Flexible fibreoptic endoscopes must be sterilized between patients. The item is heat sensitive and cannot withstand autoclaving. Which agent is the standard choice, and what additional step is mandatory after the process?
- A Ethylene oxide gas, followed by aeration for 8 to 12 hours to remove residual gas ✓
- B Glutaraldehyde 2% for 20 minutes, then water rinse only
- C Gamma irradiation at 2.5 megarad, followed by drying
- D Autoclaving at 134°C, followed by cooling
Correct answer: A. Ethylene oxide gas, followed by aeration for 8 to 12 hours to remove residual gas
Explanation
Ethylene oxide penetrates heat- and moisture-sensitive devices such as endoscopes and catheters and acts as a potent alkylating sterilant. Because EO is carcinogenic and explosive, residual gas absorbed by plastics and rubber must be removed by prolonged aeration in a heated chamber before reuse. Glutaraldehyde is a high-level disinfectant rather than a sterilant in short exposures, gamma irradiation is for industrial single-use items, and autoclaving would destroy the scope.
Reference: Ananthanarayan and Paniker's Textbook of Microbiology, 11th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.