Treatment interrupt

Forgetting to return to a patient after leaving the patient for a while

The usability failure mode

Recommended protection

Validation

Sound remains muted

The user might forget that the sound is muted while the treatment has not finished.

IEC 60601-1-8 (section 6.8.2) suggests that a reminder signal may be used, and warns from undesired changes in the settings of these signals.

Visual reminder

If the sound alarm is disabled during an alarm condition, the system should provide a special visual alarm, visible all around the patient, indicating that the alarm is muted. 

Usability test in training mode:
  1. Set an alarm condition
  2. Verify that the user responds
  3. Ask the user to do something else
  4. Observe that the user notices that the alarm condition is still there.