Category Archives: skin

Wound closure on a budget


Cyanoacrylates (CAs), around since the 40s, have been used for wounds since Vietnam. Therefore, it is odd to consider that the FDA did not approve their use for skin until 1998. Much of this came from the reports of skin injury from the short chain CAs secondary to heat generation from the polymeration reaction, as well as lack of sterile preparation.

The problem with the FDA approved items is that they are often in single use applications, sometimes have refrigeration requirements, have significant costs, and require a physician order or prescription to carry. Would using the commercially available CAs aid in austere environments? Other authors have certainly looked at their use, and this paper basically reviews a large chunk of those papers to attempt to answer that question.

Looking in MEDLINE, The Cochrane Database, Web of Science, Cinahl, CAB Abstracts,Google Scholar, and BIOSIS, the authors used multiple search terms and reviewed all pertinent abstracts and papers. They looked at use for wound closure, as well as for burns, abrasions and blisters. A total of 82 papers were eventually referenced in the final manuscript. And in the end?

Studies showed that the tensile strength of wounds closed cyanoacrylate adhesives are dependent on the length of the alkyl group. Octyl CAs approach monocryl level of strength, but methyl and ethyl CAs are significantly weaker. Since the shorter chain CAs are the non-medical products, this is important to know if you are using it for wound closure. Reports of histotoxicity had both pro and con reports for ethyl CAs, but it most reports of injuries are minor. Applying adhesive to blisters looks to be a wash, but it may have a use yet for prevention of blisters as an artificial callous.

For burns and abrasions, the octyl CAs do not have any benefit over standard bandages or Tegaderm. All CAs appear to be bacteriotoxic, but there are no patient oriented studies. All of them are performed in petri dishes, so applicability is unknown. Certainly the products can create a barrier over any wound, but outcomes have not been measured. Non-medical CAs are certainly cheaper, with one study showing a 98.5% reduction in cost.

So you have a product that doesn’t work as well, may cause inflammation, but costs significantly less. Would you use it for wound closure? The case can be made that carrying around industrial grade adhesive is useful in all aspects of wilderness medicine, even apart from medical use. Many other things may require repair, so you likely would not be carrying anything extra in your pack. And while it isn’t the best agent, it is certainly better than nothing, and there are plenty of reports of safe use for simple injuries. No, I can’t argue that you should use it to close up your chainsaw wound, but simple lacerations are amenable to repair by non-medical adhesives.

Cyanoacrylate glues for wilderness and remote travel medical care.
http://www.ncbi.nlm.nih.gov/pubmed/23131754

Denim as snake protectant?

Source: Wikimedia Commons

Denim pants, worn since 1873 by workers, and since the 50s by everyone else, have had a reduction in their use as outdoor clothing due to the emergence of performance hiking apparal. Denim jackets are markedly less popular recently. Now, what if it turns out denim protects you from envenomation? Would denim then come back as an overlander outfit?

Crotalus oreganus helleri

Source: Matthew Robinson

This article tried to ascertain whether denim has any ability to decrease the severity of snake bites, mainly be decreasing or eliminating envenomation. To study this, they used 17 different southern Pacific rattlesnakes divided into small (35-54cm) and large (66-102cm) groupings, and had them bite latex gloves that were either uncovered or covered with standard denim cloth. The paper has a very detailed methods section, including even the material in the snake cages when they were being stored!

The results were pretty surprising. There was a 60% reduction in venom for the small snakes, and 66% reduction in the large snakes. If it were simply a material thickness, a larger snake should be better at penetrating the material, but this was not borne out by the data. Since defensive strikes by nature are very fast (<0.33s), the reduction is likely from simple physics.

Thus, you can take home that denim can reduce the amount of venom you receive if a snake strikes you defensively. Sadly, the reduction is probably academic for big snakes, as the amount you receive can still be enough to kill you. Especially in the case of the snake species studied, a particularly nasty rattlesnake that has both hemorrhagic and neurotoxic venom components.

The bigger take home point from this article is that it is yet another nail in the coffin for the “small snakes are more dangerous” myth about defensive strikes. Bigger snakes will deliver more venom, regardless of what you are wearing. In this paper, they delivered 41 times the venom load of the smaller snakes, and 26 times the load when denim interfered. Please make sure and correct the next person you hear trying to propagate this myth.

And wear some denim if you’re going rattlesnake wrangling.

Denim clothing reduces venom expenditure by rattlesnakes striking defensively at model human limbs.
http://www.ncbi.nlm.nih.gov/pubmed/19942067