Emery M M, Hebert A A, Aguirre Vila-Coro A, Prager T C
Department of Dermatology, University of Texas Medical School, Houston.
J Dermatol Sci. 1991 Sep;2(5):336-40. doi: 10.1016/0923-1811(91)90026-t.
When performing electrophysiological testing, high electrical impedance values are sometimes found in neonates. Since excessive impedance can invalidate test results, a study was conducted to delineate the relationship between skin maturation and electrical skin impedance. This study investigated the skin impedance in 72 infants ranging from 196 to 640 days of age from conception. Regression analyses demonstrated a significant relationship between impedance and age, with the highest impedance centered around full-term gestation with values falling precipitously at time points on either side. Clinically, impedance values fall to normal levels at approximately four months following full-term gestation. Skin impedance values are low in premature infants, but rapidly increase as the age approaches that of full-term neonates. Low impedance values in premature infants are attributed to greater skin hydration which results from immature skin conditions such as 1) thinner epidermal layers particularly at the transitional and cornified layers; 2) more blood flow to the skin; and 3) higher percentage of water composition. These factors facilitate the diffusion of water vapor through the skin. As the physical barrier to skin water loss matures with gestational age, the skin impedance reaches a maximum value at full term neonatal age. After this peak, a statistically significant inverse relationship exists between electrical skin impedance and age in the first year of life. This drop in skin impedance is attributed to an increase in skin hydration as a result of the greater functional maturity of eccrine sweat glands.
在进行电生理测试时，有时会在新生儿中发现高电阻抗值。由于过高的阻抗会使测试结果无效，因此进行了一项研究来描述皮肤成熟度与皮肤电阻抗之间的关系。本研究调查了72名从受孕起年龄在196至640天之间的婴儿的皮肤阻抗。回归分析表明阻抗与年龄之间存在显著关系，最高阻抗集中在足月妊娠前后，在两侧的时间点上数值急剧下降。临床上，足月妊娠后约四个月时阻抗值降至正常水平。早产儿的皮肤阻抗值较低，但随着年龄接近足月新生儿，阻抗值会迅速增加。早产儿的低阻抗值归因于皮肤水合作用增强，这是由不成熟的皮肤状况导致的，如：1）表皮层尤其是过渡层和角质层较薄；2）皮肤血流量增加；3）水成分百分比更高。这些因素促进了水蒸气通过皮肤的扩散。随着皮肤水分流失的物理屏障随着胎龄的增长而成熟，皮肤阻抗在足月新生儿期达到最大值。在此峰值之后，在生命的第一年，皮肤电阻抗与年龄之间存在统计学上显著的负相关关系。皮肤阻抗的这种下降归因于小汗腺功能成熟度提高导致的皮肤水合作用增加。
