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Evaluation of Fluid Overload by Bioelectrical Impedance Vectorial Analysis
Published on: August 17, 2022
Prediction of body water compartments in preterm infants by bioelectrical impedance spectroscopy
C T Collins1, J Reid, M Makrides
1FOODplus Research Centre, Women's and Children's Health Research Institute, Women's and Children's Hospital and Flinders Medical Centre, Adelaide, South Australia, Australia. carmel.collins@health.sa.gov.au
Insights
Bioelectrical impedance spectroscopy (BIS) shows potential for assessing body composition in preterm infants, but its clinical use is limited due to wide agreement limits. Coefficients were developed for body water analysis in this population.
Area of Science:
- Neonatal research
- Biomedical engineering
- Pediatric nutrition
Background:
- Accurate assessment of body composition is crucial for evaluating nutritional interventions in preterm infants.
- Bioelectrical impedance spectroscopy (BIS) offers a potential method for assessing changes in lean body tissue and fat mass.
- Developing specific resistivity coefficients is necessary for accurate BIS analysis in preterm infants.
Purpose of the Study:
- To develop and validate resistivity coefficients for bioelectrical impedance spectroscopy (BIS) analysis of body water volumes in preterm infants.
- To assess the utility of BIS for determining total body water (TBW) and extracellular water (ECW) in this population.
Main Methods:
- 99 preterm infants (mean gestational age 32 weeks) were enrolled.
- Total body water (TBW) and extracellular water (ECW) were measured using deuterium and bromide dilution.
- Resistivity coefficients were calculated from BIS measurements and validated in a separate cohort.
Main Results:
- BIS-predicted TBW and ECW correlated well with reference methods (r=0.825 and 0.75).
- A small bias was observed (TBW 10 ml, ECW 40 ml).
- However, large limits of agreement were found (TBW ± 650 ml, ECW ± 360 ml).
Conclusions:
- Bioelectrical impedance spectroscopy (BIS) has limited clinical utility for individual preterm infants.
- The method may be useful for population-level comparisons or group analyses due to small bias.
- Further refinement of BIS techniques may enhance its applicability in neonatal care.
Background/Objectives:
To evaluate nutritional interventions in preterm infants, a simple, accurate assessment of the type of growth, that is, change in body composition through the relative contributions of lean body tissue and fat mass to weight gain, is needed. Bioelectrical impedance may provide such a method. The aim of this study was to develop resistivity coefficients appropriate for use in bioelectrical impedance spectroscopy (BIS) analysis of body water volumes in preterm infants.
Subjects/Methods:
A total of 99 preterm infants were enrolled (mean gestational age 32 completed weeks). Total body water (TBW) and extracellular water (ECW) were determined using the reference methods of deuterium and bromide dilution. BIS measurements taken at the same time allowed calculation of resistivity coefficients. Predictions of TBW and ECW obtained using these coefficients were then validated against volumes determined using the reference methods in a separate cohort of infants.
Results:
Data were available for 91 preterm infants. BIS-predicted TBW and ECW correlated well with the measured volumes (Pearson's r(p)=0.825 and 0.75, respectively). There was a small bias (TBW 10 ml and ECW 40 ml) but large limits of agreement (TBW ± 650 ml and ECW ± 360 ml).
Conclusions:
BIS appears to have limited clinical utility; however, the relatively small bias means that it may be useful for measurements within a population or for comparisons between groups in which population means rather than individual values are compared.
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