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Biomedical subjects

R Karger

Publications and source records attributed to R Karger.

11 recordsLinked to original sources
PubMed2005

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.

Blood Donors↗
PubMed2004

Does hemodilution enhance coagulability?

UNLABELLED: Recent publications reported enhanced coagulability in hemodilution determined by TEG. In contrast, earlier reports have shown prolongation of in-vivo bleeding time in anemia. In order to take a closer look at this discrepancy undiluted and diluted anticoagulated blood samples (20 % with saline solution, hydroxyl-ethyl starch 6 % (HES), autologous platelet poor plasma (PPP)) were investigated by TEG (n = 10), ball (n = 10), and hook coagulometer (n = 15) as well as tests simulating primary hemostasis ex vivo (Platelet Function Analyzer PFA-100, n = 10). RESULTS: Dilution with plasma changed TEG parameters in a way, when started by recalcification of the blood sample, which is characteristic of enhanced coagulability (r decreased in all and k in 8 of 10 samples, maximal amplitude increased in 9 out of 10). With HES, changes in TEG parameters mainly indicated reduced coagulability (k increased in 7 out of 10, MA decreased in 10 out of 10). When the coagulation was additionally activated by PTT reagent (InTEG) the TEG parameters also mainly showed hypocoagulation with the three dilution solutions. Coagulation times with ball and hook coagulometers were significantly prolonged by dilution especially with saline (+ 25 % and + 17 %, p < 0.001). Dilution always significantly (often abnormally) prolonged closure time in PFA-100 (saline + 41 +/- 18 %, PPP + 37 +/- 20 %, HES + 69 +/- 24 %) demonstrating disturbance of primary hemostasis, particularly with HES. CONCLUSIONS: From the results obtained it can be concluded that the changes in the classical TEG (without addition of PTT-reagent), suggesting an enhanced coagulability, may be caused methodically as they are also found with autologous PPP. On the other hand, a disturbance of the primary hemostasis in hemodilution has to be taken into account from the results seen with the PFA-100 and a number of published data.

Blood Coagulation↗
PubMed2004

Safety and efficacy of unmodified whole blood vs. buffy coat-depleted red cell concentrates in autologous transfusion of elective orthopaedic surgery patients.

Storing autologous blood as whole blood (WB) has been proposed for increasing the cost-effectiveness of preoperative autologous blood donation programmes. However, experimental data suggest that autologous leucocytes might lead to immunomodulation similar to the effect attributed to allogeneic leucocytes. In a retrospective analysis, the postoperative outcome of 120 patients undergoing elective orthopaedic surgery and having donated up to two units of autologous WB (AWB) was compared with that of a control group of 52 patients, whose autologous donation had been processed into buffy coat-depleted red cell concentrates (RCC). At least one autologous unit, but no allogeneic units, had been transfused in all analysed patients. Donation schemes were equally efficacious in both groups. There was no significant difference in postoperative infection rates between the two groups. Overall rates were 7.7% in the RCC group and 8.3% in the WB group. Surgical, thromboembolic and other recorded complications, length of postoperative hospital stay and days of the use of antibiotics were also not significantly different between the two groups. The results of this study suggest that transfusion of up to two units of unmodified AWB is as efficacious as the transfusion of autologous RCC and does not negatively influence the postoperative outcome in elective orthopaedic surgery.

Blood Component Transfusion↗
PubMed1999

Standardization of the PFA-100(R) platelet function test in 105 mmol/l buffered citrate: effect of gender, smoking, and oral contraceptives.

The PFA-100(R) (PFA) diagnostic system for the detection of platelet dysfunction was evaluated to determine reference ranges in a normal population. The PFA determines the primary haemostasis capacity (PHC) of anticoagulated whole blood, expressed by the system's closure time (CT). In this study the CT reference ranges were determined for blood samples collected in 105 mmol/l (3.2%) buffered citrate and the effect of gender, smoking, and use of oral contraceptives on reference ranges was assessed. Each of the 309 healthy blood donors from five blood centres was confirmed to have normal platelet function before inclusion in the study. Blood samples were tested in duplicate with both the collagen/epinephrine (Col/Epi) and collagen/ADP (Col/ADP) test cartridges. PFA reference ranges (90% central intervals of measured closure times) for both cartridge types were similar for all groups. Subgroup analysis showed that neither gender nor oral contraceptive usage had any effect on PHC. The 95% cut-off value for the Col/Epi CT was slightly higher for smokers than for non-smokers, an effect more pronounced in female than in male donors. However, the small difference did not justify establishment of specific reference ranges for smokers. Data from all included subjects were pooled to calculate the CT reference ranges for blood samples collected in 105 mmol/l buffered citrate (Col/Epi 82-150 s; Col/ADP 62-100 s). Normal levels of fibrinogen, as well as normal platelet counts and normal haematocrit levels, appeared not to influence the PHC. Because slight but significant differences of the reference ranges were observed between some of the participating sites, in-house confirmation of these reference range guidelines is recommended.

Adolescent↗
PubMed1996

[The importance of quality of whole blood and erythrocyte concentrates for autologous transfusion. A literature survey and meta-analysis of in vivo erythrocyte recovery].

UNLABELLED: The separation of whole blood into components is the state-of-the-art in transfusion of allogeneic blood. The main reasons are the negative effects of the buffy coat and the need for FFP. Nevertheless, especially in Germany whole blood is being rejected more and more even as autologous blood. However, most of the negative effects of the buffy coat do not apply to autologous blood. Additionally, these patients usually do not develop coagulation disorders and therefore do not need plasma as a hemostatic component. On the other hand, separation into components of autologous blood leads to an increase of costs and to logistic problems that restrict autologous blood predeposit to a few institutions. Therefore, we have reviewed the literature in order to find a scientific basis for this. METHODS: We analysed all articles listed by MEDLINE during the last 12 years that dealt with the quality of whole blood or red cell concentrates. In addition, all references were included that contributed relevant information to the topic. A total of 135 original articles, abstracts, reviews, letters or editorials were analysed that referred to standard preparations and storage media. In 48 papers the in vivo red cell survival was studied. 28 of which fulfilled the prerequisites to be included into a meta-analysis. The following in vitro parameters were also evaluated: pH, potassium load of the units, ATP and DPG concentration of the red cells. RESULTS AND DISCUSSION: Whole blood (resuspended in CPDA-1) and red cell units (stabilized in CPDA-1 or additive solutions) with a different buffy coat or leucocyte content have comparable pH values and red cell 2,3-DPG and ATP concentrations at the end of the approved storage time. The potassium load of a whole blood unit appears to be higher than red cell concentrates, but this is to some extent caused by the higher plasma content of whole blood and is not thought to be a clinically relevant problem for patients receiving only a few units. A number of studies demonstrate that dependent upon the leucocyte content of a red cell unit, leucocyte metabolites and enzymes are released and accumulate during storage. A detrimental influence on the integrity of the red cell membrane was found in several in vitro studies. Nevertheless, a significant improvement in red cell survival by leucocyte reduction was detected by only one group. Undoubtedly, nonhemolytic febrile transfusion reactions (NHFTR) are generally caused by an antibody-antigen interaction due to the transfusion of allogeneic buffy coat. On the other hand, there is some evidence that non-specific immunological mechanisms such as the release of histamine or cytokines are also capable of causing NHFTR. Thus, these reactions are expected to occur in autologous blood transfusion. However, so far, there are no data about the frequency and severity of these reactions and whether they are more likely to emerge after transfusion of blood units with a particular preparation. Blood transfusions can cause septic complications due to bacterial contamination of the transfused units. These fatal but rare complications may be reduced by pre-storage filtration of blood, but there is no indication that buffy coat reduction is effective. Three cases with septic complications have been reported after autologous transfusion, in two of which red cell concentrates (at least one was free of buffy coat) had been used. Thus, there is no justification for the conclusion that the risk of septic complications is increased by transfusion of whole blood. After all, whole blood and red cell concentrates exhibit only minor differences in relevant in vitro parameters. Hence, a higher incidence of adverse effects following the transfusion of autologous whole blood compared to autologous red cell concentrations is unlikely. Therefore, the 24 h in vivo recovery is considered to be the most valid criterion to assess the quality of red cell preparations.(ABSTRACT TRUNCATED)

Blood Transfusion↗