Hematology Pimp Session

HematologyPimp Session

1. What is the sequence of the intrinsic pathway of coagulation?

Prekallikrein + HMW kininogen + factor XII + exposed collagen → activates Factor XI → activates Factor IX +Factor VIII → activates Factor X + Factor V → converts prothrombin (Factor II) to thrombin → thrombin converts fibrinogen to fibrin

2. What is the sequence of the extrinsic pathway of coagulation?

Factor VII + tissue factor → activates Factor X +Factor V → converts prothrombin to thrombin → thrombin converts fibrinogen to fibrin

3. Which factors are known as the labile factors (i.e. activity lost in stored blood)?

Factors V and VIII

4. Which factor has the shortest half-life?

Factor VII

5. What are the Vitamin K dependent factors?

Factors II, VII, IX, and X and proteins C and S

6. Which factor is the convergence point for both the extrinsic and intrinsic pathways of coagulation?

Factor X

7. PT measures the function of which factors?

Factors II, V, VII, and X and fibrinogen

8. PTT measures the function of which factors?

Factors II, V, VIII, IX, X, XI, and XII and fibrinogen

9. What 2 electrolytes are required for the formation of a platelet plug?

Calcium and Magnesium

10. What is the sequence of physiologic reactions that mediate hemostasis following vascular injury?

1. Vasoconstriction

2. Platelet activation/adherence/aggregation

3. Thrombin generation

11. Uremia leads to a downregulation of?

GpIb, GpIIb/IIIA, and vWF

12. What is the treatment of choice for uremic coagulopathy?

Dialysis

13. Which drug can be given to help correct platelet dysfunction from uremia, bypass, or ASA?

Desmopressin (DDAVP)

14. DDAVP and conjugated estrogens stimulate the release of?

Factor VII and vWF

15. What platelet count is needed before surgery?

>50,000/mL

16. What platelet count is associated w/ spontaneous bleeding?

< 20,000/mL

17. What platelet count suggests the prophylactic transfusion of platelets?

<10,000

18. What is Virchow’s triad?

Stasis, endothelial injury, and hypercoagulability

19. What is the most common cause of acquired hypercoagulability?

Smoking

20. What is the most common inherited hypercoagulable state?

Factor V Leiden

21. What is the treatment for hyperhomocysteinemia?

Vitamin B-12 and folate

22. Name the prothrombin gene defect causing spontaneous venous thrombosis?

Prothrombin gene defect G20210A

23. What is the normal life of a platelet?

7-10 days

24. What electrolyte is most likely to fall after the infusion of stored blood?

Ionized calcium (citrate in stored blood binds serum calcium)

25. How long can PRBCs be stored?

~ 42 days or 6 weeks

26. What is the most common blood product to contain bacterial contamination?

Platelets (stored at room temperature)

27. What type of bacteria is usually found in contaminated platelets?

Gram-positives

28. What is the most common bacteria found w/ blood product contamination?

Gram negative rods (E. coli)

29. Who would you transfuse with leukocyte reduced packed red blood cells?

Patients with multiple reactions despite premedication with antipyretics, patients needing long term platelet support, and transplant candidates in order to prevent formation of HLA antibodies

30. What are the indications for blood transfusion?

Hgb < 10 w/ h/o CAD/COPD, Healthy symptomatic pt. w/ Hgb < 7, acute blood loss

31. What is the approximate formula to convert Hct to Hgb?

Hct / 3 = Hgb

32. 1 U PRBC should increase the Hgb and Hct by this much?

Should increase Hgb by 1 g/dL and Hct by ~3-4%

33. What happens during a type and screen?

Patient's blood is screened for antibodies and blood type is determined

34. What happens during a type and cross?

Pts. blood is sent to the blood bank and cross-matched for specific donor units for possible transfusion

35. What fluid cannot be infused with PRBC and why?

Lactated Ringer's; Calcium in LR may result in coagulation w/in IV line

36. Most common cause of transfusion hemolysis?

Clerical error leading to ABO incompatibility

37. What is the treatment for transfusion hemolysis?

Stop transfusion; fluids; Lasix; alkalinize urine w/ bicarbonate; pressors as needed

38. How long does it take for Vitamin K to take effect?

6 hours

39. How long does it take for FFP to work?

Immediately

40. How long do the effects of FFP last?

6 hours

41. What does cryoprecipitate contain?

vWF, Factor VIII, and fibrinogen

42. What does FFP contain?

All factors including labile Factors V and VIII, AT-III, protein C and S

43. What is the best method for detecting pts. at risk for bleeding?

A complete history and physical exam

44. What is the most common congenital bleeding disorder?

Von Willebrand's disease

45. What factor is deficient in hemophilia A?

Factor VIII

46. What is the preoperative treatment for hemophilia A?

Factor VIII infusion to 100% normal preoperative levels

47. What factor is deficient in Hemophilia B?

Factor IX

48. What is the treatment for hemarthrosis in a pt. w/ hemophilia A?

Initial therapy includes Factor VIII, joint rest, cold packs (3-5 days) and a compression dressing (3-5 days); Followed by active range of motion exercised 24 hrs. after Factor VIII therapy.

49. What receptor deficiency is found in Glanzmann's thrombocytopenia?

GpIIb/IIIa receptor deficiency; platelets can not bind to each other

50. What receptor deficiency is found in Bernard Soulier disease?

GpIb receptor deficiency; platelets can not bind to collagen

51. What are the desired platelet counts and Hct for a pt. with polycythemia vera before an elective operation?

Plt < 400,000/mL and Hct < 48%

52. What protein does Heparin bind to for its anti-coagulation effects?

Anti-thrombin III; Heparin-antithrombin III complex then binds factor IX, X, XI

53. What is the half-life of heparin?

60-90 minutes

54. What is the dose of protamine to reverse 100 U or 1 mg of heparin?

1-1.5 mg

55. What signs will you see in a protamine reaction?

Bradycardia, hypotension, and decreased heart function

56. How does warfarin induced skin necrosis occur?

Protein C and S have a shorter half life than Factors II, VII, IX, and X. Coumadin leads to a decrease in Protein C and S before the other factors leading to a hypercoagulable state

57. Pts. with this deficiency are at increased risk for Warfarin induced skin necrosis?

Protein C deficiency

58. What is the desired activated clotting time for routine anticoagulation?

150-200 seconds

59. What is the desired activated clotting time for cardiopulmonary bypass?

400 seconds

60. What INR is a contraindication to intramuscular injection?

INR > 1.5

61. What are the absolute contraindications to the use of thrombolytics?

Recent CVA (<2 months), intracranial pathology, and active internal bleeding

62. What are the indications for an IVC filter?

Pts. who have undergone a pulmonary embolectomy, pts. with documented PE while anticoagulated, pts. with free floating femoral, ileofemoral, IVC DVT, pts. with contraindication to anticoagulation, and pts. at high risk for DVT (head injured/orthopedic injured on prolonged bed rest)"

63. What is Argatroban?

A synthetic direct thrombin inhibitor derived from L-arginine

64. What is Hirudin?

An irreversible direct thrombin inhibitor derived from leeches

65. What is Ancrod?

Malayan pit viper venom that stimulates tPA release