Sunday, April 17, 2011

Lobsters are Hemostatic Agents Too, Part II

Okay, so there are no lobsters in this post. I know, I know: it's sad. I'm crying inside too. So for all those missing lobster references, I have decided to include this adorable picture. Who couldn't love that little lobster's face?

When I edited my last post, I half-wondered how many people went searching on the net for homemade chitosan recipes. "Mmmm tastes like lobster." Again, I must stress to the adventurous teenagers out there: Chitosan is not to be covered in butter and eaten, even if it is made from lobster exoskeletons.

Anyway, onto the next group of hemostatic agents.

Thrombin

Topical thrombin products like Evithrom, Recothrom, and Thrombin-JMI are considered part of the biologic hemostatic agents group. Naturally derived from an enzyme involved in hemostasis, thrombin products promote the body to form clots.

Sixty years ago in some dark castle without cable TV, some mad scientist got bored, thought "hmmm, I wonder what would happen if I churn blood like butter" and now we have thrombin. "It's alive! It's alive!"

Seriously, thrombin was isolated from clotted blood products sixty years ago and now we have a perfectly bio-identical hemostatic agent. Happy day.


Thrombin products come in several different types based on the type of plasma it was made from. Cow plasma products such as Thrombin-JMI (King Pharmaceuticals). These products can produce severe histamine reactions and increased antibodies in hemodialysis patients. So the side effects in some individuals have been dangerous increases in coagulation like pulmonary embolisms and on the opposite spectrum, severe decrease in clotting leading to hemorrhage and death.

Not a good choice to use as a hemostatic agent unless you want to create an even bigger mess. "Darn! The cow killed another one." (Image from http://skirmisher.org/weird-shit/cow-chucks-grass-prefers-live-chicken-dinners-as-next-best-thing-to-kfc/)

Companies such as Evithrom, Omrix, and Johnson & Johnson developed human plasma derived thrombin, which has less side effects.

Recombinant human thrombin products like Recothrom (ZymoGenetics Inc.) were also created by companies to reduce the amount of side effects that occurred with thrombin administration.

Cyanocrylates

Dermabond: Need I say more. It's a beautiful product that is commonly known about. People love it, because its the superglue of suturing products.

The cyanoacrylate family of agents are liquid monomers that reapidly react with water to form glue-like polymers. Dermabond and other cyanoacrylates are great for replacing sutures. These are more a class of wound closure products than hemostatic agents, but they deserve some attention. Otherwise they will feel left out and develop psychological issues... and have to see counselors spending hours talking about how we didn't give them attention and so that's why they have to go steal stuff from dollar stores. So, let's talk about cyanocrylates.

They were invented in 1942. A lot of the most amazing medical devices, surgeries, and triage advancements were developed in World War II. The worst war in the world's history produced some of the very best medical inventions of the 20th century. Then in Vietnam, another tragedy of humans killing humans, medicine again benefited from the heroic deeds of military medicine.

Dermabond and its constituents (octyl-2-cyanoacrylate, butyl-2-cyanoacrylate) have the advantages of rapid application, faster tissue repair time, and less need for suture follow up. They also act like waterproof barriers. (The following image shows a shoulder wound sealed with dermabond instead of sutures. Image taken from http://www.orthosupersite.com/view.aspx?rid=25358)

Dermabond and superglue originally evolved from the same product back in the 1940s and so have very similar capabilities. I have talked about superglue as a wound sealant in a past post.

Superglue can be a good disaster medicine tool. It is around the house, easy to come by, and has many of the same properties as dermabond, but with some major flaws: Superglue cannot and should not be used in deep and/or jagged-edged wounds. It also is acidc in nature and produces a chemical burn to tissue it touches. Lastly, it bonds to skin extremely well and a naive person can get glued to their patients... which works well for those loving couples that never want to be separated. But as for the rest of us who want to move on in our lives, superglue should be used with caution. Also, for the love of all that is medical: please don't use superglue (or dermabond) in armpits and buttcheeks. Not a pretty picture.

Dermabond, on the other hand, was chemically created to have a less acidic nature than its commercial cousin, but it does have its own cons. Just like superglue, it is not a good agent for wounds with jagged edges. Also, dermabond can easily breakdown in the presence of antibiotic ointments or petroleum jellies. (A good rule of thumb is to avoid scrubbing the wound or applying anything to it for 7 days after dermabond use.)

Cyanoacrylates are largely used for stopping bleeding in small wounds as a waterproof barrier, which makes them great in wilderness and disaster settings where rain and flooding can be more prevalent. As for their fastness, full binding strength is achieved in less than 2.5 minutes.

Glutaraldehyde Cross-Link Albumin Agents:

Okay, glutaraldehyde cross-link albumin agents is a mouthful to say. So let's just call them Glutes, because everyone can handle Glutes a lot better.

Glute products, like Bioglue, are most commonly used in cardiovascular surgeries, especially those involving aortic dissections and valve replacements. These are produced from companies like CryoLife and created in 1999. They come in cartridges and yes are shot into the wound. Before a bunch of crazy teenagers gets excited about shooting stuff into people's wounds, Bioglue products act more like cheese-wiz then staple guns.

Guess what. These producats are also made from cows. So the next time you're eating that steak, just think, that T-bone could have been a hemostatic agent. Mmmm Mmm good!

The cons with these products are that they may have mutagenic effects. So forget about the vat of toxic waste or the radioactive spider, you can be a superhero from messing with your Glutes. These are another product that shouldn't be applied near nerves and may also cause allergic reactions.

Morals of today's post: Cows can kill. Superglue is your friend or it can glue you to your friend. Don't stick glue in armpits or on butt cheeks. And handle your Glutes with caution.


Well, that's enough medical talk for today. TTFN.