Sterilization Indicators Shine Light on Equipment, Human Errors

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Sterilization Indicators Shine Light on Equipment, Human Errors

By Kelli M. Donley

Central 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 immobilized.

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,

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