[Does Stewart-Fencl improve the evaluation of acid-base status in stable patients on hemodiafiltration?]. / ¿Mejora la aproximación físico-química de Stewart-Fencl la valoración del equilibrio ácido-base en pacientes estables en hemodiafiltración?

INTRODUCTION: The traditional evaluation of acid-base status relies on the Henderson-Hasselbach equation. In 1983, an alternative approach, based on physical and chemical principles was proposed by P. Stewart. In this approach, plasma pH is determined by 3 independent variables: pCO2, Strong Ion Difference (SIDm), which is the difference between the strong cations (Na +, K +, Ca ++, Mg ++) and the strong anions (Cl-, lactate) and total plasma concentration of nonvolatile weak acids (ATot), mainly inorganic phosphate and albumin. Bicarbonate is considered a dependent variable. The aim of this study was to evaluate the acid-base status using both perspectives, physical chemical and traditional approach. MATERIAL AND METHODS: We studied 35 patients (24 M; 11F) on hemodiafiltration, mean age was 67,2+/-15,7, 8+/-19,2 kg. We analyzed plasma chemistry including pH, pCO2, HCO3-, base excess and Na+, K+, Cl-, Ca++, Mg++, lactate and SIDm. The SID estimated (SIDe) was calculated by Figge's formula (1000 x 2.46E-11 x pCO2 / (10-pH) + Album gr/dl x (0.123 x pH-0.631) + P in mmol/l x (0.309 x pH-0.469) and Gap of the SID as the difference SIDm-SIDe. RESULTS: pH preHD was 7,36+/-0,08 and pH posHD 7,44+/-0,08 (p < 0.001). There was no significant differences between pCO2 pre and pos-HD. HCO3 - and base excess increased during the session (p < 0.001). SIDm decreased from 46,2+/-2,9 preHD to 45+/-2,3 mEq/l postHD (p < 0.05). On the opposite, SIDe increased from 38,5+/-3,8 to 42,9+/-3,1 mEq/l (p < 0.001). The Gap Anion descended from 18,6+/-3,8 preHD to 12,8+/-2,8 mEq/l mEq/l postHD (p < 0.001) and the Gap of the SID 7,6+/-3 to 2,1+/-2 (p < 0.001). Anion Gap correlated with the Gap-SID so much pre-HDF as pos-HDF. Delta Base excess correlated only with Delta of the Gap SID. CONCLUSION: Stewart-Fencl's approach does not improve characterization of acid-base status in patients on chronic HDF. In presence of normocloremia the SIDm does not reflect the alkalinizing process of the session of hemodialysis. According this approach, hemodialysis therapy can be viewed as a withdrawal of inorganic anions, especially the sulphate. These anions are replaced by OH - and secondarily for HCO3-. The approach only improves the evaluation of unmeasured anions by the Gap of the SID, without the effect of albumin and phosphate.

[Determination of brain natriuretic peptide in patients undergoing different haemodiafiltration techniques]. / Determinación del péptido natriurético cerebral en pacientes sometidos a diferentes técnicas de hemodiafiltración.

UNLABELLED: IB-type natriuretic peptide is a cardíac neurohormone secreted by the cardíac ventricules in response to ventricular dilatation so plasma BNP level correlate with left ventricular mass and dysfunction. Dialysis patients have much greater levels of BNP due to the volume overload and because of reduced renal clearance. The aim of this study was to mesure and compare the BNP levels in three groups of patients who received different hemodiafiltration techniques: Daily online hemodiafiltration (HDFOLd), on-line hemodiafiltration (HDFOL) and low convective volume hemodiafiltration (HDF). Fifteen patients were included, five in each group. Pre and postdialysis BNP leves were measured during 8 weeks. The measure was done at the beginning of the week (long period), and at the end (short period), in order to study if there were significative differences between techniques and periods. We found significative differences between predialysis BNP levels in the short period (BNPpreC) and the long period (BNPpre-L). We also found significative differences with the posdialysis BNP in both periods; BNPpre- L vs. BNPpos-L (1069+/-1031 vs. 612 +/- 540). After comparing the three techniques the study showed significative differences between BNPpreC in HDF and HDFOL compared with HDFOld. And also after dialysis between BNPpos-C in HDFOLd compared with the other techniques. CONCLUSION: Although previous papers have shown that BNP levels have limited potential for assessment of hydration in hemodialysis patients, in this study our data demonstrate that after dialysis BNP levels decline in a significative way in the long and short period and we have found that patients on daily hemodialysis show lower BNP levels, and maybe this could be explained because daily on-line haemodiafiltration patients had lower weight rise between dialysis sessions and also better haemodynamic tolerance.

Switching from three times a week to short daily online hemodiafiltration: effects on acid-base balance.

AIMS: This study examines the effect of a change from the standard 4-5 hours 3 times a week of online hemodiafiltration (OL-HDF) to 2-2.5 hours daily (6 times a week) OL-HDF, on acid-base balance, and attempts assess the modifications of acid-base parameters, ionic concentration, and electrical charges of albumin and phosphate available for diffusion and convection mechanisms across the membrane and subsequent infusion. METHODS: In 18 patients on online HDF, blood gas, electrolytes (Na, K, Cl), lactate, phosphate, albumin, apparent strong ion difference (SIDa), effective strong ion difference (SIDe), strong ion gap (SIG), anion gap (AG), and bicarbonate and pH time-averaged concentration (TAC) and time-averaged deviation (TAD) variables were evaluated at baseline, and 1, 3, 6, 9, and 12 months after patients were switched to daily OL-HDF. Additionally, in 12 patients, the same parameters measured simultaneously at dialyzer inlet, outlet, and after reinfusion were studied. RESULTS: Throughout the study, weekly single-pool Kt/V, equilibrated Kt/V, and TAC urea remained constant. However, standard Kt/V increased and TAD urea decreased on daily OL-HDF. There were no statistical differences during the time span of 12 months in pH, cations (Na, K), anions (Cl, HCO3(-) AG, and lactate), or SIDa, SIDe, and SIG pre-HDF; while pH and HCO3(-) TAD decreased from 0.02 and 1.02 +/- 0.74 mEq/L, to 0.01 and 0.64 +/- 0.52 mEq/L, respectively (p<0.01). Net albumin charge and AG increased significantly at dialyzer outlet and decreased after reinfusion. CONCLUSIONS: We did not observe changes in the acid-base balance in patients who switched from 3 times a week to short daily OL-HDF. The main benefit observed was a lower pH and bicarbonate TAD. This shows a better physiology for daily OL-HDF.

Lupus nephritis with preserved kidney function associated with poorer cardiovascular risk control: A call for more awareness.

BACKGROUND: Despite the improvement in the prognosis of lupus nephritis (LN), the cardiovascular morbimortality remains high. The early recognition and remission of flares, while trying to avoid the metabolic adverse effects of medication, must be mandatory. AIM: The aim of our study was to assess the cardiovascular (CV) risk profile in a cohort of lupus patients with preserved kidney function after a nephritis episode, compared to patients without a nephritis flare. METHODS: 130 patients diagnosed of SLE (32 with previous nephritis flare and 98 without) were studied in order to evaluate the CV risk profile, despite the preserved kidney function. RESULTS: The most prevalent risk factors were sedentary lifestyle (57.6%), overweight/obesity (38.3%) and dyslipidemia (36%), followed by smoking (32%) and hypertension (16%). Though more than a half (53.1%) was taking CV medication, a high percentage did not reach a therapeutic target value, especially regarding obesity (11.5%) and cholesterol levels (LDL-C of 16%). The prevalence of dyslipidemia (53.1% vs 30.6%), smoking (46.6% vs 27.5%), left ventricular hypertrophy (LVH) (21.4% vs 6.4%) and lower HDL-C (48.6mg/dL vs 55.4mg/dL) were significantly different in the group with previous nephritis flare. Moreover, young patients with lupus nephritis, received more pulses of corticosteroids and cyclophosphamide, had higher prevalence of hypertension, LVH, higher proteinuria, hospital admissions and waist circumference, constituting the subgroup of patients with greater aggregation of CV risk factors. CONCLUSIONS: Patients with previous nephritis flare showed a poor control of CV risk factors despite the preserved renal function, these patients would require a closer therapeutic management.

[Kinetic of calcium, phosphate, magnesium and PTH variations during hemodiafiltration]. / Cinéica del calcio, fósforo, magnesio y variaciones de la parathormona (PTH) en pacientes en hemodiafiltracion.

Hemodiafiltration (HDF) is a technique resulting from coupling of diffusive and convective transport and thereby increase the elimination of small and middle molecules. However, may induce a convective loss from others substances such as calcium and magnesium. The aim of this study was to evaluate the effects of Ultrafiltration on the kinetics of calcium, phosphate, magnesium and parathyroid hormone. A total of thirteen patients (7 males and 6 females) on hemodialysis, were studied. Each patient was randomly dialyzed with the same dialysate calcium concentration and three different ultrafiltration rate. Schedule A: High flux hemodialysis, schedule B: HDF with 10% of weight body and schedule C: HDF with 20% of weight body. The others parameters were kept identical. Total Ultrafiltration was 2,6+/-0,9 L (9,78+/-3,78 ml/min) in A, 9,3+/-1,7 L (34,54+/-6,22 ml/min) in B and 16,3+/-3,3 L (60,94+/-12,63 ml/min) in C. Replacement fluid during dialysis was 6,85+/-1,42 and 13,65+/-2,9 L. in C and C respectively. Postdialysis total,ionized calcium and magnesium were significantly lower in schedules B and C versus A. PTH levels did not differ significantly. However, PTH changes during dialysis was -36.6+/-38.6%, 6.3+/-69.8% and 32.2+/-63.2% in A, B and C, respectively (p<0.05 A vs. C). A significant inverse correlation was found between total Ultrafiltration and postdialysis levels of total calcium (r:-0.56, p<0.001), ionized calcium (r:-0.65, p<0.001) and magnesium (r:-0.47, p<0.01). No differences were observed in pre and postdialysis phosphate levels, neither mass transfer and clearance of phosphate. We concluded that high ultrafiltration flow rates and substitution fluid without divalent cations induces a negative calcium and magnesium balance. These changes may stimulate PTH secretion during HDF. This technique did not resulted in a higher clearance or phosphate removal.

[Oxidative stress analysis in patients on hemodiafiltration on-line]. / Análisis del estrés oxidativo en pacientes en hemodiafiltración en línea.

Patients with chronic renal disease have a very high mortality due to cardiovascular disease. However, the traditional risk factors are not the only one explanation. Nowadays, there are new risk factors becoming, and one of these is the oxidative stress. Besides today we know that when these patients receive haemodialysis are being exposed to an additional oxidative stress. The aim of this study was to measure and to compare the degree of oxidative stress in two groups of patients on different dialysis techniques: a) On-Line Haemodiafiltration three times / week (OL-HDF). b) Daily Om-Line haemodiafiltration ( six times / week ) ( dOL-HDF) We studied 9 patients with chronic renal disease stage 5 on hemodialysis. They all were men, with a medium age of 72,5 +/- 6 years. Five patients were on dOL-HDFand four on tOL-HDF. Glutathione (GSH) concentration of patients on dOL-HDF before dialysis was 742+/- 153 nmol/ml and post-dialysis de 878+/- 223. Blood GSSG concentration before and after dialysis was 34+/- 14 nmol/ml y 137+/- 74 nmol/ml (p< 0,03). GSSG/GSH ratio pre-dialysis was 58+/-10 and post-dialysis 169+/-65 ( p < 0,03). In OL-HDF group GSSG concentration and the ratio GSSG/GSH also increased in a significative way from 99+/-45 nmol/ml to 179+/-66 nmol/ml, and from 161+/- 99 to 337+/-143 ( p<0,05). We also found differences in pCR concentrations between both groups; 3+/-1,4 g/l in dOL-HDF and 8,75+/-5,8 g/l in HDF OL. (p< 0,05). We did not find differences between xatine-oxidase activity before and after hemodialysis and between groups. In conclusion, patient with terminal chronic renal disease on OL-HDF receive an additional load of oxidative stress, as the increase in GSSG/GSH ratio in both groups shows. However patients on dHDF-OL shows low ratios GSSG/GSH post-hemodialysis and low pCR concentrations, and maybe this could be explained because daily on line haemodiafiltration improves purification of inflammatory mediators. Clue words: Hemodialysis, oxidative stress, glutathione, gssg/gsh ratio, xantine oxidasa.

[Determination of the dose of dialysis with integrated modules in the same monitor]. / Medición de la dosis de diálisis mediante diferentes módulos integrados en un mismo monitor.

The "gold standard" method to measure the mass balance achieved during dialysis for a given solute is based on the total dialysate collection. This procedure is unfeasible and too cumbersome. For this reason, alternative methods have been proposed including the urea kinetic modelling (Kt/V), the measurement of effective ionic dialysance (Diascan), and the continuous spent sampling of dialysate (Quantiscan). The aim of this study was to compare the reliability and agreement of these two methods with the formulas proposed by the urea kinetic modelling for measuring the dialysis dose and others haemodialysis parameters. We studied 20 stable patients (16 men/4 women) dialyzed with a monitor equipped with the modules Diascan (DC) and Quantiscan (QC) (Integra. Hospal). The urea distribution volume (VD) was determined using anthropometric data (Watson equation) and QC data. Kt/V value was calculated according to Daurgidas 2nd generation formula corrected for the rebound (eKt/V), and using DC (Kt/VDC) and QC (Kt/VQC) data. The total mass of urea removed was calculated as 37,93 +/- 16 g/session. The VD calculated using Watson equation was 35.7 +/- 6.6 and the VDQC was 35.06 +/- 9.9. And they showed an significative correlation (r:0,82 p < 0.001). The (VDQC-VDWatson) difference was -0.64 +/- 5.8L (ns). Kt/VDC was equivalent to those of eKt/V (1.64 +/- 0.33 and 1.61 +/- 0.26, mean difference -0.02 +/- 0.29). However, Kt/VQC value was higher than eKt/V (1.67 +/- 0.22 and 1.61 +/- 0.26 mean difference 0.06 +/- 0.07 p < 0.01). Both values correlated highly (R2: 0.92 p < 0.001). Urea generation (C) calculated using UCM was 8.75 +/- 3.4 g/24 h and those calculated using QC was 8.64 +/- 3.21 g/24 h. Mean difference 0.10 +/- 1.14 (ns). G calculated by UCM correlated highly with that derived from QC (R2: 0.88 p < 0.001). In conclusion, Kt/VDC and Kt/VQC should be considered as valid measures for dialysis efficiency. However, the limits of agreement between Kt/VQC and eKt/V were closer than Kt/VDC.

[An evaluation of costs in nephrology by means of analytical accounting system]. / Evaluación de costes en un servicio de nefrología mediante la contabilidad analítica.

BACKGROUND: The analytical accounting is a countable technique directed to the evaluation, by means of pre-established criteria of distribution, of the internal economy of the hospital, in order to know the effectiveness and efficiency of Clinical Units. The aim of this study was to analyze the activity and costs of the Nephrology Department of General Hospital of Castellón. METHODS: Activity of Hospitalization and Ambulatory Care, during 2003 was analysed. Hospitalization discharges were grouped in DGR and the costs per DGR were determinated. RESULTS: Total costs Hospitalisation and Ambulatory Care were 560.434,9 and 146.317,8 Euros, respectively. And the costs of one stay, one first outpatient visit and maintenance visit were 200, 63, and 31,6 Euros, respectively. Eighty per cent of the discharges were grouped in 9 DGR and DRG number 316 (Renal Failure) represented 30% of the total productivity. Costs of DGR 316 were 3.178,2 Euros and 16% represented laboratory cost and costs of diagnostic or therapeutic procedures. CONCLUSION: With introduction of analytical accounting and DGR system, the Nephrology Departments can acquire more full information on the results and costs of treatment. These techniques permits to improve the financial and economic performance.

[Peritoneal anionic transfers and their relationship with peritoneal transport and acid-base status]. / Transferencias aniónicas peritoneales y su relación con el transporte peritoneal y el estado ácido-base.

This study was designed to assess lactate and TCO2 transfers during PET and in 24-hour drained dialysate, relating them with the membrane transport type and acid-base status. Forty PETs were studied, performed in 23 clinically stable patients maintained on CAPD for 6.5 +/- 3 months using 35 mEq/l of lactated-based dialysate. No significant changes in plasma concentration of lactate and TCO2 were observed. Lactate gain (LG) was 51.91 +/- 4.86 and 220.82 +/- 22.61 mEq and TCO2 loss was 46.49 +/- 6.9 and 183.51 +/- 32.9 mEq during PET and 24 h respectively. When analyzed these transfers according to membrane transport characteristics (High/High-average group: HHAG and low/low-average group: LLAG), LG was significantly higher (53.94 +/- 3.7 vs 48.86 +/- 4.8 mEq during TEP p < 0.01, and 228.06 +/- 15.6 vs 209.96 +/- 27.2 mEq during 24 h p < 0.05). TCO2 loss was greater (48.66 +/- 7.15 vs 43.25 +/- 5.5 mEq p < 0.05 and 187.22 +/- 27.3 vs 177.93 +/- 35.3 during PET and 24 h respectively) in HHAG vs LLAG. When evaluating transfers according to patients' acid-base status (normal and acidotic group), no significant differences were found in LG, but there was a significant difference in TCO2 loss (47.7 +/- 5.9 vs 39.76 +/- 6.1 mEq p < 0.01). We did not observe significant differences in acid-base balance during PET according to membrane transport characteristics (HHAG vs LLAG). However, acid-base balance was more positive in acidotic patients' PET than in normal patients (9.87 +/- 6.6 vs 3.92 +/- 6.8 mEq p < 0.05). TCO2 loss during PET directly correlated with plasma TCO2 concentration pre-PET (r: 0.43, p < 0.01). However no significant correlation was found between plasma lactate levels and lactate gain during PET. In conclusion, the lactate gain and bicarbonate loss account for the net dialytic base balance during PET and 24 h. However, the peritoneal membrane transport characteristics as well as the acid-base status can determine a higher or lower aionic transfer (lactate and bicarbonate).

[Changes in the anion gap in patients undergoing hemodiafiltration]. / Variaciones del "anion gap" en pacientes en hemodiafiltración.

The serum anion gap (AG) is a calculated value defined as the difference between the sum of sodium and potassium and the sum of chloride and bicarbonate concentrations. Thus, the anion gap is equal to the unmeasured cations minus the unmeasured anions (UA). To evaluate the AG changes during HDF-on line, we studied 20 patients treated with this technique. Blood pH, HCO3, NA, K, Cl, albumin, phosphorus, urea, creatinine and lactate were determined pre and post-HDF. The AG, negative charger of serum albumin (CAA) and phosphate (CAP) were computed by equations. AG decreased during HDF from 23.1 +/- 3.4 mEq/l to 17.3 +/- 3.6 mEq/l (p < 0.001). The CAA rose from 10.9 +/- 0.8 to 12.3 +/- 1.7 mEq/l (p < 0.001). The CAP and lactate fell significantly during HDF (p < 0.001 and 0.05 respectively). Other unmeasured anions (UA) decreased from 7.9 +/- 3.0 to 2.4 +/- 2.7 mEq/l (p < 0.001). The CAA contributed 47.7 +/- 6.5% and 73.01 +/- 12.7% to the pre and post-HDF serum anion gap respectively. The CAP accounted for 12.4 +/- 3.4% and 8.6 +/- 1.8%, lactate 6.4 +/- 3.9% and 6.0 +/- 3.0% and UA for 33.2 +/- 7.7% and 12.2 +/- 13.6% of the anion gap pre and post-HD respectively. AG and UA correlated significantly with blood urea pre-HDF and urea generation. The increase in serum albumin and pH can mask an decreased concentration of unmeasured anions in patients treated with HDF on-line. An adjusted anion gap without effect of CAA and CAP can be obtained. With the help of this adjustments the changes in some undetermined anions organic and inorganic (sulphate and others in renal failure) can be calculated.

[Approximation to cost analysis of various types of hemodialysis using relative value units]. / Aproximación al análisis de costes de diferentes tipos de hemodiálisis mediante unidades relativas de valor (URV).

Hemodialysis sessions performed in Hospital Units have a different degree of complexity depending on the kind of patients who is receiving this treatment. This paper's aim is to apply certain weighting factors, which measure the complexity of each type of session performed, and so allow a more realistic comparison with hemodialysis sessions performed in dialysis Units. The various costs of the Castellón General Hospital Dialysis Unit were calculated. Five types of Hospital-performed sessions were defined, to which were applied concrete weighting factors called Relative Value Units (RVU). These took account of health professionals' time, disposable material and drug expenses. The cost of single hemodialysis session, before the RVU calculation was added, was 28,549 pesetas (171.58 Eu.). Thirty-two per cent of the cost was from disposable material, 29.38% for cost of health professionals time, 18.54% for structural costs, 13.4% for drug expenses, and 5.73% for the nephrologists' time. When RVU were applied, the Type I session cost (chronic renal failure patients on regular hemodialysis), was 28,882 pesetas (149.54 Eu.). As the complexity of the procedure increased, up to the Type V session (acute renal failure patients in intensive Care Units), the costs also rose to 68,448 pesetas (411.38 Eu.). We conclude that weighing the different types of hemodialysis sessions by means of RVU, allows a better measurement of the costs and achieves a more accurate comparison with others hemodialysis units.

[Comparison of dialyzers in on-line hemodiafiltration]. / Comparación de dializadores en hemodiafiltración en línea.

UNLABELLED: At present we have a great variety of high-flux dialyzers whose characteristics in vitro seem similar. On-line HDF is a technique which combines diffusion with elevated convection and uses dialysate as replacement fluid. On-line HDF provides the highest clearances for small, medium-sized and large molecules and gives the best performance from the dialyzers. Conscious of this wide choice of dialyzers we evaluated the performance of different dialyzers in renowing small and medium-large molecules. Eleven patients were included in this study, 7 males and 4 females. Every patient received 11 on-line HDF sessions with Fresenius 4008B machine, Qi 100 ml/min or 6 L/h, QB 400 ml/min, QB 800 ml/min, UF 0.5 L/h and Td 60 min. Only the dialyzer was changed: 1.9 m2 cellulose triacetate (Tricea 190G), 2.1 m2 poly methyl methacrylate of PMMA (BK-2.1P), 1.8 m2 polyester-polymer Allol or PEPA (FLX-18GWS), 2.05 m2 acrylonitrile (Filtral 20), 2.1 m2 polyamide (Poliflux 2.1) and 1.8-2.4 m2 polysulfones (HF 80, BS-1.8S, APS-900, Arylane H9, Idemsa 2000, HdF 100). Arterial pressure, venous pressure and transmembrane pressure (TMP) were monitored. Plasma, urea, creatinine, phosphate, uric acid and beta 2m concentrations were measured at the beginning and at the end dialysis from arterial and venous blood lines, and arterial blood line with the slow flow method. Recirculation, dialyzer solutes clearance and solute reduction rates were calculated. No significant differences were found in arterial pressure, venous pressure and recirculation. Small molecule removal was similar except in BK-2.1P and HdF 100 dialyzers which were lower and higher respectively. There were differences in TMP and beta 2m removal among dialyzers employed. Mean TMP, beta 2m clearance and beta 2m reduction ratio were: Tricea 190G (TMP 336 mmHg, beta 2m K 79 ml/min and beta 2m reduction ratio 44.9%), BK-2.1P (TMP 485, beta 2m K 102 and beta 2mRR 48.3%), FLX-18 GWS (TMP 195, beta 2m K 140 and beta 2mRR 54.6%), Filtral 20 (TMP 245, beta 2m K 132 and beta 2mRR 54.1%), Poliflux 2.1 (TMP 209, beta 2m K 158 and beta 2mRR 56.0%), HF 80 (TMP 208, beta 2m K 160 and beta 2mRR 57.4%), BS-1.8S (TMP 186, beta 2m K 179 and beta 2mRR 59.6%), APS-900 (TMP 174, beta 2m K 176 and beta 2mRR 64.8%), Arylane H9 (TMP 206, beta 2m K 171 and beta 2mRR 59.9%), Idemsa 2000 (TMP 203, beta 2m K 169 and beta 2mRR 60.4%), HdF 100 (TMP 152, beta 2m K 186 and beta 2mRR 64.6%). CONCLUSIONS: Of the dialyzers evaluated in on-line HDF, cellulose triacetate and PMMA have a smaller beta 2m removal and their use is limited by an elevated TMP. The polysulfones provide greater beta 2m removal with lower TMP, particularly the APS-900 and HdF 100 dialyzers. The acrylonitrile, PEPA and polyamide are intermediate.

[Usefulness of the Biofeedback Diacontrol module in the automatic programming of plasmatic conductivity and ionic mass transfer]. / Utilidad del módulo de "Biofeedback" Diacontrol en la programación automática de la conductividad plasmática y la transferencia de masa iónica.

Programmed variable sodium in the dialysate can improve hypotension during hemodialysis but may also alter sodium balance and thus resulting in a increase of water intake and weight gain between dialysis sessions. The aim of this study was to evaluate the changes on plasma volume (PV), Ionic Mass Transfer (IMT) and plasma conductivity (PC) with two different hemodialysis techniques. We studied 10 patients during a four-period protocol (one week each: PF1-DC1-DC2PF2): 120 dialysis sessions. During periods PF1 and PF2, the dialysis procedure was as usual, with exponential decrease of dialysate conductivity (DC) profile (15.7 mS/cm at start, 14.4 mS/cm at middle and 13.8 mS/cm at the end of the session) and UF profile (1.7 1/h at start and 0.1 1/h at the end). During periods DC1 and DC2, DC was automatically determined by a biofeedback modulae (Diacontrol) in order to reach a plasma water conductivity fixed at 14 mS/cm. All hemodialysis parameters were the same for the four periods: duration, blood and dialysate flow rates, dialysis membrane. A lower reduction of PV was evident on PF1 and PF2 (104 +/- 3.26% and -4.36 +/- 2.7%) compared with DC 1 and DC2 (-6.53 +/- 3.31% and -6.67 +/- 3.12%) (p < 0.001). No significant differences were seen in systolic, mean and diastolic blood pressure pre-HD or post-HD, UF, and weight gain, between the four periods. Hypotensive episodes were seen in 33.3% of PF1, 20% of DC1, 23.3% of DC2 and 26.6% of PF2 sessions (NS). PF1 and PF2 periods resulted in a significantly higher 30', mid and post-dialysis PC as compared to DC1 and DC2 periods (p < 0.001). The mean difference between the actual value and the prescribed value of PC at the end of the session was -0.01 +/- 0.07 mS/cm (n: 60). There was a negative correlation between the mean DC during session and the PC at 30' of session. IMT was 420.73 +/- 126.9 mEq in PF1, 311.96 +/- 161.75 in DC1, 278.34 +/- 153.14 in DC2 and 417.66 +/- 152.17 in PF2 (p > 0.001 PF1 and PF2 vs. DC1 and DC2). Diacontrol determines automatically an individualized DC profile for each patient, and accurately reaches the prescribed PC target. By reaching both the dry weight and PC settings, the water and sodium pool is maintained lower in the hemodialysis session using a biofeedback module. Clinical tolerance was similar in the two different dialysis procedures.

[Acute interstitial nephritis associated with omeprazole therapy]. / Nefritis intersticial aguda por omeprazol.

From 1 to 3% of acute renal failures are due to acute interstitial nephritis (AIN). Most of them are due to drugs. Nonsteroidal antiinflammatory drugs, penicillins and sulfonamides are the most frequently reported. Clinical presentation of drug-induced AIN has changed over time and with the use of new drugs. In fact actually the classic triad of fever, rash and eosinophilia is uncommon. Omeprazole is a drug widely used in the treatment of gastroesophageal reflux disease and peptic ulcer disease. Serious side effects are rare with this drug, but despite of its safety we can see serious adverse effects such as acute renal failure. We describe two cases of acute interstitial nephritis after use of omeprazole and a review of all the cases published in the last years.

[Interaction of the mechanisms of beta 2-microglobulin convection, diffusion, and adsorption in line hemodiafiltration]. / Interacción de los mecanismos de convección, difusión y adsorción de beta 2-microglobulina en la hemodiafiltración en línea.

The in vivo contribution of diffusion, convection ad adsorption to beta 2-microglobulin (beta 2-m) elimination by hemodiafiltration (HDF) was investigated. 11 patients (8M/3W), with a mean age of 59 +/- 10 years and weighing 62.7 +/- 8.7 kg were studied. A 1.89 m2 polysulphone membrane was used in 180 min postdilution HDF. Samples at blood inlet (bi), blood autlet (bo), dialysate outlet (do) and ultrafiltrate (uf) were taken to determine beta 2-m concentrations at 30 and 150 min. Rates of flow (Q, ml(min) prescribed were: infusion, Qinf = 103.6 +/- 12.3, Quf = 14.6 +/- 4.0 y Qb = 465 +/- 5.0. Effective Qbi was automatically measured by the machine and Qdo = 800 + Quf. The removed beta 2-m mass (M, mg/min) was obtained by multiplying rates of flow (Q, L/min) by beta 2-m concentrations (mg/L) at each sampling point. From mass balance, we calculated the mass of beta 2-m removed (mg/min) by adsorption 0.23 +/- 0.2, by convection 0.7 +/- 0.3 and by diffusion 1.0 +/- 0.4, at 30 min. At 150 min, the beta 2-m mass removed was -0.06 +/- 0.1 by adsorption 0.4 +/- 0.1 by convection and 0.3 +/- 0.1 by diffusion. In HDF, these beta 2-m eliminating mechanisms play a variable role throughout the session. The more significant conclusion is that diffusion of beta 2-m with a synthetic "open" membrane is an important method of removing beta 2-m, comparable to convection over the whole procedure. That result explain the relative efficacy of beta 2-m clearance by HDF convection, and also explain why isolated diffusion is an efficient mechanism for beta 2-m removal by high-flux hemodialysis.

[Secondary amyloidosis (AA) and renal disease]. / Amiloidosis secundaria (AA) y afectación renal.

Amyloidosis is a disease resulting from extracellular deposition of fibrillar protein in various organs. AA amyloidosis may complicate chronic inflammatory diseases, chronic infections and another chronic diseases. We review 31 patients (13 males and 18 females) with biopsy proven renal or rectal AA amyloidosis, referred to out hospital between january 1999 and november 2002. Renal failure was defined as serum creatinine > or = 1.5 mg/dl. Mean age was 58.4 +/- 15.7 years. The causes of AA amyloidosis were an underlying chronic rheumatologic disease (51.6%), chronic infection (41.9%) and a chronic inflammatory intestinal disorder (6.5%). Renal failure (RF) was detected in 20 patients (61.2%) and proteinuria and hematuria were found in 90.3% and 45.5 respectively. Proteinuria at diagnosis was 5.2 +/- 3.9 g/24 h and mean serum creatinine 3.5 +/- 3.7 mg/dl. Survival of patients without dialysis was 66.8 (51.1% RF, 90.9% non-RF) and 53.4% (38.2 RF, 77.9% non-RF) at 12 and 24 months respectively (p = 0.017). End-stage renal disease developed in 13 patients (41.9%). Ten patients were maintained on hemodialysis and 3 on CAD. Survival in dialysis at 6 and 12 months was 68.3% and 42.7% respectively. Fifteen patients died and the main causes of death were: infections (46.6) haemorrhagic complications (33.3%), cardiovascular events (13.3%) and cachexia (6.6%).

[Outcome of tunneled hemodialysis catheters as permanent vascular access]. / Seguimiento a largo plazo de catéteres permanentes en pacientes con dificultad en la obtención de un acceso vascular definitivo.

UNLABELLED: Tunneled cuffed hemodialysis catheters (THC) are developed as a means of short hemodialysis access while a more permanent form of access are maturing. The aim of this study is to investigate the effectiveness, survival and complications of the THC used for long-term vascular access. METHODS: In a retrospective study we looked at 42 THC inserted between November 2000 and October 2003, in 40 elderly patients, with systemic disease or when other vascular access was not possible. RESULTS: Procedural complications occurred in 5 cases (11.9%), which included: local haemorrhage (3), hemothorax (1) and one fatal venous tear. 6 catheters (14.2%) were removed due to complications (non-function 3 and bacteraemia 3). The total incidence of THC related infections was 0.18 episodes/1,000 catheters-days. Patients were followed up for a mean 379 days (range 1-1,140) and a total of 15,946 catheter-days. Qb and KT/V achieved at one month were 278.3 +/- 34.1 ml/min and 1.48 +/- 0.27 respectively. At the end of the follow-up, 23 patients (54.7%) were alive with catheter functioning. One, three and twelve months survival was 90.4%, 73.1% and 59.5% respectively. CONCLUSION: The THC may be a useful alternative permanent vascular access for hemodialysis patients when others vascular access are not possible.

[Multicenter study of darbepoetin alfa in the treatment of anemia secondary to chronic renal insufficiency on dialysis]. / Estudio multicéntrico de darbepoetin alfa en el tratamiento de la anemia secundaria a insuficiencia renal crónica en diálisis.

This Spanish single-arm, multicenter, prospective clinical trial assessed the maintenance of hemoglobin concentrations (Hb) between 10-13 g/dL with unit doses of darbepoetin alfa and the safety of the treatment in dialysis patients. Eight-hundred twenty-six patients with chronic renal failure (CRF) (94% receiving haemodialysis and 6% receiving peritoneal dialysis) previously maintained on stable recombinant human erythropoietin (r-HuEPO) therapy with stable hemoglobin (Hb) concentrations (mean Hb concentration = 11.7 g/dL) were switched to darbepoetin alfa at a reduced dosing frequency for 24 weeks (a 20-week titration phase plus a 4-week treatment evaluation phase). Subjects receiving r-HuEPO two or three times weekly were switched to darbepoetin alfa once weekly, and those. who were receiving r-HuEPO once weekly were switched to darbepoetin alfa once every two weeks. The initial dose of darbepoetin alfa was determined from the r-HuEPO dose at inclusion into the study using a formula equating the peptide mass of the two molecules and rounding to the nearest available prefilled syringe dose. Overall, 86.8% of patients completed the 24-weeks of study. Changing the treatment from r-HuEPO to darbepoetin alfa and increasing the dose interval did not result in any clinically significant change in the Hb concentration. From base-line to the evaluation phase, the mean Hb fell 0.09 (95% CI, -0.2; -0.0) g/dl, with an increase of 0.19 (95% CI, 0.0;0.3) g/dL i.v. and a decrease of 0.22 (95% CI, -0.3; -0.1) g/dL s.c.). This maintenance of the mean Hb concentration was accompanied by a mean 9.8% reduction of the darbepoetin alfa dose (19.7% (95% CI, -24.9; -14.2) i.v. and 4.7% (95% CI, -8.5; -0.7) s.c. Treatment with darbepoetin alfa was well tolerated and no unexpected adverse events were reported. In conclusion, the replacement of previous r-HuEPO treatment by darbepoetin alfa in the therapy of anemia secondary to chronic renal failure in diaiyzed patients was effective, well tolerated, and decreased the frequency of dose administration compared with the previous r-HuEPO treatment. Darbepoetin alfa administered once weekly or once every two weeks maintained the baseline Hb levels whilst allowing dose reduction, which was higher in patients receiving i.v. darbepoetin alfa.

[Pulmonary Sarcoidosis associated to crescentic glomerulonephritis: a case report]. / Sarcoidosis pulmonar asociada a glomerulonefritis crescéntica: descripción de un caso clínico.

Sarcoidosis is a chronic disorder of unknown etiology, characteristically by the presence of the typical noncaseating sarcoid granuloma. Any tissues can be affected, but the organ most frequently affected is the lung being more unusual in other organs. Primary glomerular involvement in sarcoidosis is unfrequent. The disorder most commonly associated is membranous glomerulonephritis. Rapidly progressive crescentic glomerulonephritis have been very scarcely reported. We report a case of rapidly progressive glomerulonephritis with crescents added to a previous membranous glomerulonephritis with the histological finding of an interstitial granuloma, which was clinically apparent in the context of a normocalcemic sarcoidosis, diagnosed as lung sarcoidosis two years before.

[Obstructive uropathy as initial manifestation of Crohn disease]. / Uropatía obstructiva como manifestación inicial de enfermedad de Crohn.

A patient with renal colicky pain caused by urinary tract obstruction, as a result of psoas abscess, is presented. It was the first manifestation of Crohn's disease. A Gram negative bacteria was isolated from the abscess. The CT images performed to evaluate the abscess suggested this etiology, even though there were no previous symptoms.