Which sterilisation method cannot be used to sterilise endotracheal tubes?

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

Answer: (C)

Radiation cannot be used to sterilize endotracheal tubes because the materials they’re made from (typically PVC with a cuff and lubricants) are susceptible to damage from ionizing radiation. Gamma or other radiation can cause polymer chain scission and plasticizer migration, leading to embrittlement, cracks, cuff leaks, or changes in flexibility. This compromises the tube’s integrity and function, which is unacceptable for an airway device.

In contrast, steam sterilization and ethylene oxide are commonly used with plastics: steam for heat-tolerant designs, and ethylene oxide for heat-sensitive items. Dry heat (hot air oven) is generally unsuitable for PVC endotracheal tubes due to the high temperatures causing deformation or melting.