Intrarenal Distribution of Blood Flow in Man

Abstract

To measure blood flow through fast and slow pathways of the kidney separately, a new method of analyzing dye-dilution curves was devised. Twenty-five patients with hypertension or renal disease were selected for study. Indocyanine green was injected into one renal artery and dye-dilution curves were recorded in blood from the ipsilateral renal vein, using a densitometer. Recirculation effect was eliminated by the curve obtained from the contralateral renal vein. For analyzing the dyedilution curves, a new mathematical model and an iterative least squares method of fitting the curve using a digital computer were employed. Basic assumption for the model was that the transit time of each molecule of the dye through fast and slow pathways was a random variable and followed a log-normal distribution. The fast flow measured by the new method was significantly decreased in 11 patients with azotemia compared with that in 14 without azotemia, while changes in slow flow were not significant. Consequently, the ratio of the slow flow to the total flow was increased in renal failure.

Circulation-Time Models of the Uptake of Inhaled Anaesthetics and Data for Quantifying Them

“…Kidney: 2.5 sec in dogs (Wolgast, 1968;Pinter, 1969). In man with hypertension (Takeuchi et aL, 1970) the renal blood volume is 45 ml. Therefore, at the standard-man flow of 1240 ml/min, circulation time would be 2.2 sec.…”

Perfusion of the Residual Renal Cortex in Patients with Chronic Renal Disease

“…It has been difficult to interpret flow per unit tissue mass calculated from the rapid flow component's rate constant in chronic renal failure: Variability has been extreme [19], In many patients the flow rate was normal or even increased [2,3,11,15,[19][20][21]24,26,38,39] , If areas in the renal cortex have an increase in flow, this could account for a compensatory increase in local glomerular filtration rate -as anticipated from animal models [7,25,32.33, 40] , Before the interpretation of the rapid com ponent could be accepted, it was necessary to examine the problems of xenon washout analysis by graphical techniques in a setting characterized by a large decrease in the per centage of the tracer entering the rapid flow component. In the analysis of xenon washout from the normal kidney the rapid flow com ponent because it is large is relatively insensi tive to analytic error [22].…”