The Role of Human Factors Guidelines in Designing Usable Systems: A Case Study of Operating Room Equipment

Recently, the Association for the Advancement of Medical Instrumentation (AAMI) adopted human engineering guidelines which represent the first formal compilation of general human factors materials for use by medical equipment designers. The applicability of these guidelines was addressed by evaluating a new microprocessor based device based on the AAMI guidelines and again using broader principles and techniques from human-computer interaction (HCI). While the device met the majority of applicable guideline recommendations, the second review identified more substantive human engineering deficiencies not addressed by the AAMI recommendations. Examples included hidden modes of operation, inconsistent signal-action mapping, complex resetting sequences, and violations of expectations. Application of these HCI issues predict confusion in using the device and limitations in diagnosing and correcting problems. Interviews with users of the device confirmed these predictions by finding that participants had major gaps, inconsistencies, and misconceptions in their mental models of the device. This investigation suggests that, in an era of microprocessor based devices, traditional human factors guidelines are only a starting point for a comprehensive approach to equipment design. To be effective as design aids (especially for designers not trained in human factors), human factors guidelines must address and incorporate HCI issues. Additionally, emphasis needs to be on methodologically oriented principles (Gould, 1988; Woods and Eastman, 1989) to aid designers in the process of design.