The usability failure mode

Recommended protection

Validation

Users do not recognize the patient condition

IEC 60601-1-8 instructs the manufacturers about certain sound features, including the melodies that represent certain medical conditions. A sample of these melodies may be found in: http://www.usyd.edu.au/anaes/alarms/

A2SubCl-6-3-3-1-c2f-Other-Sets of IEC 60601-1-8 comments: "VALIDATION by USABILITY testing is not required if each set complies with Table 3 and Table 4 (or Annex F)".

Unfortunately, in usability tests it became clear that users do not recognize properly the patient situation by these melodies. (see report by Sanderson http://www.upassoc.org/upa_publications/user_experience/past_issues/2006-3.html#sanderson ).

Urgency perception assurance

The sound should indicate the alarm condition.

The sound should reflect the urgency of the alarm condition: The experience of urgency is correlated to the pitch, amplitude and time intervals.

The urgency experience may comply with the alarm condition priority as specified in table 1 of section 6.1.2 of the international standard

A special sound should be provided for cases of technical alarm conditions (such as problems with the connections to the sensors).

Usability testing

Use the Training mode for the testing

Delays

IEC 60601-1-8 requires that the delays are disclosed in the instructions for use (section 6.4), encouraging manufacturers to avoid delays.

Disclosure by sound parameters

The risks of delays should be reflected in the alert parameters (pitch, amplitude, time intervals ...)

Functional testing

Make sure that the delays are acceptable by your users.

Flashing text

The international standard permits informative text to flash, as a means of alerting (section 6.3.2.2, Note 5).

Avoid flashing text

Flashing text is difficult to read and should be avoided.

Usability testing

Test the users comprehension of the flashing text.