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

Traditional and emerging technologies for washing and volume reducing blood products

Millions of blood components including red blood cells, platelets, and granulocytes are transfused each year in the United States. The transfusion of these blood products may be associated with adverse clinical outcomes in some patients due to residual proteins and other contaminants that accumulate in blood units during processing and storage. Blood products are, therefore, often washed in normal saline or other media to remove the contaminants and improve the quality of blood cells before transfusion. While there are numerous methods for washing and volume reducing blood components, a vast majority utilize centrifugation-based processing, such as manual centrifugation, open and closed cell processing systems, and cell salvage/autotransfusion devices. Although these technologies are widely employed with a relatively low risk to the average patient, there is evidence that centrifugation-based processing may be inadequate when transfusing to immunocompromised patients, neonatal and infant patients, or patients susceptible to transfusion-related allergic reactions. Cell separation and volume reduction techniques that employ centrifugation have been shown to damage blood cells, contributing to these adverse outcomes. The limitations and disadvantages of centrifugation-based processing have spurred the development of novel centrifugation-free methods for washing and volume reducing blood components, thereby causing significantly less damage to the cells. Some of these emerging technologies are already transforming niche applications, poised to enter mainstream blood cell processing in the not too distant future.

Use of potassium adsorption filter for the removal of ammonia and potassium from red blood cell solution for neonates

BACKGROUND

Ammonia in the plasma usually does not pass through the blood-brain barrier (BBB). However, it can affect the brain as a neurotoxin in neonates with anemia of prematurity. Excess intake of ammonia should therefore be restricted in conditions involving BBB breakdown, such as in premature neonates. A potassium adsorption filter (PAF) can remove not only potassium, but also ammonia from red blood cell (RBC) solution. PAF for neonates (PAF-n) has been recently introduced using small satellite packs. We evaluated the effects of PAF-n on the removal of ammonia and potassium from RBC solution in small satellite packs.

STUDY DESIGN AND METHODS

RBC solutions were obtained from the Japanese Red Cross Society. Two units of RBC solution (280 mL) were divided into four satellite packs (70 mL/pack). The RBC solution was passed through PAF-n (Kawasumi Laboratories Inc.) that was primed with saline (100 mL) before use. The concentrations of ammonia and potassium were measured in the solution before and after filtration (four samples of 10 mL each of filtered RBC solution) by Biomedical Laboratories.

RESULTS

Approximately 47 to 82 and 84% to 93% of ammonia and potassium were removed from the RBC solution, respectively, without dilution with saline.

CONCLUSION

PAF-n can remove ammonia and potassium from RBC solution in small satellite packs. PAF-n could therefore improve the clinical prognosis of neonates with poorly developed BBB by limiting the delivery of excess ammonia found in the RBC solution.

Effects of potassium adsorption filters on the removal of ammonia from blood products

BACKGROUND

Although ammonia in plasma does not usually pass through the blood-brain barrier (BBB), in cases of traumatic brain injury it may do so, acting as a neurotoxin on the brain. Excess intake of ammonia should be restricted in conditions involving BBB breakdown, such as traumatic brain injury. Washing is a method to remove ammonia from blood products, but fresh-frozen plasma and albumin products cannot be washed. A potassium adsorption filter (PAF) can remove not only potassium, but also ammonia from red blood cell solutions. We, therefore, examined the effects of a PAF on the removal of ammonia from a range of blood products.

MATERIALS AND METHODS

Ammonia concentrations were measured in expired red blood cell solutions, fresh-frozen plasma, and platelet concentrates and purchased albumin products before and after filtration through a PAF. The PAF was primed with saline, which was removed before the filter was used.

RESULTS

The percentages of ammonia removal from the red blood cell solutions, fresh-frozen plasma, plasma concentrates, 20% albumin and 5% albumin were approximately 76-87%, 21-31%, 53%, 77-92% and 49-63%, respectively.

DISCUSSION

A PAF appears capable of removing ammonia from a range of blood products, although the reason for the lesser effect on the ammonia concentration in fresh-frozen plasma compared to other blood products remains unknown. We hypothesise that, by lowering ammonia levels in blood products, the PAF could improve the clinical prognosis of neonates with an underdeveloped BBB or patients with BBB breakdown following traumatic brain injury.

Transfusion of irradiated red blood cell units with a potassium adsorption filter: A randomized controlled trial

BACKGROUND

The irradiation of red blood cells (RBCs) causes damage of the RBC membrane with increased potassium (K) leak during storage compared with nonirradiated RBC units of similar age. A previous in vitro study showed a mean reduction of K of 94 ± 5% with a potassium adsorption filter (PAF).

STUDY DESIGN AND METHODS

A prospective, single-center, nonblinded, randomized controlled trial (RCT) was designed to evaluate the safety and efficacy of transfusing irradiated RBC units with the PAF. Patients 18 years of age or older who received irradiated RBC units due to chemotherapy-induced anemia were randomly assigned to receive irradiated RBC units with the PAF (PAF group) or with the standard blood infusion set (control group). Primary outcome measures were safety and efficacy of the PAF (absolute change in hemoglobin [Hb] and K, respectively, in patient's blood values after transfusing the irradiated RBC units with or without the PAF).

RESULTS

A total of 63 irradiated RBC units were transfused to 17 patients in the control group, and a total of 56 irradiated RBC units were transfused to 13 patients in the PAF group. The absolute change of Hb (9.3 ± 6.3 g/L vs. 8.1 ± 5.8 g/L; p = 0.3) and the absolute change of K (-0.01 ± 0.4 mmol/L vs. -0.01 ± 0.3 mmol/L; p = 0.2) were comparable between the two groups of the trial.

CONCLUSION

The transfusion of 1 irradiated RBC unit with the PAF was as safe and efficacious as the transfusion of 1 irradiated RBC unit with the standard blood infusion set in patients with chemotherapy-induced anemia.