Vibrotactile Alarm Display for Critical Care

An essential task of care takers in an intensive care unit (ICU) is the continuous monitoring of vital body functions. To indicate that an important vital signal is above or below a certain threshold, multiple monitoring devices and measured parameters cause a large number of different urgent alarms. About 350 acoustic alarms per patient are issued per day which may result in alarm-fatigue, a desensitization for alarms. This critical condition causes a delayed or inadequate response time to alarms which in turn can have severe consequences not only for the patients, but finally also for the care takers as second victims in case of critical incidents. In cooperation with healthcare professionals, we designed a new alarm distribution system and alarm display that reduces the acoustic noise while not compromising alarm delivery to the care takers on the ICU. Each class of alarm ranging from technical alarms to critical red alarms it attributed with an adequate sensory channel ranging from on-body visual cues and vibration patterns to acoustic alarms. We developed a body-worn pervasive device by which former acoustic alarms are now presented by tactile stimuli on the upper arm of a care taker. We evaluated the perception time and error rate under task conditions that mimic the concrete demand of care tasks such as adjusting medication or bedding a patient. We evaluated the perception, learnability, distinguishability and perceived urgency for different vibration patterns. Our results show that the upper arm is a promising position to alert nurses with vibrations and our patterns conveyed different levels of urgency.