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Celestina Manzoni

Publications and source records attributed to Celestina Manzoni.

8 recordsLinked to original sources
PubMed2006

The relevance of convection in clinical practice: a critical review of the literature.

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.

Hemodiafiltration↗
PubMed2005

Relationship between urea clearance and ionic dialysance determined using a single-step conductivity profile.

BACKGROUND: 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)). METHODS: 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). RESULTS: 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. CONCLUSION: 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.

Anuria↗
PubMed2004

Ionic dialysance allows an adequate estimate of urea distribution volume in hemodialysis patients.

BACKGROUND: An adequate estimation of urea distribution volume (V) in hemodialysis patients is useful to monitor protein nutrition. Direct dialysis quantification (DDQ) is the gold standard for determining V, but it is impractical for routine use because it requires equilibrated postdialysis plasma water urea concentration. The single pool variable volume urea kinetic model (SPVV-UKM), recommended as a standard by Kidney Disease Outcomes Quality Initiative (K/DOQI), does not need a delayed postdialysis blood sample but it requires a correct estimate of dialyser urea clearance. METHODS: Ionic dialysance (ID) may accurately estimate dialyzer urea clearance corrected for total recirculation. Using ID as input to SPVV-UKM, correct V values are expected when end-dialysis plasma water urea concentrations are determined in the end-of-session blood sample taken with the blood pump speed reduced to 50 mL/min for two minutes (U(pwt2')). The aim of this study was to determine whether the V values determined by means of SPVV-UKM, ID, and U(pwt2') (V(ID)) are similar to those determined by the "gold standard" DDQ method (V(DDQ)). Eighty-two anuric hemodialysis patients were studied. RESULTS: V(DDQ) was 26.3 +/- 5.2 L; V(ID) was 26.5 +/- 4.8 L. The (V(ID)-V(DDQ)) difference was 0.2 +/- 1.6 L, which is not statistically significant (P= 0.242). Anthropometric volume (V(A)) calculated using Watson equations was 33.6 +/- 6.0 L. The (V(A)-V(DDQ)) difference was 7.3 +/- 3.3 L, which is statistically significant (P < 0.001). CONCLUSION: Anthropometric-based V values overestimate urea distribution volume calculated by DDQ and SPVV-UKM. ID allows adequate V values to be determined, and circumvents the problem of delayed postdialysis blood samples.

Hemodialysis Solutions↗
PubMed2003

Sodium removal during pre-dilution haemofiltration.

BACKGROUND: Cardiovascular instability still affects a large percentage of uraemic patients undergoing extracorporeal substitutive treatments. Post-dilution haemofiltration has been reported to be a method for improving cardiovascular stability; however, the limited removal of small molecular weight solutes together with the need for high blood flow from the fistula greatly restrict the use of this treatment. To increase the solute clearances and to partially resolve the necessity for high blood flow, the replacement solution, in a quantity about double that used in post-dilution mode, can be administered in pre-dilution mode. A high vascular stability has also been observed for pre-dilution haemofiltration. Since the lower morbidity may be due to less sodium removal when compared with haemodialysis, it would be important to characterize the sodium transport in this kind of treatment. METHODS: Nine patients underwent nine pre-dilution haemofiltration treatments (one for each patient) with on-line prepared substitution fluid. RESULTS: As mean values, total (NaF(pw)) and ionized (NaE(pw)) plasma water sodium concentrations increased from 149.4 +/- 2.8 mEq/l to 151.1 +/- 2.4 mEq/l, and from 143.1 +/- 2.8 to 144.5 +/- 1.2 mEq/l, respectively, during the treatment, suggesting a hypotonic concentration of net ultrafiltrate. Plotting the difference between final and initial ionized plasma water concentrations (fNaE(pw) - iNaE(pw)) against the difference between initial plasma water values and ionized sodium concentration in the reinfusate (iNaE(pw) - NaE(R)), a significant negative correlation was found, with the regression line that intercepts the abscissa at the (iNaE(pw) - NaE(R)) value of 8.8 mEq/l; this means that to avoid changes in NaE(pw) in our patients, the NaE(R) should be lower than the iNaE(pw) by this amount. This is quite different from the theoretical value of approximately 4 mEq/l necessary to avoid changes in NaE(pw) during haemodialysis. The ratio between the total sodium concentration in the ultrafiltrate (NaF(uf)) and NaF(pw) (alpha) at the post-reinfusion site was 0.96 and decreased to 0.94 when NaF(pw) values at the pre-reinfusion site were considered. This last value is quite close to the theoretical alpha value of post-dilution haemofiltration. CONCLUSION: As for post-dilution haemofiltration, less sodium removal, compared with haemodialysis, can partly explain the improved cardiovascular stability during pre-dilution haemofiltration.

Hemofiltration↗
PubMed2002

The importance of convective transport.

BACKGROUND: Despite technological advances in dialysis equipment and modalities, survival, morbidity, and quality of life of hemodialysis patients are still severely affected by acute intradialytic and long-term complications, possibly related to the treatment itself. Convective treatments, such as high-flux hemodialysis, hemodiafiltration, and hemofiltration are increasingly suggested as further improvements over standard diffusive hemodialysis. The membranes used for these techniques are high-flux semisynthetic and synthetic membranes. Characteristics of these membranes are high permeability, which allows convective removal of water and electrolytes and higher clearance of middle and large molecular weight solutes, and high biocompatibility, which minimizes the "inflammatory response" secondary to interactions between blood and the artificial material of the hemodialysis system. METHODS: With the specific aim of verifying the superiority of convective treatments in reducing morbidity and mortality, we performed a review of the published literature. RESULTS: Some epidemiological studies suggest that convective treatments reduce morbidity and mortality among dialysis patients. However, the results of the published prospective randomized controlled trials are conflicting. Moreover, since convective treatments are usually performed with synthetic biocompatible membranes, it is hard to separate the effect of convection from the effect of biocompatibility. CONCLUSIONS: To finally assess the effect of high-flux membranes on morbidity and mortality, the results of two randomized, controlled clinical trials (HEMO study and MPO study) specifically designed with this aim are needed.

Amyloidosis↗
PubMedDate not supplied

Nephrology: main advances in the last 40 years.

Modern nephrology has become one of the liveliest and most productive branches of medicine. Once seen as a temporary means of rescue from uremic coma, hemodialysis (HD) has allowed thousands of people with irreversible uremia to survive for many years, and evolving treatment modalities have led to a significant increase in efficacy and tolerability. At the same time, two other forms of renal replacement therapy (RRT) have been developed: peritoneal dialysis (PD) and renal transplantation. The number of end-stage renal disease (ESRD) patients requiring RRT has increased dramatically throughout the world for a number of reasons: the improved survival of patients affected by other diseases, a real increase in the incidence of chronic kidney disease (CKD) mainly due to the burden of 'metabolic syndrome', and the significant broadening of RRT acceptance criteria. This last factor means that RRT has become available to increasing numbers of elderly patients, diabetics and patients with other severe comorbidities, among whom the leading cause of death is cardiovascular disease (CVD). However, nephrology is not just a case of substituting the function of failing kidneys; it also covers the treatment of glomerular diseases, slowing down CKD progression and managing the related comorbidities, all of which have substantially improved over the last 40 yrs.

Global Health↗