1. Which of the following is NOT a potential consequence of the "storage lesion" described regarding donated blood?
a) impaired nitric oxide release from RBC's, leading to local vasoconstriction and impaired flow
b) abnormal generation of cytokines and bioreactive agents
c) loss of red blood cell deformability
d) increased CO-Hb concentrations thus leading to reduced oxygen delivery
2. Which of the following patients would benefit most from irradiated PRBC's?
a) Pt at risk for severe allergic reaction to PRBC transfusion
b) 28 week infant in the NICU with anemia
c) 6 mo M with new diagnosis of PJP
d) 1 mo male undergoing Norwood operation for HLHS
3. What is the ratio of PRBC to Plasma to Platelets that should be given for massive transfusion?
ANSWERS & EXPLANATIONS
1. D- As our understanding of transfusion medicine increases, we are learning that donated blood can be associated with a "storage lesion," meaning donated blood is different than native blood in many ways that may be physiologically detrimental. These include diminished levels of 2-3 DPG, decreased RBC deformability, impaired NO release leading to local vasoconstriction, and abnormal generation of cytokines. Increased carbon monoxide is not thought to be a significant contributor to the storage lesion.
2. C- Irradiated PRBC's are used for patients at risk for transfusion associated graft vs. host disease (TA-GVHD). In particular, these patients include those with severe T cell deficiencies or suspected of having a severe immunodeficiency. In addition, those who are undergoing bone marrow transplant, those with Hodgkin lymphoma, and those treated with certain chemotherapuetics (fludaribine, cladribine, deoxycoformicin) should receive irradiated blood products. Prematurity, cardiac surgery (unless suspected of having T cell deficiency- i.e. DiGeorge syndrome as well), and risk for severe allergic reactions are not indications for irradiated PRBC's.
3. A-1:1:1. This is done to avoid dilutional coagulopathy and thrombocytopenia that can occur when massive volumes of PRBC's are transfused without plasma or platelets. This has been shown to improve mortality and decrease length of stay. Other potential complications of massive transfusion include citrate toxicity, leading to hypocalcemia, as well as hypothermia and hyperkalemia.