Can I use a compressed air duster to freeze off a wart?

August 01, 2011 08:57AM
0 0

Let's find out!

ONE

According to wikipedia common ingredients of canned air are:
Difluoroethane, which has a boiling point of -25 C
Trifluoroethane, which has a boiling point of -46 C
and Tetrafluoroethane, which has a boiling point of -26 C

Nitrogen, which is often used for cryosurgery, has a boiling point of -196 C.

A fluid isn't considered cryonic for scientific purposes unless it's below 150 C.... but is -25 C cold enough for non-"cryo" cryosurgery?

According to this article on WebMD Medscape:

Quote
Aaron J Morgan, MD
Cell injury occurs during the thaw, after the cell is frozen. Because of the hyperosmotic intracellular conditions, ice crystals do not form until -5°C to -10°C. The transformation of water to ice concentrates the extracellular solutes and results in an osmotic gradient across the cell membrane, causing further damage.

...

Keratinocytes need to be frozen to -50°C for optimum destruction. Melanocytes are more delicate and only require a temperature of -5°C for destruction. This fact is the reason for the resulting hypopigmentation following cryotherapy on darker-skinned individuals. Malignant skin cancers usually need a temperature of -50°C, while benign lesions only require a temperature of -20°C to -25°C.

Common warts (verruca vulgaris), caused by HPV strains 2 and 4, are considered to be benign lesions. So that sounds promising! But what's that about keratinocytes needing to get down to -50 to be destroyed? I want a second opinion.

Quote
E. J. Mayeaux, Jr., MD, DABFP, FAAFP
Human tissue freezes at -2.2 C, with tissue destruction occurring at temperatures at or colder than -10 C.

...

Generally, destruction of benign lesions requires temperatures of -20 C to -30 C.

Right on, that's more like it.

Quote
Aaron J Morgan, MD
Liquid nitrogen is the best and universal freezing source because of its low boiling point and its ease of use. Other sources that are used to freeze, such as Freon, carbon dioxide, and nitrous oxide, do exist, but they are not as efficient in destroying lesions because of their higher boiling points.

Freon has a boiling point of -29 C, which is pretty darn close to di- and tetrafluoroethane, and which is actually higher than trifluoroethane.

TWO

Okay, so it would probably work. But what about issues with squirting haloalkanes directly onto your skin? Will they be absorbed and give you cancer? Let's check the MSDSes!

Difluoroethane: Hazardous only if inhaled (simple asphyxiant).
Trifluoroethane: Hazardous only if inhaled (simple asphyxiant).
Tetrafluoroethane: Hazardous only if inhaled (simple asphyxiant).

No carcinogenic or other toxicity warnings on any of these; just don't huff them. There are also warnings about potential frostbite, but that's exactly what we want.


THREE

According to the 2008 MMH-SI Physician's Fees and Coding Guide (referenced in Mayeaux), the average 50th percentile fee for "destruction [of] benign [...] lesion, first lesion" is $102, with an extra $35 added for each additional lesion.

A can of air duster costs like three, four bucks. Free, if you're performing the operation at work.


So I think the conclusion here is that you can perform do-it-yourself cryosurgery with canned air. It might not be as effective, but it will certainly be a lot cheaper.


Look for part 2, in which I get drunk and actually try this, in the future. Thanks.


BONUS FUN FACT: "Adenovirus is capable of survival in liquid nitrogen."
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Can I use a compressed air duster to freeze off a wart?

JimL2 August 01, 2011 08:57AM


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