Physiologic and Behavioral Adaptation of the Newborn

Physiologic and Behavioral Adaptation of the Newborn Neonatal period-includes the time of birth through day 28 day of life Transition to Extrauterine Life Transition Period-Infants undergo phases of instability during the first 6 to 8 hours after birth First phase of the transition period last up to 30 minutes after birth and is called the first period of reactivity Newborn’s heart rate increases rapidly to 160 to 180 beats/min or so to a baseline range of between 100 to 120 beats/min

Physiologic and Behavioral Adaptation of the Newborn First Period of Reactivity Respirations are irregular, with a rate between 60 and 80 beats/min Crackles may be present Audible grunting, nasal flaring, and retractions of the chest Brief periods of apnea Infant is alert Infant’s behavior is marked by spontaneous startle reactions, tremors, crying, and movement of the head from side to side Decrease in body temperature Generalized increase in motor activity Increase in muscle tone Onset of bowel sounds Passage of meconium Production of saliva

Physiologic and Behavioral Adaptation of the Newborn Second Period of Reactivity Occurs roughly between the second and eighth hours after birth Last from 10 minutes to several hours Periods of tachypnea and tachycardia occur Increase muscle tone, skin color, and mucus production Meconium is commonly passed at this time

Physiologic and Behavioral Adaptation of the Newborn Physiologic Adaptations Respiratory System Signs of Respiratory Distress May include Nasal flaring Retractions Grunting with expirations Increase use of the intercostals muscles Seesaw respirations instead of abdominal respirations Respiratory rate that is less than 30 or greater than 60 beats/min with the infant at rest must be reported to the pediatrician

Physiologic and Behavioral Adaptation of the Newborn Cardiovascular System Change in the pressure causes a functional closure of the foramen ovale Ductus arteriosus functionally closes within 24 hours; permanent closure may take several weeks Umbilical arteries, Umbilical vein, and ductus venosus are functionally closed and are converted into ligaments within 2 to 3 months

Physiologic and Behavior Adaptations of the Newborn Heart Rate and Sounds Newborn has a resting heart rate between 100 and 160 beats/min Normal heart rate for a newborn is 110 to 160 beats/min Heart murmurs heard during the first few weeks have no pathologic significance Murmurs result from a patent ducutus arteriosus Tricuspid regurgitation

1.A heart rate of 100 beats per minute A nurse is listening to the apical heart rate of a newborn infant. The nurse determines that the heart rate is normal if which of the following is noted? 1.A heart rate of 100 beats per minute  2.A heart rate of 140 beats per minute  3.A heart rate of 180 beats per minute  4.A heart rate of 190 beats per minute 

Physiologic and Behavior Adaptation of the Newborn Blood Volume Total blood volume in the newborn is 300 ml Hematopoietic System Red blood cells and hemoglobin Term newborn may have a hemoglobin concentration of 14 to 24 g/dl Hematocrit ranges from 51 to 56 % RBC count is 4.6 to 5.2 mm

Physiologic and Behavioral Adaptation of the Newborn Thermogenic System Thermoregulation-the maintenance of balance between heat loss and heat production Hypothermia from excessive heat loss is common and dangerous problem in neonates Nonshivering thermogenesis is accomplish primarily by metabolism of brown fat

Physiologic and Behavioral Adaptation of the Newborn Heat Loss Occurs by four modes Convection Radiation Evaporation Conduction Temperature Regulation Newborns have larger body surface-to-body weight (mass) ratio than do children and adults Flexed position of the newborn helps guard against heat loss

Physiologic and Behavioral Adaptation of the Newborn Temperature Regulation Cold Stress Imposes metabolic and physiologic demands in all infants, regardless of gestational age and condition Effects of cold stress: Infant is stressed by cold, oxygen consumption increases and pulmonary and peripheral vasoconstriction occurs Thereby decreasing oxygen uptake by the lungs and oxygen to the tissues Anaerobic glycolysis increases There is a decrease in P02 and ph, leading to metabolic acidosis

Effects of Cold Stress When an infant is stressed by cold, oxygen consumption increases and pulmonary and peripheral vasoconstriction occur, decreasing oxygen uptake; anaerobic glycolysis increases and a decrease in PO2 and pH, leading to metabolic acidosis

Physiologic and Behavioral Adaptation of the Newborn Renal System Small quantity (approximately 40 ml) of urine is usually present at birth in the bladder of a term infant Newborns should void: within 24 hours of life 2 to 6 times per day during the first and second day of life 6 to 8 voids per day after day 4 Formula-fed infants may void more frequently

Physiologic and Behavioral Adaptations of the Newborn Gastrointestinal System Bowel sounds can be heard shortly after birth Capacity of the stomach varies from 30 to 90 ml on day one depending on the size of the infant Meconium is greenish black and viscous and contains occult blood First meconium passed is sterile

Physiologic and Behavioral Adaptation of the Newborn Hepatic System Infant’s iron store in the liver is proportional to the body weight, and for the term infant, should be sufficient for 4 to 6 months Healthy term newborns, blood glucose levels stabilize at 50 to 60 mg/dl during the first several hours after birth Within the first week they should be approximately 60 to 80 Bilirubin- a yellow pigment should be approximately 60 to derived from the hemoglobin with the breakdown of RBCs and the myoglobin in muscle cells

Physiologic and Behavioral Adaptation of the Newborn Physiologic Jaundice Neonatal jaundice is considered benign, bilirubin may accumulate to hazardous levels and lead to a pathologic condition Results from characteristics of normal newborn physiology, such as increased bilirubin production due to increased RBC mass, shortened life span of the fetal RBCs, and liver immaturity

Physiologic and Behavioral Adaptation of the Newborn Physiologic Jaundice Jaundice is considered pathologic if it appears within the first 24 hours of life, if serum bilirubin levels increase by more than 6 mg/dl in 24 hours, or if serum bilirubin exceeds 15 mg/dl at any time. Some reflex behaviors are important for the newborn’s survival.

Physiologic and Behavioral Adaptation of the Newborn Kernicterus Bilirubin encephalopathy, is the most serious complication of neonatal hyperbilirubinemia Occurs when bilirubin is deposited in the basal ganglia and brain stem, disrupting neuronal function and metabolism Usually occurs when bilirubin levels are higher than 25 mg/dl Acute stage of kernicterus, the infant is lethargic, hypotonic, and has a poor suck Untreated, the infant becomes hypertonic (with backward arching of the neck and trunk), has a high –pitched cry, and may develop fever

2.Stop the breast-feeding and switch to bottle-feeding permanently A nurse is providing instructions to the mother of a newborn with hyperbilirubinemia who is being breast-fed. The nurse tells the mother to: 1.Switch to bottle-feeding during the period of high bilirubin levels and feed less frequently  2.Stop the breast-feeding and switch to bottle-feeding permanently  3.Provide water feedings between the breast-feeding periods  4.Breast-feed the newborn every 2 to 3 hours 

Physiologic and Behavioral Adaptation of the Newborn Coagulation An injection of vitamin K soon after birth helps prevent clotting problems Immune system First 3 months of life, the infant is protected by passive immunity received from the mother Infant who is breastfed receives passive immunity through the colostrum and breast milk Protection provided varies with the age and maturity of the infant and the mother’s level of immunity

Physiologic and Behavioral Adaptation of the Newborn Integumentary System Vernix Caseosa (a cheeselike, whitish substance) is fused with a epidermis and serves as a protective covering Acrocyanosis- Hands and feet appear slightly cyanotic. Caused by vasomotor instability, capillary stasis, and a high hemoglobin level Normal and appears intermittently over the first 7 to 10 days, especially with exposure to cold Healthy newborn is plump.

Physiologic and Behavioral Adaptations of the Newborn Caput Succedaneum A generalized, easily identifiable edematous area of the scalp most commonly found on the occiput Boggy edematous swelling, present at birth, extends across the suture lines of the fetal skull and disappears spontaneously within 3 to 4 days Cephalhematoma A collection of blood between a skull bone and its periosteum; therefore a cephalhematoma does not cross a cranial suture line

Skeletal system Molding Caput succedaneum Cephalhematoma Subgaleal hemorrhage Spine Extremities Oligodactyly; polydactyly; syndactyly Developmental dysplasia of the hips (DDH) Signs of skeletal problems

Physiologic and Behavioral Adaptation of the Newborn Mongolian Spots Bluish-black areas of pigmentation, may appear over any part of the exterior surface of the body, including the extremities More common on the back and buttocks Most frequently noted in babies whose ethnic origins are in the Mediterranean area, Latin America, Asia, or Africa Can be mistaken for bruises Fade gradually over months or years

Physiologic and Behavioral Adaptation of the Newborn Nevi Stork bites or angel kisses, telangietaticn nevi are pink and easily blanched Appear on the upper eyelids, nose, upper lip, lower occipital area, nape of the neck Have no clinical significance and fade by the second year of life Strawberry mark, or nevus vasculosus, is a common type of capillary hemangioma Typical lesion is a raised, sharply demarcated, bright or dark red, rough-surfaced swelling that resembles a strawberry Lesions usually are single but may be multiple with 75% occurring on the head

A. Telangiectatic nevus (stork bite) B. Erythema toxicum

Reproductive System Female Full complement of potential ova Pseudomenstruation External genitals are usually edematous with increased pigmentation Labia majora and minora cover the vestibule

Reproductive System Male Foreskin completely covers the glans Hypospadias-urethral opening is located in an abnormal position Epithelial pearls-small, white firm lesions and may be seen at the tip of the prepuce Testes can be palpated in the scrotum, and rugae cover the scrotal sac

Physiologic and Behavioral Adaptation of the Newborn Erythema Toxicum Also called erythema neonatorum or newborn rash or flea bite Lesion in different stages; erythematous macules, papules, and small vesicles Lesions may appear suddenly anywhere on the body Rash is thought to be an inflammatory response

Physiologic and Behavioral Adaptations of the Newborn Skeletal System Head is one fourth of the total body length Legs are one third of the total body length Molding-the shaping of the fetal head by the overlapping of cranial bones to facilitate movement through the birth canal during labor Infant was in the breech position in utero, the legs may be extended and remain in that position for several weeks

Signs of Developmental Dysplasia of the Hip

Physiologic and Behavioral Adaptation of the Newborn Behavioral Characteristics Sleep-Wake States Six states forms a continuum from sleep to extreme irritability Two sleep states-deep sleep and light sleep Four wake states-drowsy, quiet alert, active alert, and crying Newborn sleep approximately 16 to 19 hours per day, with periods of wakefulness gradually increasing

Physiologic and Behavioral Adaptation of the Newborn Sensory Behaviors Vision Development of the visual system continues for the first 6 months Pupils react to light, the blink reflex is easily stimulated, and the corneal reflex is activated by light touch The room is darkened, newborns will open their eyes wide and look about Newborns have the ability to fixate and track a high-contrast object horizontally and vertically Newborns will tract their parents’ eyes

Physiologic and Behavioral Adaptation of the Newborn Hearing Infant’s hearing is similar to that of an adult Loud sounds of about 90 decibels cause the infant to respond with a startle reflex Low-frequency sounds such as a heartbeat or lullaby will decrease motor activity or stop the newborn from crying Infant responds readily to the mother’s voice Smell Newborns have a highly developed sense of smell and are responsive to odors that facilitate adaptation to the extrauterine environment

Physiologic and Behavioral Adaptation of the Newborn Response to Environmental Stimuli Temperament Newborn posses individual characteristics that affect selective responses to various stimuli present in the internal and external environment Habituation A protective mechanism that allows the infant to become accustomed to environmental stimuli Consolability Newborns vary in their ability to console themselves or to be consoled

Newborn Sleep-Wake States A. Deep sleep B. Light sleep C. Drowsy D Newborn Sleep-Wake States A. Deep sleep B. Light sleep C. Drowsy D. Quiet alert E. Active alert F. Crying D B C F E A

Question The nurse is assessing a newborn at 5 hours of age and finds a soft mass over the infant’s occiput. The soft mass crosses the suture line. The nurse documents this finding as which of the following? Subgaleal hemorrhage Caput succedaneum Cephalhematoma Hydrocephalus

Key Points By full term, the newborn’s various anatomic and physiologic systems have reached a level of development and functioning that permits a physical existence apart from the mother. The neonate’s most critical adaptation to extrauterine life is to establish effective respirations.

Key Points (Cont.) Heat loss in the healthy term newborn can exceed the capacity to produce heat; this can lead to cold stress and metabolic and respiratory complications that threaten the newborn’s well-being. Physiologic jaundice occurs in 60% of term infants and 80% of preterm infants.

Key Points (Cont.) Jaundice is considered pathologic if it appears within the first 24 hours of life, if serum bilirubin levels increase by more than 6 mg/dl in 24 hours, or if serum bilirubin exceeds 15 mg/dl at any time. Some reflex behaviors are important for the newborn’s survival.