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Hematologic/Coagulation Cases in Critical Care

Hematologic/Coagulation Cases in Critical Care. Alice Ma, M.D. University of North Carolina-Chapel Hill Division of Hematology. Case 1.

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Hematologic/Coagulation Cases in Critical Care

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  1. Hematologic/Coagulation Cases in Critical Care Alice Ma, M.D. University of North Carolina-Chapel Hill Division of Hematology

  2. Case 1 • A 21 y.o. UNC student presented to the coagulation clinic from the plastic surgery clinic. He had undergone nipple piercing 11 days prior and had prolonged bleeding, requiring 2 trips to the emergency room, gelfoam application, pressure dressing, stitching, re-stitching. He was still actively bleeding. • PMHx was notable for tongue laceration at age 7 following a fall, with persistent bleeding. Thumb injury with persistent bleeding, ganglion cyst removal without abnormal bleeding.

  3. Case 1 • Family History - mother is on iron for unknown reasons. Maternal grandmother may have abnormal bleeding (pt unsure) Sister alive and well without abnormal bleeding. • Meds - none • SHx - senior at UNC, occasional alcohol, no tobacco or drugs • PEx - actively bleeding left nipple. No bruises or petechiae.

  4. Case 1- Initial Laboratory Studies • PT 13.9 sec (11-14) • aPTT 52.2 sec (22-32)

  5. Case 1 - questions • Question 1: How do we evaluate patients with an abnormal aPTT? • Question 2: What does the patient have? • Question 3: How should the patient be treated?

  6. Obligatory Confusing Coag Cascade

  7. Coagulation made easy The PTT Pathway The PT Pathway

  8. Coagulation made easy The PTT Pathway The PT Pathway X

  9. Coagulation made easy The PTT Pathway The PT Pathway V X

  10. Prothrombin Thrombin Coagulation made easy The PTT Pathway The PT Pathway V X

  11. Prothrombin Fibrinogen Thrombin Fibrin Coagulation made easy The PTT Pathway The PT Pathway V X

  12. Prothrombin Fibrinogen Thrombin Fibrin Coagulation made easy - the PT 7 V X

  13. Prothrombin Fibrinogen Thrombin Fibrin Coagulation made easy - the aPTT XII XI IX V X VIII

  14. Prothrombin Fibrinogen Thrombin Fibrin Coagulation made easy - the aPTT T E N E V X T

  15. Prothrombin Fibrinogen Thrombin Fibrin Coagulation made easy - the aPTT Twelve Eleven Nine Eight V X Ten

  16. Fibrinogen Fibrin What matters clinically XII XI • Deficiencies of factor XI, IX, VIII, VII. X, V, prothrombin and fibrinogen are clinically significant. • Inhibitors of these factors are clinically significant. • Deficiency of Factor XII, and the presence of the lupus anticoagulant are not clinically significant. IX VIII VII X V Thrombin

  17. Coagulation Made Easy- The Mixing Study • Useful to differentiate etiologies of prolonged clotting in a coagulation assay. • Patient’s plasma is mixed 50:50 with normal plasma. Coagulation assay is repeated. • If “substantial” correction is noted after mix, suspect clotting factor deficiency. • If no or minimal correction seen, suspect inhibitor.

  18. Case 1 - More Laboratory Data • aPTT - 52.2 sec (22-32) • aPTT mix - 31.5 sec

  19. Case 1 - More Laboratory Data • aPTT - 52.2 sec (22-32) • aPTT mix - 31.5 sec • Interpretation: Factor Deficiency

  20. Prothrombin Fibrinogen Thrombin Fibrin Case 1 - Which Factor(s) are deficient? Twelve Eleven Nine Eight V X Ten

  21. Case 1 - More Laboratory Data Question 2: What does the patient have?

  22. Hemophilia • X-linked recessive disorder • Hemophilia A - deficiency of Factor VIII • Hemophilia B - deficiency of Factor IX • Incidence 1/5000 live male births • Estimated 20,000 cases in US; 1,000 in NC • Racial groups affected with similar frequency

  23. Clinical Classification of Hemophilia FVIII/IX activity Clinical picture Type Severe hemarthrosis Severe < 1% Moderate 1% - 5% Mild 5% - 25% Spontaneous bleeding Serious bleeding after minor trauma Bleeding after surgery or trauma Moderate bleeding after trauma or surgery Subclinical25% - 50%

  24. Hemophilia Treatment • Replace Deficient Factor • Many Products: Two general categories: • Plasma derived • Virally inactivated • Generally reserved for individuals who are HIV/HepC positive • Recombinant • More expensive • Should be product of choice for all children and previously untreated patients • Inhibit Fibrinolysis - in mucosal bleeding

  25. Hemophilia Treatment • Clotting factor is dosed in UNITS • One Unit = amount of factor present in 1 ml of normal plasma • Replacement Factor Dosing is based on 3 variables • Volume of distribution (extravascula/intravascular) • Half-life • Level of factor required for hemostasis

  26. Hemophilia Treatment

  27. Case 1 - Followup • The patient was given a bolus dose of 4,000 units of BeneFIX (recombinant Factor IX) calculated to raise his Factor IX level to 50%. Pressure was re-applied, and the bleeding stopped. This dose of factor cost approximately $6,000. The patient is uninsured. • The patient was instructed to seek care at the regional comprehensive hemophilia center after graduation.

  28. Teaching Points • A prolonged PTT should be evaluated first by mixing study, then with factor levels, if appropriate. • Hemophilia can be undiagnosed until adulthood, especially if mild or moderate. • Treating hemophilia is expensive and complicated, and patients should be followed in a comprehensive hemophilia center.

  29. Case 2 • A 33 y.o. man presented with post-operative bleeding after a tonsillectomy. • 10/15/01 – Hb/Hct = 15.3/42.7. • PT/aPTT = 13/35.6 (22-33.4) • 10/17/01 – Tonsillectomy. • 10/17-10/24, pt took ibuprofen for pain • 10/24 early am – Pt awoke with severe bleeding • Hb/Hct in ER 14.1/38

  30. Case 2 • Bleeding did not stop with ER cauterization. • Pt given platelets, FFP, then taken to OR • Notice made of persistent venous oozing and bleeding. DDAVP given • 10/25 – Pt had persistent post-op bleeding • H/H eventually reached 9.1/25

  31. Case 2 • Bleeding History: • Lifelong nosebleeds • Gum bleeding with brushing teeth • Prolonged bleeding with nicks • Bleeding with multiple tooth extractions (characterized as delayed) • appy at age 19, wound dehisced and bled • FHx - sister with easy bruising and abnormal menstrual bleeding. Mother had hysterectomy in early 30’s.

  32. Case 2 - Questions • Question #1 - What is a reasonable screening evaluation for patients pre-operatively? • Question #2 - What is a reasonable screening evaluation for patients with a positive bleeding history? • Question #3 - What does the patient have? • Question #4 - How should the patient be treated prior to future surgical interventions?

  33. Case 2 • PT - 12.9 seconds. (11-14) • aPTT - 33.9 seconds (22-33.4). • Platelet function screen. • col/epi closure time >300 sec (84-178) • col/ADP closure time 136 sec (60-107)

  34. The platelet function screen • An in vitro method to test primary hemostasis • Measures the length of time for whole citrated blood taken up by microcapillary membranes permeated with either collagen + epinephrine or collagen + ADP to close off the microcapillaries. • Designed to replace the bleeding time

  35. The platelet function screen

  36. The platelet function screen • Prolonged in cases of platelet dysfunction (acquired or congenital) or von Willebrand’s disease. • If hematocrit is <30 or if platelet count is <100, this test will be abnormal. • Assay must be run within 4 hours of sample draw. • Sample is run on Whole Blood--NOT PLASMA!!

  37. Case 2 - More laboratory data • vWF antigen - 58% • vWF activity - 50% • Platelet aggregation studies: abnormal aggregation in response to epinephrine, ADP, arachidonic acid.

  38. Case 2 Question #3: How should the patient be treated prior to future invasive procedures?

  39. Case 2 • The patient was told he had mild Type I von Willebrand’s disease, coupled with a mild platelet dysfunction. He subsequently suffered a left ACL rupture and underwent surgical repair under coverage with DDAVP. • He did well and had no abnormal bleeding.

  40. Teaching Points • Take a bleeding history. Then, write it down. • Not all bleeding diatheses show up with a PT/PTT. • Defects in primary hemostasis cause mucocutaneous bleeding (“Oozing and Bruising”) and are best screened for by using the platelet function screen (PFA-100). • DDAVP can improve primary hemostasis.

  41. Bleeding History • Nosebleeds • Gum bleeding • Bleeding with (wisdom) tooth extraction • Easy bruisability • Bleeding with surgeries (including circumcision) • Include timing of bleeding • Menstrual bleeding • Transfusion requirements • Family history of bleeding • Hysterectomies at an early age • Bleeding with surgeries

  42. Case 3 • A 72 y.o. man suffered complications of an MVA with multiple fractures and splenic rupture 7 days prior. He is now thought to be septic and all wounds are bleeding. • Labs show H/H 7/21, Plts 14, PT 33, PTT 60 Fibrinogen 81 • After transfusion of 4 units PRBC, H/H only 8/23

  43. Case 3 - Questions • Q1. What blood products should be given to the patient? • Q2. What are the indications for use of Novo-Seven in the bleeding surgical patient?

  44. What blood products to give? • H/H 7/21, Plts 14, PT 33, PTT 60 Fibrinogen 81 • Platelets - With active hemorrhage, try to keep platelets > 50. If no bleeding, keep platelets >10 • Cryoprecipitate - With active bleeding, keep fibrinogen >100. Cryo also contains FVIII, VWF, FXIII • RBCs - With active bleeding and thrombocytopenia, plts will work better if Hgb >10

  45. Intrinsic pathway Extrinsic pathway TF, VII XI, IX, VIII Review Cascade model of hemostasis Xa generation Thrombin Generation

  46. A Cell-Based Model of Hemostasis • Initiation • Amplification • Propagation

  47. Initiation

  48. Amplification

  49. Propagation

  50. Hemostasis

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