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Biomedical subjects

B Gunnarsson

Publications and source records attributed to B Gunnarsson.

12 recordsLinked to original sources
PubMed1979

Hemodynamic changes during sequential ultrafiltration and dialysis.

Seven patients on regular dialysis were studied to elucidate the hemodynamic changes during ultrafiltration and dialysis, performed sequentially, the period of ultrafiltration (1 hour) either preceding or following dialysis (3 hours). During dialysis ultrafiltration was prevented by applying positive pressure in the dialysate compartment. Cardiac index (dye dilution: indocyanine green), heart rate, stroke volume index, blood pressure, and total peripheral vascular resistance index were measured. During ultrafiltration, cardiac index and stroke volume index decreased, but heart rate was not significantly changed. Total peripheral vascular resistance increased, resulting in unchanged blood pressure. During dialysis, the total peripheral vascular resistance decreased, but cardiac index and heart rate increased. BP decreased when the increase in cardiac index was insufficient to compensate for the decrease in total peripheral vascular resistance. PRA increased during ultrafiltration due to hypovolemia and decreased during dialysis, presumably due to decreased sympathetic activity which may also be a cause of dialysis-induced vasodilation.

Adult↗
PubMed1979

Removal of endogenous middle molecules by hemoperfusion.

In four regular dialysis patients, the removal of uremic middle molecules was studied during a three-hour hemoperfusion using a column containing 300 gm of activated carbon encapsulated with cellulose. Middle molecules in plasma were determined by high-speed gel filtration followed by gradient elution chromatography. Different adsorption characteristics were shown for the four middle molecule fractions measured. The initial clearances for middle molecule fractions were about 120 ml/min; clearances were 20-50 ml/min after two hours, and less than 25 ml/min, with release of some middle molecule fractions from the column, after three hours. The findings suggest that saturation of the column occurs after two to three hours of perfusion. Thus, prolongation of the perfusion time beyond two hours appears to be of little benefit. The reduction of middle molecules in plasma by a three-hour hemoperfusion was in magnitude, similar to that obtained by three-hour dialysis with a large surface area dialyzer or high-flux membrane.

Capsules↗
PubMed1979

[Hemodynamic changes during ultrafiltration and hemodialysis in uremia].

1. The ultrafiltration causes a reduction of blood pressure and minute output of the heart which is compensated by vasoconstriction and thus a decrease of blood pressure is prevented. 2. Changes in the salt concentrations with reduction of the osmolarity during the dialysis without simultaneous ultrafiltration lead to vasodilation and hypotension despite increase of the minute output of the heart. 3. During a usual haemodialysis (i.e. dialysis with simultaneous ultrafiltration) the vasodilating effect of the dialysis may abolish the vasoconstrictive effect of the ultrafiltration and thus may be the cause of the hypotension.

Adult↗
PubMed1979

Fibrin deposition in disposable dialyzers before and after re-use.

We have estimated the degree of fibrin deposition as well as changes in dialyzer efficiency of Gambro Optima 13.5 mu dialyzers, re-used up to six times in six regular dialysis patients. After each dialysis the dialyzer was rinsed and left filled with formaldehyde. The patients were given I-125-fibrinogen before the study. The radioactivity from the dialyzer was continuously measured during each dialysis and rinsing procedure. Urea and creatinine clearances were determined 30 min after start of each dialysis. After the last re-use the dialyzer membranes were removed and divided into sections and the radioactivity of each section was measured. Twice as much fibrin deposition was found near the blood inlet of the dialyzer as near the outlet. A higher fibrin deposition was found after each re-use than after the initial dialysis. The clearances of urea and creatinine were scarcely influenced by the re-use. The half-life of fibrinogen in the patients was in the same range as in normal subjects.

Adult↗
PubMed1978

The influence of dialysis fluid composition on the blood pressure response during dialysis.

To elucidate the relative role of osmolar (sodium) and acetate shifts during dialysis, 6 patients with problems of overhydration underwent rapid ultrafiltration for 1 hr (mean weight reduction 2.0 kg), using the 1 m2 RP 6 dialyzer. Ultrafiltration was carried out at the beginning of each of 5 dialysis treatments at weekly intervals. Ultrafiltration was undertaken without dialysis (controls) and with simultaneous dialysis using acetate (40 mmoles/1) or bicarbonate (25 mmoles/1) in the dialysis fluid with dialyzate sodium concentration of 133 and 145 mmoles/1. The systolic blood pressure and mean arterial pressure which were stable with ultrafiltration only fell slightly when a high dialyzate sodium concentration was used and much further when the dialyzate sodium concentration was kept low. These changes were apparently related to the changes in plasma osmolality. Acetate had no effect on blood pressure at the higher sodium concentration, but a slight (insignificant) additive effect when used in the low-sodium dialyzate. Shifts in osmolality (sodium concentration) seem to be more important than the effect of acetate in inducing dialysis-associated hypotension.

Acetates↗