POSTOPERATIVE ERYTHROPOIESIS IS LIMITED BY THE INFLAMMATORY EFFECT OFSURGERY ON IRON-METABOLISM

The decrease in haemoglobin concentration commonly observed after majo r surgery is usually corrected by red cell transfusions or oral iron m edication. The increased awareness of blood-transmissible diseases has led to the restrictive use of homologous blood and to interest in alt ernatives for correcting anaemia. We investigated the pathophysiology of postoperative anaemia by studying variables of erythropoiesis, iron metabolism, and inflammation in 48 consecutive patients who underwent total hip replacement. Haemoglobin concentration remained low during 14 days after surgery with only a mild increase in erythropoietin conc entration and reticulocyte count. No increase in serum transferrin rec eptor concentration was observed during the first 2 weeks after surger y. Postoperative serum ferritin increased, whereas serum iron, transfe rrin and transferrin saturation decreased significantly. There was mar ked increase in interleukin-6 and C-reactive protein with maximal valu es on the 1st and 4th postoperative day, respectively. At 6 weeks afte r surgery, haemoglobin concentration and variables of iron metabolism were almost at the preoperative level and serum transferrin receptor c oncentration was significantly increased, indicating increased erythro poietic activity. These changes were preceded by the normalization of interleukin-6 and C-reactive protein levels. Haemoglobin, iron, transf errin, and ferritin concentrations were not influenced by iron therapy during the postoperative period and no differences of erythropoietic and iron variables were observed between transfused and non-transfused patients. In conclusion, post-operative erythropoiesis is associated with an inflammatory effect of surgery on iron metabolism, which can e xplain, despite a slightly increased production of erythropoietin, the persistence of anaemia and the lack of effect of iron supplementation after surgery.