Conference Coverage

Frozen or powdered? Anticoagulation options in trauma are expanding


 

EXPERT ANALYSIS AT THE UCSD CRITICAL CARE SUMMER SESSION

References

SAN DIEGO – In the next 5-10 years, reaching for a powdered form of plasma may become the normative first-line treatment for trauma patients who present with severe bleeding. That’s because the current standard of administering fresh frozen plasma is riddled with problems, Dr. Martin Schreiber said at the University of California, San Diego, Critical Care Summer Session.

For one thing, frozen plasma takes 35 minutes to thaw. "That’s a problem, and the clotting factor function of plasma deteriorates as you freeze it and thaw it," said Dr. Schreiber, professor of surgery at Oregon Health & Science University, Portland. "Also, you need it in large volumes and that’s not good for patients with congestive heart failure on Coumadin, and the availability is limited, especially in rural settings."

Courtesy Wikimedia Commons/DiverDave/Creative Commons

Fresh frozen plasma (shown) takes about 35 minutes to thaw. Lyophilized plasma, a powder, is reconstituted in minutes prior to transfusion.

Enter lyophilized plasma (LP), a process developed by HemCon Medical Technologies in which whole blood is sterilely removed, and the plasma component is separated and turned into a powder. The powdered plasma is returned and reconstituted prior to transfusion. "You can put this stuff as a powder on a shelf in nearly any environment," Dr. Schreiber said. "It’s good for at least 3 years, it survives a broad range of temperatures, and you can restore it to plasma within a couple of minutes."

An initial study of LP showed encouraging results with the use of a freeze-dried form of plasma for resuscitation (J. Trauma 2008;65[5]:975-85). A later study by researchers including Dr. Schreiber evaluated the effects of the lyophilization process on plasma clotting factor levels in swine, by adding the antioxidant ascorbic acid (vitamin C) to the reconstitution solution, and by comparing the efficacy of LP with that of fresh frozen plasma and that of plasma and packed red blood cells in a 1:1 ratio (Arch. Surg. 2009;144[9]:829-34). "What we found was that if we gave LP with packed red blood cells in a 1:1 ratio we had 14% less blood loss than if it’s given as FFP with packed cells, which was significant," Dr. Schreiber said.

"The LP was better in terms of stopping hemorrhage. We also noticed that with the vitamin C, we suppressed inflammation and got reduced IL-6 [interleukin 6] expression. Now, the Germans, the Dutch, and the French are using LP in their military settings. Our special forces people are also using it. It’s under current development for common use in your hospital in 5-10 years. I think this stuff is good anywhere. With LP we can always maintain a 1:1 ratio and we don’t have to worry about the thawing process."

Tranexamic acid, a synthetic derivative of lysine, is another anticoagulant therapy that is likely to be used with increasing frequency, he predicted. This agent "binds plasminogen so plasminogen can’t break down fibrin so you can’t get fibrinolysis," said Dr. Schreiber, who has been deployed three times as a combat surgeon.

"This drug has been around forever and is extremely inexpensive. It’s approved by the FDA for use in tooth extraction and the oral form is approved for menorrhagia." Tranexamic acid has also been studied in 53 prospective, randomized studies involving some 3,800 subjects, mostly cardiac patients. "They show that if you use tranexamic acid, you use less blood. It reduces the amount of blood necessary for transfusing people in high-bleeding settings, but no difference in mortality, thrombotic events, myocardial infarction, or stroke. It does not seem to produce a hypercoagulable state."

Dr. Martin Schreiber

One study of tranexamic acid use by British surgeons during Afghanistan combat operations found that soldiers who received tranexamic acid were seven times more likely to live, compared with those who did not receive the agent (Arch. Surg. 2012;147:113-19). "There was a survival of 85% in tranexamic acid group, compared with about 70% in those who did not receive it," said Dr. Schreiber. "This has resulted in a change in practice in civilian trauma centers where it is being used widely."

Another anticoagulant being used is the prothrombin complex concentrate known as Kcentra, which contains all four vitamin K–dependent coagulation factors. Distributed by CSL Behring, Kcentra is approved for warfarin reversal in adult patients with acute major bleeding and for those who require emergency surgery. The max dose is 50 units/kg. "That’s about $4,445 for a 70-kg person," Dr. Schreiber said. "Why is it so good? It’s rapidly available, you don’t have to give a lot of fluid, there’s no infectious risk, and you can very rapidly increase coagulation factor function. This is where we’re headed in the future for trauma patients."

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