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Biomedical subjects

V Kretschmer

Publications and source records attributed to V Kretschmer.

At least 109 records · Page 6Linked to original sources
PubMed1991

[Transfusion effect with platelet concentrates from various cell separators].

115 patients with bone marrow aplasia/hypoplasia received a total of 567 transfusions of fresh HLA-selected platelet concentrates at random from the AS-104 and CS-3000 and, whenever possible, from both separators using the same donor. By daily platelet counting pre and up to seven days post transfusion, the posttransfusional increments per 10(11) platelets transfused were calculated. Fresh platelets collected from the AS-104 showed comparable in vivo recovery at the first day post transfusion but significantly better survival compared to those from the CS-3000. This is in line with in vitro studies published before, where better in vitro function and morphology were observed. Increased platelet yields and improval of the platelet survival of the PC's from the AS-104 should result in prolonged transfusion intervals. When additionally evaluating a limited number of PC's from the AS-104 stored in teflon bags up to five days before transfusion (n = 12), our results were not favorable compared to PC's from the CS-3000 stored in polyolefine bags. As this seemed to be due to the geometry of the bags, this was consequently changed.

Anemia, Aplastic↗
PubMed1991

[Disorders of primary hemostasis caused by albumin infusion in hemodilution].

Previous studies using the In-vitro Bleeding Test have shown that albumin impairs primary hemostasis more pronouncedly than other infusion solutions. For this reason we compared ADP (4 microM)-induced platelet aggregation in samples of platelet rich plasma containing 50% albumin. We added the same amount of platelet-poor plasma to the controls. Using this method we could show the inhibitory effect of albumin once more. This means that not only changes in rheology are responsible for the impairment of hemostasis by albumin. Platelet aggregation itself is influenced.

Blood Viscosity↗
PubMed1991

[Quality control in autologous blood donation and transfusion].

In Germany the quality control for homologous blood preparations is well-established. On the other hand, the quality assurance for autologous blood products is much more complicated, due to more problems concerning blood collection and preparation. Therefore, quality control is even more strongly indicated in autologous hemotherapy. On the basis of existing standards for the preparation of homologous blood components, we defined guidelines for the quality control of the autologous preoperative blood deposit, plasmapheresis, acute normovolemic hemodilutions and the intraoperative autotransfusions. We took into account that particularly the perioperative techniques only allow the collection of blood components with a reduced quality. The guidelines include the recommendation of adequate schooling for the staff.

Blood Cell Count↗
PubMed1991

[Preoperative donation of autologous blood and plasma].

The risk and side effects of homologous blood transfusion led to an increased interest in autologous transfusion concepts. Whereas peri- and intraoperative procedures are clinical methods, preoperative autologous blood donation belongs into the responsibility of a transfusion service in order to ensure qualified separation into blood components as well as correct storage and handling. Special knowledge in transfusion medicine is necessary for the application of preoperative autologous plasmapheresis. On the other hand, its use by clinicians under adequate controlled conditions seems to be rather safe. Although autologous transfusion includes the lowest risk, side reactions cannot be completely excluded. There is also a risk of secondary bacterial contamination. Side effects due to the specific composition of the various blood components, to alterations during storage and to the way of application have to be considered, too. Severe haemolytic transfusion reactions are mostly caused by exchange of blood samples, patients or blood units. They are to be expected in autologous blood transfusion as well. In addition, there is an increased risk of infection when autologous blood components are exchanged accidentally. There is only an indication for autologous blood if the total risk of autologous donation as well as transfusion in the individual case is lower than the statistical risk of homologous transfusion. Autologous blood donation should be offered to all patients undergoing elective surgery where blood is likely to be required and when blood donation is practicable. Preoperative autologous plasmapheresis is indicated in elective surgery if intra- and perioperative autotransfusion methods shall be used and a blood loss of at least 1.5 liters can be expected. There are a lot of organizational problems in autologous blood transfusion which can be solved by adequate information of all persons involved and close cooperation between clinicians and transfusion service. The high standard which was developed for homologous transfusion in the last 15 years has to be maintained for autologous blood transfusion, too.

Blood Transfusion, Autologous↗
PubMed1991

Plateletpheresis with the new COBE Spectra.

The COBE Spectra was evaluated in 71 plateletpheresis procedures. Using the collection and anticoagulant algorithms of the system (n = 57) we collected 4.3 +/- 1.2 x 10(11) platelets with a mean separation efficiency of 70.2 +/- 12.1%. The cell contamination was very low (leukocytes 0.5 +/- 1.0 x 10(7), red cells 1.5 +/- 2.2 x 10(7]. In four different modifications of the standard separation protocols, we tried to reduce the ACD consumption in order to shorten the donation time and to improve donor safety. A constant ACD/blood ratio of 1:9 and increase of the blood flow to 50 ml/min (n = 14) caused significantly lower yields (3.1 +/- 0.7, p less than 0.01) and visible spontaneous platelet aggregates in the collection line in 50% and in the PC's in 29% of the runs. In order to prevent platelet activation the ACD algorithm had to be maintained, but a reduction of the ACD/blood ratio to about 15% was acceptable.

Algorithms↗
PubMed1990

Primary hemostasis in hemodilution--1) Hematocrit.

There are still controversies about the influence of acute preoperative hemodilution on coagulation. Therefore, we examined the platelet function by the In-vitro bleeding test (IVBT) using composed blood samples of different hematocrit but constant platelet concentration. We found an inverse correlation between hematocrit and bleeding time (p less than .05), volume (p less than .001) and flow (p less than .001). These data suggest a considerable impairment of primary hemostasis, due to low hematocrit. The cause may be an alteration of the hemorheology as well as the interaction between red cells and platelets themselves.

Bleeding Time↗
PubMed1990

Primary hemostasis in hemodilution--2) Infusion solutions.

Various infusion solutions are used during preoperative hemodilution or for substituting intraoperative blood loss. We examined the influence of saline 0.9%, albumin 5%, dextran 6% gelatin 3.5% and hydroxyethyl starch 6% (HES, mw 40,000 and 450,000) on primary hemostasis using the In-vitro bleeding test (IVBT) on composed blood samples of different hematocrit but constant platelet concentration. All infusion solutions tested caused longer bleeding times, depending on the volume used. Saline and albumin had the strongest effect, whereas high molecular weight HES or dextran showed hardly any impairment, if used in a quantity of less than 20% of the blood volume. Autologous plasma seems to be the best substitute in hemodiluted patients, at least if more than 20% of the blood volume has to be substituted by infusion solutions.

Bleeding Time↗
PubMed1990

[Effect of erythrocyte contamination on thrombocyte storage].

The influence of red cells on the storage of platelet concentrates (PC) is still questionable. Therefore, we investigated 40 PCs with 4 different red cell concentrations (less than or equal to 5000, 10,000, 50,000 and 100,000/microliters), but equal leukocyte contamination, in a paired study during 5 day storage. In correlation to the red cell contamination, there was a significant reduction of platelets, discoids and especially "functional active" platelets already after addition of the red cells, which was due to a spontaneous platelet aggregation. The difference increased during the storage (p less than 0.05 and p less than 0.001). The other parameters investigated (pH, aggregation, adherence, beta-TG) showed the well-known storage alterations, but no special influence of the red cells. Therefore, PCs should contain the least red cell contamination for storage purposes.

Blood Preservation↗
PubMed1990

Plateletapheresis with the new cell separator AS-104.

Summarizing several studies, it can be shown that the new cell separator AS-104 (Fresenius), in comparison to the older systems, provides a real advantage concerning the separation efficiency, the purity of the platelet concentrates (PC), the platelet function and the donor safety. The results of 5 different separation protocols demonstrate the technical flexibility and developmental potential of this system. From the experience of 580 plateletapheresis runs the successful improvement of the cell separator, and the disposables can be documented as the frequency of disturbances and discontinuations are reduced considerably. The preliminary results of an uncontrolled, not randomized transfusion study of 244 transfusions in 49 patients show comparable posttransfusion increments as obtained with PC of the CS-3000 (Baxter).

Blood Transfusion↗
PubMed1990

[Use of phospholipids (Fibraccel) for hemostasis in thrombocytopenic-thrombocytopathic patients].

Eight thrombocytopenic/pathic patients received an intravenous infusion of phospholipids. In-vitro-bleeding test, thrombelastography and resonance thrombography were performed in order to show the hemostatic effect. There was no case in which phospholipids had an efficacy comparable to the transfusion of platelets. Two patients suffered from a severe anaphylactoid reaction after the administration of phospholipids.

Adolescent↗
PubMed1990

Separation of platelet concentrates (PC) from buffy coat (BC) using the bottom and top drainage (BAT) system.

By the preparation of platelet concentrates (PC) from buffy coat (BC), the blood component separation may be improved considerably. One can use new bag systems with bottom and top drainage (BAT) which allow partial automation of the separation procedure. Thus, it is possible to produce very pure red cell concentrates (RCC) and FFP, as well as BC, by one separation step under well standardized conditions. Several preparative factors influence the quality of the PCs, especially the storage of the whole blood and the BC. Optimal yields (0.72-0.78 x 10(11) platelets), separation efficiency (67.7-70.8%) and lowest cell contamination (leukocytes 0.1-0.2 x 10(8), red cells 0.2-0.3 x 10(8) per concentrate) were obtained with whole blood stored for 1 h and BC for 2-4 h before resuspension by 30 min face-over-face-rotation. In respect to the release of leukocyte proteases during the storage, the BC should not rest for more than 2-3 h before separation of the platelets in order to prevent potentially functional impairment of the platelets by leukocyte proteases.

Blood Component Removal↗
PubMed1990

[Immunization against blood group antigens by allogeneic bone transplantation].

33 bone allotransplants (cryopreserved) of AB0- and Rh-incompatible (donor-recipient) patients were performed to evaluate the question which AB0 Rh-incompatibility leads to immunization of the bone transplant recipient. Several different antibodies were tested pre- and postoperatively in the recipient. Regarding the Rh-system no immunization was demonstrable; however, a significant increase of antibody leads was found regarding the AB0-system. Thus, in bone bank techniques AB0 compatibility is important for allogeneic bone transplantation in young women. Otherwise, there is a risk for the development of MHN in case of pregnancy. Blood group-typing is not necessary in other patient groups. Although no Rh-antibodies were demonstrable, a similar mechanism can be postulated for the Rh-system. We, thus, conclude that in allogeneic bone tx in young women the Rh-system has to be taken into consideration.

ABO Blood-Group System↗
PubMed1990

[Perioperative blood coagulation therapy and diagnosis].

The risks and adverse reactions of fresh frozen plasma (FFP) and coagulation components have changed considerably in the last few years because of the spread of HIV on the one hand, and the advances in preparation and sterilisation of the coagulation components on the other hand. Therefore, the indication for FFP and the various coagulation components deserves permanent consideration. FFP is still the therapeutical means of choice for the treatment of acquired (complex) plasmatic coagulation disorders, even though the (still) small risk of virus transmission in Middle Europe has to be taken into account. Coagulation components are primarily indicated in congenital (isolated) plasmatic coagulation disorders. Only in gross or very acute acquired coagulation disorders are coagulation components needed in addition to FFP. The same regimen is recommended for the use of antithrombin III (AT III) concentrates. In cases of acquired antithrombin deficiency, antithrombin III substitution is indicated only when the anticoagulation by heparin alone or in combination with FFP is insufficient or when the heparin dose required might cause an unacceptable bleeding risk, e.g. in simultaneous thrombocytopenia. Then AT III becomes an important therapeutic agent, especially in DIC. In addition, information regarding a rational and economic substitution of FFP and coagulation components is given, and other substitutes are mentioned which could possibly be used with less risk. Finally, the necessity of accurate diagnosing is emphasized. Close cooperation between the physicians in the clinics and in the department of transfusion medicine/hemostaseology reduces unnecessary and inadequate application of coagulation components. This also means an improvement in the patient's therapy.

Antithrombin III↗
PubMed1990

[Fulminant autoimmune cold-type hemolysis with marked elevation of monothermic cold agglutinins. Successful therapy with membrane plasmapheresis].

Autoimmune hemolytic anemia associated with cold autoantibodies is rare in infancy. In a 7 months old infant with severe hemolysis, a hemoglobin of 5.9 g/dl and a cold agglutinin titer of 1:8000, even the transfusion of warmed, packed red cells (37 degrees C) lead to hemolysis. Hemoglobin fell to 2.8 g/dl despite prevention of exposure to cold, parenteral steroids and immunoglobulins. Cold agglutinin titer fell to 1:8 after plasma separation. Subsequent transfusion did not lead to hemolysis and permanent remission was achieved.

Agglutinins↗
PubMed1989

In vitro bleeding test--a simple method for the detection of aspirin effects on platelet function.

We investigated platelet function of 21 healthy blood donors before, 4 hrs and 1 to 7 days after a single oral dose of 0.02 (n = 3), 0.05 (n = 3), 0.1 (n = 3), 0.5 (n = 2) and 1.0 g (n = 10) aspirin. Three additional donors received 0.02 g aspirin/day for 5 days. A new and simple in vitro bleeding test (Thrombostat) using whole blood was far more sensitive than all other tests for platelet function (subaquatic bleeding time, thrombelastrogram, resonance-thrombogram, platelet adherence, spreading and aggregation). With this method using 2mM CaCl2 as additional agent all donors showed significantly increased in vitro bleeding volumes, for at least 2 days after ingestion of 0.1 to 1 g aspirin. In the majority of cases the aspirin effect could be detected even after 5-6 days. In 2 of 3 donors even 0.05 g aspirin was detectable. There was already a definite effect seen after 2 days in all 3 cases when 0.02 g was ingested daily. The new in vitro bleeding test should be suitable for the control of low dose aspirin prophylaxis of arterial thromboembolic disorders.

Aspirin↗