Association between volume status as assessed by bioelectrical impedance analysis and echocardiographic parameters in peritoneal dialysis patients

Background: The majority of patients undergoing peritoneal dialysis (PD) suffer from volume overload and this overhydration is associated with increased mortality. Thus, optimal assessment of volume status in PD is an issue of paramount importance. Patient symptoms and physical signs are often unreliable indexes of true hydration status. Summary: Over the past decades, a quest for a valid, reproducible, and easily applicable technique to assess hydration status is taking place. Among existing techniques, inferior vena cava diameter measurements with echocardiography and natriuretic peptides such as brain natriuretic peptide and N-terminal pro-B-type natriuretic peptide were not extensively examined in PD populations; while having certain advantages, their interpretation are complicated by the underlying cardiac status and are not widely available. Bioelectrical impedance analysis (BIA) techniques are the most studied tool assessing volume overload in PD. Volume overload assessed with BIA has been associated with technique failure and increased mortality in observational studies, but the results of randomized trials on the value of BIA-based strategies to improve volume-related outcomes are contradictory. Lung ultrasound (US) is a recent technique with the ability to identify volume excess in the critical lung area. Preliminary evidence in PD showed that B-lines from lung US correlate with echocardiographic parameters but not with BIA measurements. This review presents the methods currently used to assess fluid status in PD patients and discusses existing data on their validity, applicability, limitations, and associations with intermediate and hard outcomes in this population. Key Message: No method has proved its value as an intervening tool affecting cardiovascular events, technique, and overall survival in PD patients. As BIA and lung US estimate fluid overload in different compartments of the body, they can be complementary tools for volume status assessment.

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Measurement of Fluid Shift in Capd Patients Using Segmental Bioelectrical Impedance Analysis

Peritoneal Dialysis International ◽

10.1177/089686089901900418 ◽

1999 ◽

Vol 19 (4) ◽

pp. 386-390 ◽

Cited By ~ 11

Author(s):

Joon Ho Song ◽

Seoung Woo Lee ◽

Gyeong A. Kim ◽

Moon-Jae Kim

Keyword(s):

Peritoneal Dialysis ◽

Bioelectrical Impedance Analysis ◽

Bioelectrical Impedance ◽

Impedance Analysis ◽

Water Volume ◽

Tissue Fluid ◽

Body Segment ◽

Fluid Shift ◽

Solution Exchange ◽

Segmental Bioelectrical Impedance

Objective To determine, using segmental bioelectrical impedance analysis (BIA), the characteristics of fluid shift of each body segment in continuous ambulatory peritoneal dialysis (CAPD) patients during and after peritoneal dialysis (PD) solution exchange. Design Observational study with repeated measurements of bioelectrical impedance, which is inversely related to tissue fluid content. Patients Thirteen clinically stable CAPD patients. Methods Bioelectrical impedance was measured at frequencies of 5, 50, 250, and 500 kHz in each body segment four times: (1) before and (2) after drainage of dialysate, and (3) at 1 hour and (4) at 2 hours after exchange of new 1.5% dextrose PD solution. Results Impedance of both arms was significantly increased at 1 hour post exchange at all frequencies. In the trunk, impedance at all frequencies increased significantly after drainage, decreased significantly at 1 hour post exchange, and then increased again for the next hour without significance. Impedance of both legs showed a decreasing tendency at all frequencies during and after exchange. Net calculated water volume changes between the time before drainage and 2 hours post exchange were –0.5 L in the trunk, –0.25 L in both arms, +0.47 L in both legs, –0.28 L in total. The change in body weight between the time before drainage and 2 hours post exchange was –0.21 kg, on average, and significantly correlated with total net calculated water volume change ( p = 0.009). Conclusions Each body segment of the CAPD patient has its own characteristic pattern of fluid shift in response to PD solution exchange or dwell. Segmental BIA may be a useful tool for understanding the physiological changes in fluid shift in CAPD patients.

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