Blood Disorders Flashcards
_____ plays a critical role in platelet adherence/adhesion
vWF
What is the most common hereditary bleeding disorder?
vWF
Common s/s of vWF
- Easy bruising
- Recurrent epistaxis
- Menorrhagia
Pts usually unaware until questionnaire/surgery
Classification of inherited vWF disease
Know Type 1 is most mild, type 3 is severe but also rare
Diagnostics for vWF
PT/aPTT usually normal
- bleeding time is prolonged
- Need Hematologist
What type of blood products do we usually give vWF?
Factor 8, cryo, specific factors for pt
Treatment for vWF
Correct the deficiency of vWF
• Using desmopressin
• By the transfusion of the specific factor
• Cryoprecipitate
What is the dose for DDAVP for vWF?
.3 mcg/kg - .8 mcg/kg
In 50 ml of NS over 15-20 min
What is DDAVP?
Basically synthetic vasopressin: stimulates the release of vWF by endothelial cells
What is the maximal effect and duration of time for DDAVP?
30 minutes
6-8 hrs
Side effects of DDAVP
What is the biggest one?
Hyponatremia is the biggest
Headache, rubor, hypotension, tachycardia, and water intoxication
In order to decrease water intoxication, hyponatremia, and consequent seizures, the administration of _____, orally or intravenously, should be restricted for _______ hours after the use of the drug
Water
4-6 hrs
Hyponatremia s/s chart
In common preparation, the cryoprecipitate is not submitted to _________ and, therefore, poses an increased risk of _______
Viral attenuation
Infection
What can you use for vWF if unresponsive to DDAVP?
Cryoprecipitate
____ unit of cryo raises fibrinogen levels by _____ mg/dL
1 unit
50 mg/dL
How is factor VIII concentrate prepared?
from the pool of plasma from a large number of donors and undergoes viral attenuation
What does factor VIII contain?
factor VIII (obviously)
vWF
When is factor VIII commonly given?
Pre op
During surgery
What are anesthesia considerations for vWF?
- Prior evaluation by a hematologist
- When indicated, DDAVP should be infused 60 minutes before the surgery
- Normalization of the bleeding time and improved levels of F VIII should be confirmed before the surgery in patients
- Patients with coagulopathies undergoing neuroaxial block = increased risk of developing a hematoma and compression of neurological structures
- Avoid traumas during the anesthesia
- Arterial puncture is not recommended
- Laryngeal trauma during tracheal intubation may cause hematoma = postoperative obstruction of the airways
- IM avoided
What is acquired bleeding?
Bleeding from:
- heparin
- warfarin
- fibrinolytic
-antiplatelets
Heparin molecular set up
Negatively charge, CHO containing glucuronic acid residues
What are 2 types of heparin?
Unfractionated
LMWH
Heparin inhibits _____
Thrombin
What is thrombin used for?
Converting fibrinogen to fibrin
Heparin derives it anticoagulant effect by activating _________
antithrombin III
What labs do you get when pt is on heparin?
aPTT, ACT
What is heparin rapidly reversed by?
How?
Protamine
+ polypeptide forming a stable complex neutralizing heparin
LMWH is more effective at _______ compared to UFH
VTE prophylaxis
LMWHs have a more predictable ___________, fewer effects on __________, and a reduced risk for _________.
pharmacokinetic response
platelet function
heparin-induced thrombocytopenia (HIT)
T/F
Monitoring of LMWH is performed routinely
False
What does warfarin interfere with?
What coagulation factors are dependent on this (the thing we are interfering)?
hepatic synthesis of vitamin K
Factors II, VII, IX, X
What is the normal/slower way to reverse warfarin?
How fast does it take to correct?
Vitamin K
6-8 hrs
What is the more rapid reversal of warfarin?
prothrombin complex concentrates, recombinant factor VIIa and FFP
How do fibrinolytics act?
By converting plasminogen to plasmin, which in turn cleaves fibrin, thereby causing clot dissolution
Examples of fibrinolytics
Tissue plasminogen activator (tPA), streptokinase (SK), and urokinase (UK)
What are antifibrinolytic agents?
What do these do?
tranexamic acid, ε–aminocaproic acid, and aprotinin
inhibits the conversion of plasminogen to plasmin
Consideration for antiplatelets
- D/c drugs on time
- platelet transfusion
What is DIC?
Disseminated Intravascular Coagulopathy
- Systemic activation of the coagulation system simultaneously leads to thrombus formation and exhaustion of platelets and coagulation factors
What underlying disorders may precipitate DIC?
trauma, amniotic fluid embolus, malignancy, sepsis, or incompatible blood transfusions
DIC pathway picture
What will labs look like in DIC?
- Reductions in PLT
- prolongation PT, PTT, and thrombin time (TT)
- elevated concentrations of soluble fibrin degradation products
Management of DIC requires alleviating the ________ condition precipitating ________ activation
Underlying
Hemostatic
Treatment for DIC includes:
blood component transfusions to replete coagulation factors and platelets consumed in the process
What is generally contraindicated in DIC?
Why?
Anti-fibrinolytics
Potential for catastrophic thrombotic complications
What are prothrombotic disorders?
Factor V Leiden
HIT
What is factor V used for?
Protein for normal clotting
- When enough fibrin has been made, a substance called activated protein C inactivates factor V, helping stop the clot from growing any larger than necessary
What is factor V Leiden?
Mutations of the genes for factor V
- abnormal version of factor V that is resistant to the action of activated protein C
In factor V leiden, is factor V responsive to activated protein C?
No!
It cannot easily stop factor V from making more fibrin (making more clots)
Factor V Leiden is associated with an increased risk of developing an episode of ________ (with or without a ____)
DVT
PE
Do you usually put pts with factor V Leiden on anticoagulants?
What about in pregnancy? Why?
Yes to both
- to prevent venous or placental thrombosis, because improved placental blood flow is likely to lead to better pregnancy outcomes
Most factor V Leiden are silent until ______
Pregnancy
What are the first presentations of factor V Leiden?
DVT
repeated missed abortions
recurrent late fetal losses
Common anticoagulation therapies for factor V Leiden?
warfarin
unfractionated heparin
LMWH
HIT describes an _________ drug reaction occurring in as many as ____% of patients after exposure to unfractionated heparin or (rare cases) LMWH
Autoimmune-mediated
5%
When does thrombocytopenia occur in HIT?
5-14 days after initial therapy
What is the hallmark finding for HIT?
decrease in PLT < 100,000
HIT results in _____ activation and potential for _________
Platelet
Venous/arterial thromboses
Evidence suggests that HIT is mediated by what immune complexes?
composed of IgG antibody, platelet factor 4 [PF4], and heparin
Patients developing HIT during heparin therapy experience substantially increased risk for ________ (absolute risk ____%-____%)
Thrombosis
30-75
HIT pathway picture
A diagnosis of HIT should be entertained for any patient experiencing what?
thrombosis or thrombocytopenia during or after heparin administration
What is one of the most important things to do in suspected HIT cases?
D/C heparin STAT
- including unfractionated heparin, heparin-bonded catheters, heparin flushes, LMWH
Alternative _____ _______ must be administered concurrently in HIT
non-heparin anticoagulation
What is usually substituted for heparin in HIT?
What are examples of this drug?
direct thrombin inhibitor
- bivalirudin, lepirudin, argatroban
Wha can you use to treat VTE in HIT? What is the class of this drug?
Fondaparinux
- synthetic Factor Xa inhibitor
Typically, PF4/heparin immune complexes clear from the circulation within _____ months
3
How do you treat anti-thrombin 3 deficiency?
Platelets
TXA dose for adult and peds
1-2 grams for adults
15 mg/kg peds
What is a weird side effect of TXA?
TXA toxicity
- they can lose color vision
What is the apache score?
Used to evaluate pts with DIC and sepsis
