Stability of hemoglobin solution during extended storage.

Hemoglobin solution, proposed as a blood substitute, must be stable for a long period of time in order to be stockpiled and be readily available when massive clinical transfusions are required. Hemoglobin solutions, prepared by crystallization and maintained in blood bags under sterile conditions, were stored at -20 degrees, 4 degrees, and 25 degrees C. At several intervals, methemoglobin content, p50, n values, osmolality, oxygen capacity, Na, K, and pH were assayed. Solutions maintained at -20 degrees C demonstrated no alterations in these parameters after 2 years of storage. Solutions kept at 4 degrees C remained stable for 12 months. After 12 months and especially after 18 months, deterioration was evident inthe refrigerator-stored solutions, as demonstrated by an increase in methemoglobin content and a decrease in P50. Attempts to store hemoglobin in liquid form at room temperature without alterations in structure and function of hemoglobin were unsuccessful. The characteristics of hemoglobin prepared from fresh or outdated blood were essentially the same.