Testing of Auditory Clinical Alarms in ICU/CCU

Abstract

Almost all medical devices in ICU/CCU have a built-in clinical alarm system to alert when there are changes in a patient’s condition. The objective of this study is to investigate the effectiveness of the existing alarm system in ICU/CCU. Two summative usability tests were conducted to test the effectiveness of existing and new alarm signals based on IEC 60601-1-8:2006 standard. Further formative test is conducted to study the perception of urgency associated with a number of tones in the alarm signals. The findings indicate that the existing auditory alarm signal in ICU/CCU does not indicate the urgency of the alarm conditions. The simulation test indicates that the respondents preferred 282Hz, 500Hz and 800Hz for low, medium and high-risk alarm respectively. The one-sample proportion z test on urgency mapping indicates that the proportion of responses for the highest risk is more than 50% for a single tone test signal. These results show that a single tone test signal being perceived as the highest risk is regardless of frequency. It can be concluded the auditory alarm designed based on this IEC 60608-1-8:2006 standard is not effective. As such it is proposed that the incorporation of the new alarm frequencies and tones will improve the effectiveness of the alarm signal