[The delay of a time-limitation for thawed blood. New perspectives]

In order to comply with the needs for delayed transfusion in current practice (rare blood types dispatched to other centers, thawed blood not finally transfused to a patient, blood bank supply of Rh negative blood), we have investigated preservative media for thawed blood. We have previously shown that thawed RBC concentrates resuspended in isologous or autologous plasma remain viable and functional for 72 hours. We have extended these investigations by resuspending thawed RBC concentrates in an original synthetic preservative medium designed in our laboratory, containing: (table; see text) The following parameters have been investigated before freezing and during 15 days following thawing and washing: sterility, pH and 2,3-DPG, ATP and energy charge, free Hb levels in the supernatant, 24 h post-transfusion life and half-life of 51Cr-labeled RBC. This preservative allows the conservation of thawed RBC for up to nine days at +4 degrees C. During that time, sterility is maintained, pH is 6.80, 2,-3-DPG levels are 50% of the original values, ATP levels are 100% of the original values, free Hb is 122 mg per blood unit, energy charge is 0.90; RBC labeled 7 days after thawing showed a 89% survival rate 24 h after transfusion and a half-life of 19 days.