SR 19 - Blood and Blood Products Flashcards
Define - PT
Prothrombin time
Tests extrinsic coagulation pathway (Warfarin)
Define - PTT
Partial Thromboplastin Time
Tests intrinsic coagulation pathway (Heparin)
Define - INR
International normalized ratio (reports PT results)
Define - PRBC
Packed red blood cells
One unit - 300mL
No platelets or clotting factors
Can be mixed with NS to infuse faster
Remember - RBCs have the antigens - so O is the universal RBC donor (they have no antigens for plasma antibodies to react against)
-/+ only really matters for girls who still may get pregnant at some point
Define - FFP
Fresh frozen plasma
Replaces clotting factors
No RBCs, WBCs, platelets
Remember - plasma has the antibodies - so AB is the universal plasma donor (Since they both antigents, they cannot have AB antibodies swimming around in their blood)
Define - Cryoprecipitate
Replaces fibrinogen, von Willebrand factors, some clotting factors
Which electrolyte is most likel to fall with the infusion of stored blood? Why?
Ionized calcium
The citrate preservative used for the storage of blood binds serum calcium
What changes occur in the storage of PRBCs?
Decreased Calcium Decreased 2,3-DPG Decreased pH Decreased PMNs Increased potassium Increased hydrogen
What are generaly guidlines for blood transfusions?
Acute blood loss, history of CAD/COPD - Hb
Which blood type is the universal donor for PRBCs?
O negative
Which blood type is the universal donor for FFP?
AB
What is type and screen?
Determine blood type and screen for antibodies
What is type and cross?
Cross-matched with specific donor units for possible transfusion
Define thombocytopenia
Low platelet count
Common causes of thrombocytopenia in the surigcal patient?
Sepsis H2 blockers Heparin Massive transfusion DIC Antibiotics Spurious lab value Swan-Ganz catheter
What can be given to correct platelet dysfunction from uremia, ASA or bypass?
DDAVP (desmopressin)
Leads to increased levels of coagulation factor (F) VIII, von Willebrand factor (vWF), and tissue plasminogen activator
What common medication causes platelets to irreversibly malfunction?
ASA
Inhibits cyclooxygenase
What is Plavix?
Clopidogrel
Irreversibly inhibits platelet P2Y12 ADP receptor
Blocks fibrin crosslinking of platelets
What platelet cout is associated with sponatneous bleeding?
How high should the platelet count be before surgery?
> 50,000
When should ‘prophylaxtic’ platelet transfusion be given?
What is microcytic anemia ‘until proven otherwise’ in a man or postmenopausal woman?
Colon cancer
Why not infuse PRBCs with LR?
Calcium in LR may result in coagulation within the IV line
Use NS
How long can PRBCs be stored?
6 weeks (42 days)
What is the most common cause of transfusion hemolysis?
ABO incompatibility as a result of clerical error
What are the symptoms of a transfusion reaction?
Fever Chills Nausea Hypotension Lumbar pain Chest pain Abnormal beleding
What is the treatment for transfusion hemolysis?
Stop transfusion Profide fluids Perform diuresis (with lasix) to protect kidneys Alkalinize urine with bicarb Pressors as needed
What component of the blood transfusion can cause a fever?
WBCs
What is the transfusion ‘trigger’ Hct in young healthy patients?
21%
What is the ‘optimal’ Hct in a patient with a history of heart disease and stroke?
30%
When should ASA administration be discontinued preoperatively?
1 week
Platelets live for 7-10 days
(Use clinical judgement if patient is at risk for MI or stoke, may be better to continue the ASA and use excelelent surgical hemostasis instead)
What can move the oxyhemoglobin dissociation curve to the right?
Acidosis
2,3-DPG
Fever
Elvated Pco2
To the right means better unloading of O2 (Right = release)
What is the normal life of RBCs?
120 days
What is the normal life of platelets?
7-10 days
What factor is deficient in hemophilia A? What coagulation study is elevated?
Factor VIII
PTT
What is the preoperative treatment of hemophilia A?
Factor VIII infusion to 100%+ normal preoperative levels
What factor is deficient in hemophilia B? Elevated coagulation study?
Factor IX
PTT
What is von Willebrand’s disease? Elevated coagulation study?
Deficiency of vWF and factor VIII-C
Autosominal dominant
Bleeding time
What is used to correct vWF deficiency?
DDAVP or cryoprecipitate
What is the effect on the coagulation system if the patient has a deficiency in protein C, protein S, or antithrombin III?
A hypercoagulable state
What is a ‘left shift’ on a CBC?
Juvenile polymorphonuclear leukocytes (bands)
What is the most common inherited hypercoagulable state?
Factor V leiden
What is Xigris?
Actived protein C
Which is used in severe sepsis
