Relationship between Maturation of the Skin and Electrical Skin Resistance

Abstract

ABSTRACT. In 16 newborn infants (24 6-39 wk 6 days 830-33908) at ages between 0-70 days, the skin's electrical resistance was measured. Over 30 min we sequentially measured direct current resistance between two skin electrodes placed on the abdomen. The resistance was found to be low in very premature infants with gestation ages of 30 wk or less. It increased with both gestational age and postnatal age. In these infants, the resistance measured at 30 min during the first 4 days of life (3.4 + 0.3 KQ; mean + SD) was significantly less than that found at 20-70 days It has been demonstrated that electrical skin resistance is exclusively located within the stratum corneum (1, 2), and the resistance is directly related to the thickness of the stratum corneum (3,4). The skin of premature infants is thin, gelatinous, edematous, translucent (5), and has little capacity to produce sweat (6). These skin properties of newborn infants are important characteristics related to gestational age. Although the assessment of these characteristics is simple, they are unfortunately qualitative in nature. The effect of these premature skin characteristics on the electrical resistance ofthe skin may change with advancing gestational age and therefore skin resistance may provide a quantitative measure of skin maturity. This study was designed to evaluate the relationship between the electrical skin resistance and the skin maturity of newborn infants. MATERIALS AND METHODSconsent was obtained from the parents. In the study of the skin, investigators have attempted to utilize measured electrical skin resistance both to direct current and alternating current. We arbitrarily chose to measure resistance to direct current. The electrodes were stainless steel disks 1.5 cm in diameter. Two electrodes were placed on the skin at a fixed distance of 3 cm between their centers. The electrodes were applied with rubber straps as commonly used in electrocardiographs which allowed a nearly constant pressure with each application. The electrical connection to the skin was made using electrocardigram electrode jelly (Keratin cream, Fukuda Co., Tokyo, Japan). The electrodes were always applied to the surface of the abdomen midway between the xiphisternum and the umbilicus.Prior to the application of the electrodes, the skin surface was cleansed with a wet towel and then with ethanol to remove the vernix caseosa and other lipid materials. Immediately after the electrodes were positioned on the skin a constant voltage of 0.4 V was delivered between the two electrodes. The electrical current through the skin ranged between 5 and 150 microamperes. An ohm-meter (Hi-calc tester, Hioki Co., Tokyo, Japan) was used to measure skin resistance to direct current. Two resistors of 3kQ and 50kQ (usual fixed resistors for electrical circuits) were used in the calibration of the ohm-meter. The changes in resistance between the two electrodes were recorded sequentially at 2-min intervals for 10 min, and then at 5 min intervals for 20 min. The timer was started when the e...

Human Newborn Skin: The Effect of Isopropanol on Skin Surface Hydrophobicity

“…In addition to biochemical analysis, various electrical meas- urements have been used to study human skin (6)(7)(8)(11)(12)(13)(14)(15). During the last trimester, for example, the production of vernix in conjunction with development of the stratum corneum markedly changes the surface electrical properties of the fetus (16,17).…”

“…In the newborn period, the skin surface has been studied using electrical conductance as a measure of surface hydration (7). Capacitance, a closely related electrical measurement, has been used extensively in the stud y of the skin of adult humans and animals (6,8,13,14). The evaporimeter, a commonly used instrument in studies of transepidermal water loss, measures capacitance changes in polymer films as a function of humidity at various distances from the skin surface ( 18).…”