Forecasting correct sodium balance in hemodiafiltration procedures involving infusions.

Four patients, stable on acetate hemodialysis (AHD), were switched to acetate-free biofiltration (AFB) which differs from AHD and bicarbonate hemodialysis (BHD) in that the dialysate contains no buffer, which is given intravenously as a hypertonic (1/6 M) Na bicarbonate solution. Within the 1st month the patients developed thirst and hypertension attributed to a positive Na balance. The aim of this investigation was to check this (1) by a study based on the predictable changes induced in the body compartments of 13 patients by the infusion and ultrafiltration (UF) of a hypertonic solution and (2) by direct determination and calculation of 28 Na mass balances in BHD and AFB. The theoretical model indicated that infusion of 4.87 liters of a 166.7 mEq/l Na bicarbonate solution and UF of the same amount caused a positive balance of 233 mosm of Na. The Na mass balances showed a relationship between Na transmembrane gradient and loss or gain of Na in both methods (p less than 0.0001). The slopes of the regression lines were not significantly different but there was a highly significant difference between the y axis intercepts (p less than 0.0001), which indicates that the same Na transmembrane gradient that gives no net change of Na in BHD, induces a net gain of 240 mosm (120 mEq of Na) in AFB and that to obtain the same Na balance dialysate Na should be reduced by about 8 mEq/l in AFB. These data are the same as the theoretical forecast which could be extended to all hemodiafiltration methods in which solutions of any tonicity have to be infused, in order to correctly predict the Na balance.

Transport of water and solutes in uremic patients with chronic hepatic disease in CAPD.

Ten patients with chronic hepatic disease (CHD) were compared with 34 non-CHD (N) pts. All patients underwent a peritoneal equilibration test; the asymptotic curves for small solutes transport were transformed into straight lines; protein transport was also expressed as a straight line; the slopes of these linear functions were used as index of solute transfer. CHD patients showed increased UF and transport of all solutes. The well-known relationships between UF and glucose absorption and between UF and dialysate sodium concentration were observed in N, but not in CHD patients. In patients without hepatic disease there was also a relationship between UF and the glucose transport slope, which was not observed in CHD pts. These results are probably due to the influence of hepatic lymph production plus increased lymphatic removal, observed in non uremic patients affected by cirrhosis, on the mechanisms of water and solute transport in CAPD. CHD patients can be managed either with CAPD or with short frequent exchanges. Ascites production can be evaluated by the difference between the observed UF in a patient with CHD and the expected UF in N patients.

Hemodialysis with "adequate" sodium concentration in dialysate.

This investigation was undertaken to define the "adequate" sodium concentration in the dialytic fluid allowing to maintain a stable plasma effective osmolality during dialysis. Isonatric dialysate is shown to miss this aim by inducing a predictable postdialytic hypernatremia. To avoid this effect a new approach was made. 17 clinically stabilized patients, previously dialyzed over a period of at least 2 years with a dialysate sodium concentration of 133 mEq/l, underwent dialysis with the "adequate" sodium concentration in the dialysate for over 3 years. During dialysis cramps, headache, hypotension, hypertensive crises and postdialytic weakness were reduced in frequency and nearly disappeared. No deterioration in blood pressure control occurred and improvement in some general parameters (hematocrit, glucose and insulin metabolism, well-being) was reported after prolonged treatment.

Acute renal failure after rifampicin: a case report and survey of the literature.

A new case of acute renal failure after rifampicin is presented, together with a review of the 36 similar cases published up to date in the literature. Evidence is provided that irregularities in drug intake, either as true intermittent treatment or as discontinuation of continuous therapy, play an important role in the pathogenesis of such reactions. Renal failure appeared after a rather long uneventful interval from the beginning of rifampicin therapy, ranging from 1 month to more than 1 year. Its clinical course was favourable in all but one case; the histological picture was mainly of tubulo-interstitial type. The controversial immunological data reported in the literature are reviewed; an increase of histamine release by rat mast cells has been found in presence of rifampicin plus the serum of our patient: the implications of this finding are discussed, suggesting a possible immunological factor in the pathogenesis of acute renal failure after rifampicin.