Blood loss and transfusion

Question 1

What is a blood transfusion?

Answer 1

The process of transferring blood or blood-based products from one individual into the circulatory system of another individual of the same species

Question 2

What are the reasons for performing a blood transfusion?

Answer 2

Increase the Hb content of the blood; increase circulating volume; increasing plasma albumin content; provide coagulation factors; provide functional platelets

Question 3

What are the different types of blood products?

Answer 3

Fresh whole blood (FWB; PCV ~40%), packed red cells (PCV ~70%), fresh frozen plasma (FFP), cryoprecipitate (contains coagulation factors)

Question 4

When should you consider transfusion?

Answer 4

Acute blood loss > 20% of blood volume; > 10-15% of blood loss was peri-operative; acute anemia

Question 5

True/False: clinical signs are more important than arbitrary trigger values when considering transfusion.

Answer 5

True

Question 6

What are the clinical signs of blood loss?

Answer 6

Pale mucus membranes; elevated heart rate; low blood pressure; weak pulse; blood in surgical sponges and suction container

Question 7

How do you estimate blood loss?

Answer 7

Standard surgical sponge may contain 5 mL blood; blood loss (mL) = (PCV of suctioned fluid x vol in canister (mL))/preoperative patient PCV

Question 8

True/False: assuming donor PCV of 40%, 2 mL whole blood/kg BW raises PCV of recipient by 1%

Answer 8

True

Question 9

How do you calculate how much blood to give?

Answer 9

Blood to be transferred (mL) = ([PCV required - PCV recipient] x blood volume of recipient (mL))/PCV of donor

Question 10

What are the doses for blood transfusion?

Answer 10

Dogs: 10-40 mL/kg
Cats: 5-20 mL/kg

Question 11

What rate should you transfuse blood at?

Answer 11

Start with 0.25 mL/kg for first 30 min to test for reaction; continue with rate 5-10 mL/kg/h; complete transfusion within 4 hours

Question 12

True/False: when transfusing blood, it is generally ok to mix it with Ringer solution.

Answer 12

False. Ringer contains Ca; blood will clot again

Question 13

What is the best option to use for providing coagulation factors?

Answer 13

Cryoprecipitate

Question 14

When giving a transfusion to provide coagulation factors, how long can blood be stored?

Answer 14

Fresh whole blood: use within 6 hours
Fresh plasma: use within 6 hours
FFP: fresh plasma stored at -4 F for

Question 15

What are some side effects of using plasma for transfusion?

Answer 15

May trigger an allergic reaction; may trigger immunity against blood group Ag’s (blood typing necessary)

Question 16

What type of blood should be used when providing functional platelets?

Answer 16

Use fresh whole blood; obtain blood in plastic container; store in room temp; use within 8 hours

Question 17

What are some examples of adverse transfusion reactions?

Answer 17

Blood type incompatibility; allergic reaction (anaphylaxis); alteration of the immune system (problems during next transfusion; neonatal isoerythrolysis in foals)

Question 18

What are some side effects of transfusion?

Answer 18

Circulatory overload; transfusion related acute lung injury (TRALI); citrate induced hypocalcemia (tetany); sepsis (bacterial contamination); transmission of infectious diseases (FIV, FELV, hemobartonella, anaplasma, etc.)

Question 19

What are the two types of blood type incompatibility reactions?

Answer 19

Acute reaction: life threatening; hemolysis (horses and cattle); agglutination
Slow reaction: decreased RBC life span (few days)

Question 20

What are the signs of an acute blood type incompatibility reaction?

Answer 20

Increased HR, decreased BP, increased RR, dyspnea; tremors, vomiting, wheals, urticaria, fever; pain at injection site; hemolysis, Hb-uria, renal failure, DIC; CV collapse; less signs under anesthesia

Question 21

How do you treat an acute blood type incompatibility reaction?

Answer 21

Stop transfusion; epinephrine IV (for anaphylactic reactions); antihistamines IV (only at the beginning); fast acting corticosteroids IV; fluids (depending on volume status); oxygen supplementation (TRALI); analgesia, etc.

Question 22

True/False: blood typing and cross-matching for horses are difficult and unreliable.

Answer 22

True

Question 23

What is major cross-matching?

Answer 23

Donor RBC + recipient plasma

Question 24

What is minor cross-matching?

Answer 24

Recipient RBC + donor plasma

Question 25

What is oxyglobin?

Answer 25

Chemically stabilized bovine hemoglobin

Question 26

What is oxyglobin used for?

Answer 26

Used to treat anemia in dogs

Question 27

What are some side effects of using oxyglobin?

Answer 27

May cause circulatory overload; can cause an allergic reaction if given repeatedly; can temporarily cause yellow discoloration of the skin, mucous membranes, and sclera