Objectives and References

• Objectives of the study guide
  • Review of blood products
  • Provided case examples
• References
  • Nelson & Couto Chapter 87
  • Ettinger Chapter 130
  • Silverstein & Hopper Chapter 69
  • VIN readings

Canine Blood Types

• At least 8 different blood groups in dogs
• Dog Erythrocyte Antigen (DEA)
  • DEA 1
  • Considered most significant
  • No naturally occurring antibodies; thus, acute reactions with the first transfusion are rare
  • Antibodies develop after the first transfusion if an incompatible donor is used
  • DEA 7
  • Approximately 15% of DEA7(-) animals have naturally occurring antibodies
  • Can lead to mild delayed transfusion reactions after the first transfusion
  • Universal donor characteristics
  • Ideally negative for all DEAs (except DEA4)
  • DEA 1 negative is the most common and accepted donor type
  • DEA 4 is present in almost all North American dogs

Canine Donor and Recipient Matching Methods

• Blood type matching
  • DEA 1 negative is ideal, even for dogs that have previously received transfusions
  • Kits are available to test for DEA 1 and other types (Dal and Kal)
• Cross-matching
  • Most commonly practiced method before transfusion
  • Ideal to perform even with DEA 1 negative donor
  • Two types of cross-match:
  • Major: Donor red blood cells mixed with recipient serum (antibodies)
  • Minor: Donor serum (antibodies) mixed with recipient red blood cells

Canine Cross-Matching

• Major cross-match is more critical than minor
• Blood collection
  • Use heparin and EDTA tubes from both donor and recipient
  • Mixing whole blood is unreliable and not recommended
  • RBCs should be washed
• Testing
  • Mix washed RBCs and plasma in test tubes or well plates (recommended), or on a slide (less ideal)
  • Cross-matching kits are purchasable
• First transfusion
  • Does not require a cross-match in emergencies or financial constraints
  • Post-transfusion packed cell volume (PCV) or hematocrit (Hct) is higher in animals cross-matched, even for a first-time transfusion

Feline Blood Groups

• Three main blood types
  • Type A: Most common type
  • Type B: Common in breeds such as Persians, Himalayans, Abyssinians, Turkish Vans, and British Shorthairs
  • Type AB: Rare; also referred to as Type C, although AB designation is preferred
• Characteristics of feline blood types
  • Type A has low-titer anti-B antibodies; mild transfusion reactions occur if blood from Type B donor is given
  • Type B has high-titer anti-A antibodies, which can lead to severe (and potentially fatal) reactions with Type A or AB blood
  • Type AB has no naturally occurring alloantibodies and possesses both antigens

Feline Donor-Recipient Matching

• Matching is essential due to fatal consequences of mismatched transfusions
  • Administering Type A blood to a Type B cat is deadly, even in minimal volume
  • Cross-matching follows the same protocol as in canines
  • Cross-matching does not eliminate the risk of minor incompatibilities; thus, always recommended
  • Typing kits are available to detect A, B, and AB types; however, other feline types (MIK and FEA) have also been identified

Ideal Donors - Canine and Feline

Canine Donor Requirements

• Must be healthy and fully vaccinated
• Weight greater than 30 kg
• PCV must exceed 35%
• DEA 1 negative or a universal donor with all DEAs negative
• Negative for infectious diseases including heartworm, Babesia, and Rickettsial
• Good temperament

Feline Donor Requirements

• Must be healthy and fully vaccinated
• Weight greater than 4 kg
• Negative for FeLV, FIV, and Mycoplasma haemofelis
• PCV must exceed 35%
• Known blood type
• Good temperament for sedation reliability

Collection and Storage of Blood

• Collection method
  • Use jugular vein; surgically prepped
  • Sedation may be required
  • Utilize collection bags containing anticoagulants
  • Acid citrate dextrose (ACD)
  • Citrate phosphate dextrose (CPD)
  • Citrate phosphate dextrose adenine (CPDA)
• Storage duration
  • Blood can be stored for 3-4 weeks if refrigerated
  • ACD ratio: 1.3 ml ACD to 10 ml whole blood
  • For thrombocytopenia use must occur within 8 hours

General Blood Collection Points

• 10-20% of the donor's body weight may be collected
  • 500 ml maximum in a dog weighing over 30 kg
  • 50 ml maximum in a cat
• Administer fluids to the donor post-donation, especially if collection volume exceeds 10%
• Two formulas for calculating necessary transfusion volumes
  • $V = 10 imes rac{90 imes (30-15)}{42} = 321 mL$
  • $V = 2 imes 10 imes (30-15) = 300mL$

Blood Administration

• Must warm blood to room temperature or body temperature before administration
• Room temperature is acceptable but overheating should be avoided to prevent hemolysis or clotting
• Reducing viscosity and preventing patient hypothermia is critical
• Use of a blood filter is recommended to remove micro-thrombi
• Avoid administering through the same catheter as calcium- or dextrose-containing fluids

Administration Rates

• Normovolemic patients: 5-10 mL/kg/h
• Hypovolemic patients: up to 20 mL/kg/h maximum
• Maximum volume limit: 20 mL/kg/day
• For cardiac or renal disease, restrict the administration rate to 2 mL/kg/h but review circumstances

Blood Product Selection

• Choices depend on patient diagnosis and condition
• There is no universally set number for PCV or Hct
• 1 unit of fresh whole blood can be separated into 2-3 blood products
• Conditions to consider for blood product choice:
  • Chronic hemorrhage, hemolysis, non-regenerative anemia, thrombocytopenia, clotting factor deficits, hypoalbuminemia
  • Normovolemia, chronic hemorrhage, hemolysis, non-regenerative anemia, coagulopathies
  • Consideration for thrombocytopenia: use platelet-rich plasma (PRP) or platelet concentrate
  • Clotting factor deficiencies may require plasma (fresh frozen or frozen)

Hemostasis Overview

• Primary hemostasis refers to initial vascular injury response
• Secondary hemostasis refers to downstream coagulation processes
• Fibrinolysis involves the breakdown of clots post-hemostasis
• Injury leads to:
  • Adhesion (GPIb-vWf interaction)
  • Activation (thrombin and aggregation through GPIIb/IIIa)

Pathways of Hemostasis

Primary Hemostasis

• Blood vessel injury triggers vasoconstriction and platelet plug formation
• Involves platelet activation and interactions with the subendothelial collagen
• Primary hemostatic plug comprises platelets, vWF, and fibrinogen

Secondary Hemostasis

• Critical components include tissue factor and various clotting factors in intrinsic and extrinsic pathways leading to fibrin formation
• Pathways are interrelated; coagulation times can be prolonged by several conditions
• Communication between different clotting factors ensures efficiency

Identifying Clotting Disorders

Clinical Signs

• Primary hemostatic defects manifest as:
  • Petechiae and bleeding in skin and mucous membranes
  • Rarely hematomas
  • Immediate bleeding after venipuncture
• Secondary hemostatic defects show:
  • Rare petechiae
  • Common hematomas
  • Delayed bleeding into muscles, joints, and body cavities

Primary Clotting Disorders

• Include conditions like thrombocytopenia and thrombopathia
• Commonly involve assessment of manual platelet counts and correlate with clinical signs

Von Willebrand Factor Deficiency

• Classified into three types:
  • Type 1: Low concentration of normal vWF
  • Type 2: Low concentration of abnormal vWF
  • Type 3: Absence of vWF
• Common breeds affected: Doberman Pinschers and several others
• Diagnosis often involves Buccal Mucosal Bleeding Time (BMBT) tests

Treatment for vWF Deficiency

• Type 1: Administer DDAVP prior to surgery
• Type 2 or Type 3, or Type 1 in crisis: require more aggressive treatment including fresh whole blood or cryoprecipitate

Summary of Thrombocytopenia Causes

• Decreased platelet production can result from several conditions:
  • Immune-mediated thrombocytopenia
  • Infectious causes (Anaplasma spp., Bartonella spp.)
• Increased platelet destruction can be driven by various conditions including DIC, neoplasia, and drug-induced issues

Secondary Clotting Disorders

• Related to congenital issues like Hemophilia A or B
• Vitamin K antagonism causes critical bleeding issues and can arise from rodenticide exposure
• Liver dysfunction is commonly related to prolonged clotting tests but typically does not produce life-threatening bleeding

Blood Products Overview

• Blood products discussed include:
  • Plasma (Fresh Frozen Plasma, regular plasma)
  • Platelet-rich plasma (PRP), cryoprecipitate
  • Packed red blood cells (pRBC), whole blood
• Selection is based on conditions like hemorrhage, coagulopathies, or anemia, and requires careful monitoring of patient status

Blood Products and Their Indications

Clinical Case Examples

Case 1

• Patient: 9-year-old FS mixed breed canine, 20 kg
• Presented with septic abdomen due to intestinal perforation; hypotensive with a systolic blood pressure of 60
• Albumin level at 1.1 mg/dL; consider options to raise albumin

Case 2

• Patient: 2-year-old F Doberman Pinscher
• Presented with lethargy and anorexia; signs include pale mucous membranes, petechiae, and melena
• Blood work showing platelets at 10,000, Hct at 18%, total protein at 4.0, and BMBT at 15 minutes; ask for diagnosis and treatment

Case 3

• Patient: 2-year-old FS German Shepherd dog, spayed earlier the same day
• Bleeding from incision site, with normal PT/PTT but prolonged BMBT; consider diagnosis and treatment

Case 4

• Patient: 4-year-old MC domestic short hair cat (DSH)
• Hit by car (HBC) with a Hct of 22% and imaging revealing hemoabdomen; outline options for intervention

Case 5

• Patient: 4-year-old MC Labrador
• Hit by car (HBC) with an Hct of 28% and imaging showing hemothorax; discuss treatment options

Case 6

• Patient: 8-year-old FS Corgi
• Presenting with seizures, with blood work showing platelets at 15,000 and Hct at 32%; explore possible treatment options

Case 7

• Patient: 4-year-old MC Labrador
• Presenting with severe lethargy and anorexia; blood work revealing Hct at 24%, with PT/PTT unable to be measured; consider treatment options

Case 8

• Patient: 8-year-old FS Miniature Schnauzer
• Receiving treatment for pancreatitis, though developing petechiae and ecchymoses; CBC showing platelets at 70,000 and increased PT/PTT; diagnose and propose options

Conclusion

• Emphasize importance of understanding blood types, donation processes, and the management of transfusion-related complications.
• Acknowledge the critical role of blood products in veterinary medicine and ongoing research to improve outcomes in transfusion practices.
• Highlight the necessity of individualized treatment plans based on patient specifics, ensuring optimal results in treating hematologic disorders.