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Bioelectrical impedance vector analysis (BIVA) in stable preterm newborns
Ana Vitoria Barban Margutti1, Carolina Reis Bustamante, Maísa Sanches
1Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo (USP), Ribeirão Preto, SP, Brazil.
Insights
Preterm infants show bioelectrical impedance analysis (BIVA) vector patterns suggesting lower total body water and soft tissues compared to term infants. This indicates reduced fat-free mass and fat mass in premature babies.
Area of Science:
- Neonatal physiology
- Body composition analysis
Background:
- Bioelectrical impedance analysis (BIVA) is a method to assess body composition.
- Phase angle (PA) and vector analysis on the RXc graph provide insights into cellular integrity and fluid status.
- Understanding body composition in premature infants is crucial for nutritional and clinical management.
Purpose of the Study:
- To evaluate the vector behavior on the RXc graph using BIVA and phase angle (PA) in stable premature infants.
- To test the hypothesis that preterm infants exhibit BIVA patterns indicative of less total body water and soft tissues compared to term infants.
Main Methods:
- A cross-sectional study was conducted on 108 preterm neonates.
- Bioelectrical impedance was measured using 800 mA at 50 kHz.
- Vector analysis was performed using specialized BIVA software.
Main Results:
- Most preterm infants fell outside the normal reference range for term infants on the RXc graph.
- A tendency for vector points to disperse in the upper right quadrant of the RXc graph was observed.
- Phase angle values were 4.92° (±2.18) for infants < 7 days and 4.34° (±2.37) for infants ≥ 7 days.
Conclusions:
- Premature infants demonstrate distinct BIVA vector patterns compared to term infants.
- Preterm infants generally have lower absolute body water, fat-free mass, and fat mass.
- BIVA provides valuable data on body composition differences in premature neonates.
Objective:
To observe the behavior of the plotted vectors on the RXc (R - resistance - and Xc - reactance corrected for body height/length) graph through bioelectrical impedance analysis (BIVA) and phase angle (PA) values in stable premature infants, considering the hypothesis that preterm infants present vector behavior on BIVA suggestive of less total body water and soft tissues, compared to reference data for term infants.
Methods:
Cross-sectional study, including preterm neonates of both genders, in-patients admitted to an intermediate care unit at a tertiary care hospital. Data on delivery, diet and bioelectrical impedance (800 mA, 50 kHz) were collected. The graphs and vector analysis were performed with the BIVA software.
Results:
A total of 108 preterm infants were studied, separated according to age (< 7 days and ≥ 7 days). Most of the premature babies were without the normal range (above the 95% tolerance intervals) existing in literature for term newborn infants and there was a tendency to dispersion of the points in the upper right quadrant, RXc plan. The PA was 4.92° (±2.18) for newborns < 7 days and 4.34° (±2.37) for newborns ≥ 7 days.
Conclusion:
Premature infants behave similarly in terms of BIVA and most of them have less absolute body water, presenting less fat free mass and fat mass in absolute values, compared to term newborn infants.
