EVAPORATION RATE AND SKIN BLOOD-FLOW IN FULL-TERM INFANTS NURSED IN AWARM ENVIRONMENT BEFORE AND AFTER FEEDING COLD-WATER

Earlier results have shown that some infants born by elective Caesarea n section start to sweat in a warm environment while others do not, an d that sweating can be inhibited by feeding cold glucose. To determine whether these earlier observations, indicating a difference in postna tal temperature adaptation, could be reproduced in vaginally born infa nts, we measured the rate of evaporation from the skin surface, body a nd skin temperatures from several sites, skin blood flow and respirato ry rate in newborn infants nursed in a warm environment, before and af ter feeding cold water. In all infants the body and skin temperatures increased in the warm environment (p < 0.01), with a decreasing differ ence between oesophageal and leg skin temperature (p < 0.01). Visible sweating occurred in 9/14 infants at a rectal temperature of 37.5 degr ees C. In the infants who started to sweat, evaporation rate increased from 5.6 +/- 2.8 (SD) g/m(2)/h 15 min before sweating to 15.7 +/- 10. 6 g/m(2)/h (p < 0.05) when sweat became visible and the infants were f ed cold water. After feeding of cold water the evaporation rate decrea sed and within 10 min returned to a value not significantly different from the pre-sweating value. Interscapular skin blood flow had increas ed by 42% (p < 0.01) at the time of sweating and decreased by 22% (p < 0.01) after feeding cold water. In the infants who did not start to s weat, no increase in evaporation rate was noted and the changes in ski n blood flow were not statistically significant. The infants who start ed to sweat did not differ from those who did not regarding maternal m edication during delivery. We conclude that some, but not all, newborn infants start to sweat at a body temperature of 37.5 degrees C. In th e infants who start to sweat, sweating and an increase in skin blood f low can be inhibited by feeding cold water. There seem to be individua l differences in the regulation of body temperature in newborn infants , possibly due to the delayed change in the central temperature set-po int in some infants.