Masimo’s existing General Alarm sound, whilst being compliant with the current IEC-60601-1-8 Standard. At Masimo we continue to work on improvements to the alarm sounds, through close collaboration with Professor Judy Edworthy, a world-leading expert on alarms. This enables us to factor in the latest research on clinical alarms, as well as advise on suitable testing methods. Professor Edworthy is also a member of the committee working on updating the IEC-60601-1-8 Standard. Professor Edworthy and others continue to conduct important research in this area, whilst looking into how alarm sound and categorisations can be applied more effectively. The new Standard is due for release sometime later in 2020.

I plan to share some sound examples for this work section soon.

(Image at top of page) Working in my studio with Professor Judy Edworthy - August 2018