Thermal balance in infants.

A theoretical model of heat balance is presented that could clarify the matching of babies' wrapping with their environments. Best estimates of metabolic heat input and heat loss by all known routes are defined for 22 parts of the body surface. The variation of these with core temperature, posture, skin vasodilatation, and the onset of sweating are calculated: first, by using presumed skin temperatures and second, by following iterative calculation of the skin temperature and the consequent total heat losses. Calculation of the highest tolerable ambient temperature (HTAT) for a given set of clothes, underbedding, and covers shows that a well-wrapped baby lying face down could have an HTAT 10 degrees C lower than if he/she were lying supine. Representative values for highest and lowest tolerable temperatures (defined in text) are presented for the first 6 mo of life. Retrospective estimation of thermal balance from death-scene data on clothing and bedding can permit assessment of hyperthermia or hypothermia as a contributing cause of death. Recommendations are made on the avoidance of hyperthermia.

Skin color measurements in terms of CIELAB color space values.

The principles of color measurement established by the Commission International d'Eclairage have been applied to skin and the results expressed in terms of color space L*, hue angle, and chroma values. The distribution of these values for the ventral forearm skin of a sample of healthy volunteers is presented. The skin-color characteristics of a European subgroup is summarized and briefly compared with others. Color differences between individuals were identified in terms of one, two, or all three color-space parameters. Because the method is quantitative and the principles internationally recognized, these color-space parameters are proposed for the unambiguous communication of skin-color information that relates directly to visual observations of clinical importance or scientific interest.

Sleeping position and infant bedding may predispose to hyperthermia and the sudden infant death syndrome.

Southern New Zealnd has one of the highest postneonatal mortality rates in the developed world (8.1/1000 livebirths) and 77% of these deaths are attributed to the sudden infant death syndrome (SIDS). Both hyperthermia and sleeping position have previously been implicated in SIDS. A theoretical model to estimate the thermal balance of infants used here shows that the head, and particularly the face, becomes the main route for heat loss when thick clothing and bedding are used. This thermoregulatory role could be compromised by the prone sleeping position. It is postulated that particular cultural combinations of infant care practices (sleeping position, clothing, bedding, and room heating) may facilitate hyperthermia and explain widely disparate rates of SIDS in different countries and ethnic groups.