Diagnosis and Treatment: Use and Misuse of Temperature and Humidity in Care of the Newborn Infant

INFANTS delivered from the warm uterus into a cool environment invariably experience a considerable loss of body heat, and since the rate of cooling is almost always greater than the rate of heat production body temperature promptly falls. The rate of fall, the final level of equilibrium, and the distribution of temperatures of the various tissues and organs are quite dependent upon the ambient conditions of temperature and humidity which are provided for infants in the first minutes, hours, and days of life. If the artificial climate is too warm and humid to allow for the dissipation of heat liberated by metabolic processes the newborn infant becomes febrile and tachypneic. This is particularly likely in small infants whose physiologic mechanisms of heat loss are easily overwhelmed. The environmental conditions must be adjusted because death from hyperthermia may ensue rather quickly. However, there is usually no problem of recognition when warm limits have been exceeded; as a result temperature and humidity are never deliberately misused in this way in the care of newborn infants. Induced hyperthermia is almost always the result of technical accidents. Since there is now convincing evidence that newborn infants exhibit homeothermic responses to thermal stimuli and that the survival of small neonates can he improved by placing them in warm and moderately humid environments, it may also be said that physicians rarely misuse temperature and humidity in a manner which would permit uncontrolled heat loss. Thus, if we omit the issue of deep hypothermia for the moment the present-day questions about the proper use of temperature and humidity are concerned not with the extremes but with the middle of the climatic scale.