The preservative-exchange method using a sextuple-bag system for a 10-week storage period of red blood cells

Prolonged storage of red blood cells in a liquid state was achieved by replacing the preservative using a sextuple-bag system. The bag system consists of one primary bag containing citrate-phosphate-dextrose (CPD) solution, three satellite bags containing saline-adenine-glucose-phosphate-maltose (SAGP-maltose) solution, and two empty satellite bags to remove plasma and buffy coat. Preservative can be exchanged three times in this closed system. The system is able to supply nutrients, such as glucose, and to remove harmful metabolites, such as lactic acid, by exchanging the preservative during storage. As a result, red cells stored by this method showed much higher levels of total adenylate and morphological score after the second preservative exchange, when compared with red cells stored by the conventional method (P < 0.01). Judging from these two in-vitro parameters, red cells may tolerate storage for at least 10 weeks in a liquid state. This method might be useful for 'predeposit autologous transfusion', as it is more convenient and more cost effective than the freeze-preservation method.