Visual Interfaces for Medical Alarms

Medical Alarms can also be visual. Some research has been done to improve hemodynamic monitoring device displays. Responses to abnormal values are delayed when workload for the anesthesiologist is high,33 prompting interest in improving current visual displays. Furthermore, the clinical decision process often rests on the practitioner's interpretation of a patient's hemodynamic parameters. Thus, it is important that this information be presented in a way that assists with decision making and minimizes errors of interpretation.

Two observational studies have compared different visual displays of data to traditional visual monitors.34,35 Each evaluated errors in performing a designated task as well as response time to completion. One measured how quickly subjects recognized a change in a parameter34 and the other measured how long it took for anesthesiologist to manipulate a set of abnormal parameters to a stable set.34,35 Both studies used computerized simulations of anesthesiology cases, with subjects serving as their own controls. In one study, subjects were required to identify when changes in physiologic parameters occurred using different visual formats.34 Response time and accuracy to the simulated cases was compared among a histogram, polygon, and numerical display. Subject responses were more accurate with the histogram and polygon displays (p=0.01).

In the other study, 20 anesthesiologists with an average working experience of 5 years were required to perform specific tasks on an anesthesia simulator35 (see Chapter 45). The tasks consisted of returning a set of abnormal hemodynamic parameters to normal using intravenous medications. A specific time for the completion was determined and this time was compared among 3 different visual interfaces. Trial time was significantly shorter with the traditional display (p<0.01), yet there were fewer failed trials using the other monitor displays (26% with the profilogram display, 11% with the ecological display, and 42% with the traditional display). The slower time with the non-traditional displays could have resulted from the subject's lack of experience with such screens. Nevertheless, the newer interfaces produced fewer failed attempts at arriving at the appropriate hemodynamic parameters on the simulator, suggesting that these displays might improve the clinical decision process.

None of the studies comparing traditional auditory medical alarms and visual monitor displays reported any adverse event associated with the newer technology. However these studies are limited by the artificial nature of the experiments.29,34,35 Anesthesiologists have many tasks to perform during anesthesia, often amidst great distraction. Attending to monitors is only one aspect of their workload. Because these laboratory experiments do not include all of the different "real world" problems and diversions that an anesthesiologist might face, it is difficult to generalize them to the workplace. Also, because this experimental task might be taken out of the context of caring for a patient in the operating room, the subject might simply focus on the completion of the experimental task and not consider other tasks that the anesthesiologist would be required to perform in a real situation.

From www.ahrq.gov