Effect of rate and delay of cooling during initial cooling process: in vitro effect on red cells.

ABSTRACT

BACKGROUND: Whole blood is stored at room temperature (RT) until processing into components. After separation and filtration, the RCC has to be cooled from RT to +2 - 6°C. Different start times of the cooling process and different cooling rates can be encountered in daily routine. The effect of these parameters of the initial cooling of leucoreduced red cell concentrates (LR-RCC) on in vitro quality is not known. METHODS: In paired experiments (n=12), LR-RCCs in SAGM were cooled immediately after preparation from RT to +2 to +6°C either 'fast' (within 2½ h) or 'slow' (within 10-24 h) or 'slow' after a holding period of 6, 12, 18 or 24 h. Units were then stored at +2-6°C for 42 days and sampled at regular intervals for in vitro analysis. RESULTS: Irrespective of the start time and cooling rate during the initial cooling process, all units maintained good in vitro quality up to Day 42 with haemolysis <0·8%. Adenosine triphosphate (ATP) levels remained >2·7 µmol/g Hb in 99% of all units up to Day 35. Differences in pH, ATP content and 2,3-DPG content between the groups were largest at Day 2 or 3 but generally disappeared during storage. CONCLUSION: Start time and cooling rate of the initial cooling process had minor effects on in vitro quality of red cells. LR-RCCs can be stored up to 24 h before cooling down to +2-6°C without deleterious effects on in vitro parameters during 42-day storage.