Beitrage zur Infusionstherapie = Contributions to infusion therapy最新文献

The routine use of platelet concentrates has greatly increased during the last years. Most of the concentrates are transfused to hematologic patients, who frequently receive additional red blood cells. These polytransfusion regimens often result in the formation of HLA- or platelet-specific antibodies, which lead to refractoriness to further platelet support. In order to avoid this problem, the number of HLA antigens transmitted should be reduced. Therefore, a consequent leukocyte depletion of all blood products administered to multitransfused patients seems to be necessary. If antibodies are already preformed in the patient's serum, compatible platelets have to be selected for transfusion.

Four plasmapheresis procedures (manual blood bag centrifugation plasmapheresis, and the three plasmapheresis machines P.C.S./Haemonetics, Autopheresis-C/Baxter-Travenol, Plasmapur Monitor/Organon Teknika) were studied comparatively. The three machine procedures could be performed more easily and more rapidly and were well accepted by donors, autologous donors (patients) and staff. Compared with the traditional, well established manual procedure, a possible impairment of the plasma donors seems reduced rather than raised. Activation of the hemostatic system of the donors, measured with very sensitive methods, was found to be less pronounced when plasmapheresis was performed with the machines than when it was performed conventionally. The plasma product obtained by machine plasmapheresis was found to be of higher quality. All three systems showed less activation of the clotting system. Especially the plasma obtained by the P.C.S. showed a higher clotting factor yield. Plasma obtained by the Autopheresis-C and by the Plasmapur Monitor (both systems are equipped with filters) was markedly less contaminated with cells. The recently found low activation of the clotting system of plasma recipients, however, showed no differences when plasma obtained conventionally or by the Plasmapur Monitor was used. In summary, the new machine plasmapheresis devices offer a good alternative to the conventional blood bag centrifugation method and set new standards for the production of high quality plasma.

Transfusion of blood and blood components may be fraught with serious immunologically mediated side effects. Acute hemolytic reactions are still the most common cause of fatal transfusion sequelae. The incidence of alloimmunization against erythrocyte antigens as studied in long-term transfused patients with thalassemia depends on the age at the beginning of transfusion therapy. HLA alloimmunization is often associated with refractoriness to platelet transfusions and febrile transfusion reactions. Neonatal alloimmune thrombocytopenia and post-transfusion purpura are elicited by platelet-specific antibodies reacting with determinants on platelet glycoproteins IIb/IIIa, Ib/IX, and Ia/IIa. Another serious complication of transfusion therapy, transfusion-related acute lung injury, is caused by granulocyte-specific alloantigens in donor plasma. Graft-versus-host disease is a rare but dangerous complication of blood transfusion which mainly affects patients with impaired T-cell-related immunity.

Peripheral blood stem cells are an alternative to bone marrow-harvested stem cells. We report on the feasibility of predicting optimal timing for leukapheresis by means of blood monitoring for CD34-positive cells by flow cytometry. In addition to monitoring, determinations of CD34-positive cells also are predictive for the hemopoietic potency of cells harvested by leukapheresis, as close correlations of numbers of CFU-GM and of CD34-positive cells, respectively, in leukapheresis samples are determined. Our data are indicating that flow-cytometrical determinations of CD34-positive cells are helpful in the setting of blood stem cell harvesting by leukapheresis, both for optimal timing of the procedure and for real-time estimation of the hemopoietic potency of cells harvested.

In a multicenter study on HIV prevalence the German Red Cross Blood Banks provide information on the safety of blood products and the epidemiology of HIV infections in blood donors in the FRG. Although statistically not yet significant, there are trends to an increasing number of HIV infections especially in young male blood donors. Beside an increasing number of heterosexually transmitted infections, in recent years more donors found to be infected admitted homosexual contacts. Obviously, the awareness of HIV risks is poor. The data suggest that there may be a spread of HIV infections in the general population. As the risk of HIV infection can no longer be regarded to be limited to the known risk groups, an increasing effort to educate people on HIV risks is necessary not only in blood donors but even more in the general population. The epidemiologic trends result from parts of the donor population. Aware of these trends, donor selection has been intensified by the blood banks and resulted in changes to more donations from low-prevalence populations. Therefore, the residual risk of an HIV infection by blood products can still be considered as 1:300,000 to 1:3 million in the FRG.

The gel centrifugation test (ID Microtyping System)--a new method for antibody screening--was compared with solid phase systems (Solidscreen, Capture R, Ready ID) and the conventional tube test. 141 different antibodies were tested and the results were compared. The ID Microtyping System identified 138 (98%) of all antibodies, the tube test 110 (78%), Capture R 86 (61%), Ready ID 79 (56%) and Solidscreen 75 (53%). The results in identification of all antibodies except cold agglutinins (n = 107) were: in the ID Microtyping System 98% (105), tube test 76% (82), Capture R 70% (75), Ready ID 68% (73) and Solidscreen 61% (65).

The hazards of homologous blood transfusions have been controlled but not eliminated by modern blood banking methods. In addition to the possibility of transmission of infectious diseases, blood transfusion has been reported to induce immunosuppression and thereby impair the host resistance of surgical patients. Experimental and clinical research, particularly in cardiac surgery, have encouraged physicians to accept postoperative anemia. The influence of hemodilution on oxygen supply to the tissues was found to be an increase of local oxygen tension. When hematocrit is progressively lowered under normovolemic conditions, blood cell flux per time and tissue unit is maintained at a hematocrit level as low as 20 vol% as a result of an increase of red blood cell velocity. An increasing number of cardiac operations have been performed upon patients belonging to Jehova's witnesses, inducing an average hematocrit of 11 vol% during extracorporeal circulation. The outcome of these patients was similar to that of patients having received blood transfusion in order to elevate oxygen supply. Some recent studies in critically ill patients demonstrate the importance of oxygen consumption as an important criterion in estimating the effect of oxygen transport. It seems to be proven that, in presence of cardiovascular stability, elevation of the hemoglobin level above 9 g/dl does not result in an increase of oxygen utilization. In accordance with the topical literature we suggest that during the perioperative period a hemoglobin level of 8.5 g/dl will become an accepted transfusion trigger. Particular patients will tolerate even much lower levels.