[show abstract][hide abstract] ABSTRACT: In the 1993 two papers showed that instantaneous ionic dialysance can be measured without the need for blood or dialysate sampling and at no extra cost, simply by using two conductivity probes placed at the dialyzer inlet and outlet or a single probe alternately activated at the inlet and outlet. Given the very close correlation between the conductivity of dialysate and its sodium content it has been suggested that ionic dialysance can be considered equivalent to effective sodium dialysance. When ionic dialysance value is known it is possible to indirectly derive the plasma water conductivity value and thus the sodium concentration. The possibility to estimate sodium dialysance and plasma water sodium concentration without the need for blood samples and laboratory determination makes it very easy to apply the sodium kinetic model changing it in a conductivity kinetic model. Moreover, because of the similar molecular weight of sodium chloride and urea it has been suggested that ionic dialysance can also be considered equivalent to effective urea clearance. Thus, it should be possible to use ionic dialysance instead of urea clearance for the routine monitoring of delivered dialysis dose. Therefore, ionic dialysance seems a very promising and easy tool to improve dialytic treatment.
[show abstract][hide abstract] ABSTRACT: BACKGROUND: Intradialytic hypotension (IDH) is still a major clinical problem for haemodialysis (HD) patients. Haemodiafiltration (HDF) has been shown to be able to reduce the incidence of IDH.METHODS: Fifty patients were enrolled in a prospective, randomized, crossover international study focussed on a variant of traditional HDF, haemofiltration with endogenous reinfusion (HFR). After a 1-month run-in period on HFR, the patients were randomized to two treatments of 2 months duration: HFR (Period A) or HFR-Aequilibrium (Period B), followed by a 1-month HFR wash-out period and then switched to the other treatment. HFR-Aequilibrium (HFR-Aeq) is an evolution of the haemofiltration with endogenous reinfusion (HFR) dialysis therapy, with dialysate sodium concentration and ultrafiltration rate profiles elaborated by an automated procedure. The primary end point was the frequency of IDH.RESULTS: Symptomatic hypotension episodes were significantly lower on HFR-Aeq versus HFR (23 ± 3 versus 31 ± 4% of sessions, respectively, P = 0.03), as was the per cent of clinical interventions (17 ± 3% of sessions with almost one intervention on HFR-Aeq versus 22 ± 2% on HFR, P < 0.01). In a post-hoc analysis, the effect of HFR-Aeq was greater on more unstable patients (35 ± 3% of sessions with hypotension on HFR-Aeq versus 71 ± 3% on HFR, P < 0.001). No clinical or biochemical signs of Na/water overload were registered during the treatment with HFR-Aeq.CONCLUSIONS: HFR-Aeq, a profiled dialysis supported by the Natrium sensor for the pre-dialysis Na(+) measure, can significantly reduce the burden of IDH. This could have an important impact in every day dialysis practice.
[show abstract][hide abstract] ABSTRACT: Anemia in chronic kidney disease dialysis patients is a complex syndrome involving many causes. Adequate dialysis can contribute to its correction through many mechanisms, including the removal of molecules that may inhibit erythropoiesis. The aim of this pilot study was to evaluate the effect on renal anemia of two synthetic, high-flux dialyzers (polynephron vs. high-flux polysulphone).
20 dialysis patients (11 male; mean age: 72 years) were randomly assigned and studied for 6 months. There were 2 dropouts in each group. Each patient underwent 3 hemodialysis treatments per week without any difference in dialysis prescription. At T = 0 and T = 6 (after 6 months), instantaneous plasma clearances and reduction rates of small solutes, ß2-microglobulin protein (ß2-µ); hemoglobin (Hb), and iron pattern were measured. The effect on anemia was evaluated by calculating the Erythropoesis Stimulating Agent (ESA) doses and the Erythropoietin Resistance Index (ERI).
Kt/V increased between T0 and T6 in both groups. ß2-µ pre-dialysis levels significantly decreased between T0 and T6 in both dialyzer groups (p<0.001 in both groups). The Hb levels increased between T0 and T6, but significantly only for the polynephron patient group (p = 0.006 and 0.142). ESA dose did not change significantly. The ERI decreased by 22.7% between T0 and T6 in the polynephron-group and increased by 14% in the others; these changes were not significant.
High-flux filters improved Hb levels, although only significantly in the polynephron group, suggesting a possible different effect. The results should be interpreted with caution and tested in an appropriately powered, large, prospective, randomized control trial.
The International journal of artificial organs 05/2012; 35(5):346-51. · 1.76 Impact Factor
[show abstract][hide abstract] ABSTRACT: Hemodialysis is complicated by a high incidence of intradialytic hypotension and disequilibrium symptoms caused by hypovolemia and a decrease in extracellular osmolarity. Automatic adaptive system dialysis (AASD) is a proprietary dialysis system that provides automated elaboration of dialysate and ultrafiltration profiles based on the prescribed decrease in body weight and sodium content.
A noncontrolled (single arm), multicenter, prospective, clinical trial.
55 patients with intradialytic hypotension or disequilibrium syndrome in 15 dialysis units were studied over a 1-month interval using standard treatment (642 sessions) followed by 6 months using AASD (2,376 sessions).
AASD (bicarbonate dialysis with dialysate sodium concentration and ultrafiltration rate profiles determined by the automated procedure).
Primary and major secondary outcomes were the frequency of intradialytic hypotension and symptoms (hypotensive events, headache, nausea, vomiting, and cramps), respectively.
More stable intradialytic systolic and diastolic blood pressures with lower heart rate were found using AASD compared with standard treatment. Sessions complicated by hypotension decreased from 58.7% ± 7.3% to 0.9% ± 0.6% (P < 0.001). The incidence of other disequilibrium syndrome symptoms was lower in patients receiving AASD. There were no differences in end-session body weight, interdialytic weight gain, or presession natremia between the standard and AASD treatment periods.
A noncontrolled (single arm) study, no crossover from AASD to standard treatment.
This study shows the long-term clinical efficacy of AASD for intradialytic hypotension and disequilibrium symptoms in a large number of patients and dialysis sessions.
American Journal of Kidney Diseases 07/2011; 58(1):93-100. · 5.29 Impact Factor
[show abstract][hide abstract] ABSTRACT: Anemia secondary to chronic kidney disease is a complex syndrome. Adequate dialysis can contribute to its correction by removing small and possibly medium/large molecules that may inhibit erythropoiesis. A clear relationship among hemoglobin, erythropoiesis stimulating agent (ESA) dose and increase in dialysis dose has been pointed out by a number of prospective and retrospective studies. Increasing attention has also been paid to the relationship between dialysis, increased inflammatory stimulus and ESA response, as dialysate contamination and low compatible treatments may increase cytokine production and consequently inhibit erythropoiesis. As medium/large molecular weight inhibitors can be removed only by more permeable membranes, convective treatment sand, particularly, online treatments, could theoretically improve anemia correction by two mechanisms: higher removal of medium and large solutes (possibly containing bone marrow inhibitors) and reduced microbiological and pyrogenic contamination of the dialysate. Unfortunately, available results are conflicting. Large, prospective, randomized studies on this topic are still needed.
Contributions to nephrology 01/2011; 168:162-72. · 1.49 Impact Factor
[show abstract][hide abstract] ABSTRACT: Many observational studies have consistently shown that high-flux hemodialysis (hf-HD) has positive effects on the survival and morbidity of chronic kidney disease stage 5 dialysis (CKD5D) patients when compared with low-flux hemodialysis, but the primary analysis of the prospective randomized Hemodialysis Outcomes (HEMO) study showed that the use of hf-HD was not associated with a significant reduction of the relative risk of mortality. More recently, the Membrane Permeability Outcome (MPO) study found that survival could be significantly improved by use hf-HD compared with low-flux dialysis in high-risk patients as identified by serum albumin ≤4 g/dl and, in a post-hoc analysis, in diabetic patients. Online hemodiafiltration (HDF) is reported as the most efficient technique of using high-flux membranes. Clearances of small solutes like urea are higher than in hemofiltration and of middle solutes like β(2)-microglobulin are higher than in hf-HD. As the number of randomized prospective trials comparing HDF and hf-HD is still very limited, no conclusive data are available concerning the effect of increased convection of online HDF on survival and morbidity in CKD5D patients. A large, randomized controlled study is needed to clinically confirm the theoretical advantages of online HDF.
Contributions to nephrology 01/2011; 168:5-18. · 1.49 Impact Factor
[show abstract][hide abstract] ABSTRACT: Oxidative stress, a recently identified factor related to the response to erythropoiesis-stimulating agents (ESAs), is increased in hemodialysis patients. The aim of this study was to verify whether ESA responsiveness improves if the anti-oxidant vitamin E (Vi-E) is placed on the blood-side layer of a synthetic polysulfone (PS) dialyzer.
This 8-month, controlled and open randomized study involved 2 groups of patients on stable ESA therapy undergoing hemodialysis using a PS dialyzer with or without Vi-E treatment. Hemoglobin, albumin, high-sensitivity C-reactive protein, interleukin-6, iron status, parathyroid hormone (PTH), Vi-E (alpha- and gamma-tocopherol levels) and the oxidative stress markers, advanced oxidation protein products, carbonyls and advanced glycation end products were evaluated every 2 months. The primary outcome measure was ESA resistance, the weekly ESA dose divided by the product between hemoglobin level and end-dialysis body weight.
Nineteen of the 20 randomized patients completed the study. During the follow-up, the ESA resistance significantly decreased (p = 0.024), greater in the Vi-E group (37%) than in the PS group (20%), but this difference was not statistically significant (p = 0.596). Baseline PTH and Vi-E levels were associated with ESA resistance. In the secondary analysis, including these covariates in the model, the difference between groups in ESA resistance became significant (p = 0.042).
Vi-E placed on the blood-side of a dialyzer may have a possible beneficial effect on ESA resistance in hemodialysis patients; baseline PTH levels seem to predict ESA resistance and were useful in showing the possible beneficial effect of Vi-E and should be considered in designing adequate-sized trials for testing this hypothesis.
Nephron Clinical Practice 03/2010; 115(1):c82-9. · 1.65 Impact Factor
[show abstract][hide abstract] ABSTRACT: Convective treatments are characterized by enhanced removal of middle and large molecular weight solutes, important in the genesis of many complications of hemodialysis, compared with conventional low-flux hemodialysis. The availability of these techniques represented an intriguing innovation and a possible means to improve the still poor prognosis of hemodialysis patients. In this study we will critically review the most important published studies evaluating the impact of convective treatments on dialysis outcomes.
The Hemodialysis (HEMO) study showed that greater urea removal nonsignificantly reduces the relative risk of mortality and that also high-flux hemodialysis was associated with a nonsignificant reduction, although a secondary analysis pointed to an advantage for high-flux membranes in subgroups of patients. More recently, the Membrane Permeability Outcome (MPO) study found that survival could be improved by use of high-flux membranes compared with low-flux dialysis in high-risk patients as identified by serum albumin < or =4 g/dl as well as in people with diabetes. In an observational study, hemodiafiltration with large reinfusion volume has been associated with a lower relative risk of mortality, compared with low-flux hemodialysis.
The biologic plausibility of advantages of convective treatments and the results of the MPO and Dialysis Outcomes and Practice Patterns (DOPPS) studies are supporting rationales for the use of convective treatments to improve survival and delay long-term complications of hemodialysis patients.
Current opinion in nephrology and hypertension 09/2009; 18(6):476-80. · 3.96 Impact Factor
[show abstract][hide abstract] ABSTRACT: The most appropriate dialysate composition is one of the central topics in dialysis treatment. The prescription of a certain dialysate composition could change in order to obtain not only an adequate blood purification but also a high tolerability. Sodium balance represents the cornerstone of cardiovascular stability and good blood pressure control. The goal of dialysis is to remove the amount that has accumulated in the interdialysis period. Potassium removal is adequate when hyperkaliemia is avoided. Bicarbonate in dialysate should be personalized in order to avoid acidosis and end-dialysis excessive alkalosis.
Contributions to nephrology 02/2008; 161:7-11. · 1.49 Impact Factor
[show abstract][hide abstract] ABSTRACT: Dialysis membrane characteristics are important for an effective and biocompatible dialysis. The properties of a membrane determine the size range of uremic toxins that are eliminated, but are also associated to patient morbidity and mortality. In this paper we describe dialysis the membrane characteristics that could influence the choice of a different type of dialysis.
Contributions to nephrology 02/2008; 161:162-7. · 1.49 Impact Factor
[show abstract][hide abstract] ABSTRACT: The attainment of a neutral sodium balance represents a major objective in hemodialysis patients. It requires that at the end of each dialysis session, total body water volume (V(f)) and total plasma water sodium concentration (Na(pwf)) are constant. Whereas to achieve a constant V(f) it is sufficient that ultrafiltration equals the interdialytic increase in body weight, it is impossible to predict the value of Na(pwf) and calculate the dialysate sodium concentration needed to obtain it without making use of kinetic mathematical models. The effectiveness of both sodium and conductivity kinetic models in predicting Na(pwf) has already been validated in previous clinical studies. However, applying the sodium kinetic model appears to be poorly feasible in the everyday clinical practice, due to the need for blood samples at the start of each dialysis session for the determination of predialysis plasma water sodium concentration. The conductivity kinetic model appears to be more easily applicable, because no blood samples or laboratory tests are needed to determine plasma water conductivity (C(pw)) and ionic dialysance (ID), used in place of plasma water sodium concentration and sodium dialysance, respectively. We applied the 2 models in 69 chronic hemodialysis patients using the Diascan Module for the automatic determination of C(pw) and ID, and using the latter as an estimate of sodium dialysance in the sodium kinetic model. The conductivity kinetic model was shown to be more accurate and precise in predicting Na(pwf) as compared with the sodium kinetic model. Both accuracy and imprecision of the 2 models were not significantly affected by the method used to estimate total body water volume. These findings confirm the conductivity kinetic model as being an effective and easily applicable instrument for the achievement of a neutral sodium balance in chronic hemodialysis patients.
Hemodialysis International 04/2007; 11(2):169-77. · 1.44 Impact Factor
[show abstract][hide abstract] ABSTRACT: Standard haemodialysis is not a very efficacious treatment of chronic uraemia and patient mortality rate is still very high. The 2002 results of the HEMO study showed that alternative treatments such as 'high-efficiency haemodialysis' and 'high-flux haemodialysis' are associated with a non-significant reduction in the relative risk of mortality (4 and 8%, respectively). In an attempt to define the clinical impact of haemodiafiltration, we review some of the efficacy data from clinical studies in light of a number of factors that may be related to the high mortality among haemodialysis patients.
Contributions to nephrology 02/2007; 158:185-93. · 1.49 Impact Factor
[show abstract][hide abstract] ABSTRACT: We have previously shown that, assuming urea distribution volume (V) remains constant for 1 month, ionic dialysance (ID) allows the dialysis dose to be calculated without the need for blood sampling. The aim of this multicenter study was to verify whether the assumption of a constant V can be extended to 1 year. In clinically stable patients receiving thrice-weekly hemodialysis at 13 dialysis centers, V and Kt/V were assessed during three dialysis sessions at baseline and 1 year later using ID as dialyzer urea clearance and the single-pool urea kinetic model. Baseline albumin, hemoglobin, and C reactive protein were prespecified covariates for predicting the change in V over time. Of the 52 enrolled patients, 40 (25 males; age 63.0+/-13.5 years) completed the study. Baseline end-dialysis body weight (62.4+/-13.7 kg) showed a non-significant 1% reduction during follow-up (-0.6+/-2.8 kg; P=0.175), whereas V significantly decreased from 29.0+/-6.8 to 27.4+/-6.0 l (-1.6+/-3.0 l or 4.5%; P=0.002). The reduction in V was greater when baseline albumin was lower (P=0.001) and baseline V was higher (P=0.005). The single-pool K(t)/V calculated using baseline V underestimated the actual value by 0.07+/-0.16 (P=0.008). The slight underestimate of Kt/V during follow-up suggests that annual V evaluations may be sufficient for dialysis dose quantification as the only risk is underestimating the actually delivered dialysis dose. However, the relationship between baseline albumin and the reduction in V over time may have nutritional value, and suggests more frequent V evaluations.
Kidney International 03/2006; 69(4):754-9. · 7.92 Impact Factor
[show abstract][hide abstract] ABSTRACT: Convective treatments (high-flux hemodialysis (HD), hemodiafiltration and hemofiltration) are characterized by enhanced removal of middle and large molecular weight solutes compared with conventional low-flux HD. As these molecules are claimed to play an important role in the genesis of many complications of chronic HD, the availability of these techniques represented an intriguing innovation and a possible means to improve the still poor prognosis of HD patients. Here we will critically review the most important published studies comparing convective treatments with low-flux HD on chronic morbidity, preservation of residual renal function, and long-term survival.
Hemodialysis International 02/2006; 10 Suppl 1:S33-8. · 1.44 Impact Factor
[show abstract][hide abstract] ABSTRACT: There are considerably fewer randomized controlled trials investigating hemodialysis (HD) than other fields of internal medicine, and no significant improvements have been observed over time. Only the National Cooperative Dialysis Study and the HEMO trial were based on hard endpoints such as morbidity and mortality, but neither considered on-line hemodiafiltration or super-flux membranes, which are thought to provide a number of advantages in terms of the cardiovascular condition of uremic patients. However, results of well-designed clinical trials showing that increasing convection may improve the clinical outcome of HD patients are still lacking. The need for maximizing removal of uremic toxins calls for more frequent HD sessions, but this may be affected by many organizational problems. Therefore, well-designed, long-term clinical trials are urgently needed to investigate which currently available therapeutic instruments can improve the clinical outcome of uremic patients.
[show abstract][hide abstract] ABSTRACT: On-line determination of ionic dialysance (ID) has been used to measure the clearance of small solutes like urea. However, attempts to determine the in vivo relationship between ID and urea clearance have led to discordant findings. The aim of this study was to determine the relationship between the mean values of repeated instantaneous determinations of ID throughout a dialysis session ((m)ID), obtained using a single-step inlet dialysate conductivity profile, and the mean values of urea clearance corrected for access recirculation (K(eu1)), total recirculation (access plus cardiopulmonary recirculation, K(eu2)), and the entire postdialysis urea rebound (K(wb)).
Eighty-two anuric patients on chronic thrice-weekly hemodialysis were studied using an Integra machine equipped with the Diascan module for the automatic determination of ID. The mean values of repeated ID measurements made at 30-minute intervals were compared with K(eu1) (available for only 31 patients), K(eu2), and K(wb).
The results in all 82 patients were: (m)ID = 176 +/- 23 mL/min; K(eu2) = 181 +/- 25 mL/min; K(wb) = 159 +/- 22 mL/min. The mean (m)ID/K(wb) and (m)ID/K(eu2) ratios were, respectively, 1.11 +/- 0.06 and 0.98 +/- 0.06. The results in the 31 patients for whom K(eu1) values were available were: (m)ID = 179 +/- 24 mL/min and K(eu1) = 200 +/- 27 mL/min; the mean (m)ID/K(eu1) ratio was 0.90 +/- 0.05.
The mean value of repeated ID determinations obtained using a single-step conductivity profile underestimates urea clearance corrected for access recirculation, and may be considered an adequate estimate of urea clearance corrected for total recirculation.
Kidney International 12/2005; 68(5):2389-95. · 7.92 Impact Factor