OR Manager - December 2019 - 17

Sterilization trumps high-level disinfection for semicritical items
Sterilization & infection prevention
n the never-ending quest to improve
patient care, we are always seeking
better ways to process medical
devices. Many leading experts now recommend
transitioning from high-level
disinfection (HLD) to sterilization for
semicritical items.
I
Semicritical items are instruments
or objects that contact mucous membranes
or nonintact skin of a patient,
but do not usually penetrate the blood
barrier or other normally sterile areas
of the body. If possible, these items
should be sterilized; if not, they should
undergo HLD, which would be expected
to destroy all microorganisms except for
large numbers of bacterial spores.
Past vs present
The use of HLD for semicritical items is
based on the Spaulding Classification
System devised more than 50 years
ago. Given the types of sterilization and
medical devices available back then, it
was acceptable to process all semicritical
items using HLD. Recent research,
however, shows some pathogens are
resistant to HLD, medical devices and
instructions for use (IFU) are becoming
more complex, and new low-temperature
sterilization modalities make it
possible to sterilize instruments in the
same amount of time-or less-as required
for HLD.
In 2017, the Association
for the Advancement
of Medical Instrumentation
(AAMI) hosted an Endoscope
Stakeholders meeting at which industry
leaders and experts discussed infection
prevention practices related to the
use of HLD for flexible endoscopes.
Based on research and discussions at
the meeting, it was recommended to
transition flexible endoscopes (many
of which are classified as semicritical
items) from HLD to sterilization. In addition,
the AAMI standards and AORN
guidelines recommend sterilization over
HLD for semicritical items.
Evaluating efficacy
A major benefit of transitioning from
HLD to sterilization is that sterilized
items are dry and packaged, whereas
those that have undergone HLD are
unpackaged and wet after the process
(sidebar, p 18). The primary difference,
however, is the significantly greater effectiveness
of sterilization compared
with HLD.
HLD kills all microbial organisms
but not necessarily large numbers of
bacterial spores, whereas sterilization
is a validated process used to render
a device free from viable microorganisms
(providing a sterility assurance
level of 10-6). HLD does provide a 6-log
reduction in microbial contamination;
however, HLD does not have a sterility
claim and therefore does not have a
sterility assurance level. Sterilization
offers twice that amount at a 12-log
reduction.
Sterilization provides quality process
monitors that verify the efficacy
of the sterilization process. Sterilizers
are tested at least daily with a biological
indicator process challenge device
(BIPCD), which provides a highly resistant
challenge to the sterilization process
and is a direct measure of the lethality
of a sterilization cycle. The BIPCD
contains a BI with a large number of
highly resistant viable bacterial spores
that are most resistant to that method
of sterilization.
This method of challenging the sterilization
process is so reliable that sterilizer
manufacturers use BIPCDs as part
of the validation of their sterilization
cycles during the half-cycle validation
testing.
Sterilization cycles are monitored
with physical monitors that record the
sterilization parameters. These parameters
are reviewed for acceptance before
releasing the load, and the records are
maintained.
All items that undergo sterilization
have both internal and external chemical
indicators (CIs). The external CIs
show that the package has been exposed
to the sterilization process, and
distinguish between processed and unprocessed
packages. Different types
of internal indicators may be used, but
they must meet the qualifications described
in the ANSI/AAMI/ISO CI standards.
Sterilized
semicritical items are provided in a ready-to-use state and are safe for
patient use.
Source: Susan Klacik. Used with permission.
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OR Manager | December 2019
17
Quality monitors are also available
for HLD. These monitors measure either
the minimum effective concentration-
the minimum concentration of HLD that
achieves the claimed microbicidal activContinued
on page 18
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OR Manager - December 2019

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