Creatinine Removal Research Articles

Establishing the presence or absence of chronic kidney disease: Uses and limitations of formulas estimating the glomerular filtration rate.

The development of formulas estimating glomerular filtration rate (eGFR) from serum creatinine and cystatin C and accounting for certain variables affecting the production rate of these biomarkers, including ethnicity, gender and age, has led to the current scheme of diagnosing and staging chronic kidney disease (CKD), which is based on eGFR values and albuminuria. This scheme has been applied extensively in various populations and has led to the current estimates of prevalence of CKD. In addition, this scheme is applied in clinical studies evaluating the risks of CKD and the efficacy of various interventions directed towards improving its course. Disagreements between creatinine-based and cystatin-based eGFR values and between eGFR values and measured GFR have been reported in various cohorts. These disagreements are the consequence of variations in the rate of production and in factors, other than GFR, affecting the rate of removal of creatinine and cystatin C. The disagreements create limitations for all eGFR formulas developed so far. The main limitations are low sensitivity in detecting early CKD in several subjects, e.g., those with hyperfiltration, and poor prediction of the course of CKD. Research efforts in CKD are currently directed towards identification of biomarkers that are better indices of GFR than the current biomarkers and, particularly, biomarkers of early renal tissue injury.

Comparison of hemodialysis with medium cut-off dialyzer and on-line hemodiafiltration on the removal of small and middle-sized molecules .

Recent data suggest that the use of medium cut-off (MCO) dialyzers in hemodialysis (HD) promotes greater clearance and reduction ratio (RR) for myoglobin and other large-sized molecules than on-line hemodiafiltration (ol-HDF), but its effects on β2-microglobulin are not clear. We compared RR and clearances of small and middle-sized molecules between high-flux ol-HDF and MCO (Theranova) dialyzer in HD (MCO-HD) as well as nutritional parameters. We retrospectively analyzed 10 patients treated first with ol-HDF who were thereafter switched to MCO-HD over a 1-year period. Three dialysis sessions in each 6-month period were examined. We calculated RR and clearance of small and middle-sized molecules. There was no significant difference between ol-HDF and MCO-HD for median serum albumin and prealbumin level, mean KT/V, mean urea and creatinine RR, mean β2-microglobulin (81 ± 5 vs. 81 ± 6%, p = 0.72) and myoglobin (60 ± 9% vs. 61 ± 7%, p = 0.59), RR or clearances. The use of MCO (Theranova) dialyzer in HD produces similar removal of urea, creatinine, β2-microglobulin and myoglobin as does ol-HDF, with good tolerance profile and without modification of nutritional status. .

Degradation of creatinine using boron-doped diamond electrode: Statistical modeling and degradation mechanism

This study investigated the degradation performance and mechanism of creatinine (a urine metabolite) with boron-doped diamond (BDD) anodes. Experiments were performed using a synthetic creatinine solution containing two supporting electrolytes (NaCl and Na2SO4). A three-level central composite design was adopted to optimize the degradation process, a mathematical model was thus constructed and used to explore the optimum operating conditions. A maximum mineralization percentage of 80% following with full creatinine removal had been achieved within 120 min of electrolysis, confirming the strong oxidation capability of BDD anodes. Moreover, the results obtained suggested that supporting electrolyte concentration should be listed as one of the most important parameters in BDD technology. Lastly, based on the results from quantum chemistry calculations and LC/MS analyses, two different reaction pathways which governed the electrocatalytic oxidation of creatinine irrespective of the supporting electrolytes were identified.

\u03b2-trace protein is highly removed during haemodialysis with high-flux and super high-flux membranes

BackgroundSerum β-trace protein (βTP, MW 23–29 kDa) is a marker of GFR impairment in renal patients. Recent papers propose to predict residual renal function (RRF) in maintenance haemodialysis (MHD) patients from serum concentrations of βTP and other small proteins, avoiding the collection of urine. Few data are available on the removal of βTP in patients treated with dialysis membranes with different flux characteristics. The aim of this study was to evaluate the effects of haemodialysis with low-flux, high-flux and super high-flux membranes on serum concentrations of ßTP in MHD patients with null RRF.MethodsSerum ßTP concentrations were measured before and after the first dialysis of the week in 51 MDH patients treated by low-flux (n = 24), high-flux (n = 17), or super high-flux (n = 10) membranes. The removal of β2-microglobulin (β2M, MW 11.8), cystatin C (Cys, MW 13.3), urea and creatinine was also analyzed.ResultsLow-flux membranes did not remove βTP, β2M and Cys whose concentration increased at the end of dialysis. High-flux membrane removed more efficiently β2M and Cys than ßTP. Super high-flux membrane had the highest efficiency to remove ßTP: mean reduction ratio (RR) 53.4%, similar to β2M (59.5%), and Cys (62.0%).ConclusionsIn conclusion, the plasma clearance of small proteins and particularly of βTP is dependent from the permeability of the dialysis membranes Therefore, the reliability of the formulas proposed to predict RRF from serum βTP and other LMWP may be affected by the different permeability of the dialysis membranes.

Biomedical analytical monitor of artificial kidney operation: Monitoring of creatinine removal

A general concept for the development of flow analysis system for non-invasive, bloodless monitoring of uremic toxins’ removal in the course of clinical hemodialysis treatment is presented. The monitor operates in both (discrete and continuous) modes of measurements. In this study as a model uremic marker creatinine has been chosen. The monitor is based on solenoid operated microdevices (pumps and valves) and an optoelectronic flow-through detector made of paired light emitting diodes allowing photometric determination of this metabolite using Jaffé method. Additionally, a simple two microsolenoid pump-based module allowing the modeling of toxin removal by artificial kidney has been developed. The developed monitor has been validated with real samples of postdialysate fluid produced by artificial kidney in the course of clinical hemodialysis treatment. The results of hemodialysis monitoring are fully comparable with those obtained using reference off-line method.

Con-Current versus Counter-Current Dialysate Flow during CVVHD. A Comparative Study for Creatinine and Urea Removal

Background: Dialysate fluid connection to the membrane in continuous dialysis may affect solute clearance. Although circuit connections are routinely made counter-current to blood flow in intermittent dialysis, no study has assessed the effect of this dialysate fluid flow direction on removal of small solutes creatinine and urea during treatment using continuous veno-venous haemodialysis (CVVHD). Aims: To assess if dialysate flow direction during CVVHD affects small solute removal. Methods: This ethics-approved study recruited a convenience sample of 26 adult ICU patients requiring continuous dialysis to assess urea and creatinine removal for con-current vs. counter-current dialysate flow direction. The circuit was adjusted from continuous veno-venous haemodiafiltration to CVVHD 20 min prior to sampling with no fluid removal. Blood (b) and spent dialysate fluid (f) were taken in both concurrent and counter-current fluid flow at 1 (T1) and 4 (T4) hours with a new treatment. Blood flow was 200 ml/min. Dialysate flow 33 ml/min. Removal of urea and creatinine was expressed as the diafiltrate/plasma concentration ratio: Uf/b and Cf/b respectively. Data lacking normal distribution are presented as median with 25th and 75th interquartile ranges (IQR), otherwise as mean with SD and assessed with the independent t test for paired data. p < 0.5 was considered significant. Results: Fifteen male patients were included with a median (IQR) age of 67 years (52-75), and APACHE ΙΙ score 17 (14-19) with all patients meeting RIFLE criteria ‘F'. At both times, the counter-current dialysate flow was associated with higher mean (SD) diafiltrate/plasma concentration ratios: T1 0.87 (0.16) vs. 0.77 (0.10), p = 0.006; T2 0.96 (0.16) vs. 0.76 (0.09), p < 0.001 for creatinine and T1 0.98 (0.09) vs. 0.81 (0.09), p < 0.001; T2 0.99 (0.07) vs. 0.82 (0.08), p < 0.001 for urea. Conclusion: Counter-current dialysate flow during CVVHD for ICU patients is associated with an approximately 20% increase in removal of small solutes creatinine and urea. Video Journal Club ‘Cappuccino with Claudio Ronco' at http://www.karger.com/?doi=441270.

Development and validation of a prognostic index for allograft outcome in kidney recipients with transplant glomerulopathy

We studied 92 patients with transplant glomerulopathy to develop a prognostic index based on the risk factors for allograft failure within five years of diagnosis (Development cohort). During 60 months (median) follow up, 64 patients developed allograft failure. A chronic-inflammation score generated by combining Banff ci, ct and ti scores, serum creatinine and proteinuria at biopsy, were independent risk factors for allograft failure. Based on the Cox model, we developed a prognostic index and classified patients into risk groups. Compared to the low risk group (median allograft survival over 60 months from diagnosis), patients in the medium risk group had a hazard ratio of 2.83 (median survival 25 months), while those in the high risk group had a hazard ratio of 5.96 (median survival 3.7 months). We next evaluated the performance of the prognostic index in an independent external cohort of 47 patients with transplant glomerulopathy (Validation cohort). The hazard ratios were 2.18 (median survival 19 months) and 16.27 (median survival 1.6 months), respectively, for patients in the medium and high risk groups, compared to the low risk group (median survival 47 months). Our prognostic index model did well in measures of discrimination and calibration. Thus, risk stratification of transplant glomerulopathy based on our prognostic index may provide informative insight for both the patient and physician regarding prognosis and treatment.

Adsorption Kinetics and Thermodynamics of Cellulose Dinitrobenzoate Prepared in Ionic Liquid for the Removal Of Creatinine

Creatinine is one of the major toxins in patients suffering from chronic renal failure. In this paper, cellulose dinitrobenzoate, with a degree of substitution (DS) of 0.15, was used as an oral adsorbent for creatinine adsorption. Cellulose dinitrobenzoate was prepared by modification of cellulose with 3,5-dinitrobenzoyl chloride in 1-butyl-3-methylimidazolium chloride (BMIMCl) ionic liquid as a homogenous medium. The effects of contact time, pH, adsorption temperature, and initial concentration of creatinine on the adsorption per unit mass of cellulose dinitrobenzoate were studied, comparatively. Results showed that the maximum adsorption per unit mass for creatinine was 3.88 mg/g. Furthermore, the adsorption process was spontaneous and exothermic. It was determined that the experimental results were well fitted to the pseudo-second-order rate equation and the Freundlich adsorption isotherm. Compared with traditional oral adsorbents, this cellulose-based adsorbent was biocompatible and could remove creatinine from dialysate effectively.

Adsorption of Creatinine on Pine Nut Shell-Based High Surface Area Activated Carbon

The objective of this research is to prepare high surface area activated carbon (AC) from agricultural biomass materials–pine nut shells–by the method of carbonization and alkaline activation. Adsorption isotherms of creatinine (CR) by pine nut shell-based high surface area activated carbon (AC) from aqueous medium have been studied. The results have been found that samples have larger capacity for removing CR from solution. The adsorption capacity of CR as intensity at first 50 min. After 50 min, it’s smooth and steady. The carbons prepared with KOH could be effectively used for the removal of CR.

Dialysate fluid flow in CVVHD: Does countercurrent flow increase clearance for small solutes?

s / Australian Critical Care 27 (2014) 43–63 47 Conclusions: Participants described a challenging environment where they transitioned from being new and an outsider to feeling a valuable part of the team. Relationships were important in providing support and education around specialist knowledge and skills. Understanding thenewgraduate’s experience can assistwith this transition and encourage the new graduates to stay in the ICU. http://dx.doi.org/10.1016/j.aucc.2013.10.013 Dialysate fluid flow in CVVHD: Does countercurrent flow increase clearance for small solutes? I. Baldwin1,∗, M. Baldwin2, N. Fealy1, P. Carty1, R. Bellomo1 1 Austin Health, Australia 2 St. Vincent’s Public Hospital, Melbourne, Australia No study has assessed the effect of dialysate fluid flow direction on small solute clearance during haemofiltration. This ethics approved study recruited a convenience sample of 12 adult ICU patients requiring CVVHDF to assess urea and creatinine removal for concurrent vs. countercurrent flow direction. The circuit was adjusted to CVVHD 20min prior to sampling with no fluid removal. Blood and spent dialysate fluid were taken in both concurrent and countercurrent fluid flow at one (T1) and four (T4) hours with a new treatment. Blood flow was 200ml/min. Dialysate flow 33ml/min. Removal of urea (Uf/b) and creatinine (Cf/b) was expressed as the diafiltrate/plasma concentration ratio. Data are presented as medians with 25th and 75th inter-quartile ranges (IQR). The Wilcoxon Signed Rank Test for paired data was used for analysis. P<0.5 was considered significant. Patient median agewas 65yrs (43–68), median APACHE II score 19 (14–29) and all patients met RIFLE criteria ‘F’. Median pre treatment creatinine was 320.5 (260–443) mol/L and urea 21.4 (12.5 – 33.5) mmol/L. At both times countercurrent dialysateflowwas associatedwith higher diafiltrate/plasma concentration ratios: T1 0.92 (0.85–1.00) vs. 0.71 (0.64–0.79), P=0.0005; T2 0.95 (0.85–1.00) vs. 0.74 (0.66–0.77), P=0.0005 for creatinine, and T1 1.00 (0.99–1.02) vs. 0.83 (0.81–0.85), P=0.0005; T2 1.01 (0.97–1.03) vs. 0.83 (0.80–0.87), P=0.002 for urea. Countercurrent dialysate flow during CVVHD for ICU patients is associated with an increase of approximately 20% in diafiltrate/plasma creatinine and urea ratio. http://dx.doi.org/10.1016/j.aucc.2013.10.014 ECMO in an Australian tertiary ICU: A four year review J. Breeding1,∗, P. Nair1,2, H. Buscher1,2, S. Whittam1 1 St, Vincent’s Hospital Sydney, Australia 2 University of New South Wales, Australia Introduction: Evaluation of outcomes related to an ECMO programme requires clinically relevant data and access to comparisons with similar services. Objectives:Theprimary aimof this unit review for anAustralian mixed tertiary ICU including cardiothoracic, transplant, VAD and ECMO referral programmes, was to assess several baseline data points. Secondary goals were to compare endpoints with other reported results. Method: The ECMO database of this ICU was interrogated from 1/07/2009 to 30/06/2013 (4 years/161 runs). Baseline data included: mortality, diagnoses, run times, cannulae, settings, selected blood gas parameters, utilisation of additional therapies and selected complications. Analysis of the data involved simple comparative statistical techniques. Selected Results This centre Extracorporeal Life Support Organization Registry Report, International Summary, July 2013 VV (N=57) VA (N=80) E-CPR (N=10) VPA (N=14) Adult respiratory (N=4382) Adult cardiac (N=3401) E-CPR (N=969) Survived ECMO (%) 80.7 77.5 80 92.9 64 55 37 Survived to ICU discharge (%) 75.4 58.8 50 85.7 56 40 28 Run time (days)* 11.9 6.8 4.2 8.2 ∼9.9 ∼5.3 RRT (%) 42 57.5 30 35.7 44.5 42.7 Haemorrhagic complications (%) 36.8 63.7 50 57 42.1 55.2 Day 1 ECMO flow* 4.4 3.82 3.81 3.95 Day 1 PUMP Revs/min* 2187 3251 3256 3292 Day 1 PaO2mmHg * 109 260 289 294 Day 7 PaO2 mmHg * 95.3 169 NA 175

Aerobic exercise increases phosphate removal during hemodialysis: A controlled trial

Previous studies have suggested that exercise during hemodialysis (HD) could increase the efficacy of solute removal, although this hypothesis has not been conclusively evaluated. The goal of this study was to compare the removal of low-molecular weight solutes between HD sessions, with and without aerobic exercise. It was a controlled clinical trial, including HD patients in a randomly cross-over design, such that each patient received a HD session with exercise (intervention) and the next one without exercise (control), three times each. In the exercise sessions, patients pedaled on a cycle ergometer for 60 minutes. The total mass of removed urea, potassium, creatinine, and phosphate were calculated from the solutes concentration in dialysate (continuous spent sampling of dialysate). This was evaluated in a total of 132 HD sessions of patients with a mean age of 54 ± 15 years, 75% male and HD vintage of 3 (2-13) years. Phosphate removal in dialysate during intervention sessions was significantly higher (5.6 [2.5-18.9] vs. 5.1 [1.5-11.2] mg/min) than during control sessions, P = 0.04. The median mass of phosphate removed during control HD session was 1226 (367.8-2697.2) vs. 1348.6 (613.0-4536.2) mg/session during intervention sessions. The exercise did not modify the removal of urea (control 122.6 [61.3-286.0] vs. exercise 112.4 [51.1-250.3] mg/min, P = 0.44), creatinine (control 5.6 [2.5-13.8] vs. exercise 5.6 [2.5-12.8] mg/min, P = 0.49), or potassium (control 13.3 [11.2-15.8] vs. exercise 13.8 [6.6-15.8] mEq/min, P = 0.49). Aerobic exercise during HD increases the efficacy of phosphate removal, without changing urea, creatinine and potassium removal. The implications of this finding in mineral and bone disease and cardiovascular disease need to be evaluated on future clinical trials.

Optical measurement of creatinine in spent dialysate

The aim of the study was to develop an optical method for the estimation of creatinine (Cr) removal during dialysis using UV-absorbance. 29 hemodialysis patients on chronic 3-times-a-week hemodialysis were studied in 6 separate studies. Double-beam pectrophotometer was used for the determination of UV-absorbance in the collected spent dialysate samples. A single wavelength (SW) and a multi-wavelength (MW) model were developed using stepwise regression utilizing Cr values from the laboratory as the dependent parameter. The reduction ratio (RR) and total removed Cr (TRCr) were estimated. For blood-Cr RRb (mean ± SD) was 60.9 ± 5.0% (calibration set) and 58.1 ± 6.0% (validation set), for SW UVabsorbance RR_SW was 61.5 ± 5.9% and 57.3 ± 6.0%, and for MW UV-absorbance RR_MW was 65.8 ± 5.8% and 61.7 ± 6.4% respectively. RR_SW and RRb were not statistically different. RR_MW was higher compared to RRb (p < 0.05). TRCr_lab was 13.8 ± 3.8 mmol, TRCr_SW 14.5 ± 2.5 mmol and TRCr_MW 13.8 ± 2.6 mmol, being not statistically different. In summary, creatinine removal during dialysis can be estimated as reduction ratio and total removed creatinine with the UV-absorbance technique.

Phosphate Mass Removal during Hemodialysis: A Comparison between eKT/V-Matched Conventional and Extended Dialysis

Background and Objectives: The control of hyperphosphatemia is an unmet need in dialysis care. Compared to conventional hemodialysis (cHD), extended hemodialysis (eHD) appears to more easily control blood phosphate levels in chronically dialyzed patients. Here, we sought to compare eKT/V-matched cHD and eHD procedures in order to quantify the contribution of dialysis prescription and time in the mass removal of phosphate. Methods: Eight stable hemodialysis patients with negligible residual renal function underwent cHD and eHD sessions adjusted to provide the same eKT/V_urea. Total dialysate, total and hourly partial dialysate and blood samples were collected for comparison of mass extraction of urea, creatinine, and phosphate. Results: Mean eKT/V_urea was similar in eHD and cHD (1.30 vs. 1.28, p = nonsignificant). Likewise, mass removal of urea and creatinine during cHD and eHD were not significantly different. Conversely, phosphate mass removal was 40% higher with eHD as compared to cHD (1,219 ± 262 vs. 858 ± 186 mg, p = 0.015). Although hourly mass removal of phosphate was higher during cHD, the prolonged period of lesser but continuous removal was responsible for higher total phosphate elimination during eHD. Conclusion: In dialysis sessions matched to provide a similar eKT/V_urea, removal of phosphate increases by 40% when time is extended from 4 to 8 h. Urea-based adequacy models cannot be used to predict the amount of phosphorus removal during hemodialysis.

Preparation and performance evaluation of poly (ether-imide) incorporated polysulfone hemodialysis membranes

Biocompatible Polysulfone (PSf) hemodialysis membranes were prepared by phase inversion technique using poly (ether-imide) (PEI) as the modification agent and Polyethylene glycol (PEG-200) as the pore former. The effect of PSf/PEI blend ratio on the morphology, hydrophilicity, water content, porosity, glass transition temperature, mechanical strength, biocompatibility and permeation rate of the prepared membranes were studied and were found to be improved significantly by the incorporation of PEI in the dope solution. The scanning electron microscopy (SEM) studies revealed that, incorporation of PEI resulted in the formation of spongy sub-layer and increased the connectivity of pores between sub-layer and bottom layer. The water content and permeation rate of the membranes of PSf/PEI blend membranes were increased considerably indicating the enhancement of hydrophilicity and it was supported by lower contact angle values of the blend membranes. The existence of single well defined Tg over entire composition established the compatibility between the components in blend membranes. The biocompatibility of membranes was investigated through protein adsorption, platelet adhesion and thrombus formation on the membrane surface. Anticoagulant activity of PSf/PEI blend membranes was evaluated by measuring the activated partial thrombin time (APTT), prothrombin time (PT), thrombin time (TT) and fibrinogen time (FT). The results revealed that antithrombogenicity of PSf/PEI blend membranes was increased significantly. The efficiency of these membranes in removal of urea, creatinine and vitamin B12 were studied and found to be improved for blend membranes. Thus, it is worth mentioning to note that, the biocompatible PSf/PEI blend membranes prepared in this study would offer immense potential in hemodialysis.

A novel approach for blood purification: Mixed-matrix membranes combining diffusion and adsorption in one step

Hemodialysis is a commonly used blood purification technique in patients requiring kidney replacement therapy. Sorbents could increase uremic retention solute removal efficiency but, because of poor biocompatibility, their use is often limited to the treatment of patients with acute poisoning. This paper proposes a novel membrane concept for combining diffusion and adsorption of uremic retention solutes in one step: the so-called mixed-matrix membrane (MMM). In this concept, adsorptive particles are incorporated in a macro-porous membrane layer whereas an extra particle-free membrane layer is introduced on the blood-contacting side of the membrane to improve hemocompatibility and prevent particle release. These dual-layer mixed-matrix membranes have high clean-water permeance and high creatinine adsorption from creatinine model solutions. In human plasma, the removal of creatinine and of the protein-bound solute para-aminohippuric acid (PAH) by single and dual-layer membranes is in agreement with the removal achieved by the activated carbon particles alone, showing that under these experimental conditions the accessibility of the particles in the MMM is excellent. This study proves that the combination of diffusion and adsorption in a single step is possible and paves the way for the development of more efficient blood purification devices, excellently combining the advantages of both techniques.

Characterising Nanoporous Carbon Adsorbents for Biological Application to Chronic Kidney Disease

The study characterises a range of advanced MAST carbons derived from pyrolysed porous phenolic resins for use in biological applications, considering how the porosity of the carbons impacts both the methods used to assess potential cytotoxicity and the removal of biological molecules relevant to kidney disease. The large surface area and pore volume available for adsorption make both the microporous and the mesoporous MAST carbons suitable for creatinine removal but not for removal of the small but highly water soluble urea. However, only the highly adsorbent MAST carbons with meso- and macroporosity were able to remove the high molecular weight inflammatory cytokine IL-6. It is the adsorption of the larger biological toxins, represented by IL-6 in this study and not removed by purely microporous carbons or in current haemodialysis therapy, which could most significantly contribute to the augmentation of current haemoperfusion therapy.

Computer simulations of osmotic ultrafiltration and small-solute transport in peritoneal dialysis: a spatially distributed approach

The aim of this study was to simulate clinically observed intraperitoneal kinetics of dialysis fluid volume and solute concentrations during peritoneal dialysis. We were also interested in analyzing relationships between processes in the peritoneal cavity and processes occurring in the peritoneal tissue and microcirculation. A spatially distributed model was formulated for the combined description of volume and solute mass balances in the peritoneal cavity and flows across the interstitium and the capillary wall. Tissue local parameters were assumed dependent on the interstitial hydration and vasodilatation induced by glucose. The model was fitted to the average volume and solute concentration profiles from dwell studies in 40 clinically stable patients on chronic ambulatory peritoneal dialysis using a 3.86% glucose dialysis solution. The model was able to describe the clinical data with high accuracy. An increase in the local interstitial pressure and tissue hydration within the distance of 2.5 mm from the peritoneal surface of the tissue was observed. The penetration of glucose into the tissue and removal of urea, creatinine, and sodium from the tissue were restricted to a layer located within 2 mm from the peritoneal surface. The initial decline of sodium concentration (sodium dip) was observed not only in intraperitoneal fluid but also in the tissue. The distributed model can provide a precise description of the relationship between changes in the peritoneal tissue and intraperitoneal dialysate volume and solute concentration kinetics. Computer simulations suggest that only a thin layer of the tissue within 2-3 mm from the peritoneal surface participates in the exchange of fluid and small solutes between the intraperitoneal dialysate and blood.

Time-Dependent Associations between Total Sodium Removal and Mortality in Patients on Peritoneal Dialysis

To determine if the time-dependent association between total sodium removal and mortality in patients on continuous ambulatory peritoneal dialysis (CAPD) is confounded by markers of diet and nutrition. The study enrolled 305 incident patients who started CAPD between July 2002 and February 2007. All patients were followed until death or censoring in February 2008. Demographics, blood pressure, and markers of volume and inflammation were collected at baseline. Biochemistry, fluid and solute removal, and diet and nutrition parameters were collected quarterly and thus calculated as time-averaged values. Mean age of the study patients was 59.4 years, 42.3% were men, and 40.3% had diabetes. During the 31.4-month follow-up, 74 patients died. The time-averaged daily total sodium removal (TSR) in the overall cohort was 2.67 g (range: 2.02 g-3.47 g). Participants with a high time-averaged TSR tended to experience higher fluid, sodium, urea, and creatinine removal, mainly as a result of better residual renal function (RRF). They also had a higher nutrient intake and a higher lean body mass. Time-dependent TSR was an independent predictor of death, including when adjusted for age, Charlson index, time-dependent hemoglobin, RRF, and peritoneal transport rate (hazard ratio: 0.84; 95% confidence interval: 0.70 to 1.00; p=0.05), but the predictive effect disappeared in multivariate models after further individual adjustment for time-dependent total energy intake, total protein intake, serum albumin, and lean body mass. By contrast, the predictive effect did not disappear if the only adjustment was for time-dependent RRF. The time-dependent association between TSR and mortality in patients on peritoneal dialysis can be largely explained by diet and nutrition parameters.

Synthesis of Recognition Matrix from 4-Methylamino-N-Allylnaphthal-Imide with Fluorescent Effect for the Imprinting of Creatinine

4-Methylamino-N-allylnaphthalimide (4-MAANI), a functional monomer with fluorescent effect, was synthesized for the imprinting and specific uptake of creatinine, an important clinical marker for kidney function. 4-Methylamino-N-allylnaphthalimide was synthesized from the reaction of 4-bromo-1,8-naphthalic anhydride with allylamine to form 4-bromo-N-allylnaphthalimide and further to react with methylamine. Excitation and emission of the fluorescent monomer was investigated by both a three-dimensional plot of fluorescent intensity versus excited and emitted wavelengths and a corresponding contour plot. The photoluminescence properties of the as-prepared conjugated species were also studied. 4-Methylamino-N-allylnaphthalimide (4-MAANI) fluorescent monomer, methacrylic acid (MAA) functional monomer, ethylene glycol dimethylacrylate (EGDMA) cross-linker, and 2,2'-azobisisobutyronitrile (AIBN) initiator were then utilized in the presence of creatinine template for the processing of heat-induced polymerization. FT-IR analysis was used to confirm the successful synthesis of 4-MAANI. The specific recognition cavity for creatinine was then created from the polymer matrix after the removal of creatinine by proper solvent. The imprinting effect as well as selectivity from the creatinine containing mixture was also evaluated. The grouped clusters from the emitted fluorescent intensities of the imprinted and nonimprinted polymers before and after rebinding of creatinine were obtained and discussed. Serum spiked with a different concentration of creatinine was also used to confirm the feasibility of clinical applications in the future. Successful recognition of the creatinine molecule via the combined effect of molecular imprinting and photoluminescence of the imprinted polymeric material was thus confirmed in this work.

Efficacy of Peritoneal Dialysis during Infusion and Drainage Procedures

Inadequate dialysis is still a major cause of technique failure in peritoneal dialysis (PD). Mathematical models provide the possibility of direct and precise assessment of peritoneal transport of urea and creatinine throughout the dwell and allow calculation of optimal schedules, dwell times, and predicted adequacy of a prescribed regimen. Kinetic modeling is particularly important for automated PD. If the effectiveness of uremic toxin removal that takes place during infusion and drainage of dialysis fluid is not taken into account, the predicted adequacy of the whole PD session may be underestimated. ♢ To estimate the efficacy of urea and creatinine removal during the dialysis fluid exchange procedure. ♢ 17 patients treated with PD were included in the study. PD effectiveness during dialysate exchange was defined as the quotient k of removed amount of creatinine/BUN during the infusion and drainage of dialysate and during a dwell of the same duration as the dialysate exchange. ♢ The effectiveness of creatinine and urea removal was reduced during the exchange procedure (k(creat) = 0.68 ± 0.43 and k(BUN) = 0.87 ± 0.44) and differed between these 2 solutes (p = 0.0009). The k coefficients for urea and creatinine were well correlated (R(2) = 0.83). ♢ The effectiveness of peritoneal transport of creatinine and BUN during the inflow/outflow phase was relatively high compared to that during the same dwell time (68% and 87% respectively). This real effectiveness of the dialysate exchange procedure should be taken into account in the process of planning automated PD sessions, otherwise the predicted overall efficacy of creatinine and urea removal throughout the session may be underestimated. This underestimation is proportional to the number of dwells per day.