Understanding the effects of gamma-irradiation on potassium levels in red cell concentrates stored in SAG-M for neonatal red cell transfusion.

BACKGROUND AND OBJECTIVES: Red cell transfusions, to paediatric patients, are often gamma-irradiated to prevent transfusion-associated graft-versus-host disease. This study measured changes in potassium and other in vitro parameters immediately following gamma-irradiation of paediatric and full-size red cell concentrates (RCCs). MATERIALS AND METHODS: The effects of irradiation on potassium release in RCCs stored in SAG-M were investigated under three scenarios. In the first scenario, RCC < 5 days was split into paediatric packs, gamma-irradiated and tested for potassium and haemolysis at 0, 2, 4, 6, 24 and 48 h. In the second scenario, full-size RCCs < 5 days postcollection were gamma-irradiated and tested as for the paediatric packs. Thirdly, RCCs < 14 days postcollection were gamma-irradiated and assessed at 6 and 24 h and 7 and 14 days. Each group contained paired controls that were not gamma-irradiated. RESULTS: In all situations, gamma-irradiation resulted in a twofold increase in potassium concentrations after 24 h of storage, compared to matched unirradiated controls. This difference was detectable as early as 2 h postirradiation. Few differences were observed between control and irradiated RCCs in other key parameters, including ATP, 2,3-DPG, haemoglobin, pH, glucose and lactate concentration. CONCLUSION: Gamma-irradiation of RCCs significantly increased extracellular potassium. Irradiation of fresher RCCs results in lower potassium concentrations, which is less likely to lead to hyperkalaemia upon transfusion.

Investigating transfusion-related acute lung injury (TRALI).

AIM: Transfusion-related acute lung injury (TRALI) can be a life-threatening transfusion complication and should be considered whenever respiratory distress occurs during a transfusion. Management of donors implicated in TRALI is a n important haemovigilance responsibility for blood services. To enable this, it is imperative to develop an effective strategy for investigating TRALI. The present paper describes an effective approach. METHODS: Cases of suspected TRALI we re referred to the Platelet and Granulocyte Immunobiology Laboratory at the Australian Red Cross Blood Service-Queensland; a reference neutrophil testing service. Recipient and donor samples were tested for the presence of leucocyte antibodies. Where possible, compatibility testing was performed between donor and recipient samples. RESULTS: From March 1999 to June 2001 , leucocyte antibodies directed against neutrophil-specific or human leucocyte antigens (HIA) were detected in at least one donor in seven of the nine cases investigated. Incompatibility with patient antigens (HNA-2a, non-specific HLA and HLA B5, B16, B35) was confirmed by cross matching in three cases. CONCLUSION: TRALI is a serious non-infectious hazard of transfusion that must be reported and investigated promptly. Prompt investigations allow appropriate management of implicated donations and donors so as to minimize the incidence of TRALI. Therefore, the role of clinicians in reporting such cases and the hospital blood banks in collecting appropriate samples is critical. We suggest that hospital blood banks retain transfused donation units for at least 24 h after transfusion to expedite TRALI investigations. Due to the specialized nature of investigation, it is necessary to direct such investigations to specialist reference neutrophil testing services. In cases where the recipient has the leucocyte antibody, the use of white cell filters in future transfusions should be beneficial, because there is little evidence to substantiate the use of phenotyped blood products.