Squeezing More Uses Out of Blood Products

By Jessica Tremayne

Veterinary transfusion medicine and blood banks have come a long way from their inception, experts say, but room for growth remains.

Though these facets of veterinary medicine offer advancements that do not exist in human medicine, the profession lags in its ability to offer frequent platelet transfusions and in widespread education on the uses of blood components.

Thousands of veterinarians across the U.S. rely on commercial and nonprofit blood banks for their transfusion needs. Photo courtesy of Dr. Anne Hale

Researchers from Animal Blood Resources International in Stockbridge, Mich., and  Dixon, Calif., are helping change that by testing the viability and benefits of freeze-dried platelets. The company plans a January release for the product, pending research results. If given the go-ahead, the product will be second only to Oxyglobin in transfusion options available to animals but not approved for human medicine.

“One big problem in general practice is using whole blood before its expiration date—which at best is 45 days if refrigerated,” says Anne Hale, DVM, CEO of Animal Blood Resources International and a board member with the Association of Veterinary Hematology and Transfusion Medicine (AVHTM).

“Blood components have a longer shelf life than whole blood and can be used for much more than whole blood transfusions in cases like an animal experiencing blood loss from trauma.”

A major concern is the cost of blood and blood components, which some say is why an in-house donor is used instead of purchasing from a blood bank.

“Vets don’t know what to do with blood that has been thawed but then isn’t needed, or the warmed or opened bags,” says Ann Schneider, DVM, director of Eastern Veterinary Blood Bank in Severna Park, Md. 

Jean Dodds, DVM, founder of HemoPet in Garden Grove, Calif., says blood components like plasma are fully active for clotting factor replacement, antibodies and other plasma proteins for one year after collection. But plasma still can be used for four more years for all needs except clotting factor activity. Because this isn’t widely known, gallons of plasma are needlessly wasted every year.

Donna A. Oakley, director of the Penn Animal Blood Bank, says the cost of producing one unit of animal blood—from drawing the blood to testing and materials used—surpasses the processing fee attached to the listed price.

“Typing may be considered too expensive to do in-house for some clinics, but it should be a point of care for larger practices,” Oakley says. “Most owners are driven by altruism and little prompting is necessary.”

A Pricey Alternative Veterinarians have successfully used Biopure Corp.’s oxygen therapeutic, Oxyglobin—also known as hemoglobin glutamer-200 (bovine), or HBOC-301—since 1998. But Anne Hale, DVM, CEO of Animal Blood Resources International, warns that the cost may reduce the product’s use in 2010. (Biopure filed for Chapter 11 bankruptcy in July.) “It’s unfortunate that cost places some limitations for veterinary medicine, but it’s a fact and Oxyglobin may be one of the sacrifices,” Dr. Hale says. “The company also makes products for human use.” Hale’s company services more than 65 percent of U.S. veterinary transfusion needs.

A wise addition to purchasing blood from a reputable veterinary blood bank is initializing an in-house blood bank using donors, says K. Jane Wardrop, DVM, Dipl. AVCVP, the head of veterinary clinical pathology at Washington State University and co-editor of “Schalm’s Veterinary Hematology, Sixth Edition.”

“You can inspire clients to provide their pet as a donor by hanging donor pictures in the office, providing a free wellness exam or another token of appreciation,” Dr. Wardrop says. “As a veterinarian you need to ask yourself what you will do when an emergency patient requiring blood comes through the door. You need to be properly equipped to perform blood transfusions in-house, or have a referral veterinarian or emergency facility phone number on hand.”

Bonafide Specialty

Transfusion medicine is crucial to the profession but lacks a specialty—something that would help with quality assurance, Dr. Hale says.

“The federal government has no set standards on animal blood banks, but the American Association of Veterinary Blood Banks (AAVBB) and AVHTM both want to put a specialty option in motion as a subset of the internal medicine specialty,” Hale says.

“Both are working toward standards for the industry. AAVBB has a published first edition of ‘Standards for Blood Banking.’ AVHTM and AAVBB are working on new editions without set release dates.”

A specialty in transfusion medicine would draw the attention of new graduates to transfusion issues and validate research, which would promote the  modality.

Practical Medicine

A unit of blood can be processed into many products, including frozen plasma, packed red-blood cells, cryoprecipitate, cryosupernate and platelet concentrate. Photo courtesy of Dr. Anne Hale

Dr. Dodds says the experts are realizing that veterinarians often don’t understand what plasma is good for.

“Veterinarians could be using plasma to combat parvovirus, treat heatstroke, snakebites and spider bites, and to use as a supplement to or in replacement of colostrum for neonatal cases,” Dodds says. “For neonates, the plasma can be absorbed orally for the first 36 hours, and it works like a charm, giving puppies antibodies to boost maternal immunity and help prevent neonatal infections. Dobermans with Von Willebrand disease can benefit from fresh-frozen plasma as long as the donor has a high level of Von Willebrand factor.”

The reason plasma and other blood components may not be used to their full capability lies with the lack of practical clinical information available to veterinarians. In addition, clinicians have few opportunities to attend blood banking seminars and related university continuing education, Dodds says.

“Blood is the elixir of life,” Dodds says. “Its use as a source of antibodies to help fight disease is largely untapped. I also find that veterinarians don’t consider using the patient’s blood collected by intraoperative salvage. In the case of a chest or abdomen bleed, the blood can be taken out, filtered and replaced in almost all cases, excluding those involving massive sepsis or cancer.”

Another area of underutilization of plasma is for chronic inflammation of the gastrointestinal tract and pancreatitis. Trypsin leaking from the inflamed pancreas into the abdominal cavity can be neutralized by peritoneal lavage of plasma, containing alpha 1-antitrypsin, to counteract trypsin digestion of the bowel and other abdominal structures, Dodds says.

Typing/Testing

Two tests are marketed for animal blood-type testing. DMS Laboratories Inc. in Flemington, N.J., produces Rapid Vet-H for canine and feline testing. Alvedia Alice Veterinary Diagnostic manufactures the Feline Quick test and Canine Quick test.

Some transfusion veterinarians say testing all new patients would allow vital information to be readily available on patient charts, saving time when an emergency transfusion is needed.

“It wouldn’t be a bad idea for veterinarians to perform a blood-typing test if they are already running other bloodwork, or simply discuss the benefits of having the information with their clients to determine if adding the test would be well received,” Wardrop says.

Veterinarians who routinely perform patient blood-typing say that having the information at a moment’s notice and being able to plan accordingly for blood banking needs saves time and lives.

“Typing blood takes only a few minutes, but collecting it from a donor takes 20 to 25 minutes,” says Elizabeth Rozanski, DVM, Dipl. ACVIM, ACVECC, of the Department of Clinical Sciences and blood bank director of Cummings School of Veterinary Medicine at Tufts University.

“Knowing your patients’ blood type in advance can help you determine the types of blood to keep on hand and avoid the rush of finding an appropriate donor in the moment you need the blood,” she says.

Veterinarians who work in the blood transfusion industry say many vets do not consider blood typing an important factor when using whole blood.

“We still receive requests for whole blood when a component would be preferable to treat the patient,” says the Eastern Veterinary Blood Bank’s Dr. Schneider. 

“Many veterinarians request universal blood without having considered blood typing their patients. If all patients were blood typed, more 1.1 negative components would be available for the patients who truly need them. Also for the use of blood products in immune-mediated diseases, especially ITP.” <HOME>

This article first appeared in the October 2009 issue of Veterinary Practice News

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