Certified Nurses Operating Room (CNOR) Practice Exam

The minimum exposure time for Pre-vac sterilization at 134-138 degrees Celsius (which equates to about 273-280 degrees Fahrenheit) is critical for ensuring effective sterilization. The correct answer reflects that, at these temperatures, the exposure time required is indeed 18 minutes, which is based on established sterilization guidelines.

Pre-vacuum sterilization uses a vacuum to remove air from the chamber before steam is introduced; this method enhances the penetration of steam and ensures that all surfaces of the items being sterilized reach the required temperature and conditions for effective sterilization. The 18 minutes of exposure time at the specified temperatures is necessary to achieve a 6-log reduction in viable organisms, thereby ensuring sterility.

In this context, shorter exposure times would not allow sufficient time for steam to effectively penetrate and kill microbial life, which is why they are not viable options.