Scientists are slowly changing how to control internal bleeding. And, no, it doesn't involve an excessive amount of gauze pads. Internal, noncompressible hemorrhage remains a significant cause of preventable death, especially for soldiers. And with the success of tourniquets — even junctional ones — there's been a boom in product trials for different ways in which to stop internal bleeding, all of which give patients more time before they require surgery. Below is a list of some of these products compiled after extensive research.
How it works: The injectable polymer assists fibrin to help strengthen blood clots by binding fibrin strands together and forming “cross links.”
“We have a lot of experience designing materials for this because we do a lot of drug targeting and drug delivery, so we were able to design polymers that were similar to the technology we'd been developing in our lab. [I]nstead of targeting for drug delivery, we were targeting to stop blood flow,” said Suzie Pun, PhD, a professor of bioengineering at the University of Washington and co-collaborator on PolySTAT.
Why it's different: Most of the materials that are coming out now are biologics, which means they are made from living systems and have to be kept refrigerated, Dr. Pun said. PolySTAT is a completely synthetic material, and scientists are in the process of testing whether it will be more versatile in terms of transport and travel and whether it's possible to keep it solely asa solution or create a powder for easier access.
Estimated timeline for ED use: PolySTAT could reach human trials in about five years, but Dr. Pun said she thinks that's an aggressive timeline. “What needs to be done before then is we need to do a lot of safety testing, we have to test in multiple animal models, especially animal models that more closely mimic humans, and then we have to actually go through a process with the FDA where we get the materials approved for FDA clinical trials and then move into clinical trials.”
How it works: ResQFoam is a situ-forming polyurethane foam — two injectable liquids reacting together — that can be administered into the peritoneal space. It then expands, conforms to injured tissues, and provides a quick effect to slow or stop bleeding, keeping test animals alive for up to three hours before needing surgery.
Why it's different: “First off, it's the only one that works,” said David King, MD, a trauma and acute care surgeon at the Massachusetts General Hospital Trauma Center who has been co-developing this foam for the past seven years. Other products don't work in intracavitary hemorrhage, nor is ResQFoam intended for junctional bleeding, as are other products such as XStat.
Current Status: “We conducted a study in recently deceased human beings whereby we injected our hemostatic foam into the abdomen, and that allowed us to look at a variety of acute outcome measures, most importantly, dose selection, because human and swine anatomies are not entirely analogous. It's a major study done in a way that no one's ever really done before. We're pretty excited about it,” said Dr. King.
How it works: XStat injects small sponge-like discs into an open wound with a syringe. The sponges, which have been treated with an anti-hemorrhagic substance, expand to 15 times their size in seconds, which plugs the wound and provides necessary compression to stop bleeding. Sponges are removed before surgical repair, and a radiopaque marker makes for easy detection in an x-ray to confirm sponge removal.
Why it's different: XStat was a collaborative effort that included Harvey Mudd College engineering alumni. When he was a professor there six years ago, Kenton Gregory, MD, assigned five engineering students the task of creating a way to stop junctional hemorrhaging internally. The product is also different because it “supplies compression right on the bleeding site. You're not putting pressure from the outside in,” said Dr. Gregory, one of the inventors, the founder, chief science officer, and chairman of the board of RevMedx, and the director for the Center for Regenerative Medicine at Oregon Health & Science University.
Current status: The FDA approved XStat in April 2014, and last month, RevMedx shipped out a supply to special medic forces only. “We'll be supplying more in the coming year so we're waiting to see how it works,” Dr. Gregory said.
Estimated timeline for ED Use: “The FDA approved this with a caveat. They've only approved it for battlefield or military use. As a chairman of the board and founder of the company, I can't promote off-label use. That's against the law,” Dr. Gregory said.
“We've been contacted by countless law enforcement [agencies] and other folks about when this will be approved for non-military use. And we're actually discussing this with the FDA as we speak. Who can predict when the FDA will expand the indications for use, but we hope that they will and we're trying to collect data to support that.”
How it works: Pop the cap and apply powder directly to the bleeding site. Through osmosis, the powder dehydrates and gels the blood on contact to accelerate the natural clotting process.
Why it's different: ARISTA AH is 100 percent plant-based, synthesized from a purified plant starch. It provides a broad area of coverage on rough surfaces and in hard-to-reach areas, and is typically absorbed and cleared from the body within 24 to 48 hours by amylase enzymes.
Current status: “ARISTA is an FDA-approved, commercially available hemostat. It's been on the market since 2008, and has been used in millions of cases worldwide,” said Justine Advani, the associate product manager of BioSurgery for C. R. Bard, Inc., the company that carries ARISTA.
How it works: When blood comes in contact with poly-N-acetylglucosamine (pGlcNAc), plasma proteins are rapidly bound and absorbed. Then, fibers interact with platelets, stimulating activation and leading to the onset of the pathway. A catalytic surface for thrombin generation and accelerated fibrin clot formation results from the interaction of platelets with pGlcNAc. The fibers bind and cause blood grouping of RBCs, resulting in the exposure of phosphatidylserine, leading to their activation and direct participation in clotting.
The combination of platelet and RBC receptor-based contact with the pGlcNAc fibers results in thrombin generation and fibrin mesh formation. A hemostatic plug forms, which is improved by additional vasoconstrictive effects from the release of thromboxane by activated platelets and endothelin-1 by endothelial cells.
Why it's different: mrdh requires no prep time, no pre-mixing of reagents, no special storage conditions, and no exothermic reaction. Additionally, mrdh doesn't contain proteins or blood products, is non-immunogenic, and has no known contraindications.
Current status: mrdh received FDA clearance in 2008.
How it works: TourniCath is inserted directly into the wound track via a balloon that is cylindrical and eight inches long. The balloon inflates to two inches in diameter, which will compress most wound tracks when partially or fully inflated. Once the tip of the TourniCath device is inserted into the end of the wound track or all the way through it, the outer sheath is pulled off, and the device is inflated to about 150 mm Hg pressure with a hand bulb or an ordinary syringe. The pressure compresses the tissues internally and tamponades the bleeding vessels in the wound track, ultimately controlling the hemorrhage.
Why it's different: TourniCath is small in size and weight and can be removed through nonsurgical means. It also has a “fast speed of deployment with no need for a cover compression bandage as with the others,” according to Maynard (Mike) Ramsey III, MD, PhD, the CEO and CTO of CardioCommand, Inc., and creator of TourniCath.
Current status: Dr. Ramsey and his team presented TourniCath in September 2014 at the FDA Hemorrhage Control Device Workshop, and he said they plan to apply for FDA 510k clearance.
Estimated timeline for ED use: “We believe — and others have told us the same — that TourniCath would be very useful in civilian EDs, ORs, and eventually even in EMS and police vehicles. There are more gunshot wounds in the civilian world than in the military world,” said Dr. Ramsey. Human trials, however, won't be necessary, according to Dr. Ramsey. “Such inserted devices can gain FDA clearance without human testing. Human testing is exceptionally difficult for a number of reasons, and to the best of my knowledge, no hemorrhage control product has been tested in human clinical trials before clearance by the FDA, nor do we believe it should be required.”
How it works: A gel accelerates the natural hemostasis cascade by activating Factor XII and platelets, and adhering to the wound. The combination creates an increase in fibrin production, which leads to a quickly formed clot. The biocompatible nature of the gel allows for excess product to be left in the body to resorb. Its use is for soft organs like the liver, spleen, and kidneys.
Why it's different: It's designed exclusively for veterinarians to control traumatic bleeding.
Current status: Suneris, the company behind VETIGEL, will release the product into veterinary markets in the United Kingdom and United States this summer. Once the product launches, veterinarians in these regions will be able to order VETIGEL for use in their clinics.
Estimated timeline for ED use: “Suneris will pursue approval for human use. Notable human use opportunities may include military, emergency medicine, and human surgical use,” said Bryan Horner, a publicist at Edelman, the public relations company that represents Suneris.
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