Because you asked

Many of our local friends who are regular blood donors have approached me and asked if there is a need to give blood or platelets for Kate because of her frequent need for blood product transfusions. I am grateful for your concern and desire to be supportive in this way.

There is no "need" on our part to replenish the blood products that Kate has used. However, to ensure that blood is available for Kate and other patients who need it, the blood bank always welcomes replenishment donations.
I contacted the Central Blood Bank in Pittsburgh and they indicated that anyone desiring to give blood or platelets for replenishment is welcome to do so. In answer to your question, yes, this can be done in Kate's name. When giving just indicate you desire to make your donation for replenishment in the name of Kathryn E. Dillon - a patient of Children's Hospital of Pittsburgh. Given different blood types and platelet compatibility this will not necessarily be a direct donation to Kate, but it does help replenish the supply available for all those in need.