Newborn infants lose heat rapidly at birth and during the first half hour of life. This investigation was undertaken to determine whether the initial heat loss was due principally to evaporation, and whether or not establishment of breathing would be irregular or delayed if the initial cold stress was reduced.
Five groups, each of 10 infants, were studied during the first half hour of life. Infants in Groups I and IV remained wet and were exposed to either room air or placed under a radiant heater. Those in Groups II, III, and V were dried promptly and exposed to room air, wrapped in a blanket or warmed by means of a radiant heater. Heat loss due to radiation and convection together was twice that from evaporation. Reduction of cold stress by placing the infant under a radiant heater as soon as he is born does not impede or delay the onset of breathing. Wet infants exposed to room air lost nearly five times more heat than those who were dried and warmed.
In vigorous infants, the simple maneuver of drying and wrapping in a warm blanket is almost as effective in diminishing heat loss as placing them under a radiant heater. However, in depressed or immature infants who may be more asphyxiated or have reduced energy stores, radiant heat maintains body temperature while allowing access to the patient.