Abstract
Objective
To validate bio-electric impedance spectroscopy (BIS) by comparison with other methods for determination of body water compartments in stable subjects with an ileostomy and no or minor small bowel resection for inflammatory bowel disease (IBD).Subjects
Twenty-one subjects were included, age range 36-65 y (female/male=12/9), Crohn's disease (CD), n=14, ulcerative colitis (UC), n=6 and indeterminate colitis (IDC), n=1.Methods
Fluid compartments were assessed by the use of three independent methods: BIS, dual-energy X-ray absorptiometry (DXA) and dilution techniques (DIL); tritiated water (total body water, TBW); and bromide (extracellular water, ECW), respectively. Intra-cellular water (ICW) was calculated as TBW-ECW. For comparison TBW was also predicted according to an empirical formula. Differences were analysed using Bland-Altman plots.Results
The mean TBW values obtained from the impedance measurement differed in the order of -2.21 (DIL) to 1.41 (DXA) in women and -2.01 (DIL) to 2.61 (DXA) in men, from the measured and derived values of total body water. Prediction of TBW gave values that were close to BIS, with a mean difference of -0.31 in male subjects and +0.51 in female subjects. Assessment of ECW revealed that the mean difference between dilution and impedance was less in women than in men (PConclusion
The differences between all methods to assess fluid compartments are pronounced. To further investigate the use of the method in clinical practice for dynamic monitoring of rehydration in ileostomates with acute diarrhoea, repeated measurements together with comparison with weight fluid-balance charts are suggested.Sponsorship
The study was supported by grants from the Swedish Medical Research Council (17X-03117), Göteborgs Läkarsällskap and IB and A Lundbergs forskningsstiftelse.