Hemostsis Flashcards
Von Willebrands factor promotes what
platelet Adhesion
Von Willebrands factor is manufactured by and released from where
endothelial cells
Thrombin is also know as what factor
activated Factor II or IIa
what factor activates platelets
Thrombin IIa
Once activated via thrombin the platelet synthesizes and releases what?
Tromboxane A2
ADP
Both Thromboxane A2 and ADP promote platelet aggregation how?
by binding to receptors and activating signal transduction
uncover the fibrinogen I receptors BPIIb and IIIa
Fibrinogen ( Factor I) does what
aggregates platelets ( makes them stick together)
The most common acquired blood clotting defect is d/t what?
Inhibition of cyclooxygenase (COX) production by ASPIRIN or NSAIDs
What is factor I
Fibrinogen
What is factor II
Prothrombin
What is factor III
Tissue Factor (or Thromboplastin)
What is factor IV
Calcium
What is factor VIII
2 factors for VIII
VIII: vWF - is von Willebrands fctor
VIII: C - is anti hemophiliac factor
KNow vWF
What is factor XIII
Fibrin Stabilizing factor
All but 3 clotting factors are made from where?
liver
What are the 3 clotting factors not made from the liver? and where are they made from
Calcium (IV) - Diet Tissue Factor (III) - vascular wall vWF VIII - endothelial cells
What is factors are Vitamin K dependent factors
II- Prothrombin VII- Proconvertin IX- Christmas Factor X- Stuart Power factor C- Protein C S- Protein S
What is factor XI
there is none
Never ever ever pick factor XI for anything
Coumadin (warfarin) interferes with what Pathway
Extrinsic (III, VII)
Prothrombin time (PT) and INR assess what pathway
Extrinsic (III, VII)
Heparin interferes with what pathway
Intrinsic (XII, XI, IX, VII)
PTT and ACT assess what pathway?
Intrinsic Pathway
The most important clue to clinically significant bleeding d/o in an otherwise healthy patient is what?
history
one of the most important questions to ask preoperatively deals with what?
hemostatic responses to prior operations
The most common reason for coagulopathy in pt’s receiving massive blood transfusions is what?
the lack of functioning platelets
Platelets in Stored blood are inactive after how long
1-2 days
The only acceptable clinical indication for transfusion of PRBCs is what
to increase the O2 carrying capacity of blood
ALL procoagulants except ______ are present in FFP
Platelets
Cryoprecipitate contains what factors?
VIII (both C and vWF)
I (fibrinogen)
XIII ( fibrin stabilizing factor)
One unit of PRBCs will increase Hct what %? and what g/dL?
3-4%
1 g/dL
One unit of Platelets will increase platelet count how much
5,000- 10,000/mm3
Massive transfusion is defined as what?
1 complete blood volume in 24 hours
A pt is scheduled for a CABG surgery is heparinized. The ACT is reported to be 210 seconds. After administration of more heparin, the ACT is 240 seconds.
Question: is the pt adequately heparinized? what should you do?
- Not adequately heparinized; adequate is greater then 400 seconds
- Give FFP. FFP contains all the coagulation and anticoagulation factors made by the liver, including antithrombin. then proceed with the case
what is the normal Value?
Bleeding time
3-10 min
what is the normal Value?
Platelet count
150,000-400,000 cells/mL
what is the normal Value? prothrombin time (PT)
12-14 seconds
what does the PT assess
Extrinsic and final pathways
what is the normal Value?
PTT
25-35 sec
What does the PTT assess
Intrinsic and Final pathways
what is the normal Value?
Thrombin time?
< 30 sec
what does the Thrombin time assess?
final common pathway
what is the normal Value?
ACT
80-150 sec
what does ACT assess?
adequacy of heparinization
what is the normal Value?
Fibrinogen?
> 150 mg/dL
Heparinization is adequate if ACT is what?
> 400-450 sec ( one book says 480)
Aprotinin and Amicar work by how?
inhibiting plasmin
Aprotinin and Amicar work by inhibiting plasmin, when Plasmin is inhibited what happens?
Fibrin that is formed breaks down slowly, so bleeding is decreased
