A new system for ultrafiltration control during hemodialysis is described. The apparatus consists of a computer operated system of load cells that register variations in weight of the outlet dialysate versus inlet dialysate. Once the weight loss of the patient has been established, the gravimetric control operates on the dialysate circuit to obtain the transmembrane pressure adequate to achieve the desired ultrafiltration rate and patient weight loss. The system can be used as a complete dialysis machine or as a separate module that can be adapted to any standard dialysis machine. This module was tested in more than 220 dialysis sessions, using different membranes and ultrafiltration rates. The difference between the scheduled and the real weight loss was always less than 100 g at the end of the dialysis session. The number of technical interventions required were few, as was the rate of complications related to the system. The system is safe and reliable and offers a low cost opportunity to improve dialysis tolerance by accurate and progressive ultrafiltration during the session.
The authors compared the efficiency of standard HD (t = 240 minutes, Qb = 300 ml/min, Qd = 500 ml/min) with short HD (t = 150 minutes, Qb = 500 ml/min, Qd = 700 ml/min). The study was carried out in 11 patients in two sequential dialysis sessions, utilizing the same high surface area hollow fiber dialyzers, after a 2 day interdialytic period. With short HD, as expected, the clearance (Cl) of BUN, creatinine (Cr), and phosphates (P) was significantly higher than in standard HD:Cl BUN = 331 vs. 225, Cl Cr = 286 vs. 193, and Cl P = 231 vs. 176 ml/min. No significant difference in the total BUN extraction (measured on the total amount of exhausted dialysate) was found between the two techniques. As to Cr and P, despite higher Cl in short HD, the total extractions were significantly lower. In conclusion, in the evaluation of short HD efficiency, instantaneous Cl can be adequate for small molecules, while for larger solutes, other parameters, such as total extraction, must be considered.
We carried out an in-vivo and in-vitro evaluation of a new polyamide hollow fiber hemofilter especially designed to operate under conditions of low pressure and low blood flow, such as in continuous arteriovenous hemofiltration (CAVH). The results obtained suggest that this filter is a prototype of a new generation of hemofilters especially designed for CAVH. Its low resistance permits its use even in patients with severe hypotension. The high blood flows achieved at a given pressure reduce the risk of clotting and increase the ultrafiltration rate. When an average ultrafiltration of 20-25 ml/min is achieved in 24 hours CAVH becomes very efficient, and alternative techniques to increase its efficiency are no longer required.
Journal Article Impact of High Blood Flows on Vascular Stability in Haemodialysis Get access C. Ronco, C. Ronco Department of Nephrology, St Bortolo Hospital, Vicenza, Italy Department of Nephrology, St Bortolo Hospital, Vicenza, Italy Search for other works by this author on: Oxford Academic PubMed Google Scholar M. Feriani, M. Feriani Department of Nephrology, St Bortolo Hospital, Vicenza, Italy Search for other works by this author on: Oxford Academic PubMed Google Scholar S. Chiaramonte, S. Chiaramonte Department of Nephrology, St Bortolo Hospital, Vicenza, Italy Search for other works by this author on: Oxford Academic PubMed Google Scholar P. Conz, P. Conz Department of Nephrology, St Bortolo Hospital, Vicenza, Italy Search for other works by this author on: Oxford Academic PubMed Google Scholar A. Brendolan, A. Brendolan Department of Nephrology, St Bortolo Hospital, Vicenza, Italy Search for other works by this author on: Oxford Academic PubMed Google Scholar L. Bragantini, L. Bragantini Department of Nephrology, St Bortolo Hospital, Vicenza, Italy Search for other works by this author on: Oxford Academic PubMed Google Scholar M. Milan, M. Milan Department of Nephrology, St Bortolo Hospital, Vicenza, Italy Search for other works by this author on: Oxford Academic PubMed Google Scholar A. Fabris, A. Fabris Department of Nephrology, St Bortolo Hospital, Vicenza, Italy Search for other works by this author on: Oxford Academic PubMed Google Scholar R. Dell'Aquila, R. Dell'Aquila Department of Nephrology, St Bortolo Hospital, Vicenza, Italy Search for other works by this author on: Oxford Academic PubMed Google Scholar D. Dissegna, D. Dissegna Department of Nephrology, St Bortolo Hospital, Vicenza, Italy Search for other works by this author on: Oxford Academic PubMed Google Scholar ... Show more C. Crepaldi, C. Crepaldi Department of Nephrology, St Bortolo Hospital, Vicenza, Italy Search for other works by this author on: Oxford Academic PubMed Google Scholar B. Agazia, B. Agazia Department of Nephrology, St Bortolo Hospital, Vicenza, Italy Search for other works by this author on: Oxford Academic PubMed Google Scholar G. Finocchi, G. Finocchi Department of Nephrology, St Bortolo Hospital, Vicenza, Italy Search for other works by this author on: Oxford Academic PubMed Google Scholar E. De Dominicas, E. De Dominicas Department of Nephrology, St Bortolo Hospital, Vicenza, Italy Search for other works by this author on: Oxford Academic PubMed Google Scholar G. La Greca G. La Greca Department of Nephrology, St Bortolo Hospital, Vicenza, Italy Search for other works by this author on: Oxford Academic PubMed Google Scholar Nephrology Dialysis Transplantation, Volume 5, Issue suppl_1, April 1990, Pages 109–114, https://doi.org/10.1093/ndt/5.suppl_1.109 Published: 01 April 1990
The TINU syndrome (tubulointerstitial nephritis and uveitis) was first described by Dobrin et al. in 1975. Since then, more than 50 cases have been documented each with diverse immunopathogenetic and genetic characteristics. The aim of this report is to describe a case of TINU associated with reduced complement levels. We profile a 48-year-old white female with persistently reduced C4 complement levels during the acute phase of the pathology and with an unaltered immunologic profile. Renal biopsy evidenced a significant lymphocytic interstitial infiltration. Immunohistochemical studies of the interstitium infiltrates was positive for the presence of the T (CD3) markers (CD4 > CD8). Steroid therapy yielded a complete regression of the symptomatology with normalization of the complement levels. We suggest that it is possible to hypothesize that the various immunologic alterations associated with TINU, including the transient reduction complement levels, may be secondary to multiple inflammatory mechanisms which express themselves throughout the pathology.
Eight samples of human peritoneal tissue were obtained from patients undergoing hemicholectomy for cancer. An artery and a vein were cannulated and perfused with blood in vitro with a special circuit able to provide different perfusion pressures. Ultrafiltration and clearance studies were performed in these samples. Both ultrafiltration and small-solute clearances linearly correlated with the blood flow, demonstrating a strong dependence on this parameter. The peritoneal capillary showed a typical filtration pressure equilibrium with a constant filtration fraction at different blood flows. The results suggest that the blood flow may be a factor limiting the efficiency of peritoneal dialysis both in terms of mass transfer coefficients and maximal ultrafiltration rates.
The bicarbonate centered approach to acid-base physiology involves complex explanations for the metabolic acidosis associated with chronic renal failure. We used the alternate Stewart approach to acid-base physiology to quantify the acid-base chemistry of patients with chronic renal failure. We examined the plasma and urine chemistry of 19 patients with chronic renal failure who were predialysis and 20 healthy volunteers. We compared the plasma strong-ion-difference due to sodium,potassium,and chloride ions as well as the weak acids albumin and phosphate. We used a simplified Fencl-Stewart approach to quantify the effects of sodium-chloride, albumin, and unmeasured ions on base-excess. The chronic renal failure group had a greater metabolic acidosis, with a base-excess that differed from the healthy group by a mean of -2.7 mmol/L, p = 0.04. This was associated with a strong ion acidosis due to both increased chloride and decreased sodium. The anion gap, strong-ion-gap, and base-excess effect of unmeasured ions were similar in both groups suggesting that unmeasured ions had only a minor role in the acid-base status in this group of patients.
A new blood module for continuous renal replacement therapies has been utilized to perform CVVH in critically ill patients. The features of the new module named (HP300 and manifactured by Medica srl (Medolla, Modena) are the easy installation and transportability to the bedside, the simple and safe management and the continuous measurement of the pre and post filter pressure with automatic calculation of the end-to-end pressure drop inside the filter. The last feature permits to detect early malfunctions of the filter due to fibers clotting or due to the internal coating of the hollow fibers by plasma proteins. In both cases the efficiency of the treatment can be reduced because of a significant reduction of the ultrafiltration rates or a remarkable decay of the membrane permeability and solute sieving coefficients. In many cases this reduction is only detected when important effects on solute removal have already occurred. In our experience, the new module permitted the substitution of the filters when early malfunctions were detected and maximal treatment efficiency was therefore guaranteed over extended periods of time.
