Homeothermal adjustment in the immediate postdelivered infant monitored by continuous and simultaneous measurement of core and peripheral body temperatures

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 degrees C for the first 2 h of extrauterine life and at 24-26 degrees C for the succeeding 6 h. In group II, II were kept at 24-26 degrees 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.(ABSTRACT TRUNCATED AT 250 WORDS)