Sterilization Methods and Monitoring Flashcards

A Class 5 chemical indicator is used to monitor a steam sterilization cycle. After the cycle, the technician observes that the indicator has not reached the 'accept' window. What is the most appropriate next step?

Answer: Quarantine the load, investigate the cause of the failure, and reprocess the items.

A Class 5 chemical indicator, or integrating indicator, is designed to react to all critical parameters of the sterilization process (time, temperature, and steam). [1, 6] If it indicates a failure, the load must not be released. The proper procedure is to quarantine the entire load, investigate the potential cause of the sterilizer or process failure, and reprocess all items in the load once the issue is resolved.

Which of the following sterilization methods is most appropriate for a heat-sensitive, moisture-sensitive flexible endoscope?

Answer: Ethylene Oxide (EtO) gas

Ethylene Oxide (EtO) is a low-temperature sterilization method that is safe for heat-sensitive and moisture-sensitive items. [11, 15] Steam autoclaving and dry heat use high temperatures that would damage a flexible endoscope. [11] While peracetic acid is a liquid chemical sterilant suitable for some heat-sensitive items, EtO gas is often preferred for complex devices like flexible endoscopes due to its ability to penetrate long lumens and channels.

What is the primary purpose of aeration following an Ethylene Oxide (EtO) sterilization cycle?

Answer: To remove residual toxic gas from the sterilized items.

Ethylene Oxide (EtO) is a toxic and carcinogenic gas. The aeration phase is a critical safety step to allow the gas absorbed by the sterilized materials to dissipate, ensuring that the residual EtO levels are below the permissible exposure limits set by OSHA before the items are handled by staff or used on patients. [10, 16]

A sterile processing technician is preparing to run a routine biological indicator (BI) test in a steam sterilizer. According to HSPA standards, what is the recommended frequency for this test?

Answer: At least weekly, but preferably every day the sterilizer is in use

Best practices and standards, such as those from AAMI, recommend that biological indicator monitoring of steam sterilizers be performed at least weekly, and preferably daily, for each sterilizer and for each cycle type used. [23, 28] Additionally, any load containing an implantable device must be monitored with a BI.

The biological indicator for steam sterilization contains which type of microorganism?

Answer: Geobacillus stearothermophilus

The microorganism used in biological indicators for steam sterilization is Geobacillus stearothermophilus. [4, 7] This organism is chosen because its spores are highly resistant to heat and steam, making it an ideal challenger to verify the lethality of the sterilization process. [5, 12] Bacillus atrophaeus is used for Ethylene Oxide (EtO) and dry heat sterilization.

During the monitoring of a steam sterilizer, which of the following provides direct evidence of the lethality of the process by killing highly resistant microorganisms?

Answer: Biological indicator (BI)

A biological indicator (BI) is the most accepted means of monitoring sterilization because it directly determines whether the most resistant microorganisms (bacterial spores) have been killed. [30] While physical and chemical indicators show that the parameters for sterilization were met, only a BI confirms the actual lethality of the cycle. [27, 30]