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Biomedical subjects

B Blauhut

Publications and source records attributed to B Blauhut.

18 recordsLinked to original sources
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↗
PubMed1985

Substitution of antithrombin III in shock and DIC: a randomized study.

In 51 shock patients with DIC Antithrombin III (AT III) substitution, heparin or a combination of both substances respectively was administered. In the two groups which had been given AT III substitution the concentration of AT III rose considerably higher than the activity. There was a drop of the platelet count in both groups which had received heparin. C1 esterase inhibitor was diminished in the beginning but spontaneously increased in all groups. This increase was slowest in the group without substitution of AT III. The blood loss in cases of traumatic shock was considerably higher in the group which had received both substances. The consumption of AT III concentrates was slightly higher in the combined therapy group than in the AT III group. The duration of symptoms of DIC was considerably shorter in the two substituted groups than in the heparin group. It is concluded that additional administration of heparin does not improve the effect of AT III substitution in patients with DIC and that side effects such as thrombocytopenia and an increased blood loss are likely to develop when both substances are given simultaneously.

Antithrombin III↗
PubMed1985

[Noninvasive monitoring using echocardiography. II. Determination of cardiac output and comparison of volatile anesthetics].

In order to prove definitely that echocardiography is a noninvasive and safe method that can be used in the perioperative period to assess cardiac function and evaluate the effects of pharmacologic agents on the heart, we have carried out further sonographic studies concerning cardiac output and the effects of volatile anesthetics on left ventricular contractility. In series A (n = 12), we compared different sonographic techniques (uni-dimensional, two-dimensional, pulse Doppler echocardiography) with invasively measuring cardiac output by thermodilution in ICU patients and in the immediate preoperative phase before CABG with a Swan Ganz catheter that was already inserted. M-mode echocardiography proved to be best and correlated well with invasively gained values (y = 0.57 + 0.96x, r = 0.795, p less than 0.01). Use of the Teichholtz formula to estimate left ventricle volumes seems to be imperative. The two-dimensional technique yielded less favorable results, the pulse Doppler method being least informative. In series B (n1 = n2 = n3 = 6) the effects of halothane, enflurane and isoflurane MAC 1.0 and 1.5 on left ventricular performance were assessed in patients undergoing cholecystectomy or gastrectomy under standard anesthetic conditions. The results support the already well-known pharmacologic effects of these drugs, with minimal decrease in contraction with isoflurane. Critical interpretation of the different sonographic parameters, however, is just as important as considering various existing interdependances. Finally, when comparing our numerical values with other 1.0 MAC effects reported in the literature, there was also very good agreement.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1984

[Antithrombin III substitution in patients in shock].

In a trial involving 61 patients suffering from shock and DIC, the relations between the concentration of heparin, the effect of heparin on coagulation and the activity of AT III were studied. The effect of heparin decreased to one-half when the activity of AT III was 75 per cent of the average normal level. At 50 per cent AT III, the effect of heparin was negligible. When AT III was substituted the disappearance rate of the AT III activity from circulation was considerably increased in the case of acute DIC, while the concentration of AT III when measured immunologically, did not show an increased disappearance. This difference suggests increased consumption of AT III by active serine proteases of coagulation. In patients substituted with AT III, the duration of acute DIC was between 16 h and 19 h, while it was 3.3 days in patients who received heparin. The survival rate of most severe cases of DIC showed a distinct trend towards improvement, but significance was lacking, probably due to the small number of comparable cases. When AT III and heparin were given simultaneously, there was no further shortening of the duration of DIC; however, severe bleeding complications occurred in some cases. The substitution of AT III was calculated on the following basis: In acute DIC an increase in AT III activity of 1 per cent can be expected when 1 unit/kg body weight is given. The same dose of AT III increases the plasma level by 1.8 per cent when the clotting system is unaffected.

Antithrombin III↗
PubMed1976

[Early influence of acute preoperative haemodilution with human albumin and ringer's lactate on coagulation (author's transl)].

Acute haemodilution was performed in 10 patients scheduled mainly for vascular surgery. Before induction to anaesthesia 910 +/- 29.1 ml whole blood was taken and simultaneously replaced as follows: 50% of that amount with 3,6% albumin solution, another 50% X 3 with lactated Ringer solution. The haematocrit was thus lowered from 39.8 +/- 1.71 to 28.4 +/- 1.7 vol%. Extensive clotting studies were performed to investigate the early influence of haemodilution on the clotting mechanisms in the time span between the end of blood collection and the point of surgical anaesthesia. The group of patients with normal clotting studies prior to haemodilution has shown a slight and short-lasting hypercoagulability. This has been proven by a shortening of r and k in TEG, by a shortening of non-activated Partial Thromboplastin Time (means activation of the XII and XI factor) and also, by the presence of an activated factor Xa and by an increase of maximum platelet aggregation and of platelet factor 3 availability. This mechanism of clotting activation is similar to the one observed after marked blood loss. It was assumed that this minor, early and short-lasting hypercoagulability has no further influence on the well known usual intra- and post-operative changes in clotting mechanisms (intra-op lowered, post-op enhanced coagulability). In contrast to the patients with normal clotting, a clotting defect due to preexisting liver-cell damage becomes worse during the haemodilution, which method in the presence of hepatic insufficiency therefore is contraindicted. A few additional data on input-output, serum and urine electrolytes and on 2,3 DPG have been gathered during our study. They indicate a positive fluid balance and the necessity for a close watch of electrolytes. The possible trend of 2.3 DPG elevation which has also been found might reflect a compensatory mechanism increasing oxygen transport capacity of haemoglobin if the above described method of haemodilution is used.

Adolescent↗