Evaluation of a potassium removal filter on irradiated red cells stored in SAGM

Irradiation of red cell concentrates RCCs) can lead to well-documented elevated extracellular potassium concentrations. Transfusion of these products has the potential, if given as a massive/rapid transfusion, to lead to transient hyperkalemia. A potassium absorption filter (PAF) has recently been developed and has been proven to effectively remove excess K(+) . However, data are lacking on the red cell quality parameters over storage after irradiation.

Thirty RCCs were pooled and split into 3 groups of 10. All RCCs were irradiated on day 14 and filtered on day 28 (group 1 control), day 15 (group 2) or day 17 (group 3). Pre-irradiation, pre- and post-filtration and day 28 samples were taken for each study. Standard red cell quality parameters were measured over storage at the above time points.

Losses for haemoglobin, haematocrit and volume were minimal after filtration with all units containing >40 g Hgb unit(-1). Statistically, significant differences were observed for K(+) and Na(+) levels in groups filtered at either 24 or 72 h post-irradiation, and this was observed directly after filtration and remained by day 28. Filtration had no significant impact on any other parameters measured.

PAF effectively removed supernatant potassium (93%) from all RCC units. Early removal of K(+) at either day 15 or 17 on RCCs subsequently stored to day 28 had no measurable effect on red cell quality, suggesting this may be a useful device to ensure further safety for at-risk immunocompromised patient groups requiring irradiated RCCs.