Hemostasis, bleeding, and blood transfusions Flashcards
Review Clotting Cascade.
Bleeding may occur with a deficiency of any factors except for which factor?
.
Factor XII.
Hemostasis:
- lab tests
- -what is each one
- -which factors are being assessed
Platelet count (150K-400K)
PT: measures ability of blood to form stable clot. Factors VII, X, V, prothrombin, and finbrinogen (Extrinsic Pathway)
PTT: evaluates adequacy of fibrinogen(I), prothrombin(II), factors V, VIII, IX, X, XI, XII (intrinsic/common pathways)
Bleeding time: time from injury to cessation of bleeding from both wounds is measured.
Thrombin Time: evaluates fibrinogen to fibrin conversion with an external source of thrombin (time to clot formation)
PTT is used to assess UFH or Warfarin?
PT/INR is used to assess UFH or warfarin?
What is the PTT in patients with VII deficiency?
What is the normal range of Bleeding Time?
What would cause a prolonged Thrombin time?
UFH.
Warfarin
Normal, b/c PTT measures the intrinsic pathway.
Bleeding Time: normal is 5-10minutes
Prolonged fibrin time:
- low fibrinogen levels
- abnormal fibrinogen
- fibrin and fibrinogen split products
- heparin
Von Willebrand Dz:
- pathophysiology
- site of bleeding
- inheritance
- MC in which gender?
- Lab study results
- tx
Patho: reduced factor VIII activity and von willebrand activity
Site Bleed: mucocutaneous
Inheritance: autosomal dominant
MC in women and men
Labs:
- prolonged PTT
- normal PT
- abnormal platelet function
Tx:
- cryoprecipiatate infusions
- DDAVP (releases VW from endothelial cells)
Hemophilia A
- pathophys
- site of bleeding
- MC in which gender
- lab study results
- tx
Patho: reduced or absent factor VIII activity
Site bleed: joints and intramuscular
MC in men
Lab results:
- prolonged PTT
- normal PT
- normal platelet function
Tx:
-purified factor VIII products
What are some acquired bleeding disorders?
advanced liver dz
anticoagulation therapy
acquired thrombocytopenia
platelet inhibiting drugs
uremia
Liver Dz:
-how does this cause bleeding disorder?
Inability to synthesize proteins leads to decreased levels of prothrombin(II) and factors V, VII, and X.
Anticoagulation therapy:
- what is warfarins effects on the clotting cascade?
- what agent reverses warfarin?
- what is heparin effects on the clotting cascade?
- what agent reverses heparin?
Warfarin:
- depression of clotting factors II, VII, IX, X
- reversed with FFP or vit K in an emergency
Heparin:
- increased speed of antithrombin III (inhibiting the clot), binds to and neutralizes IX, X, XII
- reversal with protamine sulfate
What are the 3 mechanisms of acquired thrombocytopenia?
What are some platelet inhibiting drugs?
Drugs associated with bleeding?
3 mech:
- decreased platelet production in bone marrow
- increased destruction of platelets in peripheral blood (heart valves)
- splenic pooling in enlarged spleen
Platelet inhibitors:
- ASA
- NSAID
- Plavix
Drugs:
- warfarin
- heparin
- plavix
- ASA
- Herbal:
- garlic, ginger, ginko, ginseng, st johns wort
Intraoperative Bleeding: SHOCK:
-tx
Tx:
- massive transfusion of PRBC
- controlled with gelfoam, surgicel, floseal, tisseel
Post op bleeding:
- MC cause
- other causes
- what are the three main categories of post op bleeding?
MC cause: poor hemostasis during surgery
Other:
- residual heparin
- shock
- altered liver function
3 main categories:
-primary bleeding: occurs during operation.
- reactive bleeding: happens within 24hrs of operation, hemorrhage rxn from ligature coming loose from vessel.
- secondary bleeding: 7-10d post op, erosion of vessels, usually seen with bad infection.
DIC:
- characterized by what?
- results
- cause
Characterized by intravascular coagulation and thrombosis that is diffuse instead of localized at site of injury.
Results in systemic deposition of platelet fibrin microthrombi that causes diffuse tissue injury…..death.
Cause:
- release of tissue debris into bloodstream after trauma or obstetric catastrophe
- extensive endothelial damage to vascular wall
- hypotension
- operations with large blood loss (prostate, lung, malignant tumors,)
- burns, sepsis, snake venom
DIC
- dx
- lab results
- tx
Dx:
-diminished levels of coagulation factors and platelets
Labs:
- prolonged PT and PTT
- hypofibrinogenemia
- thrombocytopenia
- presence of fibrin and fibrinogen products (d-dimer)
Tx:
- remove precipitating factors
- severe DIC:
- -cryoprecipitate best method to replace fibrinogen loss
- platelet transfusion
- FFP
What are the 5 types of transfusable RBC
Whole blood
Packed red blood cells
Washed red blood cells (gets rid of plasma)
Leukoreduced (irradiated) red blood cells
Divided or pediatric unit
One unit of packed red cells into an average 70kg person raises the HCT ___% and hgb by ___g/dL
Describe the difference between type/screen and type/cross?
one unit of packed red cell into a 70kg person raises the hct by 3% and hgb 1g/dL
Type/Screen: dont have bleed ready to go, they just know which type of blood to get if they need it.
Type/Cross: type your blood and get the transfusable ready to go.
