Page 161 - Biomedical Engineering and Design Handbook Volume 2, Applications

140 MEDICAL DEVICE DESIGN

Devices must be rugged. They should be designed not to break if they are to fall on the floor dur-
ing a medical emergency. They must be able to withstand fluids that are sometimes all around in a
medical setting. They must be able to tolerate electrical surges, and they should operate even when
placed in unconventional orientations.
If they can be made to work correctly in dusty or dirty environments, or at extreme temperatures,
then they can be used under severe field conditions. However, most medical devices are expected to be
used in clean conditions at moderate temperatures. Such conditions prevail in most modern hospitals
in the developed world. In third-world countries or during combat, however, medical environments are
not as well-controlled.

4.7.11 Governmental Regulatory Requirement
The U.S. Food and Drug Administration (FDA) is the main regulatory body for medical device
approval in the United States. It is the job of the FDA to determine that a new medical device is both
safe and effective. Each medical device must meet both criteria of safety (it can do no harm) and
effectiveness (it must do what it purports to do).
Most new medical devices must undergo a process of premarket notification. Certain class I
devices (see the FDA Web site at www.fda.gov) are exempt from this requirement. There are certain
respiratory-related devices in the list of class I devices, but, in general, they are ancillary to respira-
tory diagnostic measurement and health care.
If the medical device is intended to be used in a new way or is based on a fundamental scientific
technology different from other devices, then the approval process is extremely thorough and is
called premarket approval (PMA). If the device can be justified as a minor modification of a device
that has received prior FDA approval for manufacture, then it undergoes an abbreviated 501(k)
approval process. Neither of these processes is a trivial step, and specialists are often employed just
to guide the device through to approval.
Medical device approval processes in other countries may or may not be similar to the process in
the U.S. Mutual Recognition Agreements and may be negotiated between different governments to
allow judgments by national conformity assessment bodies to be accepted in other countries.

REFERENCES

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American Association for Respiratory Care, 1994b, Clinical Practice Guideline: Static Lung Volumes. Respir
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American Association for Respiratory Care,1996, Clinical Practice Guideline: Spirometry. Respir Care.
41(7):629–636.
American Association for Respiratory Care, 1999, Clinical Practice Guideline: Single-breath Carbon Monoxide
Diffusing Capacity. Respir Care. 44(5):539–546.
American Thoracic Society, 1991, Lung Function Testing: Selection of Reference Values and Interpretive
Strategies. Am Rev Respir Dis. 144(5):1202–1218.
American Thoracic Society, 1995a, Single Breath Carbon Monoxide Diffusing Capacity (transfer factor). Am Rev
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American Thoracic Society, 1995b, Standardization of Spirometryó1994 Update. Am Rev Respir Dis.
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Clausen, J. L. (ed), 1982, Pulmonary Function Testing Guidelines and Controversies: Equipment, Methods, and
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CNN, 2000, Oxygen tank mix-up blamed in deaths of Ohio nursing home residents. Dec. 14, 2000;
http://www.cnn.com/2000/US/12/14/nursinghome.deaths.ap.