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Biomedical subjects

B Blauhut

Publications and source records attributed to B Blauhut.

At least 19 recordsLinked to original sources
PubMed1999

Indications for prothrombin complex concentrates in massive transfusions.

A major hemorrhagic insult may require massive transfusions to maintain oxygen transport and hemostasis. Thus an adequate transfusion budget must consider losses, patient's blood volume, critical levels of laboratory parameters, replacement rates of coagulation factors from the extravascular space, and the efficacy of blood products. The substitution of large quantities of blood or red cell concentrates can induce and aggravate a complex haemostatic disorder. Some patients develop generalized microvascular bleeding. A transfusion regimen is described, which in our hands can reduce complications of massive transfusion. For hemostatic support, platelet concentrates and fresh frozen plasma are the treatment of choice. Localization and persistence of bleeding, hepatic disease, and vitamin K deficiency due to medication or intestinal malabsorption may require the supplementary use of prothrombin complex concentrates. Furthermore, antithrombin and fibrinogen concentrates may be indispensable.

Adult↗
PubMed1995

Hepatitis C virus--does it penetrate the haemodialysis membrane? PCR analysis of haemodialysis ultrafiltrate and whole blood.

Hepatitis C virus (HCV) transmission to haemodialysis patients occurs by a route which remains to be clarified. Most studies show a significant correlation between anti-HCV-seropositivity and the number of blood transfusions or the duration of dialysis respectively. However, even in patients who have not received a blood transfusion the prevalence of HCV infection was significantly higher than in controls. We studied 58 patients on regular haemodialysis using a second-generation enzyme-linked immunosorbent assay (ELISA II) followed by a second-generation recombinant immunosorbent assay (RIBA II) for HCV. For all antibody-positive or indeterminate patients, polymerase chain reaction (PCR) analysis was done using both whole blood and dialysed ultrafiltrate. We were able to show by PCR that no HCV RNA (cells or cell particles) passed through the dialysis membranes.

Adult↗
PubMed1994

Comparison of the effects of aprotinin and tranexamic acid on blood loss and related variables after cardiopulmonary bypass.

Aprotinin reduces blood loss after cardiopulmonary bypass, but may sensitize recipients and is expensive. Tranexamic acid, a synthetic antifibrinolytic, has less disadvantages, but opinions differ regarding its efficacy. We studied three groups of patients undergoing cardiopulmonary bypass for coronary disease: recipients of aprotinin (total dose 4.2 x 10(6) kallikrein inhibiting units, n = 14), recipients of tranexamic acid (total dose 20 mg/kg body weight, n = 15), and nonmedicated controls (n = 14) during 24 hours after cardiopulmonary bypass. Compared with controls, aprotinin reduced blood loss, the number of patients requiring transfusions, and the mean number of transfused red cell units (all with p < 0.05), whereas the recipients of tranexamic acid did not differ either from aprotinin recipients or from controls. Aprotinin and tranexamic acid both mitigated the early postoperative reduction of adenosine diphosphate-induced platelet aggregation seen in the controls (p < 0.05). Postoperative increases of plasma concentrations of the prothrombin activation fragment F1 + 2 and the thrombin-antithrombin III complex showed an activation of intravascular coagulation, without any intergroup differences. The balance between concentrations of tissue plasminogen activator and the type 1 plasminogen activator inhibitor disclosed an activation of fibrinolysis, without differences between the groups. The concentrations of D-dimer, a breakdown product of cross-linked fibrin, remained at baseline in the recipients of aprotinin and tranexamic acid but tripled in the controls (p < 0.05). By contrast, the plasma antiplasmin activity was equally depressed in the tranexamic acid and the control groups but decreased less in the recipients of aprotinin (p < 0.05). This discrepancy may reflect the different modes of action of the two agents, which may make aprotinin more efficacious than tranexamic acid in the "nonfibrinolytic" act of protecting platelet function against attack by plasmin during cardiopulmonary bypass.

Aged↗
PubMed1993

[Comparison of 7 anti-hepatitis C virus enzyme immunoassays of the 2nd generation in blood donation services].

Seven enzyme-linked immunosorbent assays for the detection of antibodies to hepatitis C virus were compared: three assays with synthetic peptides in the coating showed overproportional higher rates of initial reactive and also the highest rate of so-called false-positive results in comparison with the RIBA assay. One assay with synthetic peptides had also the most false-negative results in comparison with RIBA-reactive results. The best results are found in assays with recombinant proteins, in which proteins derived from the NS-4 region are present.

Antigens, Viral↗
PubMed1991

Effects of high-dose aprotinin on blood loss, platelet function, fibrinolysis, complement, and renal function after cardiopulmonary bypass.

The use of aprotinin to reduce blood loss after cardiopulmonary bypass is under debate. Concern has been raised about the renal effects of aprotinin. We administered a mean aprotinin dose of 4.2 x 10(6) kallikrein-inhibiting units to 13 patients with coronary disease undergoing cardiopulmonary bypass for 74 +/- 5 minutes (mean +/- standard error of the mean); 13 comparable patients having cardiopulmonary bypass served as control subjects, and all were studied postoperatively for 24 hours. Aprotinin reduced postoperative blood loss by 50% (p = 0.0082). Two of the 13 patients who received aprotinin needed one red cell unit each versus a total of 18 units in eight of 13 control patients (p = 0.0096). Blood pressure, hemoglobin value and serum protein concentration were higher after operation in the aprotinin group (p less than 0.05 to p less than 0.01). Platelet counts did not differ, but plasma thromboxane was lower in aprotinin recipients (p less than 0.001). In control patients fibrinogen degradation products (D dimer) doubled, and alpha 2-antiplasmin activity was halved during and after cardiopulmonary bypass (p less than 0.01 to p less than 0.001), whereas aprotinin patients showed no changes. The complement breakdown products C4a, C3a, and C3dg as well as C9 neoantigen increased from prebypass baseline in both groups (p less than 0.001); the increment of C3a and C3dg was greater in the aprotinin than in the control patients (p less than 0.001). Serum electrolytes, osmolality, and creatinine remained normal in both groups of patients. Creatinine clearance was normal or above normal and virtually identical in both groups. Osmolar clearance and fractional sodium excretion were higher in the aprotinin group than in the control group shortly after cardiopulmonary bypass (p less than 0.05 to p less than 0.01); renal function was unremarkable the next morning. No adverse clinical effects attributable to aprotinin were seen. In summary, aprotinin offers advantages for cardiopulmonary bypass.

Antithrombin III↗
PubMed1991

[Risks and side effects of autologous transfusion].

Several versions of autologous transfusion are becoming increasingly popular. This review deals with their risks and side effects, which are still insufficiently documented. Basically, a number of preexisting conditions amounting to a subnormal performance and reserve capacity of several organ systems contraindicates preoperative donations, but 'critical' values of relevant parameters are still under debate. Since a preoperative deposit implies that the same individual donates several units within a few weeks, reaction rates must be related to the number of donors rather than that of donations. Viewed this way, the risk of--usually cardiocirculatory and sometimes serious--incidents is two times higher in autologous than in homologous donors. The reduction of oxygen transport capacity is a matter of concern. In order to avoid a mixed-venous p02 less than 35 mm Hg, which indicates an impending oxygen deficit, all 'non-hemoglobin' factors impacting on tissue oxygen supply must be normal even with 10 g/dl of hemoglobin; lower Hb values are undesirable. The use of erythropoietin to boost the preoperative harvest of red cells may not, by itself, be risky, but the accelerated pace of donations obviously is. The quality of cellular blood products prepared by intraoperative machine autotransfusion still leaves much to be desired. The suspicion that adenine and, especially, fibrinogen degradation products may be immunosuppressive, raises questions about the liberal use of autologous fresh frozen plasma. Bacterial contamination of reservoirs and the presence of tumor cells as well as fat droplets from bone marrow cannot be dismissed as being unimportant. Suction devices activate coagulation and fibrinolysis. Altogether, the risks of autologous transfusions, though different from those of homologous blood, require further efforts aimed at their reduction.

Blood Component Transfusion↗
PubMed1991

[Current methods in blood preservation: recovery of blood components using a multi-bag system].

A new method of blood preparation by use of a multiple plastic bag system is prescribed. Buffy coat free red cell suspensions in additive solution (SAG-M), fresh frozen (recovered) plasma and random platelet concentrates can thus be produced. Apart from the so far clinically not instantaneously available stored platelets the storage time of the red cells is remarkably increased up to 42 to 49 days and the cellular contaminations (red cells and leucocytes in platelet concentrates, thrombocytes and leucocytes in FFP) are markedly diminished leading to a higher quality of these components. The Red Cross Blood Transfusion Service of Upper Austria presents its data obtained by the use of a quadruple plastic bag (RC Transfusion Production Center Eugendorf/Salzburg) with cellular contamination parameters far below the generally accepted limits. Apart from the increased quality of the components a very high level of clinical acceptance concerning especially the stored random platelet concentrates has been experienced. In conclusion the necessity of changing to a multiple bag system is strongly emphasized thus not only better fulfilling the clinical needs for the different blood components but also delivering higher qualities. Red cell preparations containing the buffy coat should therefore not be used any longer.

Blood Coagulation Factors↗
PubMed1990

[Personal computer-assisted "acceptable hemoglobin concentration". An example of preoperative autologous blood donation].

At rest, the actual cardiac output (CO) exceeds the CO required to cover the oxygen consumption VO2, provided the hemoglobin level and the non-Hb parameters impacting on cellular oxygen supply (e.g. paO2, pH and body temperature) are normal. The size of this hemodynamic buffer as a function of Hb levels and the non-Hb parameters can be quantified for any clinically conceivable combination including VO2. As Hb levels decrease, the patient's condition is progressively destabilized in the sense that the gradual vanishing of the buffer makes him increasingly sensitive to abnormalities of the non-Hb parameters, such as hypermetabolism, arterial hypoxemia, and alkalosis. This concept is used to illustrate the course of patients participating in an autologous blood predeposit program.

Anesthesia, General↗
PubMed1990

[Hemostatic disorders in anesthesiology and surgical intensive care].

Apart from straightforward haemorrhage, bleeding problems in anaesthesiology and intensive care are predominantly due to multifactorial haemostatic derangements caused by a depletion of procoagulant factors, inhibitors, and platelets. In certain settings, these events are complicated by an enhanced procoagulant and decreased fibrinolytic activity of the endothelium. This functional turnabout of the vasculature promotes disseminated intravascular coagulation (DIC). A rational therapeutic approach is based on estimates of the patient's losses and his volume of blood, adequate and repeated haemostatic monitoring, and an individually tailored substitution considering the critical levels of the informative parameters, i.e. the platelets, fibrinogen, Quick and aPTT, together with the haemostatic efficacy of the available preparations. Whenever possible, subclinical trends towards abnormal bleeding should be identified and countered by appropriate measures before an actual and potentially life-threatening haemostatic breakdown develops.

Anesthesia↗
PubMed1989

Is there a generally valid, minimum acceptable hemoglobin level?

The different versions of autologous blood transfusion have rekindled interest in a generally valid 'minimum acceptable hemoglobin concentration' of patients around or below 10 g Hb/dl. The adequate Hb concentration capable of covering the oxygen demands of the body depends on several variables measurable at the bedside: oxygen consumption VO2, arterial oxygen tension paO2, body temperature, arterial and mixed venous pH, and cardiac output CO as the most important compensatory variable in anemia. Because of the strain imposed on the myocardium and the coronary circulation, anemia should not raise CO to more than twice the resting value, i.e. less than 10 l/min. Similarly, the mixed venous pO2, as an indicator of tissue oxygenation, should not fall below 35 mm Hg. With these two restrictions, we studied the relationships of the above-mentioned parameters in a computer-supported model. Under otherwise similar conditions, pvO2 falls with an increase in VO2, a decrease in paO2, a decrease in the temperature, an increase in pH, and a decrease in CO. A resting and slightly acidotic patient without other impediments of his cellular oxygen supply--e.g. the patient on chronic hemodialysis--tolerates a Hb level of 6-7 g/dl with a pvO2 barely exceeding 35 mm Hg and a CO approximately 50% above baseline. By contrast, the hypermetabolic and hypoxemic intensive care patient needs Hb levels in the low normal range, i.e. 12-13 g/dl, especially if he is also alkalotic. A generally valid 'minimum acceptable hemoglobin level' does not exist; the adequate Hb concentration is an individual characteristic needing careful attention.(ABSTRACT TRUNCATED AT 250 WORDS)

Anemia↗
PubMed1988

[Relation of hypoxia and edema of the intestinal wall and skin to colloid osmotic pressure].

Whereas the impact of colloids and crystalloids on hypoxia and edema has been extensively debated with respect to pulmonary function, their corresponding effects on the systemic circulation have been largely ignored. Manifest edema of the intestine and skin develops, however, when the serum colloid osmotic pressure (COP) is lowered to 15 mm Hg or less by crystalloid infusions. Hypoxia of wounds, which may be aggravated by crystalloids, impairs healing and antibacterial defense, and its has been speculated that edema and/or hypoxia of the intestine may be associated with postoperative gastrointestinal dysfunction. We therefore studies the relationship between lowering and restoration of the COP, the pO2 of the intestinal surface and skin, and tissue edema. We generated an acute hypoproteinemic fluid overload reducing the COP from around 20 to 10 mm Hg in 56 rabbits by means of a 50% plasma loss and excess replacement with Ringer's lactate. We measured the COP with a membrane having a cut-off level of 20,000 d, the cardiac output (with derivation of further hemodynamic data) with an electromagnetic flow probe around the ascending aorta, and the tissue pO2 (pO2t) in mm Hg with the Dortmund 8-channel surface electrode. After 30 min without infusion (Fig. 1), we assigned 14 animals each at random to 4 treatment groups: (1) no treatment (O); (2) 20% albumin 7.5 ml/kg (A); (3) furosemide 2 mg/kg i.v. given three times at 30-min intervals (F); and (4) the combination of both agents (AF). During the infusion-free interval, the cardiac output and pO2t fell by 20%-30% of baseline (Table 1).(ABSTRACT TRUNCATED AT 250 WORDS)

Acid-Base Equilibrium↗