Bioimpedance monitoring of cellular hydration during hemodialysis therapy

Abstract

Introduction The aim of this paper is to describe and demonstrate how a new bioimpedance analytical procedure can be used to monitor cellular hydration of End Stage Renal Disease (ESRD) patients during hemodialysis (HD). Methods A tetra-polar bioimpedance spectroscope (BIS), (UFI Inc., Morro Bay, CA), was used to measure the tissue resistance and reactance of the calf of 17 ESRD patients at 40 discrete frequencies once a minute during dialysis treatment. These measurements were then used to derive intracellular, interstitial, and intravascular compartment volume changes during dialysis. Findings The mean (± SD) extracellular resistance increased during dialysis from 92.4 ± 3.5 to 117.7 ± 5.8 Ohms. While the mean intracellular resistance decreased from 413.5 ± 11.7 to 348.5 ± 8.2 Ohms. It was calculated from these data that the mean intravascular volume fell 9.5%; interstitial volume fell 33.4%; and intracellular volume gained 20.3%. Discussion These results suggest that an extensive fluid shift into the cells may take place during HD. The present research may contribute to a better understanding of how factors that influence fluid redistribution may affect an ESRD patient during dialysis. In light of this finding, it is concluded that the rate of vascular refill is jointly determined with the rate of "cellular refill" and the transfer of fluid from the intertitial compartment into the intravascular space.

Monitoring Intracellular (Vc), Interstitial (Vi) and Intravascular (Vb) Volume Changes During Dialysis (HD) in a Chronic Unit (CU) Compared to an Acute Unit (AU) Setting

“…Of note, many patients at both centers (especially chronic ptients) experienced a gain in intracellular fluid (shown by the negative values on the horizontal axis. Montgomery et al [15] discussed the potential intracellular volume increase that may take place during dialysis.…”

A system to monitor segmental intracellular, interstitial, and intravascular volume and circulatory changes during acute hemodialysis

“…Details of the analytical algorithm used to derive individual fluid compartment volumes from the impedance spectroscopic recordings are given in previous articles [30][31][32]. We hypothesize that this new instrument will be able to quantify changes in the three fluid compartments as fluid volume is removed during hemodialysis.…”

Evaluation of a new non-invasive measurement technique based on bioimpedance spectroscopy to estimate blood alcohol content: a pilot study

“…However, bioimpedance also finds its way into clinical applications, e.g. monitoring the hydration status of the body during hemodialysis [10][11][12]. Preliminary findings of the current study with regard to the possible application of BIS for estimating blood alcohol levels were partly published during a technical conference [13].…”