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Biomedical subjects

V Wizemann

Publications and source records attributed to V Wizemann.

At least 73 records · Page 4Linked to original sources
PubMed1985

Mechanisms of altered myocardial contractility during hemodialysis: importance of changes in the ionized calcium to plasma potassium ratio.

Hemodialysis is associated with alterations in myocardial contractility, but duration and precise determinants responsible for these changes are unknown. We investigated the effect of several variables, established to influence left ventricular (LV) contractility, which normally changed during dialysis: the plasma concentrations of ionized calcium, potassium, bicarbonate, and magnesium and the removal of uremic toxins. The influence of three different isovolemic bicarbonate-dialysis procedures in 16 patients with normal (group 1) and hypertrophied myocardium (group 2) was assessed by echocardiography prior to and up to 44 h following each dialysis. During the first procedure, ionized calcium and potassium concentration decreased, but LV performance remained unchanged in both groups. The second procedure with increased ionized calcium and decreased potassium concentration resulted in an improvement of mean circumferential fiber shortening (VCF from 1.15 to 1.56 circ/s (P less than 0.001) in group 1 and from 1.05 to 1.16 circ/s (P less than 0.05) in group 2. The positive inotropic effect declined gradually up to 12 h (group 1) and 2.5 h (group 2) respectively. In the third procedure when ionized calcium was increased and potassium concentration remained unchanged contractility did not improve. Removal of uremic toxins, decrease in magnesium, and increase in bicarbonate concentrations were comparable during each procedure. These results suggest that the ionized calcium to potassium ratio is the important determinant of dialysis-related augmentation in LV contractility. In LV hypertrophy the expected contractile response is diminished indicating a depressed inotropic state.

Adult↗
PubMed1985

Dialysis-induced cardiac arrhythmias: fact or fiction? Importance of preexisting cardiac disease in the induction of arrhythmias during renal replacement therapy.

Frequency and grade of premature ventricular depolarizations were assessed in 10 patients on maintenance renal replacement therapy. All medication was withdrawn prior to the study. Each patient was treated sequentially by 8 different methods [acetate and bicarbonate hemodialysis (HD), hemofiltration, hemodiafiltration, ultrafiltration, use of 5 different membranes]. Despite marked changes in serum electrolyte concentrations there was no difference in frequency or grade of premature ventricular beats between the periods before, during, and after renal replacement therapy. Comparison of the 8 methods tested revealed no superiority of 1 method during the observation period of 192 h for each patient. In a second group of 8 patients with confirmed coronary artery disease, acetate HD had no effect on grade and frequency of ventricular arrhythmias, although arrhythmias occurred more often (p less than 0.05) and were more dangerous. We therefore conclude that the incidence of ventricular arrhythmias is primarily dependant on the presence of preexisting coronary artery disease and that HD or related methods do not increase the risk of ventricular ectopies in patients without digitalis medication.

Adult↗
PubMed1984

Therapeutic effects of short-term plasma exchange in endogenous uveitis.

We studied the effects of plasma exchange in nine patients with endogenous uveitis and in one patient with Behçet's syndrome (a total of 15 episodes of uveitis). Topical or systemic drug therapy, which was begun four to 12 weeks before admission, was continued throughout the entire study period of five weeks. Plasma exchange was carried out in four sessions during a one-week period. In each patient a total of 12 liters of plasma was removed and replaced by a 3% human albumin electrolyte solution. Immediately after the plasma exchange period there was a reduction of cellular infiltration of the anterior chamber and vitreous body in all injured eyes. In 21 of 30 instances there was complete remission of inflammatory activity for the control period of 18 months after four plasma exchange sessions. All patients had improved visual acuities. The only side effect was incompatibility reactions to human albumin in two cases.

Adolescent↗
PubMed1984

Influence of fluid removal rate during hemodialysis on left ventricular performance and exercise tolerance in patients with coronary artery disease.

The effect of hemodialysis (HD) on left ventricular (LV) function and exercise tolerance were measured at rest and during exercise using gated equilibrium radionuclide ventriculography in seven patients with confirmed coronary artery disease (CAD). To separate the effects of fluid removal rate on LV function in CAD, we investigated the same patients with identical overall volume loss of 4 liters during two different treatment times (4 hr and 2 hr). HD significantly increased resting LV ejection fraction (EF) from 55.7 +/- 8% to 64.7 +/- 8% (P less than 0.01) during the 4 hr HD and from 58.1 +/- 9 to 68.1 +/- 10 (P less than 0.05) during the 2 hr HD. Indicating ischemia, EF decreased at pre- and postdialysis peak exercise without differences between both treatments. HD also resulted in an improved segmental wall motion score. Exercise duration as well as S-T segment depression and angina score improved during HD, whereas heart rate, blood pressure and double product remained unchanged. We conclude that HD improves global and regional resting LV function and exercise tolerance in patients with CAD. The degree of interdialytic hydration and not the degree of fluid removal per time affects LV performance in CAD. Since LV function is the major prognostic factor in CAD, those patients require volume restriction and/or shorter interdialytic phases.

Adult↗
PubMed1983

Gastrointestinal blood loss in patients undergoing maintenance dialysis.

Gastrointestinal blood loss was measured for 14 days in 19 patients treated by hemodialysis and in 2 patients treated by chronic ambulatory peritoneal dialysis. 51Cr was used as a marker for erythrocytes. Fecal blood loss was 5.0 +/- 3.3 ml/day in hemodialysis patients who were not taking drugs affecting thrombocyte aggregation and 4.6 +/- 4.3 ml/day in those receiving sulfinpyrazone. There was no relationship between the severity of anemia, duration of dialysis, dose of heparin, grade of uremic intoxication, or dose of aluminum hydroxide and amount of fecal blood loss. It is concluded that gastrointestinal blood loss is not a major determinant of anemia in chronic renal failure. However, sulfinpyrazone is preferable to acetylsalicylic acid for prevention of shunt thrombosis in uremic patients because of their propensity for gastrointestinal bleeding.

Adult↗
PubMed1983

Efficacy of membrane filtration, influence on hemostasis, immunoglobulins and inflammation mediators during daily plasma exchanges.

Plasma exchange (PE) by membrane filtration was performed with the following hollow fibers: cellulose-diacetate (Plasmaflo 01, Plasmaflo 02, Asahi, Japan), polypropylene (Plasmaflux, Fresenius, FRG) and polymethylmethacrylate (Plasmax, Toray, Japan). The elimination-coefficient (EC) for certain plasma proteins was calculated. With all hollow fibers no correlation between the EC for about ten plasma proteins with a molecular weight of 54.000 dalton up to 2.400.000 dalton. The mean EC-values for the fibers studied were: 0.32 (Plasmaflo 01), 0.52 (Plasmaflo 02), 0.52 (Plasmaflux) and 0.58 (Plasmax). Membrane filtration performed with the single needle technique using either Plasmaflo 02 or Plasmaflux resulted in a significantly lower efficiency with mean EC-values of 0.33 and 0.32 respectively. After three or four days of PE treatment using three liters of 3% human albumin solution as replacement fluid several alterations in parameters of hemostasis were altered: Antithrombin III levels dropped to 35% of normal value after each plasma exchange but increased to normal range within 24 hours during the observed period of four consecutive PE, Fibrinogen concentration dropped permanently to a preexchange value of 40% of the initial concentration after three plasma exchanges. A 40-50% decrease was also observed for prothrombin, plasminogen and alpha-2-macroglobulin after plasma exchange. A decrease in the platelet count ranging from 5 to 25% after each plasma exchange was observed but returned to the initial level before the next treatment. The concentrations of IgG IgA and IgM decreased to less than 20% of preexchange values and C 3 and C 4 to 20-30: of preexchange values after three plasma exchanges.(ABSTRACT TRUNCATED AT 250 WORDS)

Filtration↗
PubMed1983

Myocardial perfusion and left ventricular performance during long and short haemodialysis in patients with coronary heart disease.

In seven patients with confirmed coronary heart disease and stable blood pressure control acetate haemodialysis improved left ventricular performance and exercise tolerance. Similar positive effects were obtained by a four hour dialysis (one litre fluid removal/hour) and a two hour dialysis (two litre fluid removal/hour). In this group of patients weight gain and overhydration between dialyses appears to be the major risk for myocardial perfusion and rapid weight reduction by acetate dialysis appears adequate therapy. One practical consequence from our study is to minimise fluid overload in coronary heart disease and we try to avoid iatrogenic induction of thirst by decreasing dialysate sodium from 140 mmol/litre to 125-135 mmol/litre. As far as myocardial risk factors are concerned it appears that it is more important to focus on interdialysis weight gains than on acute dialysis therapy.

Adult↗