The gas most commonly used in cryosurgery is?

Appeared in: NHM UP Staff Nurse - 2016

Explanation

Nitrogen (N₂), in its liquid form, is the most widely used agent for cryosurgery.
Its primary advantage is its extremely low boiling point of -196°C, which allows for rapid and effective destruction of targeted tissue.
The intense cold causes intracellular water to crystallize, leading to cell membrane rupture and necrosis (cell death).
It is versatile and used across many specialties, most notably in dermatology for treating lesions like warts, actinic keratoses, and superficial skin cancers.

Option A: Oxygen (O₂) is not used as a cryogen. It is a highly reactive gas that supports combustion and is essential for cellular respiration, not for freezing tissue.
Option B: Carbon Dioxide (CO₂) is used in cryosurgery, but it is not the most common agent. It exists as a solid (dry ice) at -78.5°C, which is significantly warmer than liquid nitrogen, making it less potent for many procedures.
Option D: Hydrogen (H₂) is not used in medicine as a cryogen. It is a highly flammable and explosive gas, making it extremely dangerous for clinical use.

Clinical Relevance

Nursing practice connection: Knowing Cryosurgery and Cryogenic Agents helps nurses interpret findings accurately and avoid errors in routine assessment, medication administration, and patient teaching.
Cryosurgery is a common minor surgical procedure performed in outpatient settings for various benign and malignant skin conditions.
Nurses play a key role in patient education, explaining the procedure, expected sensations (stinging, burning), and post-procedure care, which includes wound care, monitoring for infection, and managing blistering.
A nurse must ensure patient safety by confirming the correct site and preparing the necessary equipment, including the liquid nitrogen canister and application devices (spray tips, cotton swabs).

How to Approach the Question

This is a factual recall question that tests your knowledge of common medical procedures.
First, identify the keywords in the question: 'gas', 'most commonly used', and 'cryosurgery'.
'Cryosurgery' implies using extreme cold to destroy tissue. This should trigger your memory about different substances used for freezing (cryogens).
Evaluate the options provided. Think about the properties of each gas in a medical context.
Recall that liquid nitrogen is famous for being extremely cold and is frequently mentioned in the context of dermatology for freezing warts and other lesions.
Compare this with other options. CO₂ (as dry ice) is also cold but less so than liquid nitrogen. O₂ and H₂ are not used for freezing due to safety (combustibility/flammability) and lack of cryogenic properties in a clinical setting.

Concept Tested & Keywords

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E6 Gynecology Williams p. 120-150

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