I found an interesting journal article that I'm reading now.
http://www.dsmb.univr.it/documenti//...gato942926.pdf
"A large infusion of RBCs may be associated with hyperviscosity syndrome, which is characterized by increased blood viscosity and decreased cardiac output and blood flow velocity and results in reduction of peripheral oxygen delivery. Additional complications may be phlebitis, septicemia, bacterial infection, and air/clot embolism. 24"