Newborn transitioning and mgmt Flashcards
Birth
-Hypoxic event as newborns transition from placenta as organ of gas exchange to lungs
-1st 24 hours is most precarious
Neonatal period
-1st 28 days of life
-Most dramatic changes
-1st hour is golden hour of life (extrauterine transition is most critical)
-Full transition occurs within 1st 6-10 hours
CV adaptations
-Shunts (foramen ovale, ductus venosus, ductus arteriosus) close w/ 1st breath
-Increased release of catecholamines
-When umbilical cord is clamped, 1st breath is taken
-Closed shunts become nonfunctional ligaments
-HR goes from 110-160 to 120-130
-BP highest after birth, hits plateau after week
-Transient fxnal cardiac murmurs may be heard during neonatal period as result of changing dynamics of CV system at birth (usually benign)
-Blood volume depends on amt of blood transferred from placenta at birth (80-100 mL/kg of BW
-Early (30-40 sec) or late (after 3 min) clamping of umbilical cord changes circulatory dynamics during transition
-Cord blood is “nature’s 1st stem cell transplant” bc it possesses regenerative properties and can grow into different types of cells in the body
CBC values
-Fetus has more RBCs vs adult
-Fetal RBCs are larger in size vs adult and so can carry more O2
-Newborn’s RBCs have lifespan of 80-100 days, compared to 120 in adults
-Hgb levels peak within 1st few hours
-Physiologic anemia of infancy (Hgb initially declines d/t decrease in neonatal red cell mass)
-Leukocytosis (high WBC) is present d/t birth trauma
-Delayed cord clamping causes higher HnH
Cord clamping
-Delayed cord clamping (30-60 sec) is recommended for improved maternal and infant health and nutrition
-Allows blood flow btwn placenta and neonate to continue, which may improve Fe status up to 6 m after birth and increase Hgb levels
-In preemies, improves circulation, better RBC volume, decreased need for blood transfusion, lower incidence of hemorrhage
-Does not increase risk of postpartum hemorrhage
Summary of fetal to neonatal circulation
-Clamping umbilical cord after birth eliminates placenta as reservoir for blood
-Onset of respirations causes rise in PO2 in lungs and decrease in pulmonary vascular resistance which increases pressure in RA of heart, which causes closure of foramen ovale min after birth
-W/ increase in O2 after 1st breath, increase in systemic vascular resistance occurs which decreases vena cava return, which reduces blood flow in umbilical vein
-Closure of ductus venosus causes increase pressure in aorta, which forces closure of ductus arteriosus within 10-15 hrs after birth
Normal newborn blood values
-Hgb: 16-18
-Hct: 46-68
-Pt: 150-350
-RBC: 4.5-7.0
-WBC: 10-30
Respiratory system adaptations
-1st breath of life generates increase in transpulmonary pressure and results in diaphragmatic descent
-Hypercapnia, hypoxia, acidosis resulting from normal labor becomes stimuli for initiating respirations
-Surfactant
-Chest wall is floppy, accessory muscles are ineffective
-Fluid must be removed from lungs and replaced w/ air
-If fluid is removed too slowly or incompletely, transient tachypnea occurs
-Neonate born by C-section doesn’t have same benefit of birth canal squeeze as does the newborn born by vaginal birth
-Shallow and irregular breaths, 30-60 per min
-Periodic breathing: cessation of breathing that lasts 5-10 sec during 1st days of life
-Apneic periods > 15 sec w/ cyanosis and HR changes require further evsl
Surfactant
-Surface tension-reducing lipoprotein found in newborn’s lungs that prevents alveolar collapse at end of expiration and loss of lung volume
-Lines alveoli to enhance aeration of gas-free lungs, thus reducing surface tensions and lowering the pressure required to open the alveoli
-Permits decrease in surface tension during lung expansion (prevents atelectasis) and an increase in surface tension during lung expansion (to facilitate elastic recoil on inspiration
Body temp regulation
-Normal temp is 97.9-99.7 F
-Lose heat easily after birth, have skin-to-skin w/ mother to maintain body temp
-Thermoregulation: maintaining the balance between heat loss and heat production in order to maintain the body’s core internal temp
-Very vulnerable to underheating and overheating
-Temp decreases by 3-5 degrees within min after leaving uterus
-Heat loss thru 1) radiation 2) convection 3) evaporation 4) conduction
-Newborn prone to overheating d/t limited insulation and sweating ability
-Primary health regulator in hypothalamus and CNS
-Newborn 1st experiences an increase in NE in response to cold environment, causes triglycerides to stimulate brown fat metabolism
-Neutral thermal environment: body temp maintained w/o increase in metabolic rate or O2 use; ideal for growth and stability
-Environmental temp decreases –> increased O2 consumption –> tachypnea –> metabolic rate increases
-NST: brown adipose tissue oxidized in response to cold exposure, produced during 3rd trimester
-Cold stress: excessive heat loss that requires newborn to use NTS and tachypnea, highest risk within 1st 12 hrs and for preemies
Factors that contribute to heat loss
-Thin skin w/ blood vessels close to surface
-Increased skin permeability to water, lack of shivering ability to product heat until 3 m/o
-Limited storage of metabolic substances (glucose, glycogen, fat)
-Limited use of voluntary muscle activity or mvmt to produce heat
-Large surface area-to-body mass ratio
-Lack of subq fat
-Little ability to conserve heat by changing posture
-No ability to adjust own clothing
-Inability to communicate body temp
Conduction
-Transfer of heat from one object to another when 2 objects are in direct contact w/ each other
-Ex: newborn’s body touches solid surfaces such as cold mattress, scale; touching baby w/ cold hands
-Use warmed cloth diaper ot blanket to cover cold surfaces
-Skin-to-skin w/ mother
Convection
-Flow of heat from body to cooler surrounding air or to air circulating over body
-Ex: cool breeze flows over newborn, cool room, outside air currents
-Keep baby out of direct cool drafts such as open doors, windows, fans, AC
-Transport baby in warmed isolette instead of carrying them
Evaporation
-Loss of heat when liquid is converted to vapor
-Insensible loss: skin and respiration, individual is not aware of it
-Sensible loss: sweating, objective and can be noticed
-Ex: body covered w/ amniotic fluid when born, evaporates shortly thereafter
-Dry newborns w/ warmed blankets and placing cap on head
-Promptly changing wet linens, clothes, diapers
Radiation
-Loss of heat to cooler, solid surfaces that are in proximity but not in direct contact w/ newborn
-Amt of heat loss depends on size of cold surface area, surface temp of baby, and temp of receiving surface area
-Ex: newborn placed in single-wall isolette next to cold window (newborn becomes cold even tho in warm isolette)
-Keep cribs and isolettes away from outside walls, cold windows, and ACs
-Use radiant warmers for transporting newborns and when performing procedures
Cold stress prevention
-Prewarmed blankets and hats
-Warmed isolette
-Drying baby after birth
-Skin-to-skin w/ mother
-Early breastfeeding
-Heated O2
-Radiant warmers
-Deferring bathing until baby is stable, use heat source when bathing
-Avoiding placement of skin temp probe over bony area or one w/ brown fat, bc it does not give accurate assessment of whole-body temp
-Most temp probes placed over liver when newborn is supine or side-lying
Hepatic system fxn
-Liver slowly assumes fxn placenta handled during fetal life
-Most enzymatic pathways present in newborn but in active at birth, become active at 3 m
-RBCs destroyed –> Fe released and stored by liver
-If mother’s Fe intake was adequate during pregnancy, sufficient Fe has been stored in newborn’s liver for use during 1st 6 m
-Birth results in loss of maternal glucose source (essential for brain metabolism)
-Term baby’s glucose is 80% of maternal level at birth
-Glucose is main source of energy for 1st hours after birth, initiate early milk feeding
Bilirubin
-Principle source of bilirubin is hemolysis of erythrocytes (8-10 mg/kg/day)
-Bilirubin declines to adult level 10-14 days after birth
-When unconjugated bilirubin is deposited in skin and mucous membranes as result of increased bilirubin levels, jaundice in skin, sclera, and mucous membranes occurs
-Jaundice can cause brain damage
-Causes of jaundice: bilirubin overproduction, decreased bilirubin conjugation, impaired bilirubin excretion
GI system adaptations
-pH of stomach contents is mildly acidic, reflecting pH of amniotic fluid
-Bowel sounds may be hypoactive on 1st day
-Intestinal mucosal barrier remains immature for 4-6 m following birth
-Colonization occurs within 24 hrs and is required for vitamin K production
-Microbes passed from mother via suckling, kissing, caressing
-Breastmilk provides passive immunity (antibodies and leukocytes)
-Rapid gain in physiologic capacity of stomach during 1st 4 days
-1st 24 hrs of life, stomach doesn’t stretch –> will expel extra milk
-Advised to have small, frequent feedings
-If baby fulling overfull during feeds becomes norm, may lead to unhealthy eating habits later
-Excrete fatty stools
-Lose 5-10% of BW within 1st week
-Must intake 108 kcal/kg/day from birth to 6 m to gain weight
Stool
-1st stool is meconium (greenish black, tarry, passed within 12-24 hrs)
-2nd stool is transitional (greenish brown to yellowish brown, thinner, seedy)
-3rd stool is milk stool (yellow-gold, loose, stringy to pasty, sour-smelling)
-If formula-fed, stools will be tan or yellow in color and firmer
-Newborn fed earlier –> pass stool earlier –> reduction in bilirubin buildup
Renal system changes
-1 million nephrons present by 34 weeks
-Kidneys immature, lacks ability to handle body’s fluid homeostasis
-Limited in ability to concentrate kidneys until 3 m (until that time, newborn voids frequently and urine has low USG of 1.001-1.020)
-6-8 voidings daily is average = adequate fluid intake
-Renal cortex develops at 12-18 m
-GFR is 30% of normal adult values at birth, reaching 50% by 10th day and 100% by 1st year
-Possibility of fluid overload is increased in newborns, remember this w/ IV therapy
