Blood-component therapy: selection, administration and monitoring

Transfusion of blood products is a frequent necessity in small animal practice. Transfusion medicine has become more sophisticated with increased access to blood components, knowledge of blood types, and cross-matching requirements. Although potentially life saving, this procedure does carry some risk. In addition to selecting the appropriate blood product, several steps need to be completed to prepare the product for administration and the patient for receiving a transfusion.     

Canine and feline blood transfusions: controversies and recent advances in administration practices

ObjectivesTo discuss and review blood transfusion practices in dogs and cats including collection and storage of blood and administration of products. To report new developments, controversial practices, less conventional blood product administration techniques and where applicable, describe the relevance to anaesthetists and anaesthesia.Databases usedPubMed and Google Scholar using dog, cat, blood transfusion, packed red blood cells and whole blood as keywords.ConclusionsBlood transfusions improve oxygen carrying capacity and the clinical signs of anaemia. However there are numerous potential risks and complications possible with transfusions, which may outweigh their benefits. Storage of blood products has improved considerably over time but whilst extended storage times may improve their availability, a phenomenon known as the storage lesion has been identified which affects erythrocyte viability and survival. Leukoreduction involves removing leukocytes and platelets thereby preventing their release of cytokines and bioactive compounds which also contribute to storage lesions and certain transfusion reactions. Newer transfusion techniques are being explored such as cell salvage in surgical patients and subsequent autologous transfusion. Xenotransfusions, using blood and blood products between different species, provide an alternative to conventional blood products.     

In vitro lysis and acute transfusion reactions with hemolysis caused by inappropriate storage of canine red blood cell products

Background: Transfusion of red blood cell (RBC) products carries considerable risk for adverse reactions, including life‐threatening hemolytic reactions. Objective: To report the occurrence and investigation of life‐threatening acute transfusion reactions with hemolysis in dogs likely related to inappropriate blood product storage. Animals: Four dogs with acute transfusion reactions and other recipients of blood products. Methods: Medical records were reviewed from 4 dogs with suspected acute hemolytic transfusion reactions after receiving RBC products at a veterinary clinic over a 1‐month period. Medical records of other animals receiving blood products in the same time period also were reviewed. Blood compatibility and product quality were assessed, subsequent transfusions were closely monitored, and products were diligently audited. Results: During or immediately after RBC product transfusion, 4 dogs developed hemolysis, hemoglobinuria, or both. Two dogs died and 1 was euthanized because of progressive clinical signs compatible with an acute hemolytic transfusion reaction. Blood type and blood compatibility were confirmed. RBC units from 2 blood banks were found to be hemolyzed after storage in the clinic's refrigerator; no bacterial contamination was identified. After obtaining a new refrigerator dedicated to blood product storage, the problem of hemolyzed units and acute transfusion reactions with hemolysis completely resolved. Conclusions: Acute life‐threatening transfusion reactions can be caused by inappropriate storage of RBC products. In addition to infectious disease screening and ensuring blood‐type compatibility, quality assessment of blood products, appropriate collection, processing, and storage techniques as well as recipient monitoring are critical to provide safe, effective transfusions.     

Principles of transfusion medicine in small animals.

The purpose of this review was to provide the reader with an updated overview of small animal transfusion medicine, and an approach to integrating it into private practice, based on a review of the veterinary and human literature spanning the last 3 decades. Electronic, online databases that were searched included CAB International and Medline; multiple keywords or subject headings were searched that were appropriate to each of the sections reviewed: canine and feline blood groups, blood-typing and crossmatching, donors, blood collection, storage, blood components, blood transfusion, blood component therapy, blood substitutes, and adverse reactions. The safe use of blood component therapy requires knowledge of blood groups and antibody prevalence, and knowledge of the means to minimize the risk of adverse reactions by including the use of proper donors and screening assays that facilitate detection of serological incompatibility. The 2 assays available to the practitioner are crossmatching, which is readily done in-house, and blood typing. Blood typing is available in the form of a commercial testing kit, through use of purchased reagents, or via a request to an external laboratory. The risk of potentially fatal adverse reactions is higher in cats than in dogs. The decision to transfuse and the type of product to administer depend on several factors, such as the type of anemia and the size of the animal. In conclusion, transfusion medicine has become more feasible in small animal practice, with improved access to blood products through either on-site donors, the purchase of blood bank products, external donor programs, or the availability of blood component substitutes.     

Triggers for use, optimal dosing, and problems associated with red cell transfusions.

The administration of RBC components can dramatically improve tissue oxygenation in small animals with symptomatic anemia and can be life saving. This therapy is not without risk, however. Careful consideration of the transfusion trigger, appropriate screening of the donor and recipient, and selection of the optimal RBC component and dose on an individual patient basis can help to limit the occurrence of adverse transfusion-related events. Appropriate component administration techniques, careful monitoring of recipients for the development of transfusion reactions, and prompt recognition and treatment of transfusion reactions are also essential in assuring safe transfusion practice.     

Use of blood and blood products.

It is sometimes necessary for the practitioner to transfuse the ruminant with whole blood or plasma. These techniques are often difficult to perform in practice, are time-consuming, expensive, and stressful to the animal. Acute loss of 20% to 25% of the blood volume will result in marked clinical signs of anemia, including tachycardia and maniacal behavior. The PCV is only a useful tool with which to monitor acute blood loss after intravascular equilibration with other fluid compartments has occurred. An acutely developing PCV of 15% or less may require transfusion. Chronic anemia with PCV of 7% to 12% can be tolerated without transfusion if the animal is not stressed and no further decline in erythrocyte mass occurs. Seventy-five percent of transfused bovine erythrocytes are destroyed within 48 hours of transfusion. A transfusion rate of 10 to 20 mL/kg recipient weight is necessary to result in any appreciable increase in PCV. A nonpregnant donor can contribute 10 to 15 mL of blood/kg body weight at 2- to 4-week intervals. Sodium citrate is an effective anticoagulant, but acid citrate dextrose should be used if blood is to be stored for more than a few hours. Blood should not be stored more than 2 weeks prior to administration. Heparin is an unsuitable anticoagulant because the quantity of heparin required for clot-free blood collection will lead to coagulation defects in the recipient. Blood cross-matching is only rarely performed in the ruminant. In field situations, it is advisable to inject 200 mL of donor blood into the adult recipient and wait 10 minutes. If no reaction occurs, the rest of the blood can probably be safely administered as long as volume overload problems do not develop. Adverse reactions are most commonly seen in very young animals or pregnant cattle. Signs of blood or plasma transfusion reaction include hiccoughing, tachycardia, tachypnea, sweating, muscle tremors, pruritus, salivation, cough, dyspnea, fever, lacrimation, hematuria, hemoglobinuria, collapse, apnea, and opisthotonos. Intravenous epinephrine HCl 1:1000 can be administered (0.2 to 0.5 mL) intravenously or (4 to 5 mL) intramuscularly (preferable) if clinical signs are severe. Pretreatment with antipyretics and slowing the administration rate may decrease the febrile response. Blood or plasma administered too rapidly will also result in signs of cardiovascular overload, acute heart failure, and pulmonary hypertension and edema. Furosemide and slower administration of blood or plasma should alleviate this problem. Administration rates have been suggested starting from 10 mL/kg/hr; faster rates may be necessary in peracute hemorrhage. Plasma should be administered when failure of absorption of passive maternal antibody has occurred or when protein-loosing enteropathy or nephropathy results in a total protein of less than 3 g/dL or less than 1.5 g albumin/dL. Plasma can be stored at household freezer temperatures (-15 to -20 degrees C) for a year; coagulation factors will be destroyed after 2 to 4 months when stored in this manner. To maintain viability of coagulation factors, plasma must be stored at -80 degrees C for less than 12 months. When administering plasma, a blood donor set with a built-in filter should always be used. When bovine plasma is thawed, precipitants form in the plasma and infusion of these microaggregates may result in fatal reactions in the recipient.     

Increasing patient safety in veterinary transfusion medicine: an overview of pretransfusion testing

Objectives – To review the principles and available technology for pretransfusion testing in veterinary medicine and discuss the indications and importance of test performance before RBC transfusion.
Data Sources – Current human and veterinary medical literature: original research articles and scientific reviews.
Summary – Indications for RBC transfusion in veterinary medicine include severe anemia or tissue hypoxia resulting from blood loss, decreased erythrocyte production, and hemolyzing conditions such as immune-mediated anemia and neonatal isoerythrolysis. Proper blood sample collection, handling, and identification are imperative for high-quality pretransfusion testing. Point-of-care blood typing methods including both typing cards and rapid gel agglutination are readily available for some species. Following blood typing, crossmatching is performed on one or more donor units of appropriate blood type. As an alternative to technically demanding tube crossmatching methods, a point-of-care gel agglutination method has recently become available for use in dogs and cats. Crossmatching reduces the risk of hemolytic transfusion reactions but does not completely eliminate the risk of other types of transfusion reactions in veterinary patients, and for this reason, all transfusion reactions should be appropriately documented and investigated.
Conclusion – The administration of blood products is a resource-intensive function of veterinary medicine and optimizing patient safety in transfusion medicine is multifaceted. Adverse reactions can be life threatening. Appropriate donor screening and collection combined with pretransfusion testing decreases the occurrence of incompatible transfusion reactions.     

Feline transfusion practice in South Africa: current status and practical solutions

Blood transfusion therapy is often under-utilised in feline practice in South Africa. However, it is a technique that can be safely and effectively introduced in practice. Cats have naturally occurring allo-antibodies against the blood type that they lack, which makes blood typing, or alternatively cross-matching, essential before transfusions. Feline blood donors must be carefully selected, be disease free and should be sedated before blood collection. The preferred anticoagulant for feline blood collection is citrate-phosphate-dextrose-adenine. Blood can either be administered intravenously or into the medullary cavity, with the transfusion rate depending on the cat's hydration status and cardiac function. Transfusion reactions can be immediate or delayed and they are classified as immunological or non-immunological. Indications, methods and techniques to do feline blood transfusions in a safe and economical way are highlighted.     

Use of blood and blood products

It is sometimes necessary for the practitioner to transfuse the ruminant with whole blood or plasma. These techniques are often difficult to perform in practice and are time-consuming, expensive, and stressful to the animal. Acute loss of 20-25% of the blood volume will result in marked clinical signs of anemia, including tachycardia and maniacal behavior. The PCV is only a useful tool with which to monitor acute blood loss after intravascular equilibration with other fluid compartments has occurred. An acutely developing PCV of 15% or less may require transfusion. Chronic anemia with PCV of 7-12% can be tolerated without transfusion if the animal is not stressed and no further decline in erythrocyte mass occurs. Seventy-five per cent of transfused bovine erythrocytes are destroyed within 48 hours of transfusion. A transfusion rate of 10-20 ml/kg, recipient weight, is necessary to result in any appreciable increase in PCV. A nonpregnant donor can contribute 10-15 ml of blood/kg body weight at 2-4 week intervals. Sodium citrate is an effective anticoagulant, but acid citrate dextrose should be used if blood is to be stored for more than a few hours. Blood should not be stored more than 2 weeks prior to administration. Heparin is an unsuitable anticoagulant because the quantity of heparin required for clot-free blood collection will lead to coagulation defects in the recipient. Blood crossmatching is only rarely performed in the ruminant. In field situations, it is advisable to inject 200 ml of donor blood into the adult recipient and wait 10 minutes. If no reaction occurs, the rest of the blood can probably be safely administered as long as volume overload problems do not develop. Adverse reactions are most commonly seen in very young animals or pregnant cattle. Signs of blood or plasma transfusion reaction include hiccoughing, tachycardia, tachypnea, sweating, muscle tremors, pruritus, salivation, cough, dyspnea, fever, lacrimation, hematuria, hemoglobinuria, collapse, apnea, and opisthotonos. Intravenous epinephrine HCl 1:1000 can be administered (0.2 to 0.5 ml) intravenously or (4 to 5 ml) intramuscularly if clinical signs are severe. Pretreatment with antipyretics and slowing the administration rate may decrease the febrile response. Blood or plasma administered too rapidly will also result in signs of cardiovascular overload, acute heart failure, and pulmonary hypertension and edema. Furosemide and slower administration of blood or plasma should alleviate this problem.(ABSTRACT TRUNCATED AT 400 WORDS)     

Prevalence of feline blood groups in the Montreal area of Quebec,Canada

The feline AB blood group system has clinical significance because type B cats have natural alloimmune anti-A antibodies which can cause isoerythrolysis of the newborn and life-threatening transfusion reactions. In the United States, the prevalence of type B blood is estimated to be 1% to 2%. This study determined the prevalence of feline AB blood groups among 207 potential blood donor cats that included 178 domestic cats, in the Montreal area of Quebec, Canada. Blood typing was performed using a standardized tube technique. Blood types AB and B were confirmed using a backtyping technique. The frequency of blood types among the studied population was as follows: 95.2% type A, 4.4% type B, and 0.48% type AB. Among domestic cats, the frequency was 94.4% for type A, 5% for type B, and 0.6% for type AB. The frequency of type B was higher than expected, which reinforces the recommendation to ensure blood compatibility of the recipient and donor before transfusion through typing and possibly cross-matching as well.     

Advances in Exotic Mammal Clinical Therapeutics

It is imperative that the veterinarian treating exotic companion mammals stay abreast of the latest developments relating to medications and drug delivery approaches for safety and efficacy. Sustained-release formulations of commonly used drugs, as well as newer routes for administration of therapeutic agents, allow the veterinarian treating exotic companion mammals to reduce the stress associated with drug administration. Interactions can occur between vehicle and drugs when formulations are compounded; therefore, research studies are warranted regarding potential problems associated with these formulations. However, newer studies have been published that provide the basis for exploring the use of different vehicles, frequency of dosing, and drug delivery techniques for various classes of drugs in exotic mammals. The goals of this review are to not only evaluate new medications or uses for medications in companion exotic mammal patients but also review new methods of drug delivery that might be useful to the veterinarian who treats these animals.     

聚合猪血红蛋白在犬异源输血中的应用研究

对猪血红蛋白作为血液替代品的效果进行研究,提取猪血红蛋白,经PEG聚合及纯化,输给试验犬,检测、记录犬输入聚合血红蛋白前后的临床指标,并在输血后进行血常规和尿常规检测。结果表明,将聚合猪血红蛋白输入犬体内没有发生明显的溶血和凝血等输血反应,通过尿常规检测聚合血红蛋白在体内可存在7 d;第2次聚合血红蛋白输血也没有出现临床不良反应。结果显示聚合血红蛋白作为血液替代品有较好的临床应用前景。     

Massive transfusion in dogs: 15 cases (1997-2001)

OBJECTIVE: To determine clinical characteristics of dogs that received massive transfusion and identify the underlying diseases, complications, and outcomes. DESIGN: Retrospective study. ANIMALS: 15 dogs. PROCEDURE: Medical records of dogs receiving a massive blood transfusion were evaluated for transfusion volume, underlying disease process or injury, benefits and complications of transfusion, and outcome. A massive transfusion was defined as transfusion of a volume of blood products in excess of the patient's estimated blood volume (90 ml/kg [40 ml/lb]) in a 24-hour period or transfusion of a volume of blood products in excess of half the patient's estimated blood volume in a 3-hour period. RESULTS: Six dogs had intra-abdominal neoplasia resulting in hemoabdomen, 3 had suffered a traumatic incident resulting in hemoabdomen, and 6 had non-traumatic, non-neoplastic blood loss. Mean volumes of packed RBC and fresh-frozen plasma administered were 66.5 ml/kg (30 ml/lb) and 22.2 ml/kg (10 ml/lb), respectively. All dogs evaluated developed low ionized calcium concentrations and thrombocytopenia. Transfusion reactions were recognized in 6 dogs. Four dogs survived to hospital discharge. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that massive transfusion is possible and potentially successful in dogs. Predictable changes in electrolyte concentrations and platelet count develop.     

Effect of Blood Transfusion in Combination with Dextran-40 and Hypertonic Saline Solution on Cardiopulmonary Haemodynamics of Endotoxin (Lipopolysaccharide) Shock in Buffalo Calves

The intravenous (i.v.) infusion of lipopolysaccharide (LPS) of E. coli endotoxin in buffalo calves (n = 15) at 5 μg/kg bw per h for 3 h caused a significant (p<0.05) fall in plasma volume, blood volume, haematocrit haemoglobin, and systolic, diastolic and pulse pressure, mean arterial pressure and central venous pressure (CVP), with a marked rise in respiration. Treatment with a combination of i.v. infusion of 7.2% hypertonic saline solution, Plasmex-D-40 (Dextran-40) and blood successfully alleviated hypovolaemia, and raised systolic, diastolic and pulse pressure, mean arterial pressure and central venous pressure. The whole blood was collected from apparently healthy male buffalo calves 24 h prior to infusion and was transfused without cross-matching. No significant fall in haemoglobin, haematocrit and body temperature was observed after transfusion. All these values tended to remain near normal levels. However, this combination of treatment had no effect on high respiratory rate. A one-time blood transfusion did not evoke any cross-reaction and was helpful in raising haematocrit and haemoglobin close to pre-infusion values. The general symptoms of restlessness, respiratory distress, profuse salivation, violent movement of the ears, snoring, intermittent struggle, etc. were markedly reduced. All the treated animals became quiet and lay with eyes open and survived the 7 h of observation.     

The use of 25% human serum albumin: outcome and efficacy in raising serum albumin and systemic blood pressure in critically ill dogs and cats

Objective: To report on the use of 25% human serum albumin (25% HSA) (Plasbumin®), associated outcome, and efficacy in raising serum albumin and systemic blood pressure (BP) in critically ill dogs and cats. Design: Retrospective clinical study. Animals: Client‐owned cats and dogs. Interventions: Administration of 25% HSA. Measurements and main results: The medical records of 66 animals (64 dogs, 2 cats) at the Ontario Veterinary College, which received 25% HSA (Plasbumin®) from June 1997 to December 2001 were reviewed for age, body weight, clinical problems, albumin and globulin (g/L) levels pre‐ and within 18‐hour post‐transfusion and upon discharge from hospital, total solids (TS), systolic and diastolic BP pre‐ and post‐transfusion total volume administered, adverse reactions, blood products and synthetic colloids used, and outcome. Twenty‐five percent HSA was prescribed for a range of clinical problems, which were grouped into 6 categories for analysis. The age range was 4 months–12 years and body weight range 1.4–65 kg. The maximum volume administered to any dog was 25 mL/kg, mean volume administered was 5 mL/kg, maximum volume given as a slow push or bolus was 4 mL/kg with a mean of 2 mL/kg volume. The range for a constant rate infusion (CRI) was 0.1–1.7 mL/kg/hr over 4–72 hours. Forty‐seven (71%) animals survived to discharge; 11(16%) were euthanized, and 8 (12%) died. Serum albumin and TS increased significantly (P<0.0001) above pre‐transfusion levels as did systolic BP (P<0.01). Conclusions: Twenty‐five percent HSA can be safely administered to critically ill animals, and an increase in albumin levels and systemic BP can be expected.     

Complications of fluid therapy.

The intravenous administration of fluids is one of the most important aspects of patient care in hospitalized animals. Intravenous fluids are administered to replace or prevent dehydration, treat hypovolemic shock and intravascular volume depletion, correct acid-base and electrolyte abnormalities, and maintain vascular access for administration of drugs, blood product components, and parenteral nutrition. Intravenous catheterization also can provide a means of blood sample collection, thus avoiding frequent and uncomfortable venipunctures in critically ill animals. Although the benefits of intravenous catheterization and fluid administration are numerous, inherent risks are associated with the procedures, and care must be taken to avoid potential complications.     

Blood transfusion in the perioperative period

In the perioperative period, blood transfusions are most commonly administered to address acute blood loss resulting from trauma, neoplasia, or surgery. In this setting, transfusions may be life saving, allowing time for clotting or surgical hemostasis. In recent years, however, there is a growing awareness that the administration of blood products may not be a benign treatment. In addition to the more commonly cited complications such as transfusion reactions, disease transmission, and electrolyte disturbances, blood transfusions have also been linked to poor surgical outcomes, increased risk of infection, cancer recurrence, and acute lung injury. The recognition of these problems has lead to more conservative transfusion strategies, and questioning of what constitutes an appropriate transfusion trigger. In this section, we will discuss the pathophysiology of acute blood loss, the benefits and risks of transfusions in surgical patients, management of perioperative blood transfusions, and alternative strategies to minimize the need for blood products.     

Red blood cell volume as a predictor of fatal reactions in cattle infected with Theileria parva Katete

A comparison of mean corpuscular volume (MCV) and packed cell volume (PCV) was made between cattle undergoing lethal and non-lethal reactions following experimental infections with the apicomplexan protozoa, Theileria parva Katete. This work confirmed that anaemia occurs in infected animals. However, the fall in PCV was steeper in lethal reactions compared to non-lethal reactions. Our results show that animals with initially lower MCV values are more prone to fatal reaction, despite having normal PCV profiles. The study also found that small red blood cells are more likely to be infected with T. parva. These findings suggest that animals with a higher proportion of small red blood cells in circulation will be more likely to succumb to T. parva infections. The potential for using MCV as a predictor of the outcome of infection challenge is discussed.     

Hemolytic Transfusion Reactions in a Dog With an Alloantibody to a Common Antigen

Alloantibodies to high-frequency red cell antigens, defined as inherited traits occurring in 92% to 99% or more of the general population, are recognized as a cause of hemolytic transfusion reactions in humans. Here we describe a dog (dog erythrocyte antigen [DEA] 1.2-and DEA 4-positive) sensitized by prior blood transfusion, for which a compatible blood donor could not be found; transfusion of DEA 1.1-negative blood resulted in hemolytic transfusion reactions. Patient serum from days 1 (before first transfusion) and 16 was available for further testing; using 4 dogs with different blood types as potential donors, the major crossmatches were compatible using serum from day 1. However the crossmatches were all incompatible with serum from day 16, indicating that the patient was sensitized to an antigen after the first transfusion. The presence of an alloantibody against DEA 1.1 was not ruled out in this patient, but the incompatibility reactions of patient serum with red cells from donors negative for DEA 1.1 indicated that an alloantibody against a red cell antigen other than DEA 1.1 or any other known DEA for which typing reagents were available (DEA 3, 5, and 7) was present. Subsequently, red cells from 1 of the patient's siblings (DEA 1.2-, 4-, and 7-positive) were found not to agglutinate when incubated with patient's serum from day 16, ruling out the presence of an anti-DEA 7 antibody, and suggesting that an alloantibody against a common red cell antigen missing in the patient and sibling was responsible for the blood incompatibility reactions. Failure to obtain a compatible crossmatch with several universal donors in a dog previously transfused should raise a suspicion that an alloantibody to a common red cell antigen may exist and that a sibling may be a source of compatible blood.     

Red blood cell transfusions in cats: 126 cases (1999)

OBJECTIVE: To determine the number of and reasons for RBC transfusions, incidence of acute transfusion reactions, prevalence of blood types, volume of blood administered, change in PCV, and clinical outcome in cats. DESIGN: Retrospective study. ANIMALS: 126 cats that received RBC transfusions. PROCEDURE: Medical records of cats that received whole blood or packed RBC transfusions were reviewed for signalment, blood type, pre- and post-transfusion PCV, volume of blood product administered, clinical diagnosis and cause of anemia, clinical signs of acute transfusion reactions, and clinical outcome. RESULTS: Mean volume of whole blood administered i.v. was 172 mL/kg (7.8 mL/lb) versus 9.3 mL/kg (4.2 mL/lb) for packed RBCs. Ninety-four percent of cats had blood type A. Mean increase in PCV among all cats was 6%. Fifty-two percent of cats had anemia attributed to blood loss, 10% had anemia attributed to hemolysis, and 38% had anemia attributed to erythropoietic failure. Acute transfusion reactions occurred in 11 cats. Sixty percent of cats survived until discharge. CONCLUSIONS AND CLINICAL RELEVANCE: RBC transfusions resulted in an increase in PCV in cats with all causes of anemia in this study. The rate of death was greater than in cats that did not receive transfusions, but seriousness of the underlying disease in the 2 groups may not be comparable. Death rate of cats that received transfusions was not attributable to a high rate of transfusion reactions. Results confirm that pretransfusion blood typing or crossmatching is required to minimize the risk of adverse reactions.