FLUIDS-Coagulation Flashcards
Describe the difference in artery and vein anatomy
- Tunica media is thicker in arteries
- Tunica externa is the thickest layer in veins
- The tunica externa is thinner than tunica media
What are the 3 layers of arteries and veins from outer to inner
- Tunica externa (connective tissue)
- Tunica media (smooth muscle layer and elastic tissue)
- Tunica intima (endotherlium)
4 factors that contribute to the liquid state of blood
- Coagulation proteins circulate in inactive form
- Endothelium is smooth, repelling clotting factors
- Undamaged endothelium prevents activation of platelets
- Activated factors are removed by brisk blood flow
What are the 4 steps of hemostasis
- Vascular spasm
- Formation of the platelet plug (primary hemostasis)
- Coagulation and fibrin formation (secondary hemostasis)
- Fibrinolysis when clot is no longer needed
What can over abundance of procoagulants increase the risk of
- Stroke
- MI
- Thrombosis
What 2 processes favor clot formation in the body
- Procoagulation
2. Antifibrinolysis
What 2 factors favor the prevention or destruction of clots
- Anticoagulation
2. Fibrinolysis
What are 5 procoagulant substances
- Coagulation factors
- Collagen
- wVF
- Fibronectin
- Thrombomodulin
What are 4 native anticoagulant substances
- Protein C
- Protein S
- Antithrombin
- Tissue pathway factor inhibitor
What are 3 native fibrinolytic substances
- Plasminogen
- tPA
- Urokinase
What are 2 native antifibrinolytic substances
- Alpha-antiplasmin
2. Plasminogen activator inhibitor
What are 2 native vasoconstriction mediators
- Thromboxane A2
- ADP
- Serotonin
What are 2 native vasodilation mediators
- Nitric oxide
2. Prostacyclin
What are the functions of the following Coagulation factor= Collagen= wVF= Fibronectin= Thrombomodulin=
Procoagulants Coagulation factor= coagulation Collagen= Tensile strength wVF= Plt adhesion Fibronectin= Cell adhesion Thrombomodulin= Regulates naturally occurring anticoags
What are the functions of the following Protein C= Protein S= Antithrombin= Tissue pathway factor inhibitor=
Anticoagulants
Protein C= degrades factor 5a and 8a
Protein S= Cofactor for protein C
Antithrombin= Degrades factor 9a, 10a, 11a, 12a
Tissue pathway factor inhibitor= inhibits tissue factor
What are the functions of the following
Plasminogen=
tPA=
Urokinase=
Fibrinolytics
Plasminogen= Precursor to plasmin (breaks down fibrin)
tPA= activates plasmin
Urokinase= activates plasmin
What are the functions of the following
Alpha-antiplasmin=
plasminogen activator inhibitor=
Antifibrinolytics
Alpha-antiplasmin= inactivates tPA, urokinase
plasminogen activator inhibitor= Inhibits plasmin
How are platelets produced
Megakaryocytes in the bone marrow
Normal platelet level
150,000 - 300,000mm^3
What is the lifespan of the platelet
8-12 days (1-2 weeks)
How are platelets cleared
By macrophages in the reticuloendothelial system of the spleen
How does the spleen affect platelet levels
- It clears them via macrophages in the reticuloendothelial system
- Can sequester up to 1/3 of all circulating platelets
Where are up to 1/3 of platelets stored
Spleen
What are 2 essential functions of the platelet
- Structural component of the clot
2. Delivery vehicles providing many substates required for clot formation
What components are on the external membrane of the platelet
- Glycoproteins
Phospholipids
What is the function of glycoproteins on the platelet external membrane
- Repellant of healthy vascular endothelium
2. Adheres to injured endothelium, collagen, and fibrinogen
What 3 components can the glycoprotein of the platelet membrane adhere
- Endothelium
- Collagen
- Fibrinogen
How does the platelet membrane glycoprotein adhere to injured structures
- GpIb attaches to activated platelet to vWF
2. GpIIb-IIIa complex links platelets together to form plug
How are platelets linked to form a plug
GpIIb-IIIa complex links the platelets together
What is the function of platelet membrane phopholipids
It’s a substrate for prostaglandin synthesis
-Which produces thromboxane A2
What is the function of thromboxane A2
Platelet activation
A platelet which has synthesized prostaglandin can then activate other platelets
What are 7 internal platelet components
- Actin and myosin
- Thrombosthenin
- ADP
- Calcium
- Fibrin-stabilizing factor
- Serotonin
- Growth factor
What are the functions or the following internal platelet components Actin/Myosin= Thrombosthenin= ADP= Calcium= Fibrin-stabilizing factor= Serotonin= Growth factor=
Actin/Myosin= plt contraction to form plug
Thrombosthenin= plt contraction assist
ADP= Plt activation and aggregation
Calcium= Coag cascade Fx 4
Fibrin-stabilizing factor= Crosslinks fibrin (Fx 13)
Serotonin= Activates nearby plts
Growth factor= Repair damaged vessel wal
What 2 components that are contained inside the plt aid in platelet contraction
- Actin and myosin
2. Thrombosthenin
What 2 components that are contained inside the plt aid in plt activation
- ADP
2. Serotonin
How does undamaged endothelium prevent platelet function
By secreting
- Prostaglandin I2
- Nitric oxide
What are 3 functions of prostaglandin I2 and where is it secreted
Secreted by healthy endothelium
Inhibits plt function by
- preventing vWF adherence
- TxA2 activation on plt
- release of storage granules
How does nitric oxide prevent platelet function
It inhibits TxA2 receptor on the plt
What are 5 platelet surface receptors
- GPIb
- ADP
- TxA2
- Thrombin
- GPIIb-IIIa
What 3 actions are responsible for the contraction of injured vessels
- SNS reflex
- Myogenic response
- Release of vasoactive substances (TxA2)
What is the purpose of vascular spasm following injury
- reduces blood loss
2. Helps procoagulatns remain in affected area
What is primary homeostasis, including the 3 step-process
Formation of platelet plug via
- Adhesion
- Activation
- Aggregation
What 2 actions occur during primary homeostasis adhesion
- Collagen is exposed and plts adhere via Gp Ia/IIa and Gp VI receptors
- vWF is synthesized and released to bind with GpIb receptor
What is the function of vWF
ADHESION
to bind with GpIb receptor on the plt and anchor it to the subendothelium
What is Von willebrand disease
A disorder of plt adhesion
How are platelets activated during primary homeostasis
Expose collagen and thrombin activate the plts
What happens once plts are activated by collagen and thrombin
Plts release ADP and thromboxane A2 which activate nearby plts
How are nearby plts activated
The original plt releases ADP and thromboxane A2
Which substance released by the plt can aid in vasoconstriction
TxA2
What does plt contraction do (3)
- Promotes plt plug
- Releases alpha granules (fibrinogen, fibronectin, vWF, plt Fx 4, plt growth factor)
- Recruits other plts to injured site
What are 2 glycoproteins that are expressed on an activated plt
GpIIb and GpIIIa
How is plt aggregation accomplished
GpIIb/IIIa receptor complex links activated plt to form plug
What factors are required to help configure GpIIb/IIIa to accept fibrinogen
TxA2 and ADP
What is the primary purpose of the coagulation cascade
To produce firbin
When is the coagulation cascade not necessary
When injury is minimal and only plt plug is needed
What is the different events that initiate the extrinsic vs intrinsic pathway
Extrinsic = when coagulation is initiated outside of the intravascular space
Intrinsic = When coagulation is initiated inside the intravascular space
What is a mnemonic for coagulation factors
Foolish People Try Climbing Long Slopes After Christmas Some People Have Fallen
What are the coagulation factors in order
- Fibrinogen
- Prothrombin
- Tissue factor
- Calcium ions
- Labile factor
- Stable factor
- Antihemophilic factor
- Christmas factor
- Stuart-Power factor
- Plasma thromboplastin antecedent
- Hageman factor
- Fibrin stabilizing factor
Where are the coagulation factors synthesized
Diet = Fx 4
Vascular wall = Tissue factor (Fx 3)
Liver = all other factors
Which factors are vitamin k dependent
Fx 2, 7, 9, 10
Which clotting factors are co-factors
5 and 8
Which clotting factor begins the common pathway
Fx 10
Which clotting factor initiates the extrinsic path
TF (Fx 3)
Which clotting factor initiates the intrinsic path
Fx 12
What labs measure the intrinsic vs extrinsic path
Intrinsic = PTT, ACT Extrinsic = PT, INR
Which factors are part of the common pathway
10, (5), 2, 1
Which factors are part of the intrinsic pathway
12, 11, 9, (8)
Which factors are part of the extrinsic path
TF/Fx3, 7, 4
Which anticoagulant inhibits the extrinsic pathway
Warfarin
How does Fx 7 activate Fx 10
Requires Fx 4 (calcium)
What is the purpose of Fx 5
In the common pathway, it functions in a positive feedback role that accelerates production of prothrombin activator
How is Fx 2 (prothrombin to thrombin) activated
By prothrombin activator and plt phospholipids
Which clotting factor has the shortest half-life.
Why is this significant
Fx 7 (4-6 hrs)
Significance = first factor to become deficient in pts with liver failure, vitamin K deficiency, and taking warfarin
What is the first factor to be depleted in pts with liver failure, vit K deficiency or taking warfarin
Fx 7
What activates Fx 12
Blood trauma, and exposure to collagen
What activates Fx 11
Fx 12a
Requires HMW kininogen and accelerated by prekalikrein
What activates Fx 9
Fx 11a
What activates Fx 10
Fx 9a and 8
What factor is missing with hemophilia A
Fx 8
What is the mnemonic for the extrinsic path
For 37 cents, you can purchase the extrinsic pathway
What is the mnemonic for the intrinsic path
If you can’t buy the intrinsic path for $12, you can buy it for $11.98
What is the mnemonic to remember the common pathway
The final common path can be purchased at the five (5) and dime (10) for 1 or 2 dollars on the 13th month
What is the primary goal of the extrinsic or intrinsic pathway
To produce prothrombin activator, which initiates the common pathway by activated Fx 2 to 2a (thrombin)
What is the function of thrombin (2a)
It’s a proteolytic enzyme that changes fibrinogen to fibrinogen monomer
How is fibrin incorporated into the plt plug
Activated fibrin-stabilizing factor (13a) facilitates cross-linkage of fibrin fibers and completes the clot
What factor is required to complete fibrin activation and cross-link
Fx 13a and Fx 4(Ca++)
What are 4 mechanisms the body uses to prevent indefinite clot formation
- Vasodilation and washout ADP and TxA2
- Antithrombin inactivates thrombin (2a) and Fx 9a-12a
- Tissue factor path inhibitor neutralizes tissue factor
- Protein C and S inhibit Fx 5a and 8a
What is the role of antithrombin
Inactivates thrombin 2a and Fx 9a-12a
What is the role of tissue factor path inhibitor
Neutralizes tissue factor (3a)
What is the role of Protein C and S
Inhibition of Fx 5a and 8a
Where is plasminogen synthesized
The liver
What is plasmin
A proteolytic enzyme the degrades fibrin into fibrin degradation products
What lab measures fibrin degradation
D-Dimer
How is plasminogen activated
Injured tissue releases tissue plasminogen activator (tPA)
Plasminogen is incorporated into the clot and is dormant until it is activated
Where are the following released
tPA=
Urokinase=
Streptokinase=
tPA= Injured tissue Urokinase= produced and released by kidneys Streptokinase= Streptococci secretion
What is the clinical use of plasmin activators
Dissolve thrombi and restore blood flow
How is fibrinolysis terminated when no longer needed
tPA inhibitor = inhibits conversion of plasminogen to plasmin
Alpha-2 antiplasmin = inhibits action of plasmin on fibrin
What are 2 enzymes that convert plasminogen to plasmin
tPA
Urokinase
What are the 3 phases of the cell-based coagulation cascade
- Initiation
- Amplification
- Propagation
What is the initiation phase of the cell-based coagulation cascade
When TF is expressed, the TF/7a reaction activates factor 10 (common path) making a small amount of thrombin (2a)
What is the amplification phase of the cell-based coagulation cascade
Plt and cofactors amplify large-scale thrombin production
Activation of plts, Fx 5, and 11
What is the propagation phase of the cell-based coagulation cascade
Large quantities of thrombin are produced on the surfaces of plts
How does the propagation phase begin
When Fx 10 is activated by Fx 4 (Ca++), 8, and 9 on the surface of the plt
What is the end-result of the propagation phase
The phase produces a positive feedback mechanism the produces enough thrombin to activate fibrin
Why do thrombin levels remain low in the initiation phase of the cell-based coagulation cascade
Tissue factor pathway inhibitor (TFPI) limits the amount of tissue factor released
What phase are plts activated in the contemporary coagulation model
The amplification phase
What does aPTT measure
activated partial thromboplastin time
Intrinsic and final common pathways
The time it takes to form a clot using phospholipid and cCa++
Normal PTT value
25-32 seconds
How reduced are clotting factors before a change is seen with aPTT
by more than 30%
What does PT measure
Prothrombin time
Measures the extrinsic and final common pathway
Time it take to form a clot using tissue factor and Ca++
What does INR measure
Calculation that standardizes PT results
Ratio between pts PT and standard mean PT
What is the normal INR and goal for pt s on warfarin
Normal = 1
On warfarin = 2-3
What does the ACT measure and its purpose
Activated clotting time
Purpose = to guide heparin dosing
What is normal ACT level
90-120 seconds
What does a plt count NOT measure
The function of the plt, only the amount of plt
What does bleeding time measure
Plt function
Evaluates the ability to form a plt plug
What is a normal bleeding time
2-10 minutes
What does a D-Dimer measure
Fibrinolysis
Elevated D-dimer = likely a thrombus somewhere in the body
What are the 5 components of a TEG
R time K Time alpha angle Max amplitude Amplitude at minutes after MA
R Time: Definition= Normal value= Problem area= Treatment=
Definition= Time to begin forming clot
Normal value= 6-8 min
Problem area= coagulation factors
Treatment= FFP
K Time: Definition= Normal value= Problem area= Treatment=
Definition= Time until clot achieves fixed strength
Normal value= 3 - 7 min
Problem area= Fibrinogen
Treatment= Cryo
Alpha angle: Definition= Normal value= Problem area= Treatment=
Definition= Speed of fibrin accumulation
Normal value= 50-60 sec
Problem area= Fibrinogen
Treatment= Cryo
Max amplitude (MA): Definition= Normal value= Problem area= Treatment=
Definition= Measures clot strength
Normal value= 50-60 mm
Problem area= Platelets
Treatment= Plts, DDAVP
Amplitude at min after MA: Definition= Normal value= Problem area= Treatment=
Definition= Height of amplitude after 60 min
Normal value= MA - 5
Problem area= Excess fibrinolysis
Treatment= TXA, aminocaproic acid
How is a prolonged TEG R time treated
FFP
How is a prolonged K time treated
Cryo
How is a low alpha angle treated
cryo
How is a low MA treated
Platelets
What 3 locations produce endogenous heparin
Basophils
Mast cells
Liver
What pathway of coagulation cascade is affected by heparin
Intrinsic and final common pathway
Heparin MOA
Binds to antithrombin forming a heparin-AT complex. This accelerates ATs anticoagulant ability
What is the function of the heparin-AT complex
To neutralize thrombin (2a), and activated Fx 9-12
Inhibits plt function
If heparinization has failed, what should be considered
AT deficiency
Describe the properties of the heparin compound
Large, negatively charged, water-soluble compounds
Small Vd
How is heparin metabolized
Heparinase
How is heparin eliminated
Degradation by macrophages
Renal excretion
What is the aPTT when heparin is therapeutic
1.5-2.5 normal ( 50-88 sec)
When is ACT measured in conjunction with surgical heparin administration
Baseline (before heparin)
3 min post administration
Then q30 min
What 3 physiologic factors affect ACT
- Hypothermia
- Thrombocytopenia
- Deficient fibrinogen, Fx 7 or Fx 12
What are 5 side effects of heparin
- Hemorrhage
- HIT
- Allergic reaction
- HoTN
- Decreased AT concentration
What are 3 contraindications for heparin use
- Neurosurgical procedures
- HIT
- Regional anesthesia (neuraxial)
Describe the protamine compound
Highly alkaline
Strong positive charge
What is the MOA of protamine
The positive charge of protamine and negative charge of heparin create a neutralization reaction that stops heparins activity
Protamine dosing
1 mg for every 100 units of heparin in circulation
How is the heparin-protamine complex cleared
Via the reticuloendothelial system
What is unique about protamine administration alone
It is an anticoagulant
What are 3 important side effects of protamine
- HoTN
- Pulmonary HTN
- Allergic reaction
Why does HoTN occur with protamine administration and how is this attenuated
Histamine release
Give over >5 min
Why can pulmonary HTN occur with protamine administration
TxA2 and serotonin release
What can indicate a possible allergic reaction to protamine
- Fish allergy
2. Previous sensitization to NPH insulin
What is warfarin MOA
Inhibition of the enzyme vitamin K epoxide complex. This complex converts inactive vit K to active vit K
Which clotting factors are inhibited by warfarin and why
Fx 2, 7, 9, 10 b/c they are vit K dependent
Protein C and S
Describe the protein binding ability of warfarin
Highly protein-bound
What lab values monitor warfarin therapeutic concentrations
PT/INR
What are the antidotes for warfarin
Vit K
FFP
What are 2 treatment for warfarin reversal
Recombinant fx 7a
Prothrombin complex concentrate (PCC)
Describe the vitamin K compound
Fat-soluble vitamin
Requires fat and bile for absorption
What are 5 risk factors for vitamin k deficiency
- Poor dietary intake
- Abx therapy killing off gut flora
- Malabsorption d/t obstructive biliary tract
- Hepatocellular dx
- Neonates
What organ is Vit K function dependent on
Liver
How long does vitamin k take to restore concentration of dependent clotting factors
4-8 hrs
Why can’t vitamin K be given IV
It can cause life-threatening anaphylaxis
What are 4 classes of antiplatelet drugs
- ADP receptor inhibitors
- GpIIb/GpIIIa Receptor antagonists
- COX inhibitors
- Cox-2 inhibitors
What are 4 examples of ADP receptor inhibitors
Have -CLO- or -GREL- in the name
- CLOpidoGREL
- TiCLOpidine
- PrasuGREL
- TicaGRELor
What are 3 examples of GpIIb/IIIa receptor antagonists
With an AB or BA (for GpIIB/IIIA
- AbciximAB
- EptifiBAtide
- TirofiBAn
What are 2 examples of non-specific COX inhibitors
Aspirin
NSAIDs
What are 2 examples of COX-2 inhibitors
Rofecoxib
Celecoxib
What are 4 classes of anticoagulant drugs
- Heparins
- Thrombin inhibitors
- Fx 10 inhibitors
- Vit K antagonists
What are 4 examples of heparin anticoagulants
Unfractionated 1. Heparin LMWH 2. Enoxaparin 3. Dalteparin 4. Tinzaparin
What are 2 examples of thrombin inhibitors
- Argatroban
2. Bivalirudin
What is an example of a Fx 10 inhibitor
FondaparinuX
How many days before a procedure should ADP receptor inhibitors be stopped
Clopidogrel = 7 days Ticlopidine = 14 days Prasugrel = 2-3 days Ticagrelor = 1-2 days
How many days before a procedure should GpIIb/IIIa receptor antagonists be stopped
Abciximab = 3 d Eptifibatide = 1 d Tirofiban = 1 d
How long before a procedure should thrombin inhibitors be stopped
Argatroban = 4-6 hrs Bivalirudin = 2-3 hrs
How many days before a procedure should warfarin be stopped
2-4 days
How do cox inhibitors prevent plt aggregation
By blocking COX-1 and stopping conversion of arachidonic acid to PG and ultimately TxA2
What is the MOA of aminocaproic acid and TXA
Plasminogen activation inhibitor; prevents conversion of plasminogen to plasmin
What is the MOA of aprotinin
Inhibits plasmin, kallikrein, thrombin, protein C
What is the MOA of DDAVP
Stimulates factor 8 and vWF factor release
What is von Willebrand disease
Disorder of plt function
Plt count is normal but do not function properly
What are 2 key function of vWF
- Anchors plt to vessel wall at site of injury (adhesion)
2. Carries inactivated factor 8 in the plasma
What are the 3 classifications of von Willebrand disease
Type 1 = mild reduction in vWF production
Type 2 = The vWF produced doesn’t work well
Typw 3 = Sever reduction in amount of vWF produced
What labs will be altered in a pt with von Willebrand dz
PTT = increased
Bleeding time = increased
No changes in PT/INR, Plt count or fibrinogen
How does DDAVP aid in procoagulation
It stimulates the release of endogenous vWF
Increases Fx 8 activity
What coagulopathic disease is DDAVP best suited.
Von Willebrand dz type 1
DDAVP is a synthetic analog of which hormone
ADH
Which von Willebrand dz type is DDAVP not appropriate
Type 3 dz does not respond to desmopressin
Dose for DDAVP
0.3 mcg/kg IV
Following DDAVP administration, how long before bleeding time improves
12-24 hrs
2 Side effects of desmopressin
- Vasodilation (esp w/ rapid administration)
2. Hyponatremia (d/t free water retention)
What What is the first-line agent for patients with Type 3 von willebrand disease
Purified 8-vWF concentrate
The risk of transfusion related issues is decreased
What blood products are indicated for treatment of pts with von Willebrand disease
Cryo = has fx 8, 13, fibrinogen, and vWF FFP = contains all clotting factors
What coagulating factors are in cryoprecipitate
Fx 8, 13, vWF
Also has fibrinogen
What factor is deficient in Hemophilia A
Factor 8
What are signs of severe hemophilia A
Spontaneous bleeding into joints, muscles, and vital organ
Which labs will be altered in pts with hemophilia A and why
PTT will be prolonged
B/c fx 8 is part of the intrinsic pathway (PT is not affected)
All other labs are normal
What should the pt with hemophilia A receive before surgery
Factor 8 concentrate
What is the half-life of factor 8 concentrated
8-12 hrs
What other treatment options are available for pts with hemophilia A undergoing surgery
FFP
Cryo
DDAVP
TXA (dental procedures)
What should always be available for pts with hemophilia A undergoing surgery
Type and crossmatch
What is hemophilia B
Factor 9 deficiency
What treatment can be given prior to surgery in pts with hemophilia B
Factor 9-prothrombin complex concentrate
What is the dose for recombinant factor 7
90-120 mcg/kg
In which pts can recombinant factor 7 be useful
Hemophilia A or B pts that develop inhibitor that prevent exogenous Fx 8 or 9 from achieving therapeutic goals
What are the risks of giving recombinant factor 7 in hemophilia pts
It can increase the risk of arterial thrombosis (MI or embolic stroke) or venous thrombosis
What is DIC
disseminated intravascular coagulation
It is characterized by simultaneous hemorrhage and systemic thrombosis
What become deficient with DIC and why
Plt, fibrinogen, and clotting factors
Because they are consumed from being used to stop bleeding while forming microvascular thrombi
What labs are altered in DIC
PT/PTT = increased D-Dimer = increased Plt = decreased Fibrinogen = decreased
What causes tissue hypoxia and acidosis in DIC
Generalized thrombin formation that creates microvascular clots impairing tissue perfusion. Leads to organ failure
Why is hemorrhage a problem in DIC
Due to widespread fibrin deposition, fibrinogen, coag factors, and plts are consumed. There is nothing left for hemostasis where it is needed
Are fibrinolytics part of DIC
Yes, Release of tPA and urokinase-type plasminogen activator occurs
What are 7 signs of DIC
- Ecchymosis
- Petechiae
- Mucosal bleeding
- Bleeding at IV puncture sites
- Prolonged PT/PTT
- Increased D Dimer
- Decreased fibrinogen and AT
What 3 conditions are associated with high risk for developing DIC
- Sepsis (gram-neg bacilli)
- Obstetric complications (pre-E, placental abruption, AFE)
- Malignancy (adenocarcinoma, leukemia, lymphoma)
What is affected by AT deficiency
The ability to inactivate Fx 9, 10, 11, and 12 leading to thrombin (2a) inhibition
Heparin responsiveness
What are pts with AT deficiency at risk for
VTE
Treatment for AT deficiency
AT concentrate
FFP
What is the etiology of heparin-induced thrombocytopenia
The body initiates an immune response against heparin after it binds to plt factor 4
IgG antibodies activate platelets resulting in uncontrolled clot formation
Why is the plt count low during HIT
Because the plt have been activated by IgG antibodies and used to form widespread clots
What is the difference in pathology between HIT type 1 and 2
Type 1 = heparin induced plt aggregation
Type 2 = Antiplatelet antibody IgG attack factor 4 immune complex causing plt aggregation
What is the precipitating event of HIT type 1 vs type 2
Type 1 = large heparin doses
Type 2 = any heparin dose
What is a typical plt count in HIT type 1 vs type 2
Type 1 < 100,000
Type 2 < 50,000
What is the onset of HIT type 1 vs type 2
Type 1 = 1-4 days post heparin
Type 2 = 5-14 days post heparin
What is the coagulation status in HIT type 1 vs type 2
Type 1 = minimal
Type 2 = hypercoagulable
What is the treatment for HIT type 2
Direct thrombin inhibitors:
Bivalirudin
Hirudin
Argatroban
What is the function of protein C
Anticoagulant effect by inhibiting Fx 5a and 8a
What is protein S
a co-factor of protein C
What is the result of protein C or S deficiency
Hypercoagulable state
Increased risk of thrombosis
What is the treatment of protein C or S deficiency
Initial thromboembolic event is treated with heparin, then pt transitioned to warfarin
What is Factor 5 Leiden mutation
Resistance to anticoagulant effect of protein C
What are 4 thrombotic disorders
- AT deficiency
- HIT
- Protein C or S deficiency
- Factor 5 Leiden mutation
3 ways the RBC function is affected by sickle cell disease
- Deoxygenation of hgbS leads to sickling
- Sickling causes RBCs to clump and cause obstruction in microvasculature, impairing tissue perfusion
- Sickle cells are more prone to hemolysis and removal by spleen (shorter life-span)
What does anesthetic management of the pt with sickle cell disease focus on
Preventing the following:
- Pain
- Hypothermia
- Hypoxemia
- Acidosis
- Dehydration
How is a sickle cell vaso-occlusive crisis treated
Analgesia
IV hydration
What is the result of a vaso-occlusive crisis
Impaired tissue perfusion
Ischemic injury
What causes acute chest syndrome in pts with sickle cell disease
Thrombosis Embolism Infection Hypoventilation Narcotics Splinting Pain
Diagnosis parameters for acute chest syndrome in sickle cell disease
CXR with new lung infiltrates
One of the following symptoms: chest pain, dyspnea, cough, wheezing
When is acute chest syndrome most likely to occur
in the postoperative period
What is a sequestration crisis
When the spleen removes RBCs from circulation at a faster rate than the bone marrow produces them leading to anemia and hemodynamic instability
What can cause an aplastic crisis and how is it manifested
Causes = viral infection (parvovirus B19)
Manifestation = Bone marrow suppression can cause anemia