Open AccessContinuous Monitoring of Plasma, Interstitial, and Intracellular Fluid Volumes in Dialyzed Patients by Bioimpedance and Hematocrit Measurements
Author(s) -
Michel Y. Jaffrin,
Marianne Fenech,
Jean-François de Fremont,
Michel Tolani
Publication year - 2002
Publication title -
asaio journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.961
H-Index - 66
eISSN - 1538-943X
pISSN - 1058-2916
DOI - 10.1097/00002480-200205000-00021
Subject(s) - hematocrit , body water , extracellular fluid , intracellular fluid , interstitial fluid , chemistry , volume (thermodynamics) , fluid compartments , plasma volume , body fluid , blood volume , dialysis , extracellular , anesthesia , body weight , surgery , medicine , thermodynamics , biochemistry , physics
Bioimpedance spectroscopy (BIS) permits evaluation of extra- and intracellular fluid volumes in patients. We wished to examine whether this technique, used in combination with hematocrit measurement, can reliably monitor fluid transfers during dialysis. Ankle to wrist BIS measurements were collected during 21 dialysis runs while hematocrit was continuously monitored in the blood line by an optical device. Extracellular (ECW) and intracellular (ICW) water volumes were calculated using Hanai's electrical model of suspensions. Plasma volume variations were calculated from hematocrit, and changes in interstitial volume were calculated as the difference between ECW and plasma volume changes. Because accuracy of ICW was too low, changes in ICW were calculated as the difference between ultrafiltered volume and ECW changes. Total body water (TBW) volumes calculated pre- and postdialysis were, respectively, 3.25+/-3.2 and 1.95+/-2.5 liters lower on average than TBW given by Watson et al.'s correlation. Average decreases in fluid compartments expressed as percentage of ultrafiltered volume were as follows: plasma, 18%; interstitial, 28%, and ICW, 54%. When the ultrafiltered volume was increased in a patient in successive runs, the relative contributions of ICW and interstitial fluid were augmented so as to reduce the relative drop in plasma volume.