Heat balance

The goal in controlling the infant or child’s environment is to minimize the energy expended in order to maintain a normal temperature, and to eliminate thermal stress. With a normal body temperature, the infant or child has a minimal metabolic rate and minimal oxygen consumption which serves to ensure cardiac output is maintained.

Infants and neonates (under 36 weeks’ gestation) rarely shiver when exposed to a cold environment and must rely on non-shivering, or chemical thermogenesis, to produce heat. Oxygen and glucose are consumed during non-shivering thermogenesis; therefore, the infant who already has low glucose and oxygen levels may become hypoxaemic or hypoglycaemic when faced with added thermal stress. Measures to keep the environment normothermic are paramount in order to maintain homeostasis.

Heat loss

It is vital that care providers understand the principles of heat balance in order to be able to provide a normothermic environment for the infant. The two key principles are: (1) to block avenues of heat loss (four mechanisms of heat transfer); and (2) to provide heat and environmental support to maintain a normal temperature.

Four mechanisms of heat transfer