Individual Renal Plasma Flow Research Articles

Hemodynamic and sympathetic responses to human atrial natriuretic peptide infusion in patients with cirrhosis

To determine the potential usefulness of atrial natriuretic peptide (ANP) in patients with cirrhosis, we examined the effects of the infusion of a iow dose of α-human ANP (αhANP, 25 ng · kg −1 · min −1 for 30 min) on renal, splanchnic, systemic hemodynamics and sympathetic outflow in eight patients. Pulmonary arterial plasma ANP concentrations increased from 59 ± 9 to 328 ± 41 pg/ml (mean ± S.E., p < 0.05). Mean values of glomerular filtration rate and renal plasma flow were not significantly changed. Individual renal plasma flow responses differed from one patient to another. Renal plasma flow increased in two patients, decreased in three and did not change in the other patients. Renal plasma flow changes were correlated with basal renal plasma flow values ( r = −0.938, p < 0.05) but not with arterial pressure changes or renal vein plasma norepinephrine concentration changes. Azygos blood flow increased from 0.43 ± 0.10 to 0.63 ± 0.13 l/min ( p < 0.05) and the hepatic venous pressure gradient decreased from 19.9 ± 1.5 to 17.5 ± 2.9 mmHg in post-infusion ( p < 0.05). Mean arterial pressure decreased significantly by 18% and cardiac output by 12 %. Systemic vascular resistance and pulmonary arterial plasma norepinephrine concentrations were not significantly modified. Thus, in patients with cirrhosis, ahANP appears to have a direct vasodilating action on renal arterioles when basal renal vascular tone is high. In addition, although αhANP might exert a portal hypoytensive action, αhANP induced arterial hypotension as a result of both low cardiac output and a lack of increased sympathetic vascular tone. The arterial hypotensive action may, thus, limit the therapeutic use of low doses of αhANP in cirrhotic patients.

Individual Renal Plasma Flow Determination in 2 Minutes

A method is described for determining effective renal plasma flow, using the renal counts 1 to 2 minutes after injection and applying background subtraction as a ratio to the total amount of radioactivity injected intravenously with appropriate correction for kidney depth. It appears that this simple approach for determination of effective renal plasma flow within a matter of 2 minutes is accurate and reliable, and should be useful for a number of applications when it is important to determine total and individual renal plasma flow. The approach is recommended as a screening procedure in lieu of the determination of blood urea nitrogen and serum creatinine, with the additional advantages of gross morphology and determination of individual renal plasma flow in an absolute as well as relative manner.

Individual Renal Plasma Flow Determination without Ureteral Catheterization

Individual Renal Plasma Flow Determination without Ureteral Catheterization