Neonatal Adjustment and Fetal Lung Development: A Comprehensive Guide, Exams of Nursing

Download Neonatal Adjustment and Fetal Lung Development: A Comprehensive Guide and more Exams Nursing in PDF only on Docsity! 1 NORMAL NEWBORN (CHP 28) BEST GUIDE 2024 NEW UPDATE GRADED A • Neonatal Adjustment o Depends On: ▪ State of maturity ▪ Meds prenatally – including L&D ▪ Pathologic processes ▪ Postnatal hazards o ½ all neonatal deaths occur w/n 1st 24h o Newborn period is time from birth through 1st 28 days of life o Neonatal Transition - 1st few hours of life in which newborn stabilizes respiratory and circulatory functions • Fetal Lung Development o 1st 20 wks –(Ground work) lung development is limited to differentiation of pulmonary, vascular, and lymphatic structures o 20-24 wks – alveolar ducts begin to appear; primitive alveoli 24-28wks ▪ Alveolar epithelial cells differentiate into: • Type I cells – structures necessary for respiratory gas exchange • Type II cells – structures that provide for synthesis and storage of surfactant ▪ Surfactant – composed of group of active phospholipids (lecithin and sphingomyelin) which are critical for alveolar stability o 28-32wks – number of type II cells increases further, and surfactant is produced by choline pathways within them o 35wks – surfactant production peaks and remains high until term o Preterm infants are given surfactant until term o Newborn lecithin/sphingomyelin (L/S) ratio – 2:1 – lungs mature • Initiation of Respirations o Two radical changes must take place for lungs to function: ▪ 1) Pulmonary ventilation must be established through lung expansion following birth ▪ 2) A marked increase in pulmonary circulation must occur o Mechanical – chest expansion o Sensory – change in temperature o Chemical – hypoxia • Mechanical Events o Fluid must be removed from lungs to permit adequate movement of air – approximately 80-110mL of fluid remains in resp passages of term fetus at time of birth o During the birth process, the fetal chest is compressed, increasing intrathoracic pressure and squeezing a small amount of fluid out of the lungs. After the birth of the 2 newborn’s trunk, the chest wall recoils which creates a negative intrathoracic pressure which is thought to produce a small, passive inspiration of air that replaces fluid that was squeezed out. (Only 1/3 of fluid is squeezed out) • Chemical Events o Cord clamps ▪ Cessation of placental gas exchange ▪ Increased PCO2 ▪ Decreased pH and PO2 ▪ Stimulation of aortic and carotid chemoreceptors, initating impulses that trigger brain’s respiratory center • Sensory Events o Physical and sensory influences help respirations begin ▪ Auditory ▪ Tactile – thoroughly drying newborn; place on mother (skin-skin) ▪ Visual o After birth, newborn experiences lights, sounds and effects of gravity o Joint movement helps sustain respirations • Newborn Respirations o 30-60 bpm o Initially diaphragmatic, shallow, and irregular in depth and rhythm o Periodic breathing – breathing pattern characterized by pauses lasting 5-15sec (Short periods of apnea) o Newborn’s must breathe through nose o Activity influences rate o O2 Sat – 96-98% w/n 1st 4h – VERY IMPORTANT o Stress – nasal flaring, retractions, seesaw breathing • Apnea o Cessation of breathing lasting more than 20s; less than 20s w/ cyanosis, bradycardia and/or limpness o Apnea may or may not be associated w/ changes in skin color or heart rate o Pathophysiology: immature CNS o Nursing management: monitor cardiorespiratory status, keep warm, note activity, how long is apneic, HR, color changes, pulse ox, labs • Fetal Circulation o Maintain blood flow to placenta to provide fetus w/ oxygen and nutrients while removing carbon dioxide and other waste products o Blood flows from placenta through umbilical vein which enters abdominal wall of fetus (umbilicus – belly button) o Divides into w branches: ▪ Small amount goes into liver and empties into inferior vena cava through 5 o Murmurs usually involve invomplete closure of ductus arteriosus or foramen ovale o Capillary refill should be less than 2-3sec o BP: 67/41 to 80/58 (7 ½ - 8lbs) – varies w/ wt and size o BP is highest after birth and plateaus in 4-6 days o Take apical pulse for 1 full minute o Cardiac Workload ▪ 1st 2h – when ductus arteriosus remains mostly patent – 1/3 of left ventricular output returned to pulmonary circulation ▪ R vent output reflex systemic venous return and L vent output reflex pulmonary venous return ▪ Before birth – R vent does 2/3 cardiac work – resulting in increased size and thickness of R vent at birth ▪ After birth – L vent must assume large share of cardiac workload and it progressively increases in size and thickness ▪ R sided heart defects are better tolerated than L sided heart defects • Hematologic Adaptations o Physiologic anemia in infancy – caused by initial decline in HgB o Factors affecting degree of anemia: ▪ Supplies of: • Vitamin E • Folic acid • Iron ▪ Amount of growth during 1st year o RBC have lifespan of 80-100 days (2/3 that of adult) o Blood volume of term is estimated to be 80ml/kg of body wt • Term Infant Lab Values o HgB 14-20mg/dl o HcT 43-63% o WBC 10,000-30,000mm3 o Platelets 150,000 – 350,000mm3 o Sodium 129-144 mEq/L o Glucose 45-94 mg/dL o Calcium 8.2-11.1 mg/dL o Potassium 3.4-9.9 mEq/L o Chloride 103-111 mEq/L • Temperature Regulation o Newborns – homeothermic o Attempt to stabilize internal (core) body temp w/n narrow range o At birth, temp falls 2-3C which triggers cold induced metabolic responses and heat production 6 o Thermoregulation r/t rate of metabolism and oxygen consumption o Neutral Thermal Environment (NTE) – rate of oxygen consumption and metabolism are minimal and internal body temperature is maintained because of thermal balance o NTE Range – 32-34C (89.6F – 93.2F) o Factors that Affect NTE: ▪ Less SUBQ fat than adult ▪ Blood vessels of newborn closer to skin than those of an adult – blood is more easily influenced by changes in environmental temperature ▪ Flexed posture of term infant decreases surface area exposed to environment – reducing heat loss ▪ Size and age also affects ▪ O2 consumption increases if environment is too cold or too hot • Heat Loss o Newborn’s poor thermal stability is due primarily to excessive heat loss rather than impaired heat production o Convection – loss of heat from warm body surface to cooler air currents o Radiation – losses occur when body heat rises to cooler surfaces and objects not in direct contact w/ body o Evaporation –loss of heat incurred when water is converted to vapor – loss by evaporation is immediately after birth (failure to dry baby) o Conduction – loss of heat to cooler surface by direct skin contact o After dry, highest losses through radiation and convection • Heat Production o Brown adipose tissue (BAT ) – brown fat – 1st appears 26-30wks gestation and continues to increase until 2-5wks after birth – provides heat o Nonshivering thermogenesis (NST ) – occurs when skin receptors perceive drop in environmental temp and, in response, transmit sensation to stimulate sympathetic nervous system o Shivering – form of muscular activity common in cold adult – rarely seen in newborn o Vasomotor control • Hepatic System o Liver frequently palpable 2-3cm below right costal margin o Functions of Liver: ▪ Iron Storage and RBC Production • RBC destroyed after birth and iron content stored in liver until needed for new RBC production • Iron stores are determined by total body HgB content and length of gestation • Mother’s intake also influences • Newborn has 270mg of iron at birth and about 140-170mg of this amount is Hgb 7 • Jaundice ▪ Carbohydrate Metabolism • Neonate carbohydrate reserves are relatively low • Neonatal glycogen stores are twice that of adult • Placental removal – newborn enters “energy crunch” • Glucose – main source of energy 1st 4-6h after birth • First 2h – serum blood glucose level declines, then rises, and finally reaches a steady state 2-3h after birth • As glycogen stores deplete, newborn compensates by changing from predominately carbohydrate metabolism to fat metabolism ▪ Conjugation of Bilirubin • Unconjugated (indirect) bilirubin – bad – breakdown product derived from Hgb that is released primarily from RBC – potentially toxic • Conjugated (direct) bilirubin – good – conversion of yellow lipid- soluble pigments into water-soluble pigments • Total serum bilirubin – sum of conjugated (direct) and unconjugated (indirect); at birth it is <3mg/dL o Yellowish discoloration of skin and sclera of eyes that develops from deposits of yellow pigment bilirubin in lipid/fat-containing tissues o Occurs in 50% of term and 80% of preterm infants o 3 Types of Jaundice: ▪ Physiologic (after 24h) ▪ Breast Milk Jaundice/Breast Feeding Jaundice ▪ Pathologic (before 24h) • Physiologic Jaundice o Caused by accelerated destruction of fetal RBCs, impaired conjugation of bilirubin, and increased bilirubin reabsorption from intestinal tract o Normal biological response o Occurs after 24h o Peaks between 3-5 days o Normal disappears after 7d term and 9d preterm – not visible after 14d o Serum bilirubin levels are about 4-6mg/dl before yellow coloration appears o Factors that Give Rise to Jaundice ▪ 1) Increased amounts of bilirubin delivered to liver • Increased blood volume combined w/ faster RBC destruction • 2-3x greater production/breakdown • Forceps/vacuum use ▪ 2) Defective uptake of bilirubin from plasma • Does not ingest adequate calories ▪ 3) Defective conjugation of bilirubin • Hypothyroidism or inadequate calorie intake 10 o Pathophysiology ▪ Rh negative women (any blood type) ▪ Mixing of blood (most common at birth when mix) ▪ Antibodies form ▪ Subsequent pregnancy w/ Rh+ fetus (usually seen in 2nd prego ▪ Hemolytic breakdown ▪ Baby has severe anemia – can cause brain damage, organ failure, and even death ▪ Crosses placenta – born jaundice – body sees fetus RBC as foreign body o Treatment ▪ Prenatal prevention • Rh moms: screen w/ indirect coombs • Rhogam given to all Rh- women at 28wks or whenever a blood occurs ▪ Newborn period • Direct coombs • Assess for jaundice ▪ Coombs test ▪ Indirect coombs phototherapy- exposure to high intensity light – decreases serum bilirubin levels in skin by facilitating biliary excretion of unconjucated bili ▪ Exchange transfusions – if very high ▪ Infusion of albumin ▪ Drug therapy o Kerniterus ▪ Brain damage caused by bili not bound to albumin, this crosses blood brain barrier • Gastrointestinal Systems o By 36-38wks of fetal life, GI tract is adequately mature o At term: swallow, digest, metabolize and reabsorb o Sufficient enzymes except for pancreatic o Capacity: 50-60mL o Bowel sounds w/n 1st 30-60m o Mobility of sphincter is immature ▪ Regurgitation – lay on R side after feeding to promote digestion; breast feed q2h; formula up to q4h ▪ Distention, flatus ▪ Variety of stool – meconium between 8-24h • Meconium is thick, tarry, black (green) • Transitional – part meconium/part fecal material next day or two then stools become entirely fecal material o Need 120kcal/kg/day to gain wt o Emptying every 2 ½ - 3h 11 • Coagulation o Coagulation factors II, VII, IX and X are synthesized in liver o From low point about 2-3d after birth, these coagulation factors rise slowly but don’t approach adult levels until 9mo age or older o Vitamin K dependent coagulation factors o Normal intestinal flora (needed to synthesize vitamin K) is lackin in newborn o Vitamin K given prophylactically ▪ Dose 0.5-1.0mg IM (25G 5/8in needle – vastus lateralis) • Urinary system o Structurally complete but physiologically immature o Greater water requirements than adults o Urine colorless o Bladder capacity 25ml/kg/d o Urates – “brickdust” spots – normal o Decreased ability to secrete drugs o Pseudomenstruation – blood on diaper of female – r/t w/drawal of maternal hormones o Functioning nephrons around 34-36wks o Difficulty concentration/diluting o Avoid overhydrationa and dehydration o Hydration status – very important – count diapers – 6-8 wet diapers w/n 24h normal o First voiding –if not w/n 48h call doctor • Immunologic Adaptations o Passive acquired immunities IgG (transferred to fetus in utero) – very active against bacterial toxins o Improves w/ gestational age o Low IgG levels in newborn – hypothermia – more common than fever o IgM (produced in response to blood group antigens, gram negative enteric organisms and some viruses – suspect intrauterine infection – usually does not cross placenta o IgA – found in colostrums – helps w/ passive immunity o Immunity against viral infection may last 4-8months whereas immunity to certain bacterias may disappear w/n 4-8wks • Newborn’s reaction to Stressors o Sleep wake states – “predictable) o Deep sleep – no reaction o Based on temperament and intrauterine experience o Environmental stimuli – heat, light, cold, noise o Chemical balances – hypoglycemia o Hydration status o State of health o Stressors of birth process 12 • Periods of reactivity o 1st period ▪ Lasts approx. 30 min after birth (30min – 1hr) ▪ Newborn awake and active and may appear hungry and have strong sucking reflex ▪ Promote attachment ▪ Respirations rapid (as high as 80) and there may be retractions, nasal flaring, and grunting; HR rapid and irregular; BS absent o Sleep phase ▪ Lasts few minutes – 2-4h ▪ Difficult to awaken, no interest in sucking ▪ BS audible, HR and RR baseline o 2nd period ▪ Lasts 4-6hr ▪ Awake and alert; HR/RR increases ▪ Produces respiratory and gastric mucus increases – gagging, choking, regurgitation ▪ May pass 1st meconium stool ▪ Watch for “hunger cues” – sucking/rooting and swallowing • Behavioral States of Newborn o Sleep States: ▪ Deep or quiet sleep – no eye movement, regular breathing ▪ Light sleep – (REM) – eye movement, irregular breathing, where baby spends most time o Awake State ▪ Drowsy – eyes open/closed ▪ Wide Awake – best time for assessment and mother bonding; follows and fixates, alert, minimal motor activity ▪ Active awake – intense motor movement ▪ Crying – shaky movement • Behavioral and Sensory Capabilities o Habituation - newborn’s ability to process and respond to complex stimulation – repeated stimulation = decreased reaction o Orientation – newborn’s ability to be alert to, to follow and fixate on complex visual stimuli that have a particular appeal and attraction; prefers human face and eyes and bright, shiny objects; focus on objects 7-8in from face – can follow moving objects; functionally immature but can see o Auditory – can hear, do respond to sound, HR increases w/ response – typically recognizes sounds (like mother bc heard in utero) o Olfactory – can smell – especially mother’s breast