Which of the following is the most common reason for steam sterilization failure in autoclaves?

• A. Using distilled water instead of tap water
• B. Excessive steam pressure
• C. Overloading the autoclave with materials
• D. Inadequate removal of air from the chamber

Answer: (D)

Verified step by step guidance

1. Understand the principle of steam sterilization: Steam sterilization relies on saturated steam under pressure to achieve microbial kill. For effective sterilization, steam must contact all surfaces of the materials being sterilized.
2. Recognize the role of air removal: Air is a poor conductor of heat and can create pockets that prevent steam from contacting surfaces. Therefore, removing air from the autoclave chamber is critical to ensure steam penetration.
3. Analyze common causes of sterilization failure: Using distilled water instead of tap water generally does not cause failure; excessive steam pressure is usually controlled by the autoclave settings; overloading can reduce steam penetration but is not the most common cause.
4. Identify the most common reason: Inadequate removal of air from the chamber leads to air pockets that block steam contact, resulting in sterilization failure.
5. Conclude that proper autoclave operation includes ensuring complete air removal, often by using vacuum cycles or proper venting, to achieve effective steam sterilization.