266b RBC transfusions Flashcards
RBC hemolysis - intra vs extravascular
intra - IgM/G binds –> activates compliment–> MAC forms pores
extravascular - IgG binds –> RBCs are phagocytized (spleen)
RBC hemolysis - intra vs extravascular
intra - IgM/G binds –> activates compliment–> MAC forms pores
extravascular - IgG binds –> RBCs are phagocytized (spleen)
ABO incompatible RBC transfusion effects?
rapid hemolysis from IgM activating complement
systemic inflammation - hypotension, shock
clotting activated (DIC)
renal tubule injury - acute tubular necrosis
ABO vs Rh D antibodies - which occur naturally?
ABO antibodies occur naturally
Rh D - acquired from exposure of Rh- to Rh+ blood (give Rh immune globulin to mother –I blocks antibody production)
must give Rh- RBC to Rh- patients unless emergency and especially to females of childbearing age
Autoimmune hemolytic anemia testing - direct coombs test
anti-Ig antibody (Coombs reagent) added to patient’s blood. RBCs agglutinate if RBCs are coated with Ig.
emergency RBC transfusion - what do you use?
Group O, Rh- RBCs (at least for females)
O blood group
Neither A nor B antigen on RBC surface; both antibodies in plasma
“universal donor” of RBCs
“universal recipient” of plasma.
Rh blood group - what is the issue? what can be done to prevent it? what Ig crosses the placenta?
Rh antigen on RBC surface. Rh− mothers exposed to fetal Rh+ blood (often during delivery) may make anti-Rh IgG.
In subsequent pregnancies, anti-Rh IgG crosses the placenta, causing hemolytic disease of the newborn (erythroblastosis fetalis) in the next fetus that is Rh+.
Give mother Rho immune globulin during pregnancy
IgG crosses placenta, IgM doesn’t (anti-A/B)
ABO vs Rh D antibodies - which occur naturally?
ABO antibodies occur naturally
Rh D - acquired from exposure of Rh- to Rh+ blood (give Rh immune globulin to mother –I blocks antibody production)
must give Rh- RBC to Rh- patients unless emergency and especially to females of childbearing age
Autoimmune hemolytic anemia testing - direct coombs test
anti-Ig antibody (Coombs reagent) added to patient’s blood. RBCs agglutinate if RBCs are coated with Ig.
Autoimmune hemolytic anemia testing - indirect coombs test
normal RBCs added to patient’s serum. If serum has anti-RBC surface Ig, RBCs agglutinate when anti-Ig antibodies (Coombs reagent) added.
emergency RBC transfusion - what do you use?
Group O, Rh- RBCs (at least for females)
O blood group
Neither A nor B antigen on RBC surface; both antibodies in plasma; “universal donor” of RBCs, “universal recipient” of plasma.
Rh blood group - what is the issue? what can be done to prevent it? what Ig crosses the placenta?
Rh antigen on RBC surface. Rh− mothers exposed to fetal Rh+ blood (often during delivery) may make anti-Rh IgG.
In subsequent pregnancies, anti-Rh IgG crosses the placenta, causing hemolytic disease of the newborn (erythroblastosis fetalis) in the next fetus that is Rh+.
Give mother Rho immune globulin during pregnancy
IgG crosses placenta, IgM doesn’t (anti-A/B)
acute bleeding rx?
1 - intravascular blood volume via iv fluids (avoid hypovolemia, hypoperfusion
early Hct doesn’t reflect blood loss
RBC transfusions when blood loss reaches 30% (1500 mL)
