What is the correct temperature used in autoclave method to sterilize instruments?

PGIMS Rohtak NO - 2017

Applied Microbiology & Infection control

Easy

Appeared in: PGIMS Rohtak NO - 2017

Explanation

The most commonly cited standard for steam sterilization of wrapped items is maintaining a temperature of 121°C for 30 minutes.
This process utilizes saturated steam under a pressure of approximately 15 pounds per square inch (psi) to achieve the necessary temperature.
The combination of moist heat, high temperature, and pressure effectively denatures the proteins of all microorganisms, including highly resistant bacterial spores, ensuring true sterilization.

Option A: A temperature of 40°C is far too low for sterilization. It is closer to body temperature and would not kill most microorganisms.
Option B: 100°C is the boiling point of water at standard pressure. While boiling kills many vegetative bacteria, it does not reliably eliminate all bacterial spores, so it is classified as disinfection, not sterilization.
Option C: While 126°C is a valid sterilization temperature, the combination with 20 minutes is a specific cycle that is less universally standard than the 121°C cycle. In a multiple-choice question, the most common standard is the intended answer.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Principles of Sterilization: Autoclave Parameters as background academic context rather than a clinical decision trigger.
Proper sterilization of surgical instruments is a cornerstone of infection control, critical for preventing surgical site infections (SSIs), a major cause of hospital-acquired morbidity.
Nurses and sterile processing technicians must verify that each autoclave cycle has been successful by checking physical printouts, observing the color change on chemical indicator tape, and ensuring routine biological indicator (spore tests) are performed and passed according to hospital policy.
A wet pack after an autoclave cycle is considered contaminated because moisture can wick microorganisms from the environment through the packaging. Packs must be allowed to cool and dry completely before handling and storage.

How to Approach the Question

First, identify the keywords in the question: 'correct temperature', 'autoclave method', and 'sterilize'. The term 'sterilize' is critical, as it implies killing all microbial life, including spores.
Evaluate the options based on the principles of heat sterilization. Immediately eliminate 40°C as it is too low.
Recognize that 100°C is the temperature of boiling water. Recall that boiling is a method of disinfection, not sterilization, because it doesn't reliably kill spores.
You are left with two high-temperature options: 126°C and 121°C. Both are capable of sterilization.
Recall the most common, universally taught standard for autoclave sterilization. 121°C at 15 psi for 15-30 minutes is the classic parameter. The 30-minute duration is standard for wrapped items.
Select 121°C for 30 minutes as the best and most standard answer among the choices provided.

Concept Tested & Keywords

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