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Chapter 22&24 only - Lecture notes 6
Nursing Care of the Childbearing Family (NSG-432)
Grand Canyon University
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Chapter 22: Physiologic and Behavioral Adaptations of the Newborn Intro: Neonatal period: time from birth to day 28.
Transition to Extrauterine Life -Major adaptations associated with transition from intrauterine to extrauterine life occur during the first 6 to 8 hours after birth. They are serious of events mediated by SNS and results in changes that involve HR, Resp, Temp, and GI function. -Desmond, Rudolph, and Phitaksphraiwan stages of transitions: First Stage called first period of reactivity: newborn’s heart rate increases rapidly to 160 to 180 beats/min but gradually falls after 30 min or so to baseline rate of 100/120. Respirations are irregular with the rate between 60 to 80 breaths/min. Fine crackles can be present on auscultation. Audible grunting, nasal flaring, and retractions of the chest also can be present but will cease after first hour of birth. Infant is alert and has spontaneous startles, tremors, crying, head movement from side to side. Bowel sounds are audible and meconium may be passed. Period of decreased responsiveness: Last from 60-100 min. Infant is pink and respirations are rapid and shallow up to 60 breaths/min and are unlabored. Bowel sound audible, peristaltic waves are noted over the rounded abdomen. Second period of reactivity: occurs between 2 to 8 hrs after birth and lasts from 10 min to several hours. Brief periods of tachycardia and tachypnea occur, associated with increased muscle tone, changes I skin color, and mucus production. Meconium is commonly passed at this time. -most healthy newborns go through this transition regardless of gestational age, extremely and very preterm infants do not because of physiologic immaturity.
Physiologic Adjustments Respiratory System: If umbilical cord is severed profound adaptations are necessary for survival. The most critical of these adaptations is the establishment of effective respirations. Most newborns breath spontaneously after birth and are able to maintain adequate oxygenation. Initiation of breathing: During intrauterine life oxygenation of the fetus occurs through transplacental gas exchange. A birth lungs must be established as the site of gas exchange. Clamping the umbilical cord causes a rise in blood pressure which increases circulation and lung perfusion. It has been recognized that there is no single trigger for newborn respiratory function. Initiation is combination of chemical, mechanical, thermal, and sensory factors. Chemical factors: decreased levels of oxygen and increased levels of carbon dioxide seem to have a cumulative effect that is involved in initiating neonatal breathing by stimulating and respiratory center in the medulla. Mechanical factors: Respirations in the newborn can be stimulated by changes in intrathoracic pressure resulting form compression of the chest during vaginal birth. With birth this pressure on the chest is released, and the negative intrathoracic pressure helps draw air into the lungs. Crying increases the distribution of air and promotes expansion and the positive pressure created by crying helps keep the alveoli open.
Thermal Factors: profound change in environmental temperature stimulates receptors in the skin, resulting in stimulation of the respiratory enter the medulla. Sensory Factors: At term the lungs hold approximately 20mL of fluid per kilogram. Air must be substituted for the fluid that filled the fetal respiratory tract. In days preceding labor there is reduced production of fetal lung fluid and concomitant decreased alveolar fluid volume. Shortly before the onset of labor there is a catecholamine surge that seems to promote fluid clearance from the lungs, which continues during labor. The movement of lung fluid from the air spaces occurs through active transport into the interstitial, with drainage occurring through the pulmonary circulation and lymphatic system. Infants born by cesarean I which labor did not occur before birth can experience some lung fluid retention. More likely to develop transient tachypnea of the newborn (TTNB) caused by the lower levels of catecholamines. Surfactant lowers surface tension, therefore reducing the pressure required to keep the alveoli open with inspiration, and prevents total alveolar collapse on exhalation, thereby maintaining alveolar stability. Lung expansion depends on chest wall contraction and secretion of surfactant. once respiration are established, breaths are shallow and irregular, ranging form 30-60 breaths/min with periods of breathing that include pauses in respirations lasting less than 20 seconds. Apneic periods longer than 20 seconds indicate a pathologic process sand should be evaluated. Infants are nose breathers. In most newborn infants auscultation of the chest reveals loud clear breath sounds that seem very near because little chest tissue intervenes. Abdominal breathing is characteristic of newborns. Signs of Respiratory Distress: nasal flaring, intercostal or subcostal retractions, grunting with respirations. Suprasternal or subclavicular retractions with stridor or gasping most often represent an upper airway obstruction. Seesaw or paradoxical respirations instead of abdominal respirations are abnormal and should be reported. A respiratory rate of less than 30 or greater than 60 breaths/min with the infant at rest must be evaluated. Apneic episodes can be related to several events (rapid increase in temp, hypothermia, hypoglycemia, or sepsis), that require evaluation. Tachypnea can result from inadequate clearance of lung fluid or it can be an indication of newborn respiratory distress syndrome (RDS). Acrocyanosis: bluish discoloration of hands and feet is normal finding in the first 24 hr after birth. Central cyanosis is abnormal and signifies hypoxemia: blue lips and mucus membranes. Can result from inadequate delivery of o2 to the alveoli, poor perfusion of the lungs that inhibits gas exchange, or cardiac dysfunction. Central cyanosis is a late sign of distress, newborns usually have significant hypoxemia when cyanosis appears. Infants who experience mild TTNB have signs of respiratory distress for the first 1 to 2 hours of birth and may need o2 supplemental. Cadiovascular System -Pulmonary artery pressure drops, and pressure in the right atrium declines. Increased pulmonary blood flow form the left side of the heart increases pressure in the left atrium, which causes a functional closure of the foramen ovale. In utero fetal Po2 is 20 to 30 mm Hg. After birth, when the Po2 level in the arterial blood approximates 50 mmHg, the ductus arterioius constricts in response to increased o2. Circulating hormone prostaglandin E levels also help close the ductus arteriosus. In
-heat regulation is most critical to the newborn’s survival. Thermoregulation is the maintenance of balance between heat loss and heat production. Newborns attempt to stabilize their core body temps within a narrow range. Hypothermia from excessive heat loss is common and dangerous. Newborns have thin layer of subcutaneous fat and blood vessels are close to the surface of the skin. Have larger body surface to body weight ratios than do children and adults. Heat Loss: Factos that influence heat loos to the environmental include: tep and humidity of the air flow and velocity of the air, and the temp of surfaces in contact with and around the infant. Goal is to maintain neutral thermal environment. Heat loss occurs by: Convection: flow of heat from the body surface to cooler ambient air. Radiation: loss of heat form the body surface to a cooler solid surface not in direct contact but in relative proximity. Evaporation: loss of heat that occurs when a liquid is converted to a vapor. Conduction: loss of heat from the body surface to cooler surfaces in direct contact. Thermogenesis: attempting to generate heat through increasing muscle activity. Vasoconstriction causes the skin to feel cool to touch and acrocyanosis can be present. In an effort to conserve heat, term newborns assume a position of flexion that helps guard against heat loss because it diminishes the amount of body surface exposed to the environment. Constricting peripheral blood vessels can help reduce the loss. Newborns produce heat through nonshivering thermogenesis. Accomplished through metabolism of brown fat, which is unique to the newborn and secondarily by increased metabolic activity in the brain, heart, and liver. Brown fat is located in superficial deposits in the interscapular region and axillae and in deep deposits at the thoracic inlet, along the vertebral column, and around the kidneys. Has richer vascular and nerve supple. Cold Stress: imposes metabolic and physiologic demands on all infants regardless of gestational age and condition. If the infant cannot maintain an adequate o2 tension, vasoconstriction follows and jeopardies pulmonary perfusion. Po2 is decreased and the blood pH drops. The basal metabolic rate increases with cold stress. If cold stress is protracted, anaerobic glycolysis occurs, resulting in the increased production of acids. Metabolic acidosis develops and if a defect in respiratory function is present, respiratory acidosis also develops. Hypoglycemia is another metabolic consequence of cold stress. Hyperthermia: body temp greater than 37 (99). Caused by sepsis or a decrease in heat loss. Can result form the inappropriate use of external heat sources like warmers. S/S: skin vessels dilate, skin appears flushed, hands and feet are warm to touch and the infant assumes a posture of extension. If caused by sepsis newborn is stressed: vessels in the skin are constricted, color is pale, and hands and feet are cool. If not corrected can cause cerebral damage from dehydration or heat stroke and death. Renal system: 6 to 8 voiding’s per day of pale, straw colored urine is good. Void the same time they are birthed. For the first days they excrete 15-60 ml/kg. Freq varies. Specific gravity ranges from 1 to 1. No able to concentrate urine fully till 3 months. First urine may be cloudy with higher specific gravity. May loose weight but will regain after 10 to 14 days.
Fluid and Electrolyte Balance: The daily fluid requirement for neonates weighing more than 1500g is 60 to 80 mL/kg during the first 2 days of life. From 3 to 7 days the requirements is 100-150 mL/kg/day and from 8 to 30 days it is 120- mL/kg/day. GI: The full term newborn is capable of swallowing, digesting, metabolizing, and absorbing proteins and simple carbohydrates and emulsifying fats. With the exception of pancreatic amylase. As early as 28 weeks some infants can coordinate sucking and swallowing while breastfeeding. Bottle feeding infants may not coordinate sucking and swallowing until 32 to 34 weeks. By 37 weeks they are coordinated to breath, swallow, suck. Stools: Meconium is greenish black and viscos and contains occult blood first pass is sterile the rest contain bacteria. Most healthy term infants pass meconium within the first 12 to 24 hrs of life and almost all do so by 48 hrs. Signs of GI Problems: fullness of abdomen above the umbilicus can be caused by problems such as hepatomegaly, duodenal atresia, or distention. Abdominal distention at birth usually indicates a serious disorder such as a ruptured viscus or tumors. Distention that occurs later can be the result of overfeeding or signal gastrointestinal disorders. Scaphoid (sunken) abdomen with bowel sounds heard in the chest and signs of respiratory distress, indicate a diaphragmatic hernia. Fullness below the umbilicus can indicate a distended bladder. Forceful ejection of stool and a water ring around the stool are signs of diarrhea. Carbohyrate Metabolism: the hypoglycemic infant can display the classic symptoms of jitteriness, lethargy, apnea, feeding problems, or seizures; or the infant can be asymptomatic. Jaundice: visible yellowish color of the skin and the sclera is caused by elevated serum levels of unconjugated bilirubin. Bilibrubin not bound to an albumin can cross the blood brain barrier and cause neurotoxicity. Jaundice is likely to appear when bilirubin levels exceed 5 to 6 mg/dL the newborn is at risk for hyperbilirubinemia because of distinctive aspects of normal neonatal physiology. The higher RBC mass at birth and shorter life span of neonatal RBCs mean that there is need for greater bilirubin synthesis. Conjugated hyperblirubinemia is rare, it is defined as direct bilirubin levels greater than 1 mg/dL. Jaundice Is usually considered pathologic or nonphysiologic if it appears within 24 hrs of birth, if total serum bilirubin levels increase by more than 6mg/dL in 24 hrs and if the serum bilirubin level exceeds 15 mg/dL at anytime. Hemolytic disease of the newborn caused by maternal/newborn blood group incompatibility is the most common cause of hyperbilirubinemia. It can be caused by glucose 6 phosphate dehydrogenase deficiency. Acute bilirubin encephalopathy refers o the acute manifestations of bilirubin toxicity that occur during the first weeks after birth. s/s: lethargy, hypotonia, irratibilty, seizures, coma, and death. Kernicterus refers to the irreversible, long term consequences of bilirubin toxicity such as hypotonia, delayed motor skills, hearing loss, cerebral palsy and gaze abnormalities. Breastfeeding associated jaundice (early onset) begins at 2 to 5 days of age. Breastfeeding does not cause the jaundice; rather it is a lack of effective breastfeeding that contributes to the hyperbilirubinemia. Breast milk jaundice (late
Resolves in 3 to 6 weeks. As the hematoma resolves, hemolysis of RBCs occurs and jaundice may result. Hyperbilirubinemia and jaundice may occur from a cephalhematoma after the newborn is discharged home. Subgaleal hemorrhage: bleeding into the subgaleal compartment. Associated with difficult operative vaginal birth especially vacuum extraction. Blood loss can be severe resulting in hypovolemic shock, DIC and death. s/s: boggy scalp, pallor, tachycardia, and increasing head circumference may also be early sings. Forward and lateral positioning of the newborns ears is another sign. Signs of DDH (developmental dysplasia of the hip) are asymmetric gluteal and thigh skinfolds, uneven knee levels, a positive ortolani test, and a positive barlow test. Sucking and rooting: disappears after 3 to 4 mo but can persist up to 1 yr. Grasp-palmar: lessens by 3 to 4 mo. Plantar: toes curl downward: lessens by 8 mo. Extursion: newborn forces tongue outward and disappears about fourth to fifth month. Glabellar (Myerson): newborn blinks for first four or five taps: continued blinking with repeated taps is consistent with extrapyramidal signs. Moro: response is present at birth, complete response may be seen until 8 wks. Body jerk only is seen between 8 and 18 wks. Response is absent by 6 mo. Stepping or walking: present for 3-4 wk. Crawling: disappear about 6 wk of age. Crossed extension: should be present during newborn period. Magnet: absence suggest damage to central nervous system. Weak reflex may be seen after breech presentation without extended legs or may indicate sciatic nerve stretch syndrome. Breech presentation with extended legs may evoke exaggerated response. Both lower limbs should extend against examiners pressure. Babinski (plantar) Absence requires neurologic eval. Should disappear after 1 yr. all toes should hyperextend with dorsiflexion of big toe and is a positive sign.
Chapter 24 Newborn Nutrition and Feeding
Breastfeeding is defined as the transfer of human milk from the mother to the infant; the infant receives milk directly from the mother’s breast. Exclusive breastfeeding means that the infant receives no other liquid or solid food. If the infant is fed expressed breast milk from the mother or a donor milk bank, it is called human milk feeding. Recommended Infant Nutrition: recommends exclusive breastfeeding for the first 6 months of life and continued as foods are being introduced for 1 year. Unicep and who say up to 6 mo with breastfeeding continuing for up to 2 years and beyond. Benefits of breastfeeding: enhanced bonding and attachment, empowerment and convienient. Choosing to breastfeed: same method of infant
Chapter 22&24 only - Lecture notes 6
Course: Nursing Care of the Childbearing Family (NSG-432)
University: Grand Canyon University
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