Wednesday, June 07, 2006

Medical cyanoacrylate use: why is the best summary on Dan's Data?

I stopped seeing patients about 7 years ago, but towards the end of my clinical career I started using cyanoacrylate to close wounds. What I find odd about this useful description of cyanoacrylate use is that it appeared not in a medical journal, but in an eclectic Australian blog written by a non-clinical geek polymath. What does that say about 21st century expertise and knowledge communication?
Dan's Data letters #152 - page 3

... I've used plain superglue occasionally as a wound closer, though; never for anything very dramatic, but it does indeed do the job quickly and neatly for small cuts. Many model-makers have dealt in this way with X-Acto knife cuts without leaving their workbench.

If you've got a more sizeable injury, hardware store superglue can still work well, but only if you know what you're doing, which you very probably don't if hardware store superglue is what you're using. The idea is to stitch the edges of the wound together with the glue, not just squirt it in there. Glue in the wound will only make things worse, not least because cyanoacrylate sets fast when it's wet (when used for ordinary applications, it sets because of contact with water vapour in the air; this is also why it bonds to skin so well), and gets hot when it sets fast...

Incidentally, not a lot of people know about the water-sets-superglue thing. If you need superglue to set fast, you can spritz it with a little water from a spray bottle. In a pinch, you can just spit on it, but that won't give you a good quality joint.

The water spritz won't work as nicely as regular "superglue accelerator", available from hobby shops, but it doesn't smell weird either, and it gives you more time to locate the parts - accelerator works so fast that the standard way of using it is to put the glue on one part and the accelerator on the other, then bring them together.

Entertainment can also be gained from an excessive quantity of water-thin superglue (also from hobby shops, who have far more cyanoacrylate products than you'll find at the hardware store) and a similarly excessive quantity of accelerator, in a disposable vessel like a spraycan lid. The reaction is quite enthusiastically exothermic; do it in a well-ventilated place, and not on your nice carpet.

Paradoxically, cyanoacrylate is also slightly water soluble, which is another reason why it's good for wound closing; the moistness of the skin will slowly encourage the glue to flake off (as it will if you get glue on your fingers while working on something; time is the only safe way to remove superglue, though shaving it off with a safety razor can be diverting, and leave you with no fingerprints). The glue will dissolve faster when the water's warmer, which is why model car people who want to get superglued tyres off of wheels do it by boiling the wheels.
See, now you know how to remove your fingerprints too. Handy next time you want to break into NSA headquarters and revise your identity records.

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