COMPARATIVE VIABILITY OF BLOOD STORED IN ACD AND CPD

The normal distribution of red blood cell viability for ACD and CPD units stored for 21 days was studied. For ACD and CPD units, respectively (n=41,37), the means and standard deviations were as follows: 24‐hour survival, 75.7 + 6.2 and 79.4 + 6.4; early recovery, 91.6 + 3.6 and 94.1 + 3.5; t/2, 29.4 + 3.0 and 27.9 + 4.3. Early recovery and survival were significantly higher for CPD, but more important than the difference in mean survival is that by current standards of acceptability, the incidence of donors who will be deemed undesirable is approximately 6 per cent for CPD, as opposed to 20 per cent for ACD. Neither early recovery, 24‐hour survival, nor t/2 could be shown to correlate with pH, plasma potassium, plasma sodium, per cent hemolysis, and osmotic fragility. The mean and standard deviation of survival for 18 units of 28‐day‐old CPD blood was 70.7 + 11. Since the standard error was large, the frequency distribution could not be determined, and the number of units with survivals that would fall below the minimum standard could not be ascertained. Nevertheless, comparison with 21‐day old ACD did not show a significant difference in the mean survival, although the range observed was much wider. The results also point out the need for greater number of observations with increasing duration of storage for adequate appraisal of blood preservative solutions. 1969 AABB