Which sterilisation method cannot be used to sterilise endotracheal tubes?

• A. Steam
• B. Hot air oven
• C. Radiation
• D. Ethylene oxide

Answer: (C)

Radiation sterilisation is not a method used to sterilise endotracheal tubes in routine clinical practice. Ionising radiation (like gamma irradiation) is an industrial process performed in dedicated facilities to pre-sterilise packaged devices before sale. In the theatre or clinic, devices are expected to be pre-sterilised by manufacturers or sterilised on‑site using methods such as steam autoclaving or gas sterilisation for heat‑sensitive items. Dry heat (hot air) is generally unsuitable for the plastics used in many endotracheal tubes because of the risk of deformation, and ethylene oxide is used for heat‑sensitive items but also typically handled in controlled manufacturing or centralized facilities. Therefore, radiation cannot be used to sterilise endotracheal tubes in standard hospital practice.