Designing Medical Devices for All Users

Who is the user of your medical device?  We often design our products with either the end user or the major skilled user (such as a physician) in mind.

Medical devices are often touched by someone in addition to the final intended user.  As medical device designers, we need to consider all the different users and incorporate their needs into the final device design.  Below are some points to consider.

• Identify the possible environments where your device may be used. If the product will be sold in multiple countries or regions of the world, determine whether the device has the same environment, as well.
• Identify all the users of the device, not just the target user(s), but others who will interact with the device. The users’ skills may also be different in each environment.  Therefore, the user needs in each of the different settings should be examined.  Identifying the users can be difficult.  One way to capture the users could be to follow a similar or mock product through its use within each environment.
• Determine how each user interacts with the device: One of the most useful ways to do this is by building Customer Interaction Diagrams or Use Case Diagrams. These diagrams allow you to model how people interact with the device.

Below are two examples which help illustrate these points.

The first example is a wound care dressing where the dressing is stocked in the hospital, applied to the patient while at the hospital, but is required to be changed for a time once the person has been discharged.  The person could be discharged to a skilled care facility or to their home.  Once home, the person changing the dressing could be the patient, an unskilled caregiver, or a skilled caregiver.  For this example, we now have 3 different environments and multiple skill sets for interacting with the dressing, plus the stockroom staff.  The diagram below further details the requirements for the users in the hospital environment.

Figure 1: Example of user requirements for each user in the hospital environment for the wound dressing example

How might the requirements change in the different care settings or with the different user skills?

The second example is a power surgical instrument.  In the US, this medical device will be used in a hospital or ambulatory surgical setting.  However, in Europe the same device could be used in a physician’s office.  In a surgical setting, the device is used by the surgeon during the surgery, handled by the OR nurse during setup and the surgery, will be cleaned and sterilized by either the hospital or a third party service, and stored for the next procedure.  In a physician’s setting, the physician and a nurse would be responsible for all the activities handled by multiple groups in a hospital.

Through these examples, you see that the users of medical devices are often more diverse than the key targeted users and they have needs distinct from those of the target user.  As designers of medical devices, you have the obligation to identify these requirements and translate them into design inputs.