Thermoregulation: What's New? What's Not?

n reviewing literature, as far back as the 1800s, the use of I heated incubators has improved survival rates of term and preterm infants. The idea of incubation can be traced as far back as to the Egyptians, who used heat to improve the productivity of hatching chicken eggs. As the chick embryos matured, less heat was required because the embryo generated its own heat from an increase in metabolism, related to being more mature and larger. In his travels to Egypt from France in 1799, Napoleon was impressed with the incubation theory and brought it back to France, where it was used in Parisian zoos. A French obstetrician, Tarnier, was the first to apply this idea of incubation to human premature infants in the late 19th century, where he reported improving survival of premature infants using crude incubators to warm them. The survival of these small infants was so impressive that, during this time, it was common to see infants in incubators on display at carnivals and fairs around the world. Over the next 60 years, the survival of small infants weighing less than 2000 grams increased from 38% to 66% when the infants were kept warm with incubators. Numerous studies initiated the technologically advanced development of incubators and radiant warmers used today. The theory of thermoregulation has been studied repeatedly and shown to be an effective intervention in neonatal care. Basic concepts of heat exchange and the physiology of human thermoregulation are crucial points to understand to provide a thermal-neutral environment for the premature infant. To maintain a constant central temperature within narrow limits (36.5°C–37.5°C), very low-birth-weight (VLBW) infants or sick premature infants are typically cared for either in incubators or under radiant warmers. Maintaining a constant temperature requires a balance between heat production and heat loss.