Electrostatic field can preserve red blood cells in stored blood preparations.
During the storage of red blood cell concentrates (CRCs), red blood cells are progressively destroyed and free hemoglobin and potassium concentrations increase. In this study, we focused on an electrostatic field that maintains food freshness without freezing, even at less than the freezing point. We hypothesized that the storage of CRCs under an electrostatic field could keep red blood cells in better condition than conventional storage. Each of 15 packs of 2-day-old CRCs, preserved in MAP (mannitol, adenine, glucose, phosphate, and citrate) solution (MAP-CRC) was divided into 4 smaller equal-size packs and stored at 4 degrees C in a newly developed refrigerator that can generate an electrostatic field. Each group was exposed to a 0-, 500-, 1500-, or 3000-volt (V) electric field for 30 days. Concentrations of free hemoglobin, total haptoglobin, sodium (Na), and potassium (K), and the pH, were measured in the supernatant. Haptoglobin was not detected. The Na concentration decreased with time but was significantly lower in the 0-V than in the 500-, 1500-, and 3000-V groups. K and free hemoglobin concentrations increased with time, with significantly higher values in the 0-V than in the 500-, 1500-, and 3000-V groups. The pH decreased in the 500-, 1500-, and 3000-V groups, while it did not change in the 0-V group. The pH decrease was smaller in the 500-V than in the 1500- and 3000-V groups. Storing MAP-CRC in an electrostatic field of 500 to 3000 V could decrease hemolysis in the preparation. Considering the lower pH decrease, 500 V might be the field of choice.