Storage of platelets for transfusion in additive solutions: Effects of different factors and compounds

Platelet-additive solution (PAS) can be used as a substitute for plasma for the storage of platelet concentrates (PCs) in order to improve storage con ditions, to recover plasma for other purposes, to avoid transfusion of larg e volumes of plasma to patients, and to make possible photochemical treatme nt for viral inactivation of PCs. For this reason, PAS should have a great potential for wide use in transfusion medicine. In the studies cited in thi s review, PCs were prepared from units of whole blood either by the platele t-rich plasma method or the buffy coat method. In some studies, PCs prepare d by apheresis were used. The composition of the PASs used varied. The effe cts on platelet metabolism associated with different factors and compounds in PAS are only partly known. Available studies suggest that: 1) Presence o f glucose in the platelet storage medium during the entire storage period i s necessary for platelet metabolism. 2) Acetate is used as an additional su bstrate for platelet metabolism. Acetate also reduces the production of lac tate by platelets, and by the formation of bicarbonate it maintains stable pH levels during storage. 3) The fall in pH can be rapid in PAS-containing media due to the very limited buffering capacity of PAS compared with that of plasma. 4) Platelets stored in PAS at a citrate concentration of 8 mmol/ l produce only half the quantity of lactate as that of platelets at 14-26 m mol/l of citrate. 5) Free fatty acids from plasma can be used as substrate for platelet metabolism and are supposed to be made available by the hydrol ysis of plasma triglycerides. 6) For PCs prepared by apheresis with ACD ant icoagulant presence of phosphate in PAS seems to be a critical factor to av oid low adenine nucleotide levels during storage.