title: Estimation of body water compartments in cirrhosis by multiple-frequency bioelectrical-impedance analysis.
abstract: Estimation of total body water by measuring bioelectrical impedance at a fixed frequency of 50 kHz is useful in assessing body composition in healthy populations. However, in cirrhosis, the distribution of total body water between the extracellular and intracellular compartments is of greater clinical importance. We report an evaluation of a new multiple-frequency bioelectrical-impedance analysis technique (MFBIA) that may quantify the distribution of total body water in cirrhosis. In 21 cirrhotic patients and 21 healthy control subjects, impedance to the flow of current was measured at frequencies ranging from 4 to 1012 kHz. These measurements were used to estimate body water compartments and then compared with total body water and extracellular water determined by isotope methodology. In cirrhotic patients, extracellular water and total body water (as determined by isotope methods) were well predicted by MFBIA (r = 0.73 and 0.89, respectively). However, the 95% confidence intervals of the limits of agreement between MFBIA and the isotope methods were +/-14% and +/-9% for cirrhotics (extracellular water and total body water, respectively) and +/-9% and +/-9% for cirrhotics without ascites. The 95% confidence intervals estimated from the control group were +/-10% and +/-5% for extracellular water and total body water, respectively. Thus, despite strong correlations between MFBIA and isotope measurements, the relatively large limits of agreement with accepted techniques suggest that the MFBIA technique requires further refinement before it can be routinely used to determine the nutritional assessment of individual cirrhotic patients.
authors.affiliation: Department of Gastroenterology and Hepatology, Princess Alexandra Hospital, Ipswich Road, Wooloongabba, Queensland 4102, Australia.
authors.forename: M E
authors.initials: ME
authors.lastname: Lehnert
authors.forename: D D
authors.initials: DD
authors.lastname: Clarke
authors.forename: J G
authors.initials: JG
authors.lastname: Gibbons
authors.forename: L C
authors.initials: LC
authors.lastname: Ward
authors.forename: S M
authors.initials: SM
authors.lastname: Golding
authors.forename: R W
authors.initials: RW
authors.lastname: Shepherd
authors.forename: B H
authors.initials: BH
authors.lastname: Cornish
authors.forename: D H
authors.initials: DH
authors.lastname: Crawford
mesh_terms: D001201:Ascites / Q000150:complications / Q000378:metabolism; D001823:Body Composition; D001834:Body Water / Q000378:metabolism*; D016022:Case-Control Studies; D017097:Electric Impedance; D005110:Extracellular Space / Q000378:metabolism*; D005260:Female; D006801:Humans; D007424:Intracellular Fluid; D008103:Liver Cirrhosis / Q000150:complications / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D011188:Potassium / Q000032:analysis; D011865:Radioisotope Dilution Technique
chemical_list: D011188:Potassium