Biomedical Engineering Reference
In-Depth Information
Other less common sterilization techniques include the use of ozone gas,
steam, plasma, vapor-phase hydrogen peroxide, and microwave generation.
These techniques all have their own set of human exposure and safety issues,
with OELs established for each. However, since most are in the gaseous state,
these potential stressors do not normally lead to a significant generation of any
solid/hazardous wastes or liquid waste streams that require proper regulatory
protocols. Of course, transportation regulations or the substances to the facility
are a regulatory concern and are dealt with in various fashions depending upon
the nation.
EH&S
AND
C
LEANING
,
E
TCHING AND
S
URFACE
P
REPARATION
The reliability and overall quality of the biomedical device in the field is
significantly impacted by its surface preparation during production. The most
common solvents used to clean the surface of devices include alcohols (e.g.,
isopropanol, ethanol), acetone, fluorinated/chlorinated hydrocarbons, and
water. Surface etching or anodizing normally requires the use of such acids or
alkalis as sulfuric acid, phosphoric acid, and potassium hydroxide. Mechanical
surface preparation techniques such as surface/scuff sanding and grit blasting
can produce airborne particulate matter concentrations that are at unsafe
levels.
Of course, each of these surface preparation techniques can produce
airborne concentrations of either vapors or aerosols in the breathing zone of
the employee. In addition, dermal exposures to most of these chemicals can
have significant negative consequences for those exposed. Thus, most
governmental labor agencies provide both short-term and long-term exposure
limits for the majority of surface preparatory chemicals and any resultant
airborne concentrations of undesirables produced as a consequence of
processing. With few exceptions, the three main target organs for exposures to
surface preparation chemicals and techniques include the eyes, skin, and
respiratory tract.
With respect to pertinent environmental regulations, the agents and/or
techniques utilized in the surface preparation of biomedical devices runs the
full gamut. Air pollution is a concern due to the possibility of significant
concentrations of solvent vapors being emitted from the factory stacks. Most
developed nations have some sort of established thresholds for hazardous air
