Human-Equipment Interface Technological transformations have brought widespread use of machines and tools to the work setting. Owing to this, such concepts as human-machine/equipment interfaces have become increasingly prominent. In its simplest form, human-machine interface (HMI) refers to the point or extent of interaction between a machine and its operator; taken literally, it is the area of the machine and that of the human that interact during the execution of a task. As the use of machines at the workplace increases, the HMI concept becomes more relevant. This is particularly because machines and equipment keep getting rather complicated and advanced, and as users make more and more use of them, the risk of error increases. In this regard, manufactures are under pressure to continually develop tools and machines that align with human anatomy, limitations, and skills to make the user-machine interface safer for users (Flasporer, et al., 2002).

Human-Equipment Interfaces in a Hospital Setting

In a hospital setting, medical practitioners interact with a wide array of medical devices -- for instance, i) they have to feed patients' health and medical records as well as prescriptions into a computer, in which case they interact directly with the screen through the eyes, and the keyboard or mouse through the hand; ii) they have to infuse patients using the infusion pump, where they use both their eyes and their hands to set the desired flow rate on the display surface; iii) they have to use oxygen machines to treat patients, and similarly have to set the flow control knob at the desired levels, and so on (Sawyer, 2014)....

All these represent examples of user-machine interfaces in a hospital environment that though important to a patient's healing environment; need to be controlled in order to realize the desired outcomes. It is for this reason that manufacturers are required to design their equipment in line with humans' basic sensory and physical capabilities, which include reach, strength, manual dexterity, hearing and vision (Sawyer, 2014). Effective equipment-designing is one of the key ways of controlling user interfaces and making them safer for both practitioners and patients.
The Need to Control Human-Equipment User Interfaces

Failure to control user interfaces in hospital settings could result in serious consequences (FDA, 2015). There have been numerous cases where user interfaces (both hardware and software interfaces) induced serious errors that resulted in injury and at times even death of patients (FDA, 2015). A perfect example is when a nurse, not realizing that a newly-acquired oxygen machine is scaled in discrete as opposed to continuous numbers, sets the control knob between 1 and 2 liters/min, causing a patient to become hypoxic since there is no oxygen flow (Sawyer, 2014). Another common occurrence is where a nurse misreads 7 as 1 on the infusion pump, resulting in the over-infusion of a patient; or where a nurse fails to enter dosage levels in a radiation treatment device, just because the device software did not prompt them for such data, and instead picked up a default value without giving any signal in regard to the same (Sawyer, 2014). Also quite common are cases where a crucial alarm system is disabled without…