Neonatal hypothermia cold stress Cold injury

Definition& pathophsiology Is a core temperature <35-35.5C. Rectal temp. May be mild 35-32 C or severe<32C. Neonates are prone to hypothermia because of large surface area relative to the body size and is more risk in premature and low birth wt neonates. Loss of heat may be by radiation to cooler surrounding objects or by evaporation of water from skin, or by conduction when skin come in touch with cooler objects or by convection when cool air take the heat from the skin . response to heat loss is by vasoconstriction of skin and other tissues and by nonshivering thermogenesis by using the brown fat to generate calorie and heat. Brown fat is present arround the kidneys ,adrenals and neck, between the scapula and in the mediastinum. when it used no replacement for it so it will finish when used and it is present till 6 month.it is mainly deposited during the 3rd trimester.so premature are with less brown fat. Hypothermia leads to hypoglycemia, metabolic acidosis, loss of glycogen.

aetiology Delay wrapping in cold environment at birth. prolonged resuscitation in cold delivery room. exposed body to cold bed or room after birth. Sepsis Intracranial hemorrhage

Clinical features cold injury Hypothermia cause depression in all activities of body organs leading cold skin, to poor feeding, lethargy, poor cry, bradycardia, arrhythmia, respiratory distress due to vasoconstriction and low surfactant formation, cyanosis, skin mottling, prone to sepsis, even coma and death.

Treatment and prevention In the hospital ; gradual Rewarming by putting under warmer or in incubator with gradual increase in body temp. goes with the gradual increase in incubator temp. Treat underlying causes like sepsis or intracranial bleeding . prevention is by; Rapid Wrapping the baby to remove the moist from skin at birth to let the skin dry ,and resuscitation in trolley under warmer to prevent loss of heat at birth. At home in cold season the infant should be wrapped and not exposed to cold.