The effects of phosphate, pH, and AS volume on RBCs stored in saline-adenine-glucose-mannitol solutions

RBC ATP concentrations are the most important correlate of RBC viability. Tests were performed to determine whether increased AS volume, pH, and phosphate content increased stored RBC ATP concentrations.

In three studies, packed RBCs were pooled in groups of 3 or 4 units and realiquoted as combined units to reduce intradonor differences. Pooled units were stored in the licensed ASs, AS-1 or AS-5, which contain saline, adenine, glucose, and mannitol (SAGM), or in experimental ASs (EASs) containing SAGM and disodium phosphate. Ten pools were stored in AS-1 at RBC concentrations equivalent to 100, 200, or 300 mL of AS. Six pools were stored in 100, 200, 300, or 400 mL volumes of EAS-61. Ten pools were stored in 100 mL of AS-5, 200 mL of EAS-61, or 300 mL of EAS-64. RBC ATP concentration and other measures of RBC metabolism and function were measured weekly.

RBC ATP concentrations decreased sooner with storage in increasing volumes of AS-1. In EAS-61 and EAS-64, RBC ATP concentrations initially increased and stayed elevated longer with increasing AS volume.

The addition of disodium phosphate to SAGM AS increases the RBC ATP concentrations. Reducing storage Hct appears to have a separate beneficial effect in reducing hemolysis.