Transfusion Therapy Flashcards
Most common transfusion reaction?
ABO incompatibility
ABO, Rh typing
- 2% chance of transfusion reaction after this testing
- Rh-negative patients produce anti-Rh antibodies only after being exposed
T/S (type and screen)
recipients plasma + stock RBCs (known antigen) –> watch for reactions
- 0.06% chance of reaction after this testing
T/C (type and cross)
recipients plasma + donors RBCs –> watch for agglutination (incompatibility)
- 0.05% chance of reaction after this testing
Emergency Transfusion
give type specific or type O blood
Rh-negative patients should receive anti-Rh globulin
- after 8-10 units of type O blood, don’t switch for type-specific blood
Blood Type O
no antigens, both anti-A and anti-B antibodies
- universal donor
- can only accept from O
Blood type A
A antigens, anti-B antibodies
- receive from A and O
- can’t receive from B or AB
Blood type B
B antigens, anti-A antibodies
- receive from B and O
- can’t receive from A or AB
Blood type AB
A and B antigens, no antibodies
- universal acceptor
- can’t donate to anyone except AB
Red Blood Cells
1 unit = 300 mL
180 mL of RBCS, 130 mL of storage solution
- use for acutely ill hospitalized patients
age Hct Hct Hct
Packed Red Blood Cells
used to increased O2 carrying capacity
1 unit can increase Hct 2-3%, must be ABO and Rh compatible
*Leukocyte reduced = prevent nonhemolytic reaction
Frozen RBCs
no plasma, minimal other cells
- use for red cell replacement in special circumstances
Platelets
contains platelets and some plasma
- use for platelet counts between 50-100k
contains all plasma coagulation factors
no need for ABO compatibility
Fresh Frozen Plasma (FFP)
plasma proteins, all coagulation factors
- use for bleeding from factor deficiencies (liver disease), massive transfusion, coumadin reversal
Must be ABO compatible
DON’T USE FOR VOLUME EXPANSION
Cryoprecipitate
factors VIII, XIII, fibrinogen, vWf
- used for hemophilia, vWf disease
preferred ABO compatibility
- DON’T use with hypofibrinogenemia
Factor VIII concentrate
contains factors VIII, vWf, fibrinogen
- used for hemophilia A
Factor IX concentrate
contains factors II, VII, IX, X
- used for hemophilia B
Whole blood
largely replaced by component therapy
exceptions = pediatric cardiac surgery and military hospitals
Factor VII
used in uncontrollable bleeding in surgical and hemophilia patientis
- initiates coagulation in only those sites where tissue factor is also present
DDAVP
release of endothelial stores of factor VIII and increases VIII:vWF
Estimated blood volume
weight (kg) x average blood volume
Estimated allowable blood loss
EBV x (Hct i - Hct low)/Hct i
Complications of massive transfusion
High K+, low Ca++ (citrate binds Ca)
Dilutional thrombocytopenia
Metabolic alkalosis (citrate forming HCO3)
Hypothermia
Infectious complications
CMV Hep B Hep C HIV Bacteria
Noninfectious complications
Febrile Allergic Delayed hemolytic acute hemolytic fatal hemolytic TRALI
Coagulopathic complications
typically seen in setting of massive blood transfusions
- dilutional thrombocytopenia
- DIC
- low factor levels
Acute hemolytic transfusion reaction
due to ABO or major antigen incompatibility (clerical errors)
Sx: chills, fever, chest and flank pain (may only see hypotension)
Nonhemolytic transfusion reaction
usually febrile or allergic -> caused by antibodies against donor WBC or plasma proteins
Sx: fever, hives, tachycardia, and hypotension
Tx: rule out hemolytic reaction
Prevention: leukocyte reduced PRBCs
Treatment of hemolytic transfusion reaction
- stop transfusion
- treat hypotension with fluids/pressors
- Maintain urine output
- Alkalinize urine to prevent precipitation
- Send unused blood for recheck
- Send blood sample for Hb, haptoglobin, Coombs test, DIC
- COnsider corticosteroids
Tranfusion related acute lung injury (TRALI_
noncardiogenic pulmonary edema occuring within 4 hrs of blood product
Mech: reaction between donor anti-HLA and recipients leukocytes
Tx: stop transfusion, supportive
mortality ~ 5-10%
Metabolic Complications
citrate intoxication - occurs with blood - hypothermia, liver disease and hyperventilation all increase risk - monitor ionized Ca++ - treat hypocalcemia with Ca gluconate Hyperkalemia - unlikely
Transfusion-related immunomodulation
immune suppression (beneficial or harmful) - mechanism unclear
Red Cell Substitutes and Synthetic Oxygen Carriers
perfluorocarbons and Hb-based oxygen carriers
- easy availability, universal compatibility, long shelf life, low risk of infection
- none are clinically available at this time
Primary hemostasis
constriction of blood vessels
exposure of subendothelial collagen
adhesion and aggregation of blood platelets to damaged surface
formation of hemostatic plug
Secondary hemostasis
formation of thrombin clot
conversion of fibrinogen to fibrin
Prothrombin time
PT - measures extrinsic pathway (II, V, VII, X)
INR standardizes it
Partial Thromboplastin Time
PTT - measures intrinsic pathway (VIII-XII_
- elevated with heparin
Activated Clotting TIme
modified clotting time of whole blood
measures intrinsic pathway
Bleeding time
crude way of platelet function (rarely used)
Fibrinogen
normal level (170-410) - may be depleted in massive hemorrhage or DIC
Fibrin degradation products
increased in DIC, fibrinolysis, and severe liver disease
D-dimer
specific fragment produced when plasma digests cross-linked fibrin
- increased in DIC, PE, and postop period
