Perspectives of paid whole and plasma donation.

Although payment of blood donors is rejected by the WHO, the FDA, the EU, and the Red Cross (RC), in Germany, monetary compensation of expenses is permitted not only for plasmapheresis but also for whole blood donation. The structure and organisation of the institutions ensuring the blood supply in Germany and the pertaining aspects of blood safety will be discussed. Data reported to the health authorities show that the frequency of transfusion-transmitted infection markers in the German donor population is low and that only very few infections have been transmitted through blood. This is underlined by a detailed analysis of the paid donor population of a small university blood service (UBS). The analysis documents a very stable and reliable cohort of predominantly repeat donors. Unpaid RC donors of blood units transfused to patients at the university hospital of Marburg showed a sixteen-times higher sero-conversion rate than those of the UBS (p < 0.0001). However, in a survey, 77% of the paid donors denied continuation of blood donation in the event of payment being stopped. Therefore non-remuneration would result in acute blood supply shortages. Since increased blood shortages are to be expected anyway in the near future, all measures improving the supply of safe blood, including monetary compensation, should be objectively discussed without prejudice.

Influence of ABO blood groups on primary hemostasis.

BACKGROUND: Recently, the in vitro bleeding time test (IVBT) was proved to be a very sensitive screening method for the detection of vWD, showing rather good correlation between the closure time and the level of vWF. The vWF levels have been found to be significantly lower in healthy humans who are group O than in those who belong to the other ABO blood groups (non-group O). The aim of this study was to detect whether these differences in vWF levels in normal persons correspond to differences in nonvascular primary hemostasis when investigated by the IVBT. MATERIAL AND METHODS: Healthy blood donors (n = 162) without evidence of hemostatic disorders, without ingestion of drugs for at least 2 weeks, and with normal in vivo bleeding time endpoints, normal factor VIII clotting activity levels, normal structure of vWF multimers, and normal ristocetin-induced platelet aggregation were examined by IVBT. IVBT was performed with two automated systems (Thrombostat 4000, VDG [TST]; and a platelet function analyzer (PFA-100, Dade Behring [PFA]). CaCl2 and ADP were used as aggregants for the two TST tests (TST-CaCl2 and TST-ADP), and ADP- or epinephrine (Epi)-coated membranes were used with the two PFA tests (PFA-ADP and PFA-Epi). RESULTS: Closure time in the IVBT significantly correlated with the blood groups, but in reverse order (as did blood volume; data not shown): TST-ADP (mean +/- SD): group O, 89 +/- 14.6 seconds versus non-group O, 82 +/- 13 seconds (p<0.01); TST-CaCl(2): group O, 154 +/- 28.9 seconds versus non-group O, 140 +/- 31.3 seconds (p<0.01); PFA-ADP: group O, 91 +/- 13.4 seconds versus non-group O, 86 +/- 11.9 seconds (p<0.05); PFA-Epi: group O, 112 +/- 15.4 seconds versus non-group O, 104 +/- 16.7 seconds (p<0.05). Donors with vWF < or =77.5 % had longer closure time than those with vWF >77.5 % (p<0.05). CONCLUSION: Significant ABO-group-specific differences in nonvascular primary hemostasis could be found by IVBT. The differences are small, however, and lie within the normal range. Whether these differences have any biologic relevance can only be speculated.

Measurement of primary haemostasis using a pressure clamp technique.

UNLABELLED: With the PFA-100 a sensitive and specific screening test for primary haemostasis has recently become available. An important part of the device is a capillary, providing a defined haemodynamic resistance for the perfusion of the aperture. A modified method to measure platelet function (VCP2) is presented in which the capillary essentially is replaced with an 'electronic capillary' by clamping the pressure/flow relationship. RESULTS AND CONCLUSION: Closure time (CT) and blood volume (BV) as determined by PFA-100 and VCP2 correlated well within (r = 0.922 - 0.952) and between the two methods (r = 0.86). The test variability (CV) of CT could be significantly reduced in the VCP2 method (collagen/epi 3.9 vs. 5.9%, p<0.05; collagen/ADP 3.3 vs. 6.9%, p<0.001), thus considerably increasing test reliability and reducing test variance. In preliminary clinical studies the VCP2 system showed comparable sensitivity for vWD and slightly less sensitivity regarding ASA ingestion. The test spectrum of VCP2 could be extended to more thrombocytopenic samples (< or =20 000/microl) even in combination with low haematocrit levels (20%), thus perhaps permitting the determination of the bleeding risk in bone marrow hypoplasia. Additionally, the sensitivity and applicability can easily be adapted to the desired need only by software modifications.

[Prevention and therapy of hemostatic disorders in massive transfusion]. / Prophylaxe und Therapie von Hämostasestörungen bei Massivtransfusion.

Adequate periop. analysis of hemostasis taking into account also disorders of primary hemostasis considerably contributes to prevention, early detection and appropriate treatment of hemostatic disturbances. Standard transfusion protocols are advisable in massive transfusion with respect to logistic problems. We describe an effective standard protocol based on the initial administration of blood components (red cells, plasma, platelets) in a certain fixed ratio which then is adapted according to the laboratory test results and the clinical situation of the patient. In addition, as soon as the hemostasis shows critical values, coagulation factor concentrates (prothrombin complex, fibrinogen, seldom single coagulation factors) are administered. Furthermore, desmopressin and antifibrinolytics can be successfully used in disorders of primary hemostasis, and additionally antifibrinolytics in hyperfibrinolysis or unclear diffuse bleeding.

[Need for transfusions in orthognathic surgery. No general indication for preoperative autologous blood donation]. / Transfusionsbedarf bei Dysgnathieoperationen. Keine generelle Indikation für die präoperative Eigenblutspende.

The use of deposited autologous blood instead of allogenic blood is recommended in cases of elective maxillofacial operations if the blood transfusion probability is more than 10%. As an alternative, the controlled intraoperative normovolemic hemodilution and the preoperative use of EPO (Erytropoetin) should be considered. In a retrospective study, we analyzed 438 patients who underwent orthognathic surgery. The perioperative blood loss was determined in order to calculate the transfusion probability in case of the acceptance of 7.5 g/dl hemoglobin as the critical value in patients without cardiac failures. Only four patients undergoing Le Fort I osteotomy (1.55%) or bimaxillary osteotomy (3.03%) had to be transfused. Therefore, the statistical transfusion need was clearly below 10%. Due to this, there was no general need for autologous blood donation. However, in individual cases with low hemoglobin and/or low blood volume, a transfusion need can be predicted. In those few cases, autologous blood donation may be indicated. However, in case of a more conservative indication to transfusion (hemoglobin 10 g/dl), more than 10% of the patients with bimaxillary osteotomies would have been transfused. Autologous blood donation is then indicated according to the German regulations for transfusion. If low hemoglobin values are accepted, the exact individual blood demand should be calculated, a blood saving operation technique should be used, adequate postoperative warding is necessary, and compatible allogenic red cell concentrates should be quickly available.

The Thrombostat 4000. A sensitive screening test for von Willebrand's disease.

The determination of the bleeding time (BT) is an essential diagnostic tool for von Willebrand's disease (vWD). However, the standardized Simplate BT still displays many variables and disadvantages. The present study reports on the sensitivity of the in vitro bleeding test (IVBT) in 51 vWD cases of different types and severity in comparison to the Simplate BT, and the correlation of both to each other as well as to von Willebrand factor (vWF:RCo) activity. The IVBT was performed in two modifications (2 mmol/L CaCl2 and 4 mmol/L ADP) on the Thrombostat 4000. The IVBT, particularly with CaCl2, showed clearly higher sensitivity than the BT (CaCl2: 84.3%, ADP: 61.7%, CaCl2 + ADP: 86.3, BT: 52.9%). The BT even failed in one patient with severe (type 2B) and in three with moderate vWD. The IVBT only failed in very mild forms of the disease (vW-F:RCo > 25%). In addition, the IVBT with ADP showed a close correlation to the vWF:RCo activity (r2 = 0.73). The significantly lower correlation of the BT with vWF:RCo (r2 = 0.49) was particularly due to the poor results in vWD of type 2 (type 2:r2 = 0.29; types 1 and 3:r2 = 0.61). Finally, BT and IVBT-ADP correlated with each other (r2 = 0.53), a rather good correlation considering that both are complex functional tests. It can be concluded from our study that the IVBT not only may replace the BT for most applications, but is clearly superior to BT for the screening (IVBT-CaCl2) and control of therapy in vWD.

[Risk assessment and diminution in preoperative autologous blood donation]. / Risikoabwägung und -minderung bei präoperativer Eigenblutspende.

Preoperative autologous blood donation is only indicated if a positive balance between benefit and risk can be struck. In this contribution the different aspects to be considered are described and valued. By a mathematical formula we try to correlate the different aspects somewhat more objectively. In addition, we define 4 risk groups by the state of health of the patients which allow to estimate the risk of the patient by blood donation more easily and help to reduce it by selection of the appropriate donation procedure.

[Autologous blood transfusion as whole blood or blood components?]. / Eigenblut als Vollblut oder Blutkomponenten?

Modern haemotherapy is equivalent to restrictive use of blood components. Therefore, transfusion of whole blood in homologous transfusion generally cannot be accepted. In autologous blood transfusion blood components also are preferable if they can be separated appropriately. In order to have broad application of preoperative autologous blood deposits, close cooperation to transfusion services should be established guaranteeing optimal production of blood components. If this cooperation is impossible there are no objections against the use of autologous whole blood as long as the expected blood consumption is less than 3 red cell units. Additionally, in this case storage of more than 3 weeks mostly is not necessary. The fact that whole blood is not further part of the 'Monographien' of the Federal Health Administration (BGA) does not forbid the use of autologous whole blood since the 'Monographien' only concern generally available homologous blood components.