key: cord-0040311-5lzixz8q
authors: Hale, Anne S.
title: Safety of Blood Products for the Feline Patient
date: 2009-05-15
journal: Consultations in Feline Internal Medicine
DOI: 10.1016/b0-72-160423-4/50060-3
sha: 94bf2fee2a17ff79a7679d45052dc9d988e173f8
doc_id: 40311
cord_uid: 5lzixz8q

nan

Anemia, coagulopathy, and hypoproteinemia are common disease consequences in feline patients. The feline practitioner often finds the inclusion of transfusion therapy in his or her management plan. Transfusion therapy is not a new practice option; however, developments in the field of transfusion medicine in the last 10 years have increased the availability of transfusion products. Identification of donors, recognition of infectious disease, and collection of blood components are areas that have advanced significantly, which makes the use of blood products a reasonable and commonplace therapeutic strategy for the feline practitioner. As the science of transfusion medicine has progressed, the concern for safety of blood products has moved to the forefront. Areas related to safety of a blood product include donor evaluation, record keeping, infectious disease screening, advanced storage techniques, and recognition of transfusion reactions.

Veterinary transfusion medicine has mirrored the progression of the human blood banking industry. First, concerns were related largely to defining the science responsible for transfusion compatibility. Second, efforts shifted toward the standardization of blood product production. Finally, the industry has turned interest toward quality assurance and control. The AIDS pandemic in the early 1980s led to an extensive review of human blood component evaluation and screening. Currently, the Food and Drug Administration (FDA) oversees human blood supply in the United States. Groups such as the American Association of Blood Banks have developed extensive certification programs to ensure quality control and safety in the human blood supply. 1 The United States government does not regulate the animal blood supply. However, two organizations are now in existence for the purpose of self-regulating the industry and furthering the science of veterinary transfusion medicine: The Association of Veterinary Hematology and Transfusion Medicine (http://www.vetmed.wsu.edu/ org-AVHTM) and The American Association of Veterinary Blood Banks (http://www.aavbb.org).

Safety of blood supply is related to careful donor evaluation, thorough record keeping, extensive infectious disease screen-ing, intensive quality assurance for storage and transport, and avoidance of transfusion reactions. Evaluating safety of the feline blood supply reveals some unique features. The size of the average domestic cat makes "borrowing" technology from human transfusion medicine difficult. For larger companion animals, veterinary blood bankers have utilized blood collection techniques and systems used in the human industry. The total blood volume (325 ml) of the average 10-pound cat is less than the total volume of a standard human collection set (450 ml). Therefore FDA-approved, closed-system collection sets are not available for use with feline donors. Use of an open system for collection, most commonly a 60-ml syringe and butterfly catheter, can lead to bacterial contamination of the end product. Coincidentally, bacterial contamination with Serratia marcescens in feline units is the only published incident of external contamination of transfusion products in the veterinary literature. 2 The feline donor may not be a willing volunteer. This unwillingness frequently adds the necessity for chemical restraint through sedation or anesthesia; most veterinarians who collect whole blood units from cats use anesthesia. Ketamine and diazepam continue to be a routine choice for restraint during blood donation. Concerns for the donor's ability to maintain a normotensive state during the procedure have led to exploration of other types of sedation or anesthesia. Isoflurane gas anesthesia may be used to avoid hypotension associated with most intravenous anesthetics. The presence of these drugs and stress-induced cytokines in the end product must be considered. Traditionally, safety of blood products has been limited to monitoring the "out-of-body" experience of the product from donor to recipient. 3 These issues surrounding the donor add an additional layer to the safety concerns that a feline blood banker must evaluate and resolve.

Providing a safe feline blood supply starts with donor selection. Unlike our human counterparts, feline blood bankers cannot ask for a detailed history from the donor about their recent travel, sexual activities, drug usage, and illnesses. When "volunteer" donors are used, an extensive questionnaire is recommended so that the owner can provide as much historical detail as possible. All commercial blood banks currently producing feline components control their feline donor pool strictly. Most have closed colonies of cats to allow a reliable means of detailing historical travel, drug administration, illness, and sexual activity.

Physical evaluation of the donor perhaps is more important because we are unable to certify historical data. Feline donors are screened carefully for ectoparasites, evidence of bacterial disease, and normal physiological parameters. Any deviation from normal limits should exclude the donor from use. Note that evidence of bacterial disease includes periodontal disease, chronic urinary tract infection, or open wounds less than 72 hours old. 4 Presence of external parasites represents the potential exposure to infectious disease and should exclude the donor from use until the cat has been free of ectoparasites for a minimum of 30 days. Once again, because of the lack of direct information about the donor, biochemical screening before use is recommended. A complete blood count is a necessity. Abnormal cell types, indications of inflammation, low normal red blood cell count, and/or thrombocytopenia exclude donors from use.

Record keeping must be thorough. Using a standard operating procedure to perform feline selection, phlebotomy, and collection minimizes risk of contamination, increases the proficiency of collection, and documents the process to provide accountability. Each unit of blood is tracked from donor to recipient.

Labeling of blood products includes the proper identification of the component, a unique numerical identification, the amount of blood collected, expiration date, recommended storage temperature, blood type, appropriate donor identification, additives, and the name and address of the processing facility. 5 Many veterinary blood banks now use a barcode-style system to track product from collection to delivery. The path that the unit has taken from donor to recipient is documented completely, including storage and transport at any intermediate processing or holding facility. In addition to the paper trail, aliquots of the blood components produced are maintained at the principal facility of production to provide the opportunity for testing, if requested. 6 If records are digitalized, paper copies are maintained for the life of the blood product plus 6 months past the expiration date. For example, feline packed red blood cells expire 28 days after collection and separation. Paper copies are maintained for 7 months. If records are solely paper based, copies are held for 5 to 10 years. 3

The drive to produce blood components rather than whole blood for cats has led to the introduction of several novel ways to provide a closed sterile system for use in feline blood banking. Giger 4 describes the use of a sterile docking device and a pediatric quadruple bag system. Using the human pediatric quadruple bag system, 150-ml bags with CPDA-1 are iso-lated and attached in a sterile manner to 19-gauge butterfly catheters. This provides a sterile closed system that may be used either as a gravity flow collection device or as a vacuum collection system. 4 The sterile docking device used in this technique is cost prohibitive to most veterinary practices. A semiclosed sterile system with onsite addition of CPDA-1 through an injection port has been designed by commercial blood bankers (Figure 57-1) . Use of this system has provided a costeffective means to collect feline blood by syringe or gravity flow and minimize the risk of external bacterial contamination of the blood product. Both systems use polyolefin or polyvinyl chloride as a base. Packaging in plastic allows for the sterile separation from whole blood to components. Glass is not considered a safe medium for blood storage because of its breakability and its inability to accommodate sterile component processing. Storage of product often is not considered a high priority by most practitioners, but when performed incorrectly, the recipient is placed at great risk for non-immune-related transfusion reaction. 7 Temperature, packaging, and appropriate handling during holding and transport periods are very important when trying to avoid storage lesion in blood. Storage lesion is defined as damage to the blood product during its "out-of-body" experience. Indications of storage lesion may include hemolysis, increased or decreased pH, increased ammonia, and/or increased electrolytes. See Table 57 -1 for details regarding proper storage of common feline blood components. 8, 9 Records of daily temperature are maintained for each storage device. Records also should document mode of transport and condition of the product before and after transport. Documented variations from standard operating procedure exclude the product from normal use. The end user should be made aware of any variation from standard to allow appropriate modifications of product use.

Perhaps the hardest area of compliance for safety involves the determination of infectious disease screening for donors. A recent workgroup for the American College of Veterinary Internal Medicine prepared a consensus statement on infectious disease screening. 10 Infectious diseases were categorized by capability for infection through blood products, vector status, and clinical severity of infectious state. The following recommendations were made for cats. Feline leukemia virus and feline immunodeficiency virus status should be evaluated by standard ELISA techniques, detecting antigen and antibody respectively. Evaluation for feline coronavirus is not recommended, because of the lack of correlation between antibody level and disease status. Mycoplasma haemofelis and Mycoplasma haemominutum are evaluated by microscopic slide evaluation and polymerase chain reaction (see Chapter 63). Bartonella henselae infection status is evaluated by antibody titer, blood culture, and/or polymerase chain reaction 11 (see Chapter 4).

Additional vector-borne diseases such as cytauxzoonosis, ehrlichiosis, and anaplasmosis may be added to this testing protocol, depending on the regional location of the donor. The continuing struggle for blood product safety involves the testing interval of the individual. Ideally, from a safety perspective, each unit should be tested for the pathogens listed above in addition to routine bacterial contamination. However, testing at this level increases the cost of the end product greatly. The ACVIM workgroup concluded that, although not ideal, testing should be performed on the donor annually or more frequently if indicated by a change in history or health status. 10

The final aspect of safety involves avoiding transfusion reaction in the recipient. Transfusion reaction often is divided into two distinct categories: non-immune-related and immunerelated. Both types of transfusion reaction are demonstrated in the recipient in the same way. Mildly affected recipients show hyperemia, dyspnea, hyperthermia, tachycardia, emesis, and urticaria. More severely affected individuals may demonstrate signs of secondary infection, hemolysis, anemia, thrombocytopenia, or even death. Non-immune-related transfusion reactions are caused by circulatory overload, hemolysis resulting from storage lesion, bacterial contamination, hypothermia, and hypocalcemia. Rarely, pulmonary thromboembolism may occur post-transfusion as a non-immune-related reaction. Immune-related transfusion reactions are caused by hemolysis resulting from erythrocyte incompatibility, fever, and chill secondary to lymphocyte transfer, allergy, or anaphylaxis to donor proteins, and/or lymphocyte antigen incompatibility.

Transfusion therapy is performed optimally by selection of the most appropriate blood component and administration of that component in the manner most likely to avoid transfusion reaction. Whole blood, although often a simple and readily available source, may not be the best choice for the transfusion recipient. Component therapy provides an efficient way to supply oxygen-carrying capacity, primary and secondary coagulation capability, and/or oncotic proteins to a critical patient, while it minimizes infectious disease exposure and immunerelated reactions. Quality control of components through use of standard operating procedures, the use of modern plastic storage systems, and infectious disease screening further lowers the risk for non-immune reactions. Screening of the donor and recipient for erythrocyte antigens and cross-matching minimizes the risk for immune-related transfusion reaction.

The expansion of transfusion product availability has led to the increased use of blood and blood components in the feline patient. Safety of the blood supply is promoted by careful donor evaluation, thorough record keeping, advanced storage techniques, and avoidance of transfusion reactions. Adherence to the general guidelines discussed in this chapter promotes a safe blood supply capable of enhancing the lives of feline patients with minimal risk. 

Transfusion into the next millennium

Serratia marcescens contamination of feline whole blood in a hospital blood bank

V: Quality systems

A novel method of whole blood collection in the cat

Standards for blood banks and transfusion services

Blood component testing and labeling

Procedure for feline component collection

Blood components. Collection, processing and storage

Collection and preparation of blood products

Canine and feline blood donor screening for infectious disease

Clinical and pathologic evaluation of chronic Bartonella henselae or Bartonella clarridgeiae infection in cats