Homeothermal Adjustment in the Immediate Postdelivered Infant Monitored by Continuous and Simultaneous Measurement of Core and Peripheral Body Temperatures

Abstract

To investigate the process of homeothermal acclimation to extrauterine environment, core and peripheral body temperatures in the human neonate were continuously and simultaneously recorded. Twenty-one term-delivered babies were divided into two groups. In group I, 10 babies were kept at 32–34 °C for the first 2 h of extrauterine life and at 24–26 °C for the succeeding 6 h. In group II, 11 were kept at 24–26 °C for the first 8 h after delivery. Three thermisters were used: one catheter-type placed in the rectum and two involving the zero-heat flow method placed at the sternum and footsole. Because of technical limitations, rectal temperature (Tre) was monitored until temperature in the sternum (Tst) stabilized, after which this transition from Tre to Tst was noted as Tre-st. Changes in resulting temperatures were quantitatively analyzed using Student’s t test, for both intra- and intergroup comparisons. Tre-st significantly decreased during the first 28 and 42 min for groups I and II, respectively, after which time this temperature rose and stabilized. In group I, the Tre-st reached the homeothermal stage at 2 h 49 min, while 4 h 27 min were required for group II. In group I, the footsole temperature (Tsf) reached a plateau after 2 h 10 min. In group II, Tsf showed a large decrease followed by a slow rise, with no stability achieved during the 8-hour observation period. Intergroup comparisons revealed that the mean Tsf reached conditions not significantly different from those of group I at 6 h 57 min. From the differences in changes seen in the patterns of body temperature distribution, neonates show different courses of homeothermal acclimation to extrauterine life, depending on the ambient temperature to which they are initially exposed.

Optimal Thermal Control with Sufficient Nutrition May Reduce the Incidence of Neonatal Jaundice by Preventing Body-Weight Loss Among Non-Low Birth Weight Infants Not Admitted to Neonatal Intensive Care Unit

“…Body temperature of neonates was optimally regulated with their neutral thermal environment [2][3][4]. Following delivery in a delivery room maintained at ~25 ° C (77°F), neonates were immediately wiped with cotton towels, given intraoral suction on a warm bed (~40 ° C [104°F]), hugged by their mothers (skin-to-skin contact), and then placed in a transparent thermo-controlled incubator (N-ideal H-2000, Nakamura Medical Industry, Tokyo, Japan) within 2 min of birth [2,3].…”

“…Following delivery in a delivery room maintained at ~25 ° C (77°F), neonates were immediately wiped with cotton towels, given intraoral suction on a warm bed (~40 ° C [104°F]), hugged by their mothers (skin-to-skin contact), and then placed in a transparent thermo-controlled incubator (N-ideal H-2000, Nakamura Medical Industry, Tokyo, Japan) within 2 min of birth [2,3]. Transparent thermo-controlled incubators were placed next to delivery beds in the delivery room: that is, neonates were not placed in an NICU.…”

“…Neonates remained visible and were continuously observed not only by physicians and nurses (e.g., Apgar score), but also by mothers. Neonates remained in incubators for 2 h. For the first hour, incubators were set at 34 ° C (93.2°F) [2,3]. Bed linen and clothing were also warmed at 34 ° C (93.2°F), and neonates were dressed after their respiration stabilized.…”

“…For the second hour, the temperature was turned down to 30 ° C (86°F) to help neonates adapt to normal room temperature. Finally, neonates were transferred to a bed in a normal monitoring room set at ~24-26 ° C (75.2-78.8°F) [2,3].…”

“…Optimal thermal environment during that time is an ambient room temperature of ~34 ° C (93.2°F), which "allows body temperature to remain normal while oxygen consumption and evaporative water loss are both at a minimum" [1]. In contrast to the ambient room temperature (~24 ° C/75.2°F), this optimal thermal environment helps neonatal body temperature to remain normal with circulatory stability [2][3][4], resulting in improving digestive function such as prevention of vomiting and promotion of meconium excretion [2,3]. As a result, neonates in this neutral thermal environment are fed sufficiently according to basal maintenance expenditure (~50 kcal/kg) [5], which may help prevent hypoglycemia and hypernatremia associated with severe neurologic damage [3,6,7].…”