CNOR Surgical Asepsis and Sterility 3 — Questions and Answers
Question 1: Ethylene oxide (EtO) sterilization is preferred for which category of items?
- Items requiring rapid turnover between cases
- Heat- and moisture-sensitive items such as flexible endoscopes (Correct answer)
- Implants that require biological indicator confirmation before use
- Items with heavy bioburden that steam cannot penetrate
Correct answer: Heat- and moisture-sensitive items such as flexible endoscopes
EtO sterilization is used for heat- and moisture-sensitive items that would be damaged by steam.
Question 2: Which biological indicator organism is used to monitor the efficacy of steam sterilization?
- Bacillus atrophaeus (subtilis)
- Geobacillus stearothermophilus (Correct answer)
- Clostridium sporogenes
- Staphylococcus aureus
Correct answer: Geobacillus stearothermophilus
Geobacillus stearothermophilus spores are the standard biological indicator for steam sterilization because of their high heat resistance.
Question 3: What is the minimum safe distance an unsterile person must maintain from a sterile field?
- 6 inches
- 12 inches
- 18 inches (Correct answer)
- 24 inches
Correct answer: 18 inches
Unsterile personnel must maintain at least 18 inches from any sterile field to prevent inadvertent contamination.
Question 4: During a procedure, a sterile instrument accidentally contacts the anesthesia screen. The instrument should be:
- Returned to the back table if no visible contamination is present
- Wiped with a sterile towel and returned to use
- Considered contaminated and removed from the sterile field (Correct answer)
- Rinsed with sterile saline before reuse
Correct answer: Considered contaminated and removed from the sterile field
The anesthesia screen is in the unsterile anesthesia zone; any item contacting it is immediately considered contaminated.
Question 5: Which statement about sterile draping is correct?
- Drapes may be repositioned if moved less than two inches
- Once placed, sterile drapes should not be moved (Correct answer)
- Drapes can be lifted and repositioned using sterile gloves
- Drapes may be adjusted by the circulator from the unsterile side
Correct answer: Once placed, sterile drapes should not be moved
Once sterile drapes are placed, they must not be moved because shifting could bring contaminated undersurfaces into the sterile field.
Question 6: Hydrogen peroxide plasma sterilization is contraindicated for which items?
- Stainless steel instruments
- Cellulose-based materials such as gauze and paper (Correct answer)
- Rigid metal endoscopes
- Silicone tubing
Correct answer: Cellulose-based materials such as gauze and paper
Cellulose-based materials absorb hydrogen peroxide, interfering with the sterilization process and preventing proper plasma formation.
Question 7: Which action is required before any item is considered sterile and safe to use in a sterile field?
- Visual inspection of the packaging only
- Verification of chemical indicator color change, intact packaging, and expiration date (Correct answer)
- Confirmation by the surgeon that the item appears clean
- A 10-minute aeration period after removal from the sterilizer
Correct answer: Verification of chemical indicator color change, intact packaging, and expiration date
All three elements — chemical indicator, packaging integrity, and expiration date — must be verified before using any sterile item.
CNOR Surgical Asepsis and Sterility 3
Ethylene oxide (EtO) sterilization is preferred for which category of items?