Blood Components

Front 1

The PT/PTT tests in vitro assess the patient's ____ hemostasis.

Back 1

secondary (in other words, it does not involve the platelets, only the clotting factors)

Front 2

Platelets are part of the ____ hemostasis.

Back 2

primary

Front 3

T/F: A PT value of 12 seconds means that a clot will form in 12 seconds in vivo.

Back 3

False, this would be a long time to clot in vivo. The normal ranges for PT (12.4-14.4) are just laboratory reference ranges.

Front 4

When should you order PT/PTT tests?
When are PT tests especially important?

Back 4

When you suspect a problem w/ the secondary hemostasis.

When monitoring a patient on warfarin or w/ liver disease.

Front 5

PT measures the ____ pathway.

Back 5

initiation or extrinsic

VII + TF activate Factor X which combines w/ Factor Va which convernts prothrombin to thrombin which converts fibrinogen to fibrin... (yeesh)

Front 6

Why do we need the INR equation instead of just PT times?

Back 6

b/c of small variations from lab to lab including the amount of calcium, phospholipid, and temperature... gives a STANDARDIZED record of patient's coag status

Front 7

The INR should be used for ___ NOT to predict ____.

Back 7

monitoring a patient on warfarin

bleeding b/f a procedure

Front 8

What is the problem with giving FFP as a means of reversal or anticoagulation over a period of time?

Back 8

volume overload

Front 9

What two things should be done b/f a patient on warfarin undergoes major surgery?

Back 9

1) replace warfarin w/ heparin which is easier to counteract
2) give Vit K or FFP to replace clotting factors

Front 10

PPT measures the ____ pathway.

Back 10

propagation or intrinsic

everything but factor VII

abnormal in hemophiliacs

used to monitor heparin therapy

Front 11

You graciously donate a pint of blood at the local blood drive, what is this blood most likely to be used for?

Back 11

trauma patients

Front 12

What percentage of blood if lost can make a patient hemodynamically unstable and can lead to death?

Back 12

15%

Front 13

What should you do in an acute hemorrhagic situation (e.g. GSW)?

Back 13

1) replace volume w/ saline
2) transfuse PRBCs

Transfusing whole blood or plasma and ordering PT/PTT tests are not critical.

Front 14

What is the problem w/ using whole blood instead of PRBCs?

Back 14

whole blood was stored at 4 deg C (optimal for RBCs) but this was too warm for coag factors and platelets

Front 15

What are three indications for PRBCs?

Back 15

1) Blood loss greater than 15% (remember this leads to hemodynamic instability) w/ or w/o Pulse >100 or drop in SBP > 20%
2) chronic symptomatic anemia (e.g. kidney failure -> no EPO)
3) Anemic patient prior to surgery/anesthesia w/ Hct < 24%
2)

Front 16

How do you calculate a patient's total blood volume?

Back 16

70 ml/kg of body weight

so for 70 kg person TBV = 70 X 70 = 4900 ml or 4.9 L

Front 17

What is the problem of giving a sickle cell patient w/o symptoms PRBCs b/c of a low Hct (22%)?

Back 17

This low Hct is their normal value. They can live off of this, but if you give PRBCs you can cause polycythemia and make the blood more viscous.

Front 18

One unit of PRBCs raises Hct by ?

Back 18

3%

Front 19

How long are PRBCs viable in storage?

Back 19

6 weeks (42 days) in cold temperatures

Front 20

Type A: ___ antigens on RBCs and ___ antibodies in serum.

Back 20

A, B

Front 21

Type B: ___ antigens on RBCs and ___ antibodies in serum.

Back 21

B, A

Front 22

Type AB: ___ antigens on RBCs and ___ antibodies in serum.

Back 22

A&B, no

Front 23

Type O: ___ antigens on RBCs and ___ antibodies in serum.

Back 23

No, A&B

Front 24

If you don't know the patient's blood type and you need to transfuse plasma, give ____ type? Why?

Back 24

AB, because this plasma contains no antibodies to react w/ RBCs

Front 25

If you don't know the patient's blood type and you need to transfuse RBCs, give ____ type? Why?

Back 25

O, b/c these RBCs have no A or B antigen on them so they will not react w/ any A or B antibodies in patient's serum.

Front 26

If you give an A blood type patient type B blood what will happen?

Back 26

acute hemolytic transfusion reaction leading to DIC and acute tubular necrosis

Front 27

A Rh (D) + donor can only donate blood to ____ recipients.

Back 27

Rh (D) +, b/c if recipient is Rh - they will have antibodies to the D antigen

Front 28

Three modifications of PRBCs:

Back 28

1) leukoreduction
2) washing
3) gamma irradiation

Front 29

Filtration of contaminating WBCs.

Back 29

leukoreduction

Front 30

Transfused WBCs do not work ex vivo and put patient at risk for (5)?

Back 30

1) febrile transfusion rxn
2) alloimmunization to HLA (antigens on WBCs)
3) formation of antibodies to WBCs making future transfusion more difficult
4) Viral transmission - CMV and HTLV-1 are carried in WBCs
5) Host immune system becomes preoccupied and becomes more susceptible to infections and metastases

Front 31

What is the purpose of washing PRBCs? Who is it used for most of the time?

Back 31

removes residual plasma

patients w/ history of anaphylaxis or IgA defieciency (remember if you've never seen a IgA b/f if you are transfused w/ serum containing IgA, this can cause a rxn)

Front 32

Washed RBCs must be used w/in ___?

Back 32

24 hours

Front 33

Gamma irradiation is done to prevent ?

Back 33

graft versus host disease in immunecompromised and patients receiving blood from family members

Front 34

How does gamma irradiation work?

Back 34

crosslinks DNA so WBCs are unable to proliferate, but does NOT kill viruses

Front 35

How does GVHD work?

Back 35

Immunosuppressed patient can not remove donated WBCs from circulation... donated WBCs recognizes the host as foreign and proliferate and attack the patient

Front 36

What percentage of GVHD is fatal?

Back 36

100% b/c the bone marrow is attacked

Front 37

What is a complication from gamma irradiation?

Back 37

damages Na/K pump causing K leak leading to increased extracellular K (bad for heart patients)

therefore irradiation is done right before transfusion

Front 38

How long are frozen RBCs viable?
What are they frozen in?

Back 38

10 years

glycerol

Front 39

FFP is mostly ___ but also contains ___, ____, and ____.

Back 39

water

factor V, factor VIII, and protein

Front 40

What is a massive transfusion defined as?

Back 40

receiving 10 units of RBCs (one total blood volume) in 24 hours (6 units for a smaller person)

Recall that one unit of blood is about 400 ml, so 10 units is 4000 ml, which would equal the TBV in a 60 kg person

Front 41

When is FFP indicated (5)?

Back 41

1.) Dilution coagulopathy post-massive transfusion --- you've only been giving PRBCs, they also need factors
2.) Liver disease - can't make factors
3.) Warfarin overdose - can't make factors
4) DIC - factors being used up
5) rare isolated deficiencies or certain factors (not for f VIII, IX, or vWF)

Front 42

What is cryoprecipitate?

When is it indicated?

Back 42

concentrate of large insoluble proteins in FFP (F VIII, vWF, fibrinogen, XIII, fibronectin)

HYPOfibrinogenemia- cirrhosis, acute liver failure

Front 43

Platelets are indicated (3)?

contraindicated in?

Back 43

1) bone marrow failure - underproduction
2) DIC - excess consumption
3) aspirin/clopridogel - platelet dysfxn

contraindicated in idiopathic thromobocytopenia purpura (ITP) - transfusion futile b/c antibodies will clear ALL platelets out of circulation, need to remove antibodies (plasmaphoresis)

Front 44

Why are apheresis platelets better than random donor platelets?

Back 44

RDPs are centrifuged from donated whole blood, however and unit of whole blood does not provide enough platelets for a thromobocytopenic patient, therefore 6 platelet units (from different patients) have to be

In aphereis, the platelets are all coming from same person, so you are exposed to less disease!