Newborn and Infant Care

Initial Newborn Transition, Thermoregulation, and Prophylaxis

The transition from intrauterine to extrauterine life requires rapid physiological adaptation across multiple organ systems. Immediately after delivery, assess breathing, heart rate, and the need for resuscitation; record the Apgar score at 1 and 5 minutes, but do not use it to decide whether to begin resuscitation. If the 5-minute APGAR score is lower than 7, the nurse must continue scoring and assessing every 5 minutes for up to 20 minutes. Normal vital signs in a calm, awake newborn include a heart rate of 110 to 160 beats per minute, an axillary temperature between 36.5°C and 37.5°C (97.7°F to 99.5°F), and a respiratory rate of 30 to 60 breaths per minute accompanied by brief periods of periodic breathing. Acrocyanosis can be a normal transitional finding; central cyanosis can also occur briefly immediately after birth, but persistent central cyanosis or oxygen saturation below age-appropriate targets requires prompt evaluation.

Newborns possess a unique vulnerability to thermal instability because they cannot generate warmth through shivering. Instead, they produce heat through non-shivering thermogenesis via the metabolism of vascular brown adipose tissue. When exposed to cold environments, the infant experiences cold stress, an adverse physiological cascade that triggers marked increases in oxygen consumption and glucose utilization. If left uncorrected, cold stress rapidly depletes metabolic reserves, predisposing the neonate to hypoxia, hypoglycemia, and metabolic acidosis.

To protect the infant from cold stress, the nurse must counteract the four distinct physical mechanisms through which neonates lose heat to their surroundings. Evaporative heat loss takes place when moisture on the newborn's skin, such as amniotic fluid or bathwater, turns to vapor. Conduction occurs when the infant's skin makes direct contact with cold surfaces or objects, such as a cold scale or an unheated stethoscope. Convection involves cooler ambient air currents circulating over the newborn's exposed body, such as drafts from open windows or hallways. Radiation heat loss occurs when body heat radiates toward cold solid surfaces that are nearby but not in direct contact with the newborn, such as a cold exterior wall.

Standard prophylactic medications are administered shortly after delivery to safeguard the newborn against preventable complications. Vitamin K (phytonadione) is administered intramuscularly into the vastus lateralis muscle to prevent hemorrhagic disease of the newborn. To protect the eyes, erythromycin 0.5% ophthalmic ointment is instilled into both lower conjunctival sacs to prevent ophthalmia neonatorum caused by Neisseria gonorrhoeae.