 Medical
device developers are rapidly realizing the benefits and challenges
of using CAD and manufacturing tools, rapid prototyping services,
mold design and support services, and new Web-based product
development resources. Speed-to-market was the mantra in the
1990s and with the growth of — or rather the "shrinking of"
— computerization, more features can be built into next-generation
products.
High Tech but Easy-to-use
I believe that in spite of all the hype about
speed and power and the ability to do things better than ever
before, we must consider other factors. The bottom line is
the ability to create a product that can and will be used
in a way that avoids setup problems and mistakes in usage
in the field, and offers intuitive simplicity. Medical devices
provide life-saving therapies if used properly. They are used
in several settings; emergency rooms, during critical surgery,
and in the delivery of medication. Any mistakes in setup,
use, or function of the device can put the life of the patient
at risk. Fail-safe systems are not really fail-safe, as has
been repeatedly shown in reports of user-caused errors.
Medical device designers are faced with tough
challenges, especially since regulatory agencies worldwide
are mandating fail-safe products. It is the responsibility
of the product designer and engineer to create the product
in a way that will meet the needs of the user as efficiently
as possible while not compromising the wealth of features
that can be built into the product.
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An Infusion Pump
Consider, for example, a new infusion pump for
IV drug delivery. The design engineer must understand issues such
as:
- What solutions or drugs will the pump be
used for?
- Will it be used for high volume or slow
infusion of low volumes?
- Are the drugs to be infused controlled
substances that need to be stored securely?
- Who will use this pump - a trained health
care professional such as a nurse or physician, or will
it by used at home by the patient or their family?
- Where will the pump be used - in the emergency
room, ambulance, intensive care unit, on the hospital floor
bedside or at home, or will it be for the active ambulatory
patient?
- Will this product be used in developing
countries?
- What language or symbology will be used?
- If the unit is used in a harsh, environment
what are the chances damage will be incurred?
- How will maintenance be performed and I.V.
tubing and sets be changed?
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A Clean Sheet of Paper
The designer starts with a clean sheet of paper
and initiates designs that meet the physical and functional requirements
of the product. Considerations include the shape, colors, controls,
and interfaces that give the product its unique characteristic that
will appeal to the user and enhance their ability to do their job.
Ease-of-use and reliability separate the mundane products from the
great ones. The so-called plug-and-play product will more quickly
be accepted by the user than one that requires extensive in-service
training to be able to use it.
The Layout, Wall Thickness,
and Materials
Once the initial design layout is complete, the
mechanisms, boards, cabling, and controls can be laid out more formally
and built into the design. CAD systems allow rapid assessment of
space utilization and areas of interference. Proper material selection
can offer thinner wall sections, longer runs, and greater resistance
to breakage with better impact resistance. By using appealing, colored
thermoplastic elastomers (TPEs) in the housing, a product can be
given drop impact protection and an enhanced appearance. Color displays
that have high resolution and readability from wide angles and distance
add to the tendency of the product to be used correctly. The science
of human factor interaction with the user interface must be considered
as new regulations mandate systems that are designed to prevent
mistakes.
The manufacture of the product with a good idea
of annual volume requirements must also be considered early in the
design of the product. This factor will dictate what type of tooling
will be built and used to make the parts. If new software is developed
and used, it must be carefully and extensively tested and validated.
Meanwhile, during all this development, the regulatory requirements
must be met. Design controls requirements need the attention of
the design team throughout the development program, not just when
the product is ready to be marketed. A properly run development
program will support a filing to the FDA, for example, and the filing
will be tremendously easier.
Inside or Outsource
Product development programs of any size can be
maintained and managed internally or by outsourcing some components
of the project. Depending on the talent and resources on staff within
an organization, the decision can be made to use the internal skill
set or to rely on external experts. For many companies, the use
of outside resources makes good business sense-allowing the company
to do what it does well while outsourcing parts of the project to
outside pros. This collaborative effort results in obtaining a better
product, in less time, and for less cost.
It is the ultimate responsibility of the design
engineer to develop the products that customers need, as well as
adhere to the requirements set for that product. Don't overlook
the need for in-process product reviews. Evaluate and test the prototypes.
Engage typical users with the product in the early stages of the
program. The feedback from the non-informed, eventual user can be
sometimes more insightful than a whole roomful of engineers and
designers. Consider the product from cradle to grave. Throughout
the process, consider product lifecycle, as well as disposability,
waste disposal (are batteries a disposable part of the product?)
and whether the device is recyclable.
Finally, it can be a challenge to develop a new
medical device given the current engineering and regulatory environment.
But, if executed properly, the process can be profitable, gratifying,
and an enjoyable occupation!
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