Thermoregulation in neonates

Neonatal Physiology

•  Wet skin at birth and high surface area to body ratio – lost heat via skin surface.
•  Immature hypothalamus
•  Poor energy stores and limited brown fat = limited thermogenesis (heat production) 
•  Lack of subcutaneous fat (term) and/or adipose tissue or brown fat (preterm) 

Methods of heat loss

RADIATION – heat loss from heat radiating towards a cooler surface (e.g. a cold incubator wall)

EVAPORATION – heat loss through wet skin after birth. 

CONVECTION – heat loss from cooler air circulating around warmer skin particularly when exposed and if the room is cool.

CONDUCTION – heat loss through direct contact with a cold surface (e.g. unwarmed mattress)

A baby may lose heat by both convection and conduction via direct contact with cool scales.

Prevention of hypothermia

Sources of heat loss                            Preventive measures

Conduction                                         Warming blanket

                                                            Drapes or blankets

                                                            Head covering

                                                            Warmed solutions

Convection                                          Room temperature to 26.6ºC (80ºF)

                                                            Incubator

                                                            Keep neonate covered

Radiation                                            Radiant warmer

                                                           Wrap neonate

                                                           Warm room

Evaporation                                        Drying and wrapping

                                                           Skin to skin contact

                                                           Head covering e.g. hat

                                                           Heated, humidified inspired gases

                                                           AND body humidification

                                                           Plastic bags / wrap for preterm (<28-30 weeks)-

The Metabolic triangle 

There is an important relationship between maintaining adequate oxygenation, temperature 

and blood glucose levels. A change in one affects the other.