Tranfusions and Complications

Question 1

How do we determine someone’s blood group (i.e. blood type)?

Answer 1

Forward group: which antigen on RBC when AB added (anti your antigens)? Reverse group: which AB in your plasma when RBC added? Rh: add anti Rh AB. Look for clumping in the tubes

Question 2

What is an antibody screen?

Answer 2

Any unexpected non-ABO red cell antibodies in the plasma? Come from past transfusion or pregnancy. React patient plasma and 3 sample red cell lines (which represent many but not all antigens). There is also a more extensive panel to do if initial screen is positive. No clumping = negative screen

Question 3

What is a crossmatch?

Answer 3

After type and screen and AB screen negative, electronic match - scan blood bag barcode, compare computer results to test results, then to patient. No physical mixing. If AB screen is positive, physical mix w/ sample (serologic cross match)

Question 4

What does a positive antibody screen mean?

Answer 4

Another AB is present, additional time for testing before giving units. If situation is critical, give un-crossmatched (group O). Future transfusions need to keep this in mind (might have low AB but still concern)

Question 5

So essentially, what is the goal of doing a crossmatch, esp for one who got a positive AB screen?

Answer 5

The goal is to mix donor cells with patient’s plasma to find a bag which is antigen negative for the specific ABs which they possess.

Question 6

More on un-crossmatched cells

Answer 6

Usually means O-, but if they can type your blood quickly they can give you group specific but still un-crossmatched (ie give A+ if they are A+, but still don’t know about the other ABs)

Question 7

Why is proper patient identification essential?

Answer 7

You could kill someone! proper patient ID and labeling are critical during collection. Must be labeled with First & Last names, ULI (Alberta healthcare number), and BBIN. Info on requisition must exactly match all info on the tube label. Specimen labeling must occur at bedside. Date and time of collection, 2 signatures

Question 8

Mislabeled specimen?

Answer 8

Rejected! Take again

Question 9

What immediate actions should be taken if a transfusion reaction is suspected?

Answer 9

Stop the transfusion!! keep IV running with normal saline. Always obtain full set of vital signs: Temp, HR, BP, Resp Rate and O2 sat. Clerical check: verify info on product tag against the patient’s ID band, name, ULI, BBIN. New sample

Question 10

After transfusion reaction and it is stopped, what do you do?

Answer 10

New sample, centrifuge, look for sign of hemolysis (red in plasma). Do DAT (Direct AB test), look at microscope

Question 11

What is the differential diagnosis of a fever that is temporally associated with transfusion?

Answer 11

Can be unrelated (ie pre-existing condition). If related, one of 4 things. Febrile non-hemolytic transfusion reaction, contamination/sepsis, acute hemolytic transfusion reaction, transfusion related acute lung injury

Question 12

Febrile non-hemolytic

Answer 12

Some residual WBC in blood bag release cytokines which affect the patient

Question 13

What’s your role in a transfusion reaction investigation?

Answer 13

Ask questions, document signs and symptoms, compare signs before and after, blood cultures and hemolytic workup if needed, never restart the original transfusion!

Question 14

What is the differential diagnosis of jaundice in the setting of a recent transfusion?

Answer 14

Jaundice + post-transfusion DAT with clumping indicates some immune response. Future crossmatch must be serological

Question 15

What do PT and PTT look at?

Answer 15

PT, PTT look at different sides of the coagulation cascade (intrinsic vs extrinsic I think)

Question 16

In an emergency and you want to give plasma to a type O patient, what do you want?

Answer 16

Give them type AB plasma. Less antibodies.

Question 17

If you don’t know Rh type, what do you give them?

Answer 17

Men: give Rh+ or Rh- (will cause hemolysis, but delayed and easier to treat). For women of child-bearing age: give Rh- so they don’t have reaction to fetal Rh+ blood. But if you know they have been previously exposed to Rh+ and are Rh-, you must give Rh-

Question 18

What can you make from a whole blood donation?

Answer 18

Blood components: RBCs, platelets, plasma, cryoprecipitate (fibrinogen, VWF, factor 8 precipitate after slow thawing). Can also have plasma fractionation of single products from plasma of many blood donors

Question 19

RhIG

Answer 19

Give to (all) pregnant Rh- women at 28 weeks (passive anti-D); and give again after birth if baby is Rh+.

Question 20

Other ABs

Answer 20

Can also have ABO hemolytic disease of the newborn. Just monitor, can do transfusion if serious. HDN only lasts as long as the mother’s antibodies.

Question 21

Would you give RhIG to a Rh- man who received Rh+ blood?

Answer 21

Probs not. It would take a large dose of RhIG. Not guaranteed to form Anti-D.

Question 22

Alternatives to transfusion

Answer 22

For RBC: Erythropoietin, look at Fe, folate, B12, but you need time and bone marrow capacity. For Plasma: sometimes just lacking one factors in blood, so give specific factor concentrates. For low platelets: thrombopoietin, or platelet transfusion.

Question 23

Ethical consideration for consent to transfusion

Answer 23

Need to know risk, benefits, and alternatives, plus some time to decide. Document it.

Question 24

Risks of blood component vs fractionation

Answer 24

Blood component is riskier since it could have some contamination, not purified. Fractionated parts are chemically derived etc so more pure.

Question 25

Main point of AB screen and crossmatch

Answer 25

Looking for AB for other factors other than ABO antigens.

Question 26

What to do if someone starts having a fever reaction to transfusion?

Answer 26

Stop! Then do a DAT for pre- and post-transfusion test. Maintain saline.

Question 27

Differential diagnosis of fever after transfusion?

Answer 27

Acute hemolytic transfusion reaction: react to antigens in blood, urine darkens. Febrile non-hemolytic transfusion reaction: cytokines in blood. Microbial contamination. Transfusion related acute lung injury: shortness of breath; more with plasma, anti-neutrophil AB from blood attack patient’s neutrophils, short lived. Finally, fever could be pre-existing anyways

Question 28

Non-ST elevation myocardial infarction

Answer 28

ECG reading indicating sub-endocardial ischemia. Just part of heart is infarcted.

Question 29

Differential diagnosis of jaundice after transfusion?

Answer 29

Delayed hemolytic transfusion reaction (esp a few days/weeks later). Indicated by low Hb, high bilirubin, high LDH, low haptoglobin (carries free Hb, so it gets consumed with free Hb). Post-transfusion purpura: platelets drop, rare but can be fatal. Transfusion Associated Graph vs Host Disease: in immunosuppresed, leftover lymphocytes attack host. Alloimmunization: -ve before, then exposed to foreign Ag, so now they are +ve for AB. Transfusion Transmitted Infections: be careful. Iron overload: extra Fe from new RBC, can deposit in places and cause destruction. Other option is Liver dysfunction.

Question 30

What to do if we suspect delayed hemolytic transfusion reaction?

Answer 30

Do a DAT test. This will confirm whether it is immune mediated or not.