Potassium-adsorption filter for RBC transfusion: a Phase III clinical trial

BACKGROUND: Within the past 2 years, three cases of cardiac arrest just aft er rapid transfusion of RBCs preserved for over 7 days after 15-Gy irradiat ion were found. This severe complication caused transient hyperkalemia. To prevent potassium (K+) overload by RBC transfusion at the bedside, a K+-ads orption filter made of sodium polystyrene sulfonate was developed. STUDY DESIGN AND METHODS: After in vitro and animal safety and efficacy tes ts, a Phase III clinical trial was conducted with 65 patients given transfu sions via the newly developed filter (filter group) and 37 patients in whom the filter was not used (control group) and transfusions were given at twi ce the usual flow rate (20 mL/min). RESULTS: More than 85-percent (94.4 +/- 3.8%) removal of K+ in RBCs in mann itol-adenine-phosphate (MAP) that had been preserved for more than 14 days or that were used 3 days after 15-Gy irradiation (calculated K+: 3.8 +/- 1. 3 mEq/bag) was achieved in 82 of 83 bags of MAP RBCs in the filter group, w ith 79.6 percent removed in the other, even in rapid transfusions. RBC reco very 1 day after transfusion, determined by increments in RBCs, Hb, and Hct , were 24 and 0.4 x 10(4) per muL, 0.7 and 0.3 g per dL, and 1.6 and 0 perc ent, respectively, in the filter and control groups. No adverse transfusion reactions, such as hypotension, anaphylactoid reactions, or asthma-like at tacks, were observed, except for one case of urticaria in the filter group. Mild fever (within 1 degreesC) after transfusion was observed in both grou ps. Serologic markers of hemolysis rose slightly in both groups, but there was no significant difference between the two groups. CONCLUSION: The newly developed K+-adsorption filter is useful, especially in a rapid transfusion setting.