Neonatal Thermoregulation and Fluid Balance Flashcards

A preterm infant in an open radiant warmer has excessive insensible water losses primarily due to:

Answer: Thin, immature skin with high transepidermal water loss

Preterm infants have thin, poorly keratinized skin with minimal subcutaneous fat, causing dramatically elevated transepidermal water loss.

The thermoneutral zone for a neonate is defined as:

Answer: The environmental temperature range in which metabolic rate is minimal and body temperature is normal

The thermoneutral zone minimizes metabolic oxygen consumption while maintaining normal body temperature through minimal thermogenesis.

Brown adipose tissue (BAT) in neonates is used for:

Answer: Non-shivering thermogenesis to generate heat

Neonates cannot shiver effectively; they rely on BAT metabolism (non-shivering thermogenesis) mediated by norepinephrine to generate heat.

Which sign indicates hypothermia in a neonate?

Answer: Peripheral vasoconstriction, lethargy, poor feeding, and acrocyanosis

Cold stress causes peripheral vasoconstriction to conserve heat; neonates respond with lethargy, poor feeding, and acrocyanosis.

The normal urine output for a neonate after the first 24 hours of life is:

Answer: 1–3 mL/kg/hour

Normal neonatal urine output of 1–3 mL/kg/hour reflects adequate hydration and renal perfusion after initial physiologic oliguria.

Which electrolyte imbalance is most common in preterm neonates in the first week of life due to immature renal tubular function?

Answer: Hyponatremia

Preterm neonates lose excess sodium in urine due to immature renal tubular sodium reabsorption, causing late hyponatremia.