SURFACE ELECTRICAL CAPACITANCE AS A NONINVASIVE BEDSIDE MEASURE OF EPIDERMAL BARRIER MATURATION IN THE NEWBORN-INFANT

Objective. The classical studies of epidermal barrier function in infa nts have relied on measurement of transepidermal water loss by evapori metry. This technique, although valuable, is, in practice, slow, expen sive, and susceptible to error because of convective air currents. In this prospective study, we evaluated gestation-dependent and postnatal age-dependent changes in epidermal barrier function by measurement of skin surface electrical capacitance (SEC) in 40 newborn infants rangi ng from 25 to 40 weeks' gestational age. SEC was measured in picofarad s with a dermal phase meter. Methodology. The measurements were record ed continuously during a 12-second period from the forehead at 12 to 2 4 hours of life. The baseline (C-BL) surface hydration at 1 second and the rate of change of SEC during probe occlusion (C-SL) were used as measures of surface hydration and transepidermal water movement, respe ctively. In the most premature infants (<30 weeks), these measurements were repeated daily for 5 days. Data were analyzed by analysis of var iance after logarithmic (Ln) transformation. Results. We found a signi ficant difference in Ln(C-BL) in infants born before and after 30 week s' gestation (4.91 +/- 0.36 Ln[pF] vs 2.67 +/- 0.21 Ln[pF], respective ly). Similarly, C-SL was significantly different in infants born befor e and after 30 weeks' gestation (16.42 +/- 5.55 pF/s vs 1.59 +/- 0.22 pF/s, respectively). In infants born at less than 27 weeks, both Ln(C- BL) and C-SL decreased significantly by postnatal day 5. In the term g roup (n = 25), C-SL was significantly greater in white than in black i nfants (1.96 +/- 1.32 pF/s vs. 0.95 +/- 0.55 pF/s, respectively). Conc lusion. These results demonstrate impaired epidermal barrier propertie s in immature infants, less than 30 weeks' gestation, and reveal a rem arkable rate of barrier maturation of this group in the first few days of postnatal Life. Also, the finding of decreased C-SL in black infan ts supports the hypothesis of differences in barrier function attribut able to skin types. Overall, these findings demonstrate the feasibilit y of bedside SEC measurements in the evaluation of epidermal barrier p roperties in the newborn infant.