Sterilization Indicators Shine Light on Equipment, Human Errors

December 1, 2001

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Sterilization Indicators Shine Light on Equipment, Human Errors

By Kelli M. Donley

Sterile departments tend to be hidden from the rest of the hospital, carefully
tucked away on the bottom floor, with few signs pointing out their existence to
passing patients. Similarly, chemical and biological indicators are subtly slid
into sterilization loads, away from the hustle and bustle of other events taking
place in the busy department. While obscure and perhaps unappreciated, both CS
and indicators are a top priority in an efficacious healthcare center. Without
sterile instruments, shown to be ready for use by indicators, a hospital is

Biological indicators (BIs) consist of resistant microorganism spores. These
bacteria die at a slow rate and should be killed within a normal sterilization
process. BIs are the only method of confirming that the sterilization process
was successful in killing microbial spores.1

Chris Dwyer, director of marketing at Raven Biological Laboratories in Omaha,
Neb., said BIs consist of the most difficult bacteria to kill, ensuring the
sterilization process is efficacious.

"At their core, BIs are fairly simple--they're tough bugs," Dwyer
says. "We grow different species of nonpathogenic, spore-forming bacillus,
chosen for their resistance to specific sterilization process. We concentrate
them, calibrate them, and provide a growth medium suitable for recovering
injured but surviving microorganisms," he adds. "Using a concentrated,
calibrate life challenge offers the user a high level of assurance that their
sterilizer is functioning correctly."

BIs should be used daily in a steam sterilizer, and with every load
containing an implantable medical device. Implantable device loads processed
with ethylene oxide should also have a BI. These devices should not be re-used
until the BI demonstrates the equipment was processed correctly.

"AORN guidelines for steam sterilization indicate that a process
indicator should be inside each package. If not visible from the outside, then
an additional process indicator should be placed on the outside of the
package," Dwyer said. "The guideline indicates the BIs should be used
at least weekly, preferably daily, and in each load where an implantable device
is being sterilized."

It has also been written that it is more cost effective to monitor each load
with a BI rapid readout than to have to quarantine a system if a weekly or
monthly report indicates there has been a system failure. The cost of using BIs
daily is less than the money that would be spent on potential lawsuits involved
with nosocomial infections and patient harm.1

Chemical indicators (CIs) should monitor multiple or all parameters of the
sterilization process. Integrated CIs, those that determine if all chemicals in
the process are functioning properly, were created to determine the response of
BIs to the process. The difference is CIs do not contain spores.

Using CIs in each load, along with BIs ensures that local problems-human or
mechanical errors-can be determined. Individual packages within a load can also
be specifically isolated if an indicator shows the group of instruments was not
properly sterilized. This could be from sterilization error, or perhaps the
package was packed too tightly. Other problems that could occur include air
pockets or small leaks in a steam sterilizer, packs that are too densely
wrapped, and low humidity in the area.1

Without CIs present, there is a significant risk that sterilization errors
will go undetected.

"How critical is it that the items being processed become sterile? If it
could endanger patient safety, then I would use BIs and CIs in every load,"
Dwyer said.

Dwyer says that in today's uncertain political climate, healthcare workers (HCWs)
should be more prepared to handle the unexpected. This includes be ready to
sterilize equipment efficiently every time. He says BIs and CIs only aid this
process and provide peace of mind.

"In light of recent events, it is more important than ever for HCWs to
understand the sterilization process and be up to date on current practices and
products. With instant news and instant messaging, there is greater opportunity
for instant misinformation," he said. "Those involved in sterilization
need to be able to make informed decisions regarding their facility's use of BIs
and CIs to ensure patient and employee safety. How to load the sterilizer, where
to place the BIs and CIs, how many, and how often are all questions that can
only be adequately addressed by well informed professionals."

CS managers who are interested in more information about these tools should
contact a company representative. This person will walk through the department
and will be able to properly match sterilization systems with BIs and CIs. Also,
managers can prepare a frequently asked questions list with the representative
and use the information as an educational tool for staff members.

Indicator Manufacturers

The following companies produce both biological and chemical indicators:

Allegiance Healthcare Corp,  

Anderson Medical Products Inc,

Becton Dickinson Microbiology Systems,

Getinge/Castle Inc.,

Kern Medical Products Corp,

Propper Manufacturing Company,

Raven Biological Laboratories,

SPS Medical Supply Corp,


3M Heath Care,