Introduction
Platelet transfusion has become a routine component of modern medical care. Each year, approximately 2000000 such transfusions are administered in the United States. This chapter will review the preparation, storage, clinical use and complications of platelet transfusion.
Platelet preparation
Platelet concentrates (PC) for transfusion may be obtained from routine donations of whole blood or by apheresis (AP–PC), using citrate as the anticoagulant. There are two methods for preparing PC from whole blood, the plateletrich- plasma method (PRP–PC) and the buffy coat method (BC–PC)(Fig. 46.1).
In evaluating the quality of PC, much attention is now being given to the number of contaminating leukocytes as well as to the appropriate platelet content. Problems related to contaminating leukocytes will be discussed in the section on complications of platelet transfusion. Many now recommend a totally leuko-reduced blood supply to reduce the frequency of these complications. Platelets can be filtered during infusion at the bedside, but, for reasons to be discussed, it is probably preferable to perform leukoreduction at the time of preparation of the PC. In the United States, an AP–PC or a pool of PRP–PC is considered leukoreduced if it contains less than 5 × 106 leukocytes while the standard in Europe is 1 × 106.
Whole-blood-derived PC
PRP–PC
At present, this is the only method used in North America for preparing whole-blood-derived PC. 450–500 ml (a unit) of whole blood is held for up to 8 hours at room temperature, and PRP is separated from red cells and buffy coat by low-speed centrifugation.