2. Thermoregulation & Cold Stress

what is conduction heat loss in a newborn?

heat loss through direct contact with a cold surface

• example: a cold scale

what is convection heat loss in a newborn?

heat loss to cooler moving air

• example: a draft

what is evaporation heat loss in a newborn?

heat loss as moisture on the skin dries

what is radiation heat loss in a newborn?

heat loss to a nearby cold surface without direct contact

• example: a cold window

why are newborns at increased risk for heat loss?

thin skin, large surface area, limited fat and energy stores, and ineffective shivering

how do newborns produce heat?

nonshivering thermogenesis through brown fat breakdown

what is cold stress in a newborn?

increased metabolic demand as the newborn uses oxygen and energy to maintain body temperature

how does cold stress increase a newborn’s oxygen needs? *

norepinephrine triggers brown fat breakdown, increasing metabolic rate and oxygen consumption

• can lead to tachypnea, hypoxia, and hypoglycemia

why can cold stress cause hypoxia? *

oxygen demand from burning brown fat for warmth may exceed the oxygen available

why can cold stress cause hypoglycemia? *

increased metabolic demand rapidly depletes glycogen stores

how can prolonged cold stress affect newborn circulation? *

hypoxia causes anaerobic metabolism → produces more acid → metabolic acidosis → pulmonary vasoconstriction

• pulmonary vasoconstriction can reopen or keep open fetal shunts and create more hypoxemia

which interventions help prevent newborn cold stress? *

• prewarm the room and equipment

• dry immediately after birth

• remove wet linens

• provide skin-to-skin (kangaroo) care

• feed early to keep glycogen stores up

• use heated, humidified oxygen when prescribed

• delay bathing at least 6 hours

how long should the newborn’s first bath be delayed? *

at least 6 hours and until thermally stable