The relationship of sodium retention and venous pressures to edema formation.

Two patients witlh congestive cardiac failure were pllaced on a metabolic balance regimen ancl supplemental sodium chloride was administered. Weight changes in these patients could lbe closely correlated with the amount of sodium retention and .lpl)eared to be initially independent of bra-chial venous pressure thus supporting the concept that edemna in congestive failure results from prinmary. soClium retention rather than primiary elevation in venous pressure. T HE denioiistrationl by Warren and Stead' that administration of sodium to patients with compei sated heart failure resulted ill gaini ini weight, followed by a rise ill enious pressure, was a departure from the concept of edema formation current at the time. It is now generally assumed that factors, other than increased venous pressure may initiate the retention of salt and water. However, it may still be of interest, to note that an increase of several kilograms ill the amount of extracellular fluid cati occur prior to any demonstrable change in the measurement of pressure ini the mediani cubital vein at the elbow. Electrolyte and nitrogen balances, observations of venlous pressures, and body weights acquired in the course of a metabolic balance study lent themselves to a quantitative examination of these relationships. M\IETHODS The actual variations in weight of two patients with congestive cardiac failure (patients EHP and EVJ) were related to weight changes arrived at theoretically and calculated from balance data, using the constants proposed by Reifenstein, Al-bright andl Wells.2 The (lerived values for the retention of water were then complared with carefully obtained venous plressu es. The metabolic data and the methods employed were olntaine(l bv conventional balance technics. Analytic metho(ls were as follows: nitrogen by the(c)(c2). Hiller, Pllazin and Vrtan Slvke niodification of the Kjeldlahl procedlure directlv on the urine and emul-sified samples of cliet, stool, etc. ;3 chloride by modification of the Volhard silver nitrate ammonium thiocv-anate titration directly on specimens of di-lutecl urine and on solutions of aliquots of (liet, feces, emiesis and sputum;4'6 sodium and potassium by. the Beckm.an flame photometer lilrectlv on specimens of dilute(l urine and on solutions of the ash of ali-quots of dliet, feces, emesis and sputum. Ashing was l)erfolmed in a muffle furnace at temperatures not exceeding 450 C. Each l)atient was maintained on t o levels of sodium intake, and the effect of adreno-corticotropin was observed at each level. Actual changes in weight were measured on a scale accurate to 10 Gnm. …