Concomitant Clearances of Creatinine,d-Xylose,Urea and Chlorides During Diuresis in Congestive Heart Failure

Abstract

To get evidences of the mechanisms by which diuresis is accomplished in the edematous patient with heart disease, studies have been carried out on the concentration of various substances in the blood and in the augmented output of urine. Creatinine, or the total chromogenic clearance has been advocated by Rehberg 1 as a measure of the amount of glomerular filtration. The validity of this contention has been attacked by several investigators. Marshall 2 and Jolliffe, Shannon and Smith 3 have advocated the use of sugars and especially of d-xylose excretion and concentration as the index of the amount of glomerular filtration. Inasmuch as we 5 and others 1 noted great mobilization and increases in chloride and urea output during diuresis we 3 have included determinations of these substances in our studies. The urea clearance has been established by Van Slyke and his coworkers 4 as a measure of renal function. We have calculated in addition to this clearance, a similar but more arbitrary figure for chlorides, d-xylose and creatinine. The milligrams per cent of these substances in the urine and in the blood serum were determined simultaneously; dividing the former by the latter gives the degree of concentration or the index which is multiplied by the volume of urine output in cubic centimeters per minute. For convenience we have called these final values “clearances”, though they are not established as such for anything but urea. The figure represents directly the amount of blood flow through the kidneys necessary to yield the minute output. The normal values for urea have been established at 54 for urinary flow rates from 0.5 to 1.5 cc, and at 75 for rates above 2 cc. per minute; the respective chloride rates are 0.5 to 7.5; the d-xylose rate about 90; and creatinine about 150.