Applying human factors engineering to medical device design: An empirical evaluation of patient-controlled analgesia machine interfaces

This thesis was motivated by the fact that poor design of medical devices plays a significant role in inducing human error. The hypothesis explored in the thesis is that medical equipment can be made safer, more efficient, and easier to operate by applying human factors to equipment design. The Lifecare 4100 PCA Plus Infuser, a commonly used medical device was chosen as the testbed. The thesis first describes an analysis of the Lifecare PCA interface which employed cognitive task analysis and human factor design principles. Guided by the results of the analysis, a redesigned interface was developed. A set of empirical evaluations was then conducted to compare the redesigned interface with the existing Lifecare PCA interface with novice and experienced PCA users. The results of the evaluations provided evidence of improved efficacy of the redesigned interface over the existing Lifecare PCA interface; programming times were significantly faster and fewer errors were made with the redesigned interface than with the existing one. Additionally, a significant portion of the novice population reported lower mental workload with the redesigned interface, and the experienced population reported comparable levels of workload for both interfaces, despite having much more extensive experience with the existing one. These findings demonstrate that PCA machine operation can be improved by adopting a human factors approach to interface design. They also lend support to the broader prospect of applying these methods to other devices to improve medical device safety.