Is it easier to dialyze women than men?

Since the urea kinetic model is used as an objective method for monitoring dialysis, it has been possible to shorten reasonably its duration. From the usual practice, we have observed that it is easier to reduce the dialysis time in women as compared to men. The purpose of this study is to find out the reason for such observation and to corroborate it. Fourty-two patients, 25 males and 17 females on 3-weekly dialysis (3 h/session) were studied. All patients were dialyzed under the same dialysis characteristics: 3-hour sessions, blood flow 350 ml/min, ultrafiltration 1.5 liters/h, 1.5-m2 cuprophane membrane and bicarbonate buffer. The dialysate was collected in a graduated tank. Urea concentration in plasma and in the dialysate was measured. Then, the urea distribution volume, dialyzer clearance, the KT/V index and protein catabolic rate were calculated. The KT/V value was higher in women with respect to men, 1,017 +/- 0.10 versus 0.82 +/- 0.14 (p < 0.001). The urea distribution volume value was significantly higher in men as compared to women, 60.04 +/- 6.6 versus 51.48 +/- 5.88% (p < 0.001). There were no significant differences in dialyzer clearance, protein catabolic rate or body weight. In conclusion, under identical dialysis conditions, it is easier to dialyze women than men, because women's urea distribution volume is lower than men's.

Analysis of urea distribution volume in hemodialysis

According to the urea kinetic model it is considered that the urea distribution volume (V) is that of body water, and that it is distributed in only one compartment. Since the V value is different to measure, it is normal to use 58% of body weight, in spite of the fact that it may range from 35 to 75%. In this study, we have calculated the value of V by using an accurate method based on the total elimination of urea from the dialysate. We have studied the V, and also whether the different dialysis characteristics modify it. Thirty-five patients were included in this study, 19 men and 16 women, under a chronic hemodialysis programme. The dialysate was collected in a graduated tank, and the concentration of urea in plasma and in dialysate were determined every hour. Every patient received six dialysis sessions, changing the blood flow (250 or 350 ml/min), the ultrafiltration (0.5 or 1.5 l/h), membrane (cuprophane or polyacrylonitrile) and/or buffer (bicarbonate or acetate). At the end of the hemodialysis session, the V value ranged from 43 to 72% of body weight; nevertheless, this value was practically constant in every patient. The V value gradually increased throughout the dialysis session, 42.1 +/- 6.9% of body weight in the first hour, 50.7 +/- 7.5% in the second hour and 55.7 +/- 7.9% at the end of the dialysis session. The change of blood flow, ultrafiltration, membrane or buffer did not alter the results. The V value was significantly higher in men in comparison with women, 60.0 +/- 6.6% vs. 50.5 +/- 5.9% of body weight (p < 0.001).

Treatment of nephrotic syndrome associated with idiopathic rapidly progressive glomerulonephritis and cyclosporin A

Recent reports suggest that cyclosporin A is beneficial in inducing remission of idiopathic nephrotic syndrome. Nephrotic syndrome is seen in 10-30% of patients with rapidly progressive glomerulonephritis. We report a case of a 69-year-old man with nephrotic syndrome, associated with idiopathic rapidly progressive glomerulonephritis, who was treated initially with corticosteroid and cyclophosphamide. Three months later he developed thrombophlebitis and leucopenia and cyclophosphamide was suspended. Relapse of nephrotic syndrome associated with rapidly progressive glomerulonephritis developed and therapy with cyclosporin A was used with a good response.

Low molecular weight heparin (CY-216) versus unfractionated heparin in chronic hemodialysis

In 14 patients undergoing chronic hemodialysis, we investigated the safety and efficacy of the low molecular fragment (CY-216) in comparison to unfractionated heparin (UFH) in the prevention of clotting in the extracorporeal circuit (ECC). In this study, 168 hemodialysis sessions were undertaken with UFH in 2 bolus doses (5,437 +/- 1,477 SD IU) and 231 with CY-216 in a single bolus dose [initial dose 150 anti-Xa U Institut Choay (IC)/kg]. There were no clots in the bubble trap in any UFH sessions, and 14.8% had coagulated fibers in the dialyzer. Clotting in the bubble trap was observed in 2 CY-216 sessions (0.8%) and coagulated fibers in 22.6% of the sessions. At the end of the study, the mean dose of CY-216 was 250 anti-Xa UIC/kg but a dose of 350 anti-Xa UIC/kg was needed in the 2 patients treated by recombinant human erythropoietin. Anti-Xa levels at the end of the runs were higher (0.47 +/- 0.1 U/ml) in the CY-216 group than in the UFH group (0.28 +/- 0.1 U/ml). There was a correlation between anti-Xa levels and efficacy in the CY-216 group. An anti-Xa activity above 0.4 U/ml was needed in order to minimize thrombus formation. Antithrombin III-protease complexes (ATM) and D dimer fibrin derivatives (D dimer) were used as thrombotic markers but they were of little value for the detection of fibrin formation in the ECC. Our findings suggest that CY-216 administered as a single bolus dose seems to be of similar effectiveness to UFH.