Serial assessment of biochemical parameters of red cell preparations to evaluate safety for neonatal transfusions.

Background & Objectives: Neonatologists often prefer fresh blood (<7 days) for neonatal transfusions. The main concerns for stored RBCs are ex vivo storage lesions that undermine red cell functions and may affect metabolic status of neonatal recipients. This study was designed to evaluate serial in vitro changes of biochemical parameters in different RBC preparations during storage to consider for neonatal transfusions even after storage beyond one week. Methods: Twenty five units each of whole blood (CPDA-1 RBC, SAGM RBC) were selected for serial biochemical parameter assessment after each fulfilled the quality criteria (volume and haematocrit). These units were tested serially for supernatant potassium, pH, lactate, haemoglobin, glucose and red cell 2,3 diphosphoglycerate (2,3 DPG) up to 21 days of storage. Results: Within each group of RBC, rise in mean concentration of potassium, lactate and plasma haemoglobin from day 1 to 21 of storage was significant in CPDA-1 RBC having the highest levels at day 21. From day 3 to 21, SAGM RBC had higher mean pH value than CPDA-1 RBC though this difference was not statistically significant. SAGM RBC had highest mean glucose concentration during storage than other two types of red cell preparations (P<0.005). Within each group, fall in mean 2,3 DPG concentration from day 1 to 7 was significant (P<0.05). A positive correlation existed between mean plasma potassium and haemoglobin in all three types of red cells (r=0.726, 0.419, 0.605 for CPDA-1 RBC, SAGM RBC and whole blood respectively, P<0.005). Interpretation & Conclusions: All the three red cell preparations tested revealed biochemical changes within acceptable limits of safety till 21 days of storage. CPDA-1 RBCs had the highest degree of these changes.

Spectrin interactions with globin chains in the presence of phosphate metabolites and hydrogen peroxide: implications for thalassaemia.

We have shown the differential interactions of the erythroid skeletal protein spectrin with the globin subunits of adult haemoglobin (HbA); these indicate a preference for alpha-globin over that for beta-globin and intact HbA in an adenosine 5'-triphosphate (ATP)-dependent manner. The presence of Mg/ATP led to an appreciable decrease in the binding affinity of the alpha-globin chain to spectrin and the overall yield of globin-spectrin cross-linked complexes formed in the presence of hydrogen peroxide. Similar effects were also seen in the presence of 2-,3-diphosphoglycerate (2,3 DPG), the other important phosphate metabolite of erythrocytes. The binding affinity and yield of cross-linked high molecular weight complexes (HMWCs) formed under oxidative conditions were significantly higher in alpha-globin compared with intact haemoglobin, HbA and the beta-globin chain. The results of this study indicate a possible correlation of the preferential spectrin binding of the alpha-globin chain over that of the beta-globin in the haemoglobin disorder beta-thalassaemia.

Effects of massive transfusion on oxygen availability

Objectives: To determine oxygen derived parameters, hemodynamic and biochemical laboratory data (2,3 Diphosphoglycerate, lactate and blood gases analysis) in patients after cardiac surgery who received massive blood replacement. Design: Prospective study. Setting: Heart Institute (Instituto do Coraçao), Hospital das Clínicas, Faculdade de Medicina, Universidade de Sao Paulo, Brazil. Participants: Twelve patients after cardiac surgery who received massive transfusion replacement; six of them evolved to a fatal outcome within the three-day postoperative follow-up. Measurements and Main Results: The non-survivors group (n=6) presented high lactate levels and low P(50) levels, when compared to the survivors group (p<0.05). Both groups presented an increase in oxygen consumption and O2 extraction, and there were no significant differences between them regarding these parameters. The 2,3 DPG levels were slightly reduced in both groups. Conclusions: This study shows that patients who are massively transfused following cardiovascular surgery present cell oxygenation disturbances probably as a result of O2 transport inadequacy.