Physiologic Adaptations of the Newborn Chapter 24 Physiologic Adaptations of the Newborn

Transition to Extrauterine Life First period of reactivity Lasts up to 30 minutes after birth Newborn’s heart rate increases to 160 to 180 beats/min Decreases after 30 minutes Decrease in motor activity after period

Transition to Extrauterine Life—cont’d Second period of reactivity Occurs 4 to 8 hours after birth Tachycardia, tachypnea occur Meconium passed Increased muscle tone, changes in skin color, and mucous production

Physiologic Adaptations Respiratory system Initiation of breathing Signs of respiratory distress Maintaining adequate oxygen supply Cardiovascular system Heart rate and sounds Blood pressure Blood volume

Physiologic Adaptations—cont’d Hematopoietic system Red blood cells and hemoglobin Leukocytes Platelets Blood groups

Physiologic Adaptations—cont’d Gastrointestinal system Digestion Stools Meconium Feeding behaviors

Physiologic Adaptations—cont’d Hepatic system Iron storage Carbohydrate metabolism Jaundice Coagulation Immune system

Physiologic Adaptations—cont’d Integumentary system Caput succedaneum Cephalhematoma Subgaleal hematoma Sweat glands Desquamation Mongolian spots Nevi Erythema toxicum

Physiologic Adaptations—cont’d Skeletal system At birth more cartilage then ossified bone Neuromuscular system Newborn reflexes Neurologic assessment

Physical Assessment General appearance Vital signs Baseline measurements of physical growth Weight and length Head circumference Neurologic assessment

Behavioral Characteristics Sleep-wake states Other factors influencing behavior of newborns Gestational age Time Stimuli Medication

Behavioral Characteristics—cont’d Sensory behaviors Vision Hearing Smell Taste Touch

Behavioral Characteristics—cont’d Response to environmental stimuli Temperament Habituation Consolability Cuddliness Irritability Crying

Key Points Term infant’s various anatomic and physiologic systems have reached development and function that permits physical existence apart from mother Infant has sensory capabilities that indicate state of readiness for social interaction Appearance of jaundice during first day or persistence of jaundice for more than 7 days indicates a pathologic process

Key Points—cont’d Heat loss in newborn may exceed capacity to produce heat and lead to metabolic and respiratory complications that threaten newborn’s well-being Assessment of newborn requires data from the prenatal, intrapartal, and postpartal periods Assessment proceeds systematically so each system is thoroughly evaluated

Key Points—cont’d Some reflex behaviors are important for newborn’s survival Personalities and behavioral characteristics of infants play major role in the ultimate relationship between infants and parents Each full-term newborn has predisposed capacity to handle multitude of stimuli in external world