RESUMO
PURPOSE: The widespread use of aggressive surgical procedures, along with the increasing incidence of traffic accidents, has raised the necessity of homologous blood beyond the supplies of blood banks. This fact, plus the risks of homologous transfusion and the costs of blood bank maintenance, has prompted the advance of blood saving procedures such as autotransfusion, both in the pre-deposit (preoperative autotransfusion, POA) and the surgical drainage reinfusion (postoperative autotransfusion, SDR) modalities. As there is some controversy about the use of one or the other of the above procedures, the purposes of this study were: 1) to analyse the haematological and biochemical characteristics of blood, both pre-donated and stored at 4 degrees C for 4 weeks, and that recovered from surgical drains, from patients subjected to programmed orthopaedic or heart surgery; 2) to assess the metabolic and functional state of red cells attained from that blood, and 3) to compare the results achieved. MATERIAL AND METHODS: The following data were examined: red cell count, haematocrit, haemoglobin, red cell indicates, white cell count, platelet count, free plasma haemoglobin, red cell morphology, glucose, cholesterol, triglycerides, phospholipids, serum proteins and their fractions, ions, histamine, red cell glucose and amino acid transport, and ATP and 2,3-DPG content. RESULTS: The red cells, haemoglobin and haematocrit concentrations in POA blood did not show significant variations during the storage for 4 weeks and their values were significantly higher than found in drained blood. The biochemical values showed heterogeneous variations. Glucose and amino acid uptake by red cells of POA blood slightly decreased in the first 2 weeks of storage but always less than measured in SDR red cells. In POA blood it was noticed a progressive decrease in intra-erythrocytic ATP and 2,3 DPG, those levels being normal in SDR. DISCUSSION: In spite of lower haematocrit and haemoglobin but higher free plasma haemoglobin content, drained blood had higher ATP and 2,3-DPG concentration than pre-deposit, stored blood. Drained blood showed also less ion alterations and probably a lesser immunosuppressor capability. Thus, postoperative blood recovery seems a good source of red cell, with high oxygen transport power, and so, alone or in combination with pre-donated blood, it may contribute to reduce the necessities for homologous blood and decrease its risks.