Denise Vijt

Body composition, hydration, and related parameters in hemodialysis versus peritoneal dialysis patients.

♦ Aims: Maintaining euvolemia is an important goal in patients on renal replacement therapy. However, adequate assessment of volume status in clinical practice is hampered by a lack of accurate measuring tools. A new multifrequency bioimpedance tool has recently been validated. This study compares volume status in peritoneal dialysis (PD) and hemodialysis (HD) patients in a single center. ♦ Methods: Body Composition Monitoring (BCM; Fresenius Medical Care, Bad Homburg, Germany) was performed in all patients on PD or HD without contraindication. PD patients were measured with a full abdomen; HD patients were measured at the midweek session, once immediately before and once 20 minutes after dialysis. Clinical overhydration was defined as an overhydration-to-extracellular water ratio of >0.15. ♦ Results: Total body water, extracellular water, and intracellular water were 33.7 ± 6.9 L versus 31.8 ± 8.1 L vs 33.9 ± 6.7 L, 16.4 ± 3.9 L vs 15.3 ± 4.9 L vs 16.8 ± 3.3 L, and 17.1 ± 6.2 L vs 16.5 ± 4.6 L vs 17.2 ± 3.9 L in the pre-HD, post-HD, and PD patients, respectively (p = NS). In the pre-HD and the PD patients, overhydration was 1.9 ± 1.7 L and 2.1 ± 2.3 L, whereas post-HD this was only 0.6 ± 1.7 L (p < 0.001). Clinical overhydration was more prevalent in pre-HD and PD patients compared to post-HD patients (24.1% vs 22.3% vs 10%, p < 0.001). In multivariate models, overhydration was related to age, male gender, and post-HD status. ♦ Conclusion: Although much clinical attention is paid to volume status, 24% of patients still have clinically relevant volume overload. Implementation of a reliable and clinically applicable tool to assess volume status is therefore necessary. It is possible to obtain comparable volume status in PD and HD patients.

The Personal Dialysis Capacity Test Is Superior to the Peritoneal Equilibration Test to Discriminate Inflammation as the Cause of Fast Transport Status in Peritoneal Dialysis Patients

This study evaluated the potential of the Personal Dialysis Capacity (PDC) test to discriminate fast transport status (FTS) as a consequence of inflammation versus FTS because of other causes. This distinction is important because new therapeutic options such as icodextrin and automated peritoneal dialysis can abolish the negative impact on outcome of FTS if fast transport is not caused by inflammation. A PDC test and a Peritoneal Equilibration Test (PET) were performed in 135 incident PD patients. Membrane characteristics were related with baseline biochemical parameters and C-reactive protein. After correction for other covariates, only large pore flux (J(v)L) but not surface area over diffusion distance (A0/dX) or dialysate over plasma concentration was related to C-reactive protein. Using the PDC test for detection of inflammation, positive and negative predictive values were 16/36 and 80/99, respectively, whereas with PET, positive predictive value was 5/20 and negative predictive value 92/115 (chi2 = 0.009). In a Cox regression for patient survival with correction for age, a J(v)L higher than expected by the surface area over diffusion distance, predicted outcome (P = 0.04). Patients with inflammation had a higher J(v)L (0.21 +/- 0.12 versus 0.17 +/- 0.09; P = 0.06) and a lower ultrafiltration (89 +/- 631 versus 386 +/- 601 ml/d; P = 0.06) and urine output (878.45 +/- 533.55 versus 1322 +/- 822 ml/d; P = 0.023) than patients without inflammation. There was no difference for surface area over diffusion distance (A0/dX) or dialysate over plasma concentration. A PDC test yields far more information about the peritoneal membrane characteristics than a PET. A J(v)L higher than expected by the A0/dX is an indicator of inflammation and is related to an increased mortality. The PET is not able to discriminate between FTS because of inflammation versus because of anatomic reasons, whereas the PDC test does.

Acute central haemodynamic effects induced by intraperitoneal glucose instillation

BACKGROUND The supposed lack of a haemodynamic impact of peritoneal dialysis (PD) has been challenged recently by the finding of a mild increase of peripheral blood pressure (BP) during an acute dwell. It is not clear whether, besides the effect of changes in intraperitoneal (IP) volume and/or pressure, IP glucose instillation and absorption plays a role in this. Therefore, we tested the impact of IP instillation of glucose on the evolution of central haemodynamic parameters, using SphygmoCor, during an acute dwell with two different glucose concentrations. METHODS Stable, non-diabetic PD patients (N = 22) were treated consecutively in a randomized, cross-over design (A then B or B then A) with one 1.36% (A) and one 3.86% (B) physioneal dwell of 100 min. Central BP was measured with SphygmoCor and blood was sampled for serum glucose and insulin levels every 20 min. Insulin resistance was defined as a Homeostatic Model Assessment Index (HOMA-index) >1.4. RESULTS Serum glucose levels rose during both the 1.36% and the 3.86% dwell, whereas insulin levels rose only during the 3.86% dwell. The increase of both glucose and insulin levels was more pronounced in patients with insulin resistance (11/22 patients). There was, however, no accompanying change versus baseline in haemodynamic parameters (carotid systolic blood pressure, diastolic BP, heart rate or augmentation index). CONCLUSION Despite substantial increases in blood glucose and insulin levels, there was no accompanying change in central haemodynamic parameters during an acute PD dwell with low or high glucose concentrations.