Ryoichi Motoki

Iron and erythropoietin measurement in autologous blood donors with anemia: implications for management

Background: The importance of autologous blood donation for elective surgery is recognized, and the method is being used at many hospitals. Not all patients are able to deposit a sufficient amount of blood before surgery because they cannot recover rapidly enough from phlebotomy‐induced anemia. The ability to donate sufficient blood for autologous use was studied in patients who are particularly susceptible to phlebotomy‐induced anemia.

Pharmacological approaches to reduce perioperative transfusion requirements in the aged.

SummaryAlthough iron deficiency is undoubtedly the commonest cause of anaemia even in elderly people, the aetiology is not always clear owing to various underlying diseases. Correction of anaemia is sometimes needed before surgery. The use of drugs that may influence blood coagulation, such as aspirin (acetylsalicylic acid), should be checked. Perioperative allogenic blood transfusion can often be avoided by the use of autologous blood and improved surgical techniques. Autologous blood donations are preferable in cases of planned surgery. Epoetin (recombinant human erythropoietin) in combination with iron supplementation facilitates the donation of autologous blood, even in elderly patients.Another method of avoiding allogenic blood transfusion is the collection and reuse of the blood a patient sheds in operations. During and/or after surgery, many haemostatic agents are available. Moreover, recent developments in gene engineering have enabled the utilisation of recombinant cytokines and coagulation factors. Further work remains to be done to define the proper use of these agents.

Effect of recombinant human erythropoietin on endogenous erythropoietin production in rats.

To clarify the influence of recombinant human erythropoietin (r-HuEPO) on endogenous erythropoietin production, experiments using rats were designed as follows.Firstly, to evaluate the effect of acute blood loss on endogenous erythropoietin production, five rats (Wistar; mean body weight 280g) were bled of 1.3% of body weight (g) by cardiac puncture under pentobarbital sodium (30mg/kg, ip) anesthesia, followed by periodic blood examinations, including serum erythropoietin (s-EPO) levels, hemoglobin and reticulocyte counts. Secondly, 12 rats were divided into two groups of six rats each, control and r-HuEPO-treated groups. Rats received no r-HuEPO or 200U/kg of r-HuEPO subcutaneously once a week after the first blood sampling. All rats were given iron sulphate. Blood (0.6% of body weight) was drawn from each rat at three weekly intervals. At the fourth donation, blood volume of 1.5% of body weight was drawn. The results were as follows: 1) serum erythropoietin significantly increased at 3h after phlebotomy. s-EPO level peaked at 24h after phlebotomy, then returned to normal within 7 days; 2) mean hemoglobin level in the r-HuEPO-treated group decreased gradually during the 3 weeks of blood donation; 3) after the fourth donation, the peak in s-EPO level in control group occurred on day one, whereas in half of the rats in the r-HuEPO-treated group it occurred on day 7. On the basis of our data, however, no significant difference was found in recovery from phlebotomy-induced anemia between the two groups. In conclusion, r-HuEPO seems useful for the speed correction of anemia associated with successive phlebotomy. However, our data suggest that the administration of r-HuEPO suppres endogenous erythropoietin production after acute massive bleeding. Further study remains to be done to ascertain the clinical implications of these findings.

Allogeneic red blood cell transfusion-associated thrombocytopenia Anti-HLA antibodies in recipients.

It is known that circulating immune complexes bind to platelets via the Fc-receptor and/or C3 receptor to result in platelet destruction in the mononuclear phagocyte system. We postulated that transfusion-associated thrombocytopenia is transiently caused by the bystander involvement of autologous platelets during the alloimmune destruction of allogeneic leukocytes and/or platelets in patients with anti-HLA antibodies when allogeneic blood is transfused.To clarify whether allogeneic red blood cells cause postoperative thrombocytopenia, we assessed the residual rate (%PLT) in platelet count at 1 day after surgery by estimating hemorrhage volume and the number of blood transfusion units among recipients. Of 71 patients studied, 34 received allogeneic and 37 received autologous blood transfusions. Mean %PLT in the allogeneic transfusion group was significantly lower than that in autologous transfusion group (65.1% vs 75.1%, p<0.01). In particular, %PLT after allogeneic transfusion in three recipients with broadly reactive anti-HLA antibodies was considerably low at 28%, 38% and 58% respectively.These results reveal that allogeneic transfusion sometimes causes transfusion-associated thrombocytopenia in recipients with anti-HLA antibodies. Moreover, it is suggested that anti-HLA antibody screening is necessary before allogeneic blood transfusion for recipients with a history of either blood transfusion or pregnancy.