Biomedical Engineering Reference
In-Depth Information
in which it will be used. A simple oversight can lead to
terrible delays, not to mention costs and frayed nerves, as
well as having to install or customize the facility to
accommodate the equipment's needs.
with the aid of computer-aided design (CAD) software,
preparing the necessary drawings for an instrument
maker to follow would have been prohibitively expen-
sive. In this case, the use of standard modular hardware
in a novel configuration accomplished the objective at
a minimum expense.
Criteria for involvement
Humanitarian use devices (humanitarian device
exemptions)
Humanitarian use devices are exempt from normal FDA
510(k) and PMA processes. The FDA allows the use of
such equipment on a limited number of patients where
the product might be their best hope (hence the term
''humanitarian device exemptions''). The hospital usually
treats devices of this sort as investigational and processes
the introduction of this technology by way of the IRB.
Under the HDE, such devices need not go through the
rigorous evaluation that the CE, as a technical consultant
to the IRB, must perform. However, an assessment of its
safety and efficacy must be weighed against the possible
benefits that the product can bring to the patient. In most
cases, the risk of patient injury is far outweighed by the
alternatives; e.g., permanent disability or death of the
patient if he is left untreated.
Clinical engineering services are provided in response to
the following conditions:
Requests by human investigation committee (HIC)
or IRB
Requests by medical staff
Requests to meet a ''critical'' patient need
Humanitarian use devices (humanitarian device
exemptions)
Requests by HIC or IRB
Investigational devices are evaluated for safety and effi-
cacy prior to use in the hospital as part of a study, usually
as part of the FDA premarket approval (PMA) process.
Less frequently, the CE department assesses devices that
are designed and constructed by in-house staff.
Requests by medical staff
Often, doctors return from conferences brimming with
ideas and requests to introduce new products into the
hospital. Where the products show promise of being
more cost-effective without compromising on safety and
efficacy, they become the subject of extensive CE eval-
uation and clinical trials. Through this mechanism, ben-
eficial, innovative technology can be made available to the
patient population.
Redesigning or customizing
medical devices
Improving ergonomics
Not all products come customized to a user's personal
specifications. By helping to improve the ergonomics of
equipment, the CE can help the clinician to perform
a better job more safely. Because medical devices are
regulated by the FDA, care must be exercised to ensure
that specifications are not altered in such a way as to
conflict with these regulations. Modifications are typi-
cally limited to helping improve a product's ergonomics
and do not necessarily change its specifications or per-
formance. Examples of such modifications include the
following:
Mounting an electrosurgical unit (ESU) on a wheeled
cart at waist-level height, so that a 5
0
2'' tall doctor can
operate comfortably
Providing a padded armrest and a comfortable chair
for a surgeon who is reconstructing a patient's
middle ear
Selection of foot-pedal controls to prevent accidentally
stepping on two pedals at once
Placing foam pads to protect a surgery patient from
pressure necrosis and decubitus ulcer formation
Some in-house designs have been patented, but for the
most part, the CE makes these adjustments based
Meet a ''critical'' patient need
At times, the caregiver or the CE conceives of ways to
customize or to modify a device to expand its capa-
bilities, thus providing more benefit to the patient and
possibly to the user. The CE possesses the education,
intellect, skill, and training to perform such custom-
ization or re-engineering of a device. Such modification
typically requires that the CE expend time in research.
The following example illustrates the way the CE does
engineering. For certain procedures, OR patients must
be positioned on their side, with their 'arms on the side
in parallel fashion. Standard arm rests that clamp onto
the OR table do not allow this positioning. Alerted to
this clinical need, the CE working with the OR staff
conceived of a double-decker design. Some research
revealed that the local armrest manufacturer sold
modular components. A double-decker armrest was
created from modular components. In-house manufac-
ture of a specialty device such as this would not have
been cost-effective and would have required extensive
time to design and prepare mechanical drawings. Even
