Page 56 - Safety Risk Management for Medical Devices

Usability Engineering and Risk Analysis 35

Figure 8.2 Model of User-Medical Device interaction.

2. Through either a perception error, or a cognition error, the User takes an
action that creates a Hazard. This action could be on the Medical device, or
outside of the Medical Device, e.g., a diabetic patient misreads, or misinterprets
the glucose reading on a glucose monitor and administers too high an insulin
dose to him/herself.
Using this model facilitates prediction of potential use errors, and also helps
identify the required human capabilities for interacting with the medical device.
This in turn can guide the design of the UI for safer and more effective medical
devices.
Perception examples: See, Hear, Feel. Perception may be distorted, disrupted, or
impossible depending on the environmental conditions. For example, a surgeon may
not be able to feel surface texture with a gloved hand.
Cognition examples: Interpret, Know, Compute, Decide. Cognition also, may be
difficult or compromised under conditions of stress, fatigue, heavy or multitasking
workload.
Action examples: Press, Touch, Twist, Pull, Push, Follow. Actions may be challenged
under conditions of fatigue, pain, injury, or barriers such as gloved operations.