Hydration Status Does Not Influence Peritoneal Equilibration Test Ultrafiltration Volumes

University College London Center for Nephrology, University College London Medical School, London, UK.
Clinical Journal of the American Society of Nephrology (Impact Factor: 4.61). 06/2009; 4(7):1207-12. DOI: 10.2215/CJN.01060209
Source: PubMed


The peritoneal equilibration test (PET) was developed some 25 yr ago and has been used to help prescribe peritoneal dialysis. However, PET is affected by several factors, including diabetes and inflammation. It was speculated that extracellular fluid overload would increase PET ultrafiltration volumes, and therefore the usefulness of the PET in routine clinical practice was audited.
Data from 211 consecutive patients attending a university teaching hospital for a standard PET who had multifrequency bioimpedance performance were analyzed to determine which factors affected net PET ultrafiltration volumes.
Net PET ultrafiltration volume was independent of gender, age, diabetes, residual renal function, peritoneal dialysis prescriptions (modes and dialysates), extracellular fluid volume, or C-reactive protein (CRP). There was an inverse regression with serum albumin and sodium on multiple logistical regression analysis (F = 13.4, P < 0.001 and F = 10.1, P = 0.001, respectively) and a positive regression with 24-h net peritoneal ultrafiltration volumes (F = 15.5, P < 0.001). As expected, there was a strong correlation with net sodium losses (r = 0.99, P < 0001).
It was found that PET test ultrafiltration volume in routine clinical practice was not affected by CRP, hyperglycemia, or extracellular fluid volume overload. Ultrafiltration volumes were increased in those patients with reduced serum sodium and albumin, most likely because of inflammation and protein malnutrition.

Full-text preview

Available from:
  • [Show abstract] [Hide abstract]
    ABSTRACT: Patients treated by peritoneal dialysis, especially those using automatic cyclers, are frequently found to be hypervolemic. To determine whether there are significant differences between the currently available modalities of peritoneal dialysis, we analyzed whether differences in transporter status and treatment modality had a discernible effect on extracellular fluid volumes as measured by multi-frequency bioimpedance. Two hundred prevalent peritoneal dialysis patients, 48% male, mean age 54.9 yr (SD+/-15.6), were studied using multi-frequency bioimpedance following a standard peritoneal equilibration test; 63 patients were treated by CAPD, 29 by APD, 96 by CCPD and 12 by OCCPD. There were no differences in extracellular volumes, or extracellular volume adjusted for height, or as a ratio to total body water between the groups. As expected, extracellular volume adjusted for height depended upon bodyweight (r=0.412, p<0.001), sex (r=0.457, p<0.001) and systolic blood pressure (r=0.162, p=0.023), and extracellular volume to total body water related to the reciprocal of total daily peritoneal ultrafiltration losses (r=-0.0254, p=0.003) and urine output (-0.254, p=0.003). More importantly, on logistical regression analysis the ratio of extracellular fluid to total body fluid increased with falling albumin, F=21.5 p<0.001, increasing age, F=18.5 p<0.001, urine output F=6.46, p=0.014, total daily ultrafiltration, F=3.52 and protein intake p=0.003. Extracellular fluid adjusted for total body fluid was associated with CRP (males F=6.03, p=0.03, females F=4.438, p=0.04). Patients were more likely to have an expanded extracellular fluid volume if they had reduced daily fluid losses, but also with biomarkers typically associated with poor nutrition and inflammation.
    No preview · Article · Nov 2009 · The International journal of artificial organs
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Encapsulating peritoneal sclerosis (EPS) is an uncommon but potentially devastating complication of peritoneal dialysis. We have observed an increased incidence in our centre over the last few years. To look at potential risk factors for developing EPS, we reviewed 39 cases diagnosed between 2000 and 2009 and compared these with a control group of 71 patients who had been treated by peritoneal dialysis for a minimum of 4 years. Both groups extensively used icodextrin, >80% of patients. Both groups had been treated by peritoneal dialysis for a similar time: EPS median 54 months (46-87.5), compared to controls 70 (54-79.5). However, more of the EPS group were treated with peritoneal cyclers (75% vs 46%, X(2) = 6.86, P = 0.009) and prescribed more peritoneal dialysate 14.2 l/day +/- 0.7 vs 10.8 +/- 0.5, P < 0.0001. Although both groups were fast transporters, those with EPS had higher D/P creatinine ratios on peritoneal equilibration testing, 0.84 +/- 0.1 vs 0.77 +/- 0.1, P < 0.05, and lower peritoneal test ultrafiltration volumes, 193 +/- 26 ml vs 283 +/- 21 ml, P < 0.05. Discussion. The patients in the EPS group were faster transporters, with lower peritoneal equilibration and 24-h ultrafiltration volumes, and were exposed to greater volumes of peritoneal dialysates compared to peritoneal dialysis vintage controls.
    Preview · Article · May 2010 · Nephrology Dialysis Transplantation
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: N-terminal probrain type natriuretic peptide (NTproBNP) has been proven to be a valuable biomarker for predicting cardiac events and mortality in the hemodialysis population. However recent reports have suggested that NTproBNP is a marker of volume overload rather than one of cardiac dysfunction. Therefore this study investigated the effect of fluid volume status on NTproBNP. Volume status was determined pre- and postdialysis in 72 stable hemodialysis outpatients by multifrequency bioimpedance, and the relationship to NTproBNP values was examined. The mean and median NTproBNP values were 931.9 +/- 230 and 242 (90 to 688) pmol/L, respectively. On simple correlation, NTproBNP was associated with markers of volume overload and cardiac dysfunction. However, on logistical regression analysis, the strongest association was with the predialysis ratio of extracellular water/total body water (beta 26.6, F29.6, P = 0.000), followed by postdialysis mean arterial blood pressure (beta 0.14, F17.1, P = 0.000), dialysate calcium concentration (beta -1.19, F14.1, P = 0.002), and change in extracellular fluid volume with dialysis (beta 0.27, F7.4, P = 0.009) In this study, NTproBNP was not associated with cardiac dysfunction as assessed by transthoracic echo or nuclear medicine scintigraphy but was dependent on factors associated with volume overload. However, because bioimpedance results can also be affected by malnutrition with loss of cell mass, NTproBNP may be elevated not only in patients with volume overload, but also those with malnutrition.
    Preview · Article · Jun 2010 · Clinical Journal of the American Society of Nephrology
Show more