Publications by authors named "Karin Moret"

9 Publications

  • Page 1 of 1

Agreement between different parameters of dialysis dose in achieving treatment targets: results from the NECOSAD study.

Nephrol Dial Transplant 2012 Mar 4;27(3):1145-52. Epub 2011 Aug 4.

Department of internal medicine, Máxima Medical Centre, Veldhoven, Leiden, The Netherlands.

Background: The recommended parameter of dialysis dose differs between K-DOQI and the European Best Practice Guidelines. It is not well known to what extent an agreement exists between the different parameters, nor if target and delivered dialysis dose are prescribed according to the urea reduction rate (URR), single-pool Kt/V (spKt/V) or equilibrated double-pool Kt/V (eKt/V) and which parameter is most strongly related to mortality.

Methods: In 830 haemodialysis patients from the NECOSAD cohort URR, spKt/V and eKt/V were calculated and compared according to a classification regarding the recommended treatment targets (70%, 1.4 and 1.2, respectively) as well as minimum delivered dialysis dose (65%, 1.2 and 1.05, respectively). Moreover, the relation between treatment dose and survival was assessed using Cox regression analysis.

Results: A spKt/V of ≥1.4 and URR ≥70% corresponded with eKt/V ≥1.20 (as reference method) in, respectively, 98.0 and 90.6% of patients. spKt/V of ≥1.2 and URR ≥65% corresponded with eKt/V ≥1.05 in, respectively, 95.5 and 91.2% of patients. Deviations from the reference method were significantly related to differences in urea distribution volume (spKt/V), treatment time (URR) and ultrafiltration volume (URR). The adjusted HR (95% CI) was 0.98 (0.96, 0.99) for URR, 0.51 (0.31, 0.84) for spKt/V and 0.46 (0.30, 0.80) for the eKt/V.

Conclusion: The use of URR leads to larger disagreement with the reference method (eKt/V) treatment target as compared to spKt/V. Low urea distribution volume, short treatment time and low ultrafiltration volumes are predictive parameters for overestimation of dialysis dose when utilizing the alternative methods spKt/V and URR instead of eKt/V. Delivered eKt/V, spKt/V and URR were all positively related to survival.
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March 2012

Variations in predialytic plasma conductivity in dialysis patients: effect on ionic mass balance and blood pressure.

ASAIO J 2011 Jan-Feb;57(1):53-61

Department of Internal Medicine, Maxima Medical Centre, Veldhoven, The Netherlands.

In this study, variations in plasma conductivity (PC), as a surrogate marker of plasma sodium, as well as its relation with intradialytic ionic mass balance (IMB) and blood pressure were assessed in 73 patients. Plasma conductivity and IMB were retrieved on a treatment to treatment basis during a 6-month period. Dialysate sodium concentration was 140 mmol/L. A total of 4070 treatments were analyzed. Mean coefficient of variation for predialytic PC was 1.3%, and mean intraindividual range in predialytic PC measurements during the 6-month follow-up period was 0.9 mS/cm (plasma sodium ∼ 9 mmol/L). Predialytic PC was related to both diffusive and total IMB (r = 0.91, p < 0.001; and r = 0.35, p < 0.01). The average diffusive IMB over a 6-month period was negative in 33% of patients, and the average PC increased during dialysis in 14% of patients. Averaged predialytic PC was significantly related to systolic blood pressure (r = 0.35; p < 0.01), whereas within patients, predialytic systolic blood pressure was significantly different between treatments with the lowest and highest predialytic PC (139 ± 24 vs. 147 ± 21 mm Hg; p < 0.05). In conclusion, depending on PC, diffusive ionic transfer from dialysate to patient may occur in a significant percentage of patients using a dialysate sodium concentration of 140 mmol/L. Variations in PC are related to blood pressure, which might suggest a volume-independent effect of sodium.
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April 2011

The influence of bicarbonate/lactate-buffered PD fluids on N{ε}-(carboxyethyl)lysine and N{ε}-(carboxymethyl)lysine in peritoneal effluent.

Perit Dial Int 2011 Mar-Apr;31(2):189-93. Epub 2010 Jul 29.

Division of Nephrology, Department of Internal Medicine, Maastricht University Medical Centre (MUMC), The Netherlands.

Objective: Accumulation of advanced glycation end products (AGEs) may be involved in the pathogenesis of peritoneal membrane dysfunction. As glycoxidation may play an important role in AGE formation, peritoneal dialysis fluids with low levels of glucose degradation products (GDPs) might result in a reduction in AGE concentration in the peritoneal effluent. The aim of this study was to compare the effects of conventional glucose-containing dialysis solutions and low GDP level fluids on the concentration of the AGEs N(ε)-(carboxymethyl)lysine (CML) and N(ε)-(carboxyethyl)lysine (CEL) in peritoneal effluent.

Design: Prospective randomized control study.

Methods: 23 patients were treated with either conventional glucose-containing fluid (n = 11, group A) or low level GDP fluid (n = 12, group B) during a period of 12 weeks. Before and after this period, CML and CEL were measured in peritoneal effluent.

Results: In groups A and B there were changes in CML concentrations [respectively 13.7 ± 17.0 and -16.0 ± 46.0 nmol/L (NS)] and CEL concentrations (respectively 20.3 ± 26.6 and -8.8 ± 18.9 nmol/L, p = 0.015). Residual renal function (RRF) in groups A and B was, respectively, 6.8 and 6.1 mL/min (NS). CML, but not CEL, in the peritoneal effluent was inversely related to RRF (r = -0.67, p < 0.05).

Conclusion: CEL, but not CML, in the peritoneal effluent appears to be influenced by the prescription of low GDP level fluid, probably due to the highly reduced concentration of methylglyoxal, which is needed for formation of CEL. CML is primarily influenced by RRF.
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January 2012

Conductivity pulses needed for Diascan® measurements: does it cause sodium burden?

NDT Plus 2009 Aug;2(4):334-5

Department of Internal Medicine , University Hospital , Maastricht The Netherlands E-mail:

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August 2009

Ionic dialysance and the assessment of Kt/V: the influence of different estimates of V on method agreement.

Nephrol Dial Transplant 2007 Aug 5;22(8):2276-82. Epub 2007 Jun 5.

Department of Internal Medicine, Máxima Medical Centre, Veldhoven, The Netherlands.

Background: Ionic dialysance was recently introduced as a means to assess Kt/V (K(ID)t/V). With this method, urea distribution volume (V) has to be estimated. The primary aim of the present study was to assess the agreement between equilibrated Kt/V assessed by urea kinetic modelling (eKt/V) with K(ID)t/V taking into account different estimates of V, and to assess the monthly variation in V. Secondly, the mechanisms behind the intra-treatment changes in ionic dialysance and inter-treatment variability of K(ID)t/V were assessed.

Methods: Sixty-six patients were included. eKt/V was estimated using 30 min post-treatment sampling in the second generation Daugirdas equation. V was assessed by the formulae of Watson and Chertow (V(Watson); V(Chertow)), double-pool urea kinetic modelling (V(UKM)) and by ionic dialysance (V(IOD)) [Diascan; Hospal(R)].

Results: The use of V(UKM) or V(IOD) instead of V(Watson) or V(Chertow) improved the relation between eKt/V and K(ID)t/V (both r = 0.93; P < 0.001 vs r = 0.84 and r = 0.81; P < 0.001). Mean values of eKt/V (1.19 +/- 0.21), K(ID)t/V(UKM) (1.19 +/- 0.30) and K(ID)t/V(IOD) (1.21 +/- 0.25) were comparable. Intra-class correlation coefficient of V(IOD) was 0.87 with a 1-month interval and <0.75 after 2 and 3 months. Intra-class correlation coefficient of V(DP) was 0.79 with a 1-month interval and <0.75 after 2 and 3 months. Inter-treatment variation in K(ID)t/V during six consecutive dialysis sessions was 6.1% +/- 0.6%. Changes in blood flow were the main determinant of variations in K(ID)t/V (P < 0.05). During treatment, ionic dialysance decreased by 12 +/- 13 ml/min (P < 0.001). The decline in blood volume was the major determinant of the intra-dialytic change in ionic dialysance (P < 0.05).

Conclusion: The use of V(IOD) and V(UKM) results in better agreement between eKt/V and K(ID)t/V compared with anthropometric formulae. K(ID)t/V was comparable with eKt/V and thus lower than expected for a single-pool method. V(IOD) and V(UKM), should be assessed at least monthly. K(ID)t/V varies widely between consecutive dialysis sessions, mainly due to differences in blood flow. During treatment, ionic dialysance decreases, which is related to the relative decline in blood volume.
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August 2007

An evaluation of blood volume changes during ultrafiltration pulses and natriuretic peptides in the assessment of dry weight in hemodialysis patients.

Hemodial Int 2007 Jan;11(1):51-61

Atrium Hospital Medical Centre, Gelderse vallei Hospital, Ede, The Netherlands.

Changes in blood volume (BV) during dialysis as well as plasma levels of brain natriuretic peptide (BNP) and N-terminal (NT) pro-BNP levels are possible tools to assess dry weight in hemodialysis (HD) patients. The aim of the study was to compare these parameters with other non-invasive techniques used to assess dry weight in HD patients, and to study their relation with intradialytic hypotension (IDH) and the presence of cardiovascular disease BV changes during HD, both during regular dialysis and during an ultrafiltration pulse, plasma levels of NT pro-BNP and BNP, and vena cava diameter index (VCDI) were assessed in a cohort of 66 HD patients, which was subdivided according to tertiles of total body water (TBW) corrected for body weight, assessed by bioimpedance analysis. Parameters were also related to the presence of IDH and history of cardiovascular disease. The decline in BV during regular dialysis and during an ultrafiltration pulse, as well as VCDI and BNP were significantly different between the tertiles of normalized TBW, but refill after the ultrafiltration pulse and NT pro-BNP were not. Only VCDI and the decline in BV during regular dialysis were significantly different between patients with or without IDH. Vena cava diameter index, BNP, and NT pro-BNP were significantly higher in patients with cardiovascular disease. Using bioimpedance as the reference method, changes in BV, either during regular dialysis or during an ultrafiltration pulse, as well as VCDI and BNP are all indicative of hydration state in dialysis patients, but refill after an ultrafiltration pulse is not. Only VCDI and BV changes were related to IDH. The presence of cardiovascular disease appears to influence both VCDI as well as BNP.
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January 2007

The effect of sodium profiling and feedback technologies on plasma conductivity and ionic mass balance: a study in hypotension-prone dialysis patients.

Nephrol Dial Transplant 2006 Jan 6;21(1):138-44. Epub 2005 Sep 6.

Department of Internal Medicine, Maxima Medical Centre, Veldhoven and University Hospital Maastricht, PO Box 5800, 6202 AZ Maastricht, The Netherlands.

Background: Sodium profiling improves haemodynamic tolerance in haemodialysis (HD) patients but may also influence sodium homeostasis. Changes in blood volume and plasma conductivity (PC) during HD can be modelled by feedback technology, but their effects on sodium homeostasis are not widely studied.

Methods: This randomized crossover study compared PC and ionic mass balance (IMB) as surrogate markers of sodium balance between standard HD [dialysate conductivity (DC) 14.0 mS/cm], sodium profiling (DC 15.0-->14.0 mS/cm), blood volume (BV)-controlled and PC-controlled feedback (target: post-HD PC: 14.0 mS/cm) in 10 HD patients with frequent hypotension.

Results: 440 treatments were studied. Pre-dialytic PC was significantly higher during SP (14.4+/-0.2 mS/cm) compared to standard HD (14.2+/-0.3 mS/cm), and was not different between the other manoeuvres: PC-controlled (14.1+/-0.3 mS/cm), and BV-controlled feedback (14.2+/-0.2 mS/cm). Except for the first treatment, during which IMB was lower during the sodium profile, IMB did not differ significantly between the various manoeuvres and was strongly dependent upon ultrafiltration volume and the difference between pre-dialytic PC and DC. Symptomatic hypotensive episodes occurred least frequently during BV-controlled feedback (8%) compared to the other manoeuvres (standard HD, 16%; sodium profile, 14%; PC-controlled feedback, 17%), but differences were not significant. Inter-dialytic weight gain and pre-dialytic systolic blood pressure did not differ.

Conclusions: Pre-dialytic PC increased during the sodium profile, and did not differ between BV- or PC-controlled feedback compared to standard HD. Thus, it appears that both BV- and PC-controlled feedback can be safely prescribed without substantial salt- and water-loading, at least in the short term. Analysis of IMB is useful to assess differences in sodium balance between single treatment sessions but appears of less value in a steady-state situation.
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January 2006

Blood volume control by biofeedback and dialysis-induced symptomatology. A short-term clinical study.

Nephron 2002 ;92(3):605-9

Department of Internal Medicine, St. Joseph Hospital Veldhoven, Maastricht, The Netherlands.

In earlier studies, a reduction in intradialytic procedures was observed in patients with severe intradialytic hypotension symptomatology by the use of blood volume controlled biofeedback systems. However, few data are present on the use of biofeedback-controlled treatments in patients experiencing minor intradialytic symptoms. In the present study, 157 standard and 158 biofeedback-controlled treatments were compared during a 2-month period in 16 hemodialysis patients. Both the percentage of hypotensive episodes (6.3 +/- 11.3 vs. 15.8 +/- 18.3%; p < 0.05) as well as other intradialytic symptoms (cramps, nausea, headache, abdominal pain) (11.0 +/- 12.8 vs. 18.1 +/- 16.9%; p < 0.05) were significantly less during biofeedback-controlled treatments compared to standard dialysis treatments, despite a similar decline in relative blood volume (8.8 +/- 3.5 vs. 8.3 +/- 3.1%; p = n.s.). Interdialytic weight gain and intradialytic rise in plasma sodium levels were comparable. Concluding, in this short-term preliminary study, blood volume controlled biofeedback improved dialysis tolerance also in patients with minor intradialytic symptomatology.
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March 2003

Ionic mass balance and blood volume preservation during a high, standard, and individualized dialysate sodium concentration.

Nephrol Dial Transplant 2002 Aug;17(8):1463-9

St Joseph Hospital, Veldhoven and. University Hospital, Maastricht, The Netherlands.

Background: Although a higher dialysate sodium concentration (DNa) is frequently used to improve haemodynamic stability during haemodialysis, few studies have compared ionic mass balance (IMB) during different DNa. Moreover, DNa is usually a standard prescription, whereas inter-individual pre-dialytic serum sodium levels may differ widely. The aims of the study were to assess IMB and the decline in blood volume (DeltaBV) during isovolaemic HD as well as during HD combined with ultrafiltration (UF) during DNa [140], DNa [144], and an individualized DNa [ind], in which DNa is equal to pre-HD plasma conductivity x 10.

Methods: IMB and plasma conductivity were assessed by on-line conductivity measurements (Diascan; Hospal) in 13 HD patients. After 1 h of isovolaemic HD, measurements were continued during UF+HD until dry weight. DeltaBV was assessed by an optical method (Hemoscan).

Results: During isovolaemic HD with DNa [140] and [144], Pre-Na was significantly related to IMB (r=0.83 and r=0.61; P<0.05). Diffusive Na flux into the patient occurred when the difference between DNa and pre-dialytic serum sodium was larger than 5 mmol/l. During UF+HD, IMB was 318+/-166 mmol during DNa [140], 277+/-116 mmol during DNa [ind], and 239+/-111 during DNa [144] (mean+/-SD; P<0.05 compared with the other treatment modalities) whereas DeltaBV did not differ significantly. In the five patients with a pre-dialytic sodium concentration below 140 mmol/l, ionic removal was significantly higher during DNa [ind] (324+/-87) compared with DNa [140] (228+/-127 mmol; P<0.05) without a significant difference in DeltaBV (-9.7+/-1.6 vs -7.8+/-2.3%).

Conclusion: A large difference in IMB was observed between DNa 144 and DNa 140, without a significant difference in DeltaBV. In patients with low pre-dialytic serum sodium levels, diffusive ionic influx from the dialysate into the patient may occur. In patients with low pre-dialytic sodium levels, DNa [ind] leads to an enhanced ionic removal compared with DNa [140] without large differences in DeltaBV.
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August 2002