TEMPERATURE REGULATION IN PREMATURE INFANTS

Abstract

Sixteen serial observations of oxygen consumption, carbon dioxide production, R.Q., respiratory rate, rectal temperature, and skin blood flow were made on six premature infants ranging in age from 3 hours to 12 days and weighing from 1.14 to 1.94 kg, utilizing a specially designed climatized chamber at neutral (32-34°C), low (21-23°C), and high (36-38°C) ambient temperatures. Ten premature infants ranging in age from 2½ hours to 18 days were studied at high (36-38°C) ambient temperature. At low ambient temperature, there was a mean increase of 63% in oxygen consumption even in infants under 24 hours of age. At the end of the rewarming period, rectal temperature, which had been lowered during a 20-minute exposure to 21-23°C, nearly recovered to the original level in infants in both of the age groups of 0 to 24 hours and 2 to 5 days, whereas in the 6 to 12 day old group, it returned faster than the former two and it was increased by 0.32 to 1.9°C (mean 0.9°C). At 36-38°C, ambient temperature, the mean oxygen consumption increased 18% in infants ages 2½ to 7½ hours, whereas there was no significant increase in infants ages 10 to 18 days. Sweating and significant vasodilatation generally did not occur even in the older infants. The respiratory rate was increased in most infants. It is suggested that heat loss through the respiratory tract might be important to the premature infant who has a lack of evaporative means at high ambient temperature.