AORN Sterilization 2 — Questions and Answers
Question 1: Which biological indicator organism is used to verify the efficacy of ethylene oxide (EO) sterilization?
- Geobacillus stearothermophilus
- Bacillus atrophaeus (Correct answer)
- Clostridium sporogenes
- Staphylococcus aureus
Correct answer: Bacillus atrophaeus
Bacillus atrophaeus spores are the standard biological indicator for ethylene oxide sterilization cycles.
Question 2: A surgical instrument with a lumened channel requires what minimum processing classification according to Spaulding?
- Non-critical
- Semi-critical
- Critical (Correct answer)
- Intermediate
Correct answer: Critical
Lumened instruments that contact sterile tissue or the vascular system are classified as critical items requiring sterilization.
Question 3: What is the recommended minimum free air space around packages in a steam sterilizer load?
- No spacing required if items are wrapped
- Items should be loosely arranged with space between packs (Correct answer)
- Packs must be separated by exactly 1 inch on all sides
- Items may be stacked tightly if chamber pressure is increased
Correct answer: Items should be loosely arranged with space between packs
AORN guidelines require loose arrangement with space between packs to allow adequate steam penetration and air removal.
Question 4: How long must ethylene oxide-sterilized items be aerated at room temperature before safe patient use?
- 2 hours
- 8 hours
- 24 hours
- Up to 12 days depending on material (Correct answer)
Correct answer: Up to 12 days depending on material
EO aeration times vary by material composition — some items require up to 12 days at room temperature to off-gas to safe EO residual levels.
Question 5: Which sterilization method uses the lowest temperature and is therefore safest for heat-sensitive electronics?
- Flash steam at 132°C
- Hydrogen peroxide plasma (Correct answer)
- Dry heat at 160°C
- Gravity displacement steam at 121°C
Correct answer: Hydrogen peroxide plasma
Hydrogen peroxide gas plasma sterilizes at approximately 50°C, making it suitable for heat- and moisture-sensitive devices.
Question 6: What does a Class 5 chemical integrator indicate when exposed to a steam sterilization cycle?
- Only that the package was exposed to steam
- That time, temperature, and steam quality conditions were met (Correct answer)
- That the load is sterile with certainty
- That the outer wrap was not compromised
Correct answer: That time, temperature, and steam quality conditions were met
Class 5 integrators respond to all critical parameters (time, temperature, and steam) but do not confirm sterility with the certainty of a biological indicator.
Question 7: An event-related sterility policy means that shelf life of a sterile package is determined by:
- A fixed expiration date printed at time of sterilization
- Package integrity and storage conditions rather than a calendar date (Correct answer)
- The type of sterilization method used
- The biological indicator result for that load
Correct answer: Package integrity and storage conditions rather than a calendar date
Event-related sterility holds that a properly packaged sterile item remains sterile until an event (e.g., moisture, tear, or puncture) compromises the packaging.
AORN Sterilization 2
Which biological indicator organism is used to verify the efficacy of ethylene oxide (EO) sterilization?