José L. Teruel-Briones

Mantenimiento de la función renal residual en hemodiálisis: experiencia de 5 años de una pauta de diálisis incremental

INTRODUCTION In contrast to patients treated with peritoneal dialysis, those on periodical haemodialysis (HD) do not receive programmed progressive increases in dialysis dosage, nor is residual renal function taken into account in the calculation of the total dialysis prescription; rather, only dialyser clearance is factored into the equation. In 2006, we decided to establish a progressively increasing dialysis regimen at the start of renal replacement therapy, evaluating the possibility of starting with 2 sessions of HD/week when renal clearance of urea was equal to or greater than 2.5 ml/min. This study summarises our experience during the first 5 years of application of this progressively increasing HD prescription and its repercussions on residual renal function. METHODS We included all patients who started periodical HD between 1/1/2006 and 30/9/2010 and remained on dialysis for more than three months. The follow-up period ended on 31/12/2010 (study end date). When a patient started HD, urea and creatinine clearance levels were measured based on urea and creatinine concentrations in blood samples taken before dialysis and in urine samples taken 24 hours prior to starting the first dialysis session of the week. If urea clearance was equal to or greater than 2.5 ml/min, 2 sessions of HD per week were applied, as long as the patients clinical situation allowed for it (according to the criteria of the attending physician). Residual renal function was analysed every 2 months until diuresis was less than 100ml/day, which is considered to be basically null. We evaluated the decrease in residual renal function, calculating the rate of decrease in glomerular filtration (ml/min/month) and 24-hour diuresis (ml/month) in patients receiving 2 and 3 HD sessions per week. In January 2010, we took a cross-sectional sample, evaluating glomerular filtration and how this value was associated with various clinical and laboratory parameters in patients receiving 2 or 3 dialysis sessions per week. RESULTS During the study period, 95 patients were included in the study, 41 of which (43%) started with 2 HD sessions per week, and 54 (57%) with 3 sessions per week. The mean time that patients remained on the 2HD sessions/week regimen was 11.1 ± 7.2 months (range: 2-25 months). Of the 41 patients that started with 2 HD sessions/week, 10 received a transplant while on the treatment regimen, 1 was transferred to peritoneal dialysis, 6 recovered renal function and were able to abandon dialysis treatment, 15 were switched to the 3 HD sessions/week regimen, and 9 continued on the 2 HD sessions/week regimen at the time the study ended. Of the 15 patients that were switched to the 3 HD sessions/week regimen, 4 received transplants, 3 died, and the remaining 8 continued on HD until the end of the study. A Kaplan-Meier survival analysis revealed that patients who started on the 2 HD sessions/week regimen had a greater survival rate (log-rank: 3.964; P=.04). Losses in both glomerular filtration rate and 24-hour diuresis were lower in patients on the 2 HD sessions/week regimen: 0.22 ± 0.36 ml/min/month vs 0.89 ± 1.26 ml/min/month for glomerular filtration (P=.001), and 90.59 ± 132 ml/month vs 206.23 ± 286 ml/month for 24-hour diuresis (P=.001), respectively. In the cross-sectional sample taken in January 2010, 17 patients were on the 2 HD sessions/week regimen and 47 were on the 3 HD sessions/week regimen. Serum concentrations of β2-microglobulin were significantly lower in the 2 HD sessions/week group (19.7 ± 5 vs 38.3 ± 13; P=.000). The mean haemoglobin concentration was similar between the two groups, with a significantly lower dose required of erythropoietin in patients on the 2 HD sessions/week regimen (7058 ± 3749 units/week vs 12 553 ± 10 826 units/week; P=.037). CONCLUSION In select populations, the start of HD can be administered on a progressively increasing dosage, starting with two sessions/week. In our experience, this is a safe prescription that probably contributes to preserving residual renal function.

Recuperación de la función renal en enfermos tratados con hemodiálisis

The aim of this study was to review all cases of recovery of renal function in chronic haemodialysis patients, observed in the last ten years. During the study period, 218 chronic renal failure patients were managed on haemodialysis for a minimum of 90 days. In 17 cases (8%), it was possible to interrupt dialysis after 95 to 529 days. The probability of renal function recovery was higher in patients with chronic interstitial nephritis (P=.04) or autoimmune diseases (P=.07), as well as in those starting haemodialysis treatment at a frequency of two sessions per week (P=.02). No significant differences in age, gender, glomerular filtration rate at the beginning of haemodialysis treatment, or comorbidity rate were observed. Seven patients returned to haemodialysis treatment after a dialysis-free period of 11 +/- 7 months. Two patients died for reasons unrelated to renal failure treatment, and another patient was moved to another hospital following 35 months without dialysis. The other 14 patients are alive and 8 are dialysis-free, with a monitoring period of 13 to 106 months. The conclusion reached is that there is no reason why residual kidney function should inexorably worsen after the start of haemodialysis treatment, and that functional recovery is possible in some patients.

Analysis of concordance between the bioelectrical impedance vector analysis and the bioelectrical impedance spectroscopy in haemodialysis patients.

INTRODUCTION The values of body composition provided by the two most commonly used bioelectrical impedance systems in Spain, single-frequency bioelectrical impedance vector analysis (SF-BIVA) and multi-frequency bioelectrical impedance spectroscopy (MF-BIS) are different and not comparable. OBJECTIVE Analyse whether the inter-method variability is due to bioelectrical variables measured by the different monitors, or rather due to the equations used to calculate body volume and mass. Another objective was to determine whether, despite the inter-method variability, the classification of hydration status by the two methods is consistent. MATERIAL AND METHODS Bioelectrical impedance was measured by SF-BIVA and MF-BIS immediately before a dialysis session in 54 patients on haemodialysis. In 38 patients, the study was repeated by SF-BIVA at the end of the same dialysis session. RESULTS Resistance and phase angle values provided by the two monitors at a frequency of 50kHz were consistent. For resistance, variability was 1.3% and the intra-class correlation coefficient was 0.99. For phase angle, variability and the intra-class correlation coefficient were 11.5% and 0.92, respectively. The volume values for total body water, extracellular water, fat mass and body cell mass were biased, with a level of variability that would not be acceptable in clinical practice. The intra-class correlation coefficient also suggested a poor level of agreement. SF-BIVA systems define overhydration or dehydration as a vector below or above the tolerance ellipse of 75% on the longitudinal axis. MF-BIS uses two criteria for pre-dialysis hyper-hydration: overhydration (OH) greater than 2.5 litres, or greater than 15% of extracellular water. The degree of equivalence with the results of the SF-BIVA monitor was better with the second criterion (kappa: 0.81, excellent agreement) than with the first one (kappa: 0.71, acceptable agreement). The MF-BIS system defines post-dialysis normal hydration as a difference between OH and ultrafiltratation volume between –1.1 and 1.1 litres and agreement with the SF-BIVA system for this parameter was acceptable (weighted kappa index: 0.64). CONCLUSIONS The MF-BIS and SF-BIVA systems provide similar readings for bioelectrical parameters, and the wide variation in the quantification of volume and body mass must be attributed to the different equations used for calculation. Furthermore, the criteria used by both systems to define both pre- and post-dialysis hydration have an acceptable level of equivalence.

Diálisis peritoneal paliativa: implantación de un programa de atención domiciliaria a enfermos tratados con diálisis peritoneal (DP) en situación terminal

Terminal-stage patients on peritoneal dialysis (PD) are often transferred to haemodialysis as they are unable to perform the dialysis technique themselves since their functional capacities are reduced. We present our experience with five patients on PD with a shortterm life-threatening condition, whose treatment was shared by primary care units and who were treated with a PD modality adapted to their circumstances, which we call Palliative Peritoneal Dialysis.