Ergonomics, patient safety, and engineering ethics: a case study and cautionary tale

Poor ergonomic design of complex medical equipment can lead to patient morbidity and mortality while still operating correctly. For example, patient controlled analgesia (PCA) machines are used extensively for postoperative pain, and can be programmed to give intravenous morphine every time the patient pushes the demand button. Unfortunately, such devices sometimes have poorly designed user interfaces. As an example, ergonomic flaws in the design of the Abbott Lifecare 4100 PCA Plus II machine have been held to be ultimately responsible for a number of deaths. However, despite being notified of this problem, the manufacturer was unwilling to upgrade the unit to a safer design, claiming that there was no problem with the unit in the first place that could not be handled with proper user training. This case draws attention to two important points, namely, (i) ergonomic studies on medical equipment may be abandoned in favor of early market penetration, and (ii) even when potential improvements are developed, they may be ignored by manufacturers, who may sometimes take a completely amoral approach to business decision making, focusing entirely on what is legal and expedient rather than being driven by any particular moral or ethical principles.