Storage of Platelets for Transfusion in Additive Solutions: Effects of Different Factors and Compounds

Abstract

Platelet-additive solution (PAS) can be used as a substitute for plasma for the storage of platelet concentrates (PCs) in order to improve storage conditions, to recover plasma for other purposes, to avoid transfusion of large volumes of plasma to patients, and to make possible photochemical treatment 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 this review, PCs were prepared from units of whole blood either by the platelet-rich plasma method or the buffy coat method. In some studies, PCs prepared by apheresis were used. The composition of the PASs used varied. The effects on platelet metabolism associated with different factors and compounds in PAS are only partly known. Available studies suggest that: 1) Presence of glucose in the platelet storage medium during the entire storage period is necessary for platelet metabolism. 2) Acetate is used as an additional substrate for platelet metabolism. Acetate also reduces the production of lactate 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 mmol/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 hydrolysis of plasma triglycerides. 6) For PCs prepared by apheresis with ACD anticoagulant, presence of phosphate in PAS seems to be a critical factor to avoid low adenine nucleotide levels during storage.