Infusionstherapie und Transfusionsmedizin最新文献

Objective: To evaluate potential changes in the ratio of whole-body/large-vessel hematocrit (f-cell ratio) during isovolemic hemodilution and to compare the volume effects of 2 different plasma exchange solutions (hydroxyethyl starch 200,000/0.62 6% and human albumin 5%).

Design: Prospective, randomized, controlled trial.

Setting: Operating theater in a university hospital.

Patients: 24 gynecological patients scheduled for elective surgery.

Interventions: Isovolemic hemodilution was performed using 2 different plasma exchange solutions. Plasma volume was determined using dye dilution technique before and after hemodilution. The volume of withdrawn blood was measured from the change in weight of the blood bags taking into account the specific gravity of blood.

Results: The volume of administered plasma exchange solutions exceeded the amount of withdrawn blood by 80 +/- 47 ml (p < 0.001). Plasma volume was 3,067 +/- 327 ml before and 3,517 +/- 458 ml after hemodilution. Using red cell volumes calculated from measured plasma volumes and peripheral hematocrit, a deficit of 249 +/- 133 ml (p < 0.0001) in red cells after hemodilution appeared with the measured withdrawn red cell volumes taken into account. This finding can be explained by a change in the f-cell ratio during isovolemic hemodilution. The volume effect of the exchange solutions was 1.05 for hydroxyethyl starch and 0.95 for albumin.

Conclusions: The results demonstrate that a change in the f-cell ratio occurs during isovolemic hemodilution. The estimation of red cell volume or plasma volume changes by using either the hematocrit or plasma or red cell volume determinations together with the hematocrit may lead to erroneous results.

Objective: In intensive care medicine the clinical decision to order and transfuse red blood cells (RBC) is usually based on hematocrit or hemoglobin levels. The intention of this study was to investigate whether clinical or laboratory variables, taken after the admission of patients to the intensive care unit (ICU), are able to predict the transfusion requirement of the following 72 h.

Design: The values of initially measured systolic blood pressure, hematocrit level, and the values of 2 scores of severity of disease (Acute Physiology And Chronic Health Evaluation [APACHE-II], Mortality Prediction Model [MPM]) were calculated after the admission of patients to the ICU. The decision for transfusion was based on specific criteria. The median values of the scores, those of the variables, and the median number of transfused RBC units of the surviving group were compared to the values of the group of patients who died during hospital stay. The quantity of RBC transfusions was compared to the variables and score values by linear regression analysis. Additionally, the values of the patients who did not receive blood transfusion were compared to those of patients who required RBC. Furthermore, the patient group with neurosurgical diseases was compared to the group without neurosurgical diseases.

Patients: 117 patients were prospectively and consecutively investigated in an 8-bed ICU of a university hospital.

Results: Nonsurvivors required significantly more units of RBC during the first 72 h (p < 0.05). Patients who did not require transfusion had a higher hematocrit and a lower APACHE-II value at admission (p < 0.001). In the MPM values no differences were found. Patients with neurosurgical diseases had a higher initial hematocrit value, and they required less units of RBC in comparison to patients without neurosurgical diseases. In the analysis of linear regression neither in the initially measured systolic blood pressure nor in the APACHE-II and MPM we found a strong linear correlation to the quantity of blood transfusion.

Conclusions: A hematocrit value < or = 20% and a APACHE-II score > or = 20 at the time of admission to the ICU referred to a demand for blood transfusion. We believe that these parameters are useful as predictive instruments. The initially measured systolic blood pressure had no prognostic capacity. In the individual patient a number of factors should be taken into account to decide whether to transfuse or not.

Objective: The increasing need for single-donor platelet concentrates makes it necessary to motivate platelet donors to donate regularly. The authors examined the contentment of existing donors in order to create a basis for improvements and to raise the attractiveness of donation.

Design: Open empirical data acquisition.

Setting: Institute for Transfusion Medicine at the General Hospital Vienna.

Participants: 211 platelet donors.

Interventions: Interview with a self-developed questionnaire.

Results: Whereas donors rate the work of the staff as being very good, they are less content with the surroundings in the pheresis unit. Younger and higher-educated donors as well as persons who have been donating for less than 5 years show more negative ratings than comparable groups. The financial compensation is important to ensure a high donation frequency.

Conclusions: The attractiveness of donation could be raised by improving certain aspects of donation. In order to ensure a high donation frequency donors should be granted a financial compensation, as otherwise particularly younger donors, who are more likely to be seronegative for antibodies to CMV, would not donate any more or at least not that often.

Background: Remuneration for blood donors, in the way as presently handled by governmental and communal blood transfusion services in Germany, is not generally accepted. It is feared that donors are recruited with increased risk to transmit infectious diseases, especially AIDS. Alternative incentives are discussed. After the so-called AIDS scandal in Germany, a change in the donor motivation was to be expected, associated with an increased willingness to renounce remuneration. Therefore, we performed the present survey, in which we evaluated the donor's willingness to renounce remuneration, possibilities of cashless remuneration and other alternative incentives.

Material and methods: During March and April 1994, a total of 1,157 blood donors of the University Blood Bank Marburg were questioned anonymously by a questionnaire in the framework of whole-blood donations. Beside the above-mentioned aspects demoscopic data were included (age, sex, profession, journey).

Results: Cutting of remuneration without any other compensation was refused by 86.1% of the donors, 77% would not want to further donate blood in this case. Transfer of money to a bank account instead of cash payment was accepted by 78.6%, the use of non-negotiable cheques by 68.7%. Alternative compensation by tickets for theater, concert, cinema or coupons for restaurants met with the approval of only 27.3%; under these circumstances, 36.9% would be willing to continue blood donation. With increasing age and number of donations, but largely independent of social status, donors attached greater importance to retention of remuneration.

Discussion: Cutting of remuneration would result in a considerable reduction of the willingness to donate blood within the population of donors of the governmental and communal blood transfusion services. However, an increase of virus safety of the blood products would not be reached in this way, since especially the long-term donors would be driven away. Considerable bottlenecks, particularly in the specific blood supply of hospital-integrated blood transfusion services, would have to be expected.

Background: The gel centrifugation system (ID Microtyping System, Fa. Diamed, Bensheim, FRG) is one of several new methods, which has become commercially available within the last few years for the detection of antibodies against red blood cell antigens.

Materials and methods: During 1 year we used the gel centrifugation method for antibody screening in our routine laboratory by performing 3 tests each time: 1. NaCl card (room temperature) with untreated red cells; 2. NaCl card (37 degrees C) with papain-treated red cells, and 3. Liss-Coombs card (37 degrees C) with untreated red cells.

Results: The two-stage papain test revealed some interesting phenomena: 1. In some cases the sensitivity of the papain gel test is higher than that of all other methods tested in this study, namely in the gel centrifugation technique and in the tube centrifugation technique. 2. There are reactions which seem to be directed against patients' own antigens (in the Rhesus or Kidd system), but there are no positive direct antiglobulin test and no clinical signs of hemolysis. 3. Some sera show reaction patterns which seem to have a distinct specificity, but they cannot be assigned to any of the antigens in the manufacturer's antigenogram.

Conclusions: Before a general recommendation for antibody screening with the two-stage papain test in the gel centrifugation method can be given, further investigations about the clinical value of those antibodies which are detectable only by this technique are necessary. For antibody identification further declarations in the work sheet of the panel would be desirable.

Objective: Review of different aspects of the primary interaction of complement with blood platelets in immunological reactions and the effect on platelet activation in healthy people and patients.

Data sources and selection criteria: Relevant original papers and review articles mainly of the English-written literature.

Results: Besides their major role in hemostasis and wound healing, blood platelets are involved in immunological reactions. They are not only able to interact with IgG through Fc receptors (FcR), they also react with complement components. This review summarizes interactions of complement with mainly human platelets. Such interactions may occur through complement receptors of the plasma membrane (e.g. C1q receptor, complement receptors 2 and 4), but also in a receptor-independent way including activation of the platelet by the membrane attack complex of complement C5b-9. In addition, activation of complement at the surface of the platelets may be induced after binding of anti-platelet antibodies to membrane glycoproteins (e.g. GpIIb/IIIa, GpIb/IX) or after binding of platelet-nonspecific immune complexes via FcR. Complement activation in turn may be regulated by various means including specific plasma or membrane proteins [e.g. decay-accelerating factor (DAF), membrane cofactor protein (MCP), membrane inhibitor of reactive lysis (MIRL), C8-binding protein (C8bp, homologous restriction factor hrf)]. As a further way of self-protection against complement attack, platelets may actively release C5b-9, deposited at the surface as C5b-9-enriched membrane vesicles.

Conclusions: Two lines of interaction of platelet with complement can be distinguished. On the one hand, platelets are equipped with membrane proteins which protect them from complement attack against themselves. On the other hand, membrane receptors for activated complement components as well as for IgG are expressed on the surface, which enable the platelet to intervene in immunological reactions. This property varies between platelets of different species and needs further investigation also in view of the platelet as an intersection between immunology and hemostasis.