Blood Surface Interactions (Part 2)- Exam 3 Flashcards Preview

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Flashcards in Blood Surface Interactions (Part 2)- Exam 3 Deck (72):
0

What are 3 major types of blood cells?

RBCs, WBCs, platelets

1

What do erythrocytes do?

Uptake, transport, removal oxygen and carbon dioxide

2

What are two main types of leukocytes?

Granulocytes
Agranulocytes

3

What are 3 types of granulocytes?

Neutrophils
Eosinophils
Basophils

4

What percent are neutrophils? What do they do?

60-70%; destroy bacterial and phagocytosis

5

What percent are eosinophils? What do they do?

2-4%; destroy complex products antigen-antibody reactions

6

WHat percent are basophils? What do they do?

0.5-1%; release histamine and heparin; vasodilation

7

What are two types of agranulocytes?

Monocytes
Lymphocytes

8

What percent are monocytes? What do they do?

3-8%; transform into tissue macrophages

9

What percent are lymphocytes? What do they do?

20-25%; attach destroy/ deactivate bacteria, viruses, other foreign cells, acquired immune response

10

What are platelets (thrombocytes) involved in?

Coagulation

11

What are the 5 major cell types involved in blood surface interactions?

Platelets
Neutrophils
Monocytes
Lymphocytes
Endothelial Cells

12

Platelets- Initial/Early Activation

Surface contact with ECC
Heparin (increases sensitivity)
Circulating thrombin (agonist, probably initial activator)
Platelet-activating (PAF)

13

Platelets - Late Activation

Activated Complement (C5b - C9)
Plasmin
Hypothermia
Interleukin-6
Cathepsin G
Serotonin
Epinephrine

14

Platelets respond to activation with immediate _____.

shape change

15

What shape changes do platelets in response to activation?

Express pseudo pods
Express surface receptors (GP2b/3a and GP1b)
Secrete receptors from granules (P-selectin)

16

5 actions of platelets responding to activation

1) Immediate shape change
2) GP2b/3a receptors bind to surface adsorbed fibrinogen (use fibrinogen as bridge to bind to other platelets)
3) P-selectin receptors bind to monocytes & neutrophils to form aggregates
4) Some platelets break off forming emboli
5) Some platelets release a variety of chemicals and proteins

17

Examples of the variety of chemicals and proteins that platelets release in response to activation

thromboxane-A2
platelet factor 4
beta-thromboglobulin
serotonin

18

_____ = very strong activation

neutrophils

19

Principal agonists of neutrophil

Kallikrein and C5a

20

Other neutrophil agonists are:

Factor 7a
Heparin
MAC
Interleukin 1 Beta
Interleukin 8
TNF

21

Events in neutrophil activation

*Release contents of granules
*Express MAC-1 (CD11b/CD18) & CD11c/CD18 receptors
*Express L-selectin receptor

22

Lysosomal enzymes, elastase, myeloperoxidase, hydrogen peroxide, hydroxyl radicals, hypochlorous acid, hypobromous acid, acid hydrolyses, and collagenases are contents released from _____ during neutrophils activation.

Granules

23

What does L-selectin receptor bing with?

P-selectin expressed by endothelial cells and platelets

24

What plays a major role in ischemia-reperfusion injury and responsible for much of inflammatory response associated with bypass?

Neutrophils

25

Monocyte activation is _____ during CPB.

slow

26

Monocyte activation is slow activation during CPB by (3):

C5a
Thrombin
Bradykinin

27

Monocytes are activated in ____ and ____.

wound and circuit

28

Monocytes form conjugates with platelets via ____ and express ____.

GMP-140
Tissue Factor

29

Delayed increase in tissue factor is seen ____ post CPB

20 hours

30

Monocyte activation produces and releases _____.

Cytokines

31

What cytokines are produced and released during and post CPB?

IL-6
IL-8

32

What cytokines are produced only after CPB?

IL-1
IL-2
IL-4

33

The number of lymphocyte cells are ____ first week after bypass?

reduced

34

Reduced lymphocyte response causes an _____ susceptibility of postoperative infections like septic shock and endocarditis.

increased

35

Endothelial cell activation agents are: (4)

Thrombin
C5a
Various Cytokines
TNF

36

____ cells produce prosstacyclin, heparan sulfate, thrombodulin, protease nexin-1, protein S, tissue factor and vasoactive substance like NO, endothelia, PAF, histamine, norepinephrine, and bradykinin.

Endothelial

37

What receptors do endothelial cells produce (5)?

Tissue Factor
P-selectin
E-selectin
ICAM-1
VCAM-1

38

4 actions of activated endothelial cells:

1) Synthesize tissue factor to generate thrombin
2) Initiate fibrinolysis
3) Contribute to the overall acute inflammatory response
4) Allow fluid and leukocytes to enter the interstitial space

39

What 3 hematologist factors activated by CPB are soluble factors?

Coagulation cascade
Complement cascade
Fibrinolytic system

40

What 5 hematologist factors activated by CPB are cellular factors?

Platelets
Neutrophils
Monocytes
Lymphocytes
Endothelial cells

43

What active mediators are generated by the coagulation cascade?

Kallikrein
HMWK
Thrombin

44

What active mediators are generated by platelets?

TXA2
Serotonin

45

What active mediators are generated by neutrophils?

Oxygen radicals
Elastase

46

What active mediators are generated by monocytes?

Oxygen radicals
Cytokines

47

What active mediators are generated by lymphocytes?

Cytokines

48

What active mediators are generated by endothelial cells?

T-PA
Cytokines

49

What are the 6 non-platelet related causes of possible contributions to bleeding after CPB?

Hyper fibrinolysis
Heparin excess (inadequate neutralization, rebound)
Hypothermia
Protamine excess
Consumption of soluble coagulation factor(s)
Decreased vWF

50

What are the 8 platelet related causes of possible contributions to bleeding after CPB?

-Thrombocytopenia
-Aspirin-induced platelet dysfunction
-Impaired aggregation response to agonists (epi, collagen, ADP, thrombin)
-Selective loss of youngest (most functional) platelets
-Impaired platelet-mediated clot retraction
-Plasmin-induced platelet activation/dysfunction
-Platelet activation/dysfunction by C5b-9

51

What % of normal Factor 12 (Hageman factor) concentration is needed for coagulation?

None

52

What % of normal Factor 11 (Plasma thromboplastin antecedent) concentration is needed for coagulation?

20

53

What % of normal Factor 9 (Christmas factor) concentration is needed for coagulation?

40

54

What % of normal Factor 8 (Antihemophilic factor) concentration is needed for coagulation?

30

55

What % of normal Factor 7 (Proconvertin, serum prothrombin conversion accelerator) concentration is needed for coagulation?

25

56

What % of normal Factor 10 (Stuart factor) concentration is needed for coagulation?

40

57

What % of normal Factor 5 (Proaccelerin, labile factor) concentration is needed for coagulation?

40

58

What % of normal Factor 2 (Prothrombin) concentration is needed for coagulation?

40

59

How much of normal Factor 1 (Fibrinogen) concentration is needed for coagulation?

100 mg/dL

60

What are 3 ways to control blood-surface interface?

-Develop biomaterial that mimics the endothelial cell layer.
-Prevent or block activation of the blood during bypass.
-Prevent activated blood from reaching your circuit.

61

What active mediators are generated by the fibrinolytic system?

Plasmin

62

What active mediators are generated by the complement cascade?

C3a
C5-
C5b-9

63

What is a way to prevent activated blood from reaching your circuit?

Sequestered cardiotomy suction

64

What are 5 claims of using surface-bound circuit?

-Suppress thrombin formation
-Reduce blood loss and transfusion requirements
-Attenuate inflammatory response
-Depress platelet activation
-Decrease in clinical indicators of morbidity

65

What current systems have heparin coating?

Medtronic Carmeda
Medtronic Trillium
Maquet Bioline

66

How can we prevent or block activation of the blood during bypass?

Blood modification

67

4 processes of blood modification

-Preop administration of corticosteroids
-Antifibrinolytic agents
-Platelet anesthesia
-Complement inhibition

68

What is the purpose of administering corticosteroids preoperatively?

Attenuates complement activation

69

What does Aprotinin do?

Inhibits plasmin directly

70

What happens with high doses of Aprotinin?

Partially inhibits kallikrein--platelet sparing

71

What do W-aminocarboxylic acids do?

Inhibit cleavage of plasminogen to plasmin

72

3 types of platelet anesthesia

-Reversible inhibition of platelets during procedure
-Eptifibatide (Integrilin) with or without NO
-NO provides partial protection

73

2 types of complement inhibition

-Pexelizumab
-TP 10