Formaldehyde and Ethylene oxide are example of?

NCL (MP) Nursing Officer - 2020

Applied Microbiology & Infection control

Easy

Appeared in: NCL (MP) Nursing Officer - 2020

Explanation

Both formaldehyde and ethylene oxide are chemical agents that exist in a gaseous state and are utilized for high-level disinfection and sterilization.
They are categorized as gaseous chemosterilants, which are essential for processing medical equipment that cannot tolerate high temperatures or moisture.
Ethylene oxide is widely used for sterilizing items like plastic catheters and electronics, while formaldehyde gas has been used for fumigating rooms and equipment.
Their mechanism of action involves alkylation, which damages the DNA and proteins of microorganisms, leading to their death.

Option A: This is incorrect because formaldehyde and ethylene oxide are synthetic industrial chemicals, not substances derived from natural sources like plants or minerals.
Option B: This is incorrect because both formaldehyde and ethylene oxide are gases at room temperature or used in their gaseous form for disinfection.
Option D: This is incorrect because physical disinfection relies on energy (e.g., heat, radiation) rather than chemical substances. Formaldehyde and ethylene oxide are chemical agents.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Classification of Disinfectants and Sterilants as background academic context rather than a clinical decision trigger.
Understanding the correct sterilization method is critical for infection prevention. Gaseous sterilants like ethylene oxide (EtO) are indispensable for reprocessing reusable, heat-sensitive medical devices such as flexible endoscopes, certain plastics, and electronic equipment.
Nurses must be aware of the significant safety protocols associated with gaseous sterilants. For EtO, this includes ensuring proper aeration of sterilized items to remove toxic residues before they are used on patients, thereby preventing chemical burns and tissue irritation.
What if? If an instrument were made of stainless steel and not heat-sensitive (e.g., surgical scissors), the preferred method would be physical sterilization via autoclaving (steam under pressure), not a chemical gas. Autoclaving is generally faster, more economical, and leaves no toxic residue.

How to Approach the Question

First, identify the key substances mentioned in the question: Formaldehyde and Ethylene oxide.
Recall or deduce the physical state and primary use of these substances in a healthcare or laboratory setting. Both are well-known for being used as gases for sterilization.
Systematically evaluate each option based on this knowledge.
Eliminate 'Natural disinfectant' because these are synthetic chemicals.
Eliminate 'Solid disinfectants' because they are gases.
Eliminate 'Physical disinfectants' because they are chemical agents, not physical processes like heat or radiation.

Concept Tested & Keywords

QvbHK4EexkEirUxFXALgeC

E6 Parks TextBook of Preventive & Social Medicine part 1 — Subpart A (pp 26-201 of 604) pp. 128-130, 127-129

E6 Pharmacology Katzung 16e p. 1397-1399