Electrolyte, acid-base, and hemoglobin oxygen affinity alterations following irradiation and storage of canine packed red blood cells.

BACKGROUND: Irradiation of RBC before transfusion is required to prevent transfusion-associated graft-versus-host disease for human patients undergoing hematopoietic stem cell transplantation. Additional applications for irradiated blood may exist in oncologic surgery. The effect of irradiation on canine packed RBC (pRBC) is unknown.

OBJECTIVES: The aim of this study was to explore and characterize the in vitro electrolyte, acid-base, and oxygen-carrying capacity changes to pRBC immediately following irradiation and during storage.

METHODS: Ten units of pRBC were irradiated using a linear accelerator. Concentration of potassium and glucose, percentage of free hemoglobin (fHb), hemoglobin oxygen saturation (sO2 ), total oxygen content, partial pressure of oxygen (pO2 ), the pO2 at which 50% of hemoglobin is saturated (p50), lactate, pH, and methemoglobin were measured before and following irradiation, and at 7 and 17 days post irradiation.

RESULTS: In both irradiated and nonirradiated units, a significant decrease in pH and glucose, and a significant increase in lactate and potassium were noted. The pO2 , fHb, and the p50 value in both groups increased over the first 7 days. Immediately following irradiation, the pH was significantly lower, and the potassium, lactate, and fHb were significantly higher in irradiated units compared with controls. Small but significant differences were noted between irradiation status in pH, fHb, sO2 , total oxygen content, and p50 value at 7 days post irradiation.

CONCLUSIONS: This hypothesis-generating study found irradiation and storage significantly altered in vitro properties of pRBC. The magnitude of these differences was small and the clinical impact of irradiation on pRBC may be negligible.