Transfusion and Anticoagulants Flashcards
What are the three goals of blood transfusion?
- increase oxygen carrying capacity
- restore volume
- maintain hemostasis
What value of hemoglobin is blood transfusion always indicated?
<6
Which type of transfusion has less risk and there may be administer more liberally?
Autologous
What impact does giving PRBC’s have on coagulation factors?
Dilutes coagulation factors. Give together with RBCs.
What labs monitor coagulopathy?
PTT, Pt/INR, platelet count, fibrinogen, TEG
What side effects of massive transfusion also complicate bleeding?
hypothermia and acidosis
Platelet counts of <50,000 cause what complication?
microvascular bleeding, requiring replacement
What blood product is used for urgent warfarin reversal?
FFP
What blood product is used to treat vW disease when patients are unresponsive to DDAVP?
Cryoprecipitate
What type of transfusion is when a patient donates their own blood in the weeks leading up to surgery to be administered if needed?
Preoperative Autologous donation
What are some risks/complications of Pre-op autologous transfusion?
bacteremia, hemolytic, allergenic, and antigenic reactions, anemia, incorrect blood administration.
What type of transfusion involves extracting several units of blood prior to incision and then replacing volume with crystalloids or colloids?
Acute normovolemic hemodilution
What are the benefits of acute normovolemic hemodilution?
normal Hct and clotting factors, no risk of contamination, storage problems or incorrect transfusion.
What type of transfusion involves collection of shed surgical blood that is filtered/washed and reinfused?
intraoperative blood salvage (cell saver)
What is the range of Hct we will see with administration of cell saver?
50-80%
What is the benefit or cell saver over banked blood?
better O2 carrying capacity
What does type and screen identify?
ABO and Rh group, expected antigens
What does type and crossmatch identify?
incompatibility between donor and recipient blood, by mixing them together.
How do antibodies and antigens interact?
Antibodies in the plasma of one blood type will react with the antigens on RBC surface of another
What are the two types of antigens?
AB antigens and the Rh system
What makes AB blood the universal recipient?
AB blood has both A and B antigens on the RBCs, and lack anti-A and anti-B antibodies`
What makes O blood the universal donor?
Type O blood lacks any of the AB antigens and has both A and B antibodies in the serum
What happens when Rh factor positive blood is given to an individual with Rh negative blood?
Anti-Rh agglutinins develop slowly. No reaction the first time, but second time exposure causes a reaction.
An Rh-positive babies with Rh-negative mothers carry a risk of developing what?
Erythroblastosis Fetalis, where agglutination and phagocytosis of fetal RBC’s occur
What do hemolyzed RBCs cause?
jaundice, anemia and kernicterus
What is the most common risk of transfusions?
non hemolytic reaction
How do we treat non hemolytic reactions?
anti-inflammatory and antipyretic
What are the sigs of major allergic reactions?
hemodynamic instability, bronchospasm, rash, flushing, angioedema
What does transfusion of mismatched blood lead to?
hemolytic reaction with agglutination of the donor blood and not the recipients blood
What is the most common infectious risk with blood transfusions?
cytomegalovirus
How do you differentiate TRALI from TACO?
TACO has left atrial HTN, PAOP <18
What are the two phases of TRALI?
1st is inflammatory response to stress with pulmonary sequestration of neutrophils, 2nd is neutrophil activation by transfusion, capillary leakage
How do we treat TRALI?
100% O2, max PEEP, low Vt, avoid volume overload
How do we treat TACO?
diuretics, afterload reduction
What happens to 2,3 DPG levels with long storage times?
decreases DPG levels, (less O2 carrying capacity)
Why can transfused PRBCs lead to Ventricular arrhythmia and arrest?
high levels of potassium
Citrate accumulation in the plasma from transfusion can result in what electrolyte derangement?
hypocalcemia
What affected does temperature have on coagulation?
coagulability decreases 10% for every 1 degree celsius drop in temperature
What blood product is Indicated for bleeding, and
Increases O2 carrying capacity?
Red Blood Cells
1 unit of PRBCs will increase Hgb and Hct by how much?
Hgb by 1 gram
Hct by 2-3%
What is the concentration of hematocrit in one unit of PRBCs?
60-80%
What blood product is indicated for PT/PTT >1.5x normal with bleeding, Massive blood transfusions, vitamin K deficiency, reversal of warfarin, von Willebrands, AT3 def
FFP
What blood product contains all clotting factors and inhibitors, and antithrombin III?
FFP
What is the dose of FFP? Dose for warfarin reversal?
10-15mL/kg
5-8mL/kg for warfarin
Coagulation factors need to be within what percentage of normal to produce adequate coagulation?
25%
What blood product is indicated for massive blood transfusion and active bleeding
Platelets
What is the most common cause of post-op bleeding?
platelet dysfunction
What is the dose of platelets?
1 unit/10kg of body weight.
1 unit of platelets increases the level of platelets in the body by how much?
5,000-10,000
Which blood product has the highest rate of bacterial contamination due to storage temperature?
Platelets
Which blood product is indicated for von Willebrands unresponsive to DDAVP, fibrinogen deficiency, and microvascular bleeding?
Cryoprecipitate
What coagulation factors does Cryoprecipitate contain?
Factor 1, vWF, 8, and 13
1 unit/5kg will raise fibrinogen by how much?
100 mg/dL
What is the most common inherited coagulation disorder?
Von Willebrands Disease
What are the two main function of vWF?
facilitate platelet adhesion, plasma carrier for factor 8
Von Willebrands Disease will have deficiencies in which coagulation factors?
vWF and factor 8
Which type (1,2 or 3) of vWD will cause spontaneous bleeding?
type 3
1 and 2 cause bleeding if surgery or trauma
What is the treatment of choice for vWD?
DDAVP. It increases plasma levels of vWF and augments platelet aggregation
What blood product can be given for more severe forms of vWD?
cryoprecipitate or recombinant factor 8, vWF concentrate
Which type of hemophilia is a deficiency in Factor 8?
Hemophilia A
How do we treat hemophilia A?
DDAVP, FFP, cryoprecipitate
Which type of hemophilia is a deficiency in Factor 9?
Hemophilia B
How do we treat hemophilia B?
FFP, factor 9 concentrate
Which type of hemophilia is a deficiency in Factor 11?
hemophilia C
How do we treat hemophilia C?
FFP, or factor 11 concentrate
What are some common complications that happen to people with hemophilia?
spontaneous bleeding, muscle hematoma, pain at joints from bleeding
What lab derangements of aPTT, PT and bleeding time will occur with hemophilia?
prolonged aPTT, normal PT and bleeding time
What type of hemophilia can occur with connective tissue disorders, pregnancy, or malignancy and stems from antibody production against FVIII?
acquired
what are the side effects of liver disease related to coagulation?
thrombocytopenia, decrease in clotting factors made in the liver, and a decrease in protein C, S, and antithrombin III
Patients with liver disease will have increased levels of which clotting factors?
8, vWF (up regulation)
Will aPTT and PT be accurate representations of the patient with liver disease coagulability? what is used?
no. Use viscoelastography
What is DIC?
Systemic coagulation disorder with systemic inflammation and coagulation
DIC causes multi-organ failure due to what?
widespread microvascular clotting
What causes DIC?
Ineffective tissue factor pathway inhibitor and antithrombin
What is the preferred treatment for DIC?
platelets
Should you treat DIC with anticoagulants?
yes, especially early
How does UFH and LMWH exert their anticoagulant effect?
binding with antithrombin and enhancing antithrombin 1000X
What pathway(s) do the Heparins inhibit and what factors?
Common and Intrinsic
2, 9, 10, 11, 12
How is heparin monitored intra-op?
ACT
What are the LMWHs?
enoxaparin, and dalteparin
LMWHs can cause what with epidural catheters or repeated spinal/epidural anesthesia?
spontaneous hematoma
What is the most important compilation of heparin therapy?
HIT
What are the presenting symptoms of HIT?
thrombocytopenia, resistance to heparin, and thrombosis
Which type of HIT is more severe?
Type 2, heparin dependent IgG antibodies produced
What anticoagulant can be used as a alternative for patients with a history of HIT?
fondaparinux
When do you stop fondaparinux prior to surgery?
4 days
What is the class, MOA, and surgical stop time of bivalrudin?
Direct thrombin inhibitor
inhibits thrombin
stop 4-6 hours prior
What is the class, MOA, and surgical stop time of argatroban?
direct thrombin inhibitor
inhibits thrombin
stop 4-6 hours prior
What is the class, MOA, and surgical stop time of Lepirudin?
direct thrombin inhibitor
inhibits thrombin
stop 24 hour prior
What is the class, MOA, and surgical stop time of desirudin?
direct thrombin inhibitor
inhibits thrombin
stop 24 hours prior
What is the class, MOA, and surgical stop time of Dabigatran?
direct thrombin inhibitor
inhibits thrombin
stop 2-4 days prior
What is the most frequently used anticoagulant?
Warfarin
What is the class, MOA, and surgical stop time of warfarin?
Vitamin K antagonist
Inhibits vitamin K epoxide reductase which converts vitamin K dependent coagulation factors to their active form (II, VII, IX, and X)
Stop 3-5 days prior
How is warfarin metabolized?
metabolized into active compounds
What inhibits and potentiate warfarin therapy?
dietary vitamin K (leafy greens) inhibits
liver disease, old age, alcohol potentiate
What is the goal INR for patients on warfarin?
2-3
What is the class, MOA, and surgical stop time of rivaroxaban?
Direct factor Xa inhibitor
inhibit free, clot bound, and bound to prothrombinase complex Xa
stop 1-2 days prior
What is the class, MOA, and surgical stop time of apixaban?
Direct factor Xa inhibitor
inhibit free, clot bound, and bound to prothrombinase complex Xa
stop 1-2 days prior
When can a epidural catheter be removed after giving a direct factor X inhibitor?
18 hours after the last dose, or 6 hours prior to the next dose
What class of drugs are the mainstay treatment for patients with atherosclerotic disease and CAD?
platelet inhibitors
What is the class, MOA, and surgical stop time of aspirin?
platelet inhibitor
irreversibly acetylates cyclooxygenase, preventing the formation of prostaglandin & thromboxane A2
stop 7-10 days prior
What is the class, MOA, and surgical stop time of the thienopyridines (clopidogrel, prasugrel, and ticagrelor)?
Platelet inhibitors
bind to P2Y12 receptors blocking ADP binding mediated platelet activation and aggregation
stop 7 days prior, avoid regional
What is the class, MOA, and surgical stop time of Abciximab?
Platelet Inhibitors
bind and competitively inhibit the IIb/IIIa binding sites of fibrinogen to platelets
stop 72 hours prior
What is the class, MOA, and surgical stop time of tirofiban, eptifibatide?
Platelet Inhibitors
bind and competitively inhibit the IIb/IIIa binding sites of fibrinogen to platelets
stop 24 hours prior
What is the class, MOA, and surgical stop time of Streptokinase, urokinase, and tPA ?
Fibrinolytics
activate plasminogen to plasmin which degrades fibrin and factors V and VIII
stop 1-3 hours prior
What drugs are the antifibrinolytics?
Aminocaproic acid, TXA, aprotinin
What is the MOA of anti-fibrinolytics?
competitively inhibit activation of plasminogen to plasmin
What is the drug class of choice for mucosal bleeding from nose, oropharynx, and genitourinary tract because something the secretions contain?
antifibrinolytics
What is a significant complication of TXA administration?
seizures
Why is TXA thought to cause seizures?
blockade of GABA receptors in the frontal cortex
Which medication forms an ionic bond with and neutralizes UFH?
Protamine
What type of reaction is the one between heparin and protamine?
chemical antagonism
What is the dose of Protamine?
1mg/100 units of heparin
What dose of Protamine would you give if you previously gave 5,000 units of heparin?
50 mg
Why should we try to avoid excess administration of protamine?
has some anticoagulant effects on its own by inhibition of platelets and serine proteases
Why might you have to redose protamine?
Heparin rebound, short half life. Bump with 5-15mg.
Why do we administer Protamine slowly?
histamine release from mast cells can cause hypotension
Which patients have an increased risk of anaphylaxis with protamine?
Allergy to fish, NPH insulin use, prior exposure to protamine, vasectomy
What is Desmopressin?
V2 analog of arginine vasopressin.
What does Desmopressin do?
stimulates the release of vWF from endothelial cells
What patients are treated with DDAVP?
Hemophilia A, vWD
What is the dose of DDAVP?
0.3mg/kg over 15-30 minutes
