The Newborn Adaptation
Milam 2/5/10

Respiratory Adaptations o Intrauterine Preparation
 Fetal lung development

0-20 week = developing structures

20-24 weeks= alveolar ducts begin to appear

24-28 = type I & type II alveolar epithelial cells differentiate; surfactant production begins o Type I cells structures necessary for gas exchange o Type II cells synthesis of surfactant

28-32 weeks = increased production of surfactant by type II cells

35 weeks = peak production of surfactant
 Surfactant
 Lipoprotein produced by lungs
 Major Determinant of Respiratory Ability

Reduces surface tension within the alveoli

Lecithin/Sphingomyelin (L/S) ratio has diagnostic value as to fetal lung maturity o L/S ratio of 2:1 correlates with fetal lung maturity

Slippery lipoprotein acts to reduce surface tension within the alveoli allowing the alveoli to remain partially open with breathing

Without surfactant, the alveoli collapse with exhalation and must be reopened with each new breath increasing the respiratory workload
 Fetal breathing movements

Movements develop the chest wall muscles and the diaphragm

Converts from a fluid-filled to a gas-filled organ

Breathing movements are essential for developing the chest wall muscles and the diaphragm and to a lesser extent, for regulating lung fluid volume and resultant lung growth. o Breathing
 Initiation of Breathing (pg 564)

Mechanical Events o Increased intrathoracic pressure - as chest is o squeezed removes fluid from lungs o Negative intrathoracic pressure - after birth, chest o recoils producing a small passive inspiration of air o Positive intrathoracic pressure - newborn o exhales crying with a partially closed glottis

Chemical Stimuli o Transitory asphyxia stimulates CNS response o triggered by increased PCO2 and a decreased pH and PO2 o This is called Respiratory Acidosis

Thermal Stimuli o Stimulation of skin nerve endings o Temperature decreases from 98.6 to 70 – 75 degrees F o If temperature drops too low, respirations are depressed

Sensory Stimuli o Moves from a familiar, comfortable, quiet environment to one of sensory abundance – tactile, auditory, and visual stimuli o Thorough drying of the baby provides sufficient stimuli
 Factors Opposing the First Breath


Alveolar surface tension – surfactant reduces surface tension, prevents alveoli from collapsing

Viscosity of lung fluid

Degree of lung compliance – ability of lungs to fill with air o Highlights from Respiratory
 The production of surfactant is crucial
 Newborn respiration is initiated primarily by chemical and mechanical events, in association with thermal and sensory stimulation.
 The newborn is an obligatory nose breather
 Normal respiratory rate is 30 to 60 breaths per minute
 Periodic breathing is normal, and newborn sleep states affect breathing patterns

Cardiopulmonary Adaptations o Info
 Increased aortic pressure and
 decreased venous pressure
 Increased systemic pressure and
 decreased pulmonary artery pressure
 Closure of the foramen ovale
 Closure of the ductus arteriosus
 Closure of the ductus venosus
 Oxygenated blood leaves the placenta and enters the fetus through the umbilical vein.
 After circulating through the fetus, deoxygenated blood returns to the placenta through the umbilical arteries.
 The ductus venosus, the foramen ovale, and the ductus arteriosus allow the blood to bypass the fetal liver and lungs. o Fetal Circulatory System *See handout she gave us and also pg 66)
 Ductus Venosus
 Foramen Ovale
 Ductus Arteriosus
 The shunts ensure that most of the blood supply bypasses the fetal lungs. The placenta is supplying oxygen and removing fetal carbon dioxide o Characteristics of Cardiopulmonary Physiology
 Air enters the lungs; increased PO2 stimulates relaxation of the pulmonary arteries and a decrease in pulmonary vascular resistance; Vascular flow (circulation) in the lungs increases.
 Pulmonary circulation distributes blood throughout the lungs to pick up O2/exchange Co2.
 Increased blood flow to lungs contribute to conversion from fetal circulation to newborn circulation o Blood Pressure
 Highest immediately after birth and decreases 3 hours after birth; days 4-6 plateaus at original level
 Capillary refill is indicator of peripheral perfusion. Should be 2-3 seconds
 Normal BP varies according to birth weight
 Check BP in all 4 extremities with initial assessment of a newborn
 Crying causes an increase in both systolic and diastolic BP
 See pg 569 Figure 23-3 o Comparing Fetal and Neonatal Circulation
 Fetal

Pulmonary blood vessels constricted; lungs fluid-filled

Systemic blood vessels dilated
 Ductus arteriosus large with blood flow from pulmonary artery to aorta

Foramen ovale patent with flow from R to L atrium
 Neonatal

Pulmonary blood vessels vasodilated with increased blood flow

Systemic blood vessels constricted - BP rises


Ductus begins to constrict; blood flow from aorta to pulmonary artery

Foramen ovale is closing due to increased pressure in L atrium o Heart Rate
 At birth with first cry HR=175-180
 Full-term newborn HR=120-160 depending on activity level
 Assess apical pulse for 60 seconds with the infant asleep

Assess PMI, regularity, presence of murmurs

Assess peripheral pulses for strength & equality o Heart Murmurs/Defects
 Heart Murmurs

Extra sound produced by blood flow in the heart or great vessels

90% of murmurs heard in the newborn are transient
 Heart defects
 Murmur can be present or absent
 Right-sided defects better tolerated that left-sided defects

Cardiopulmonary function in some malformed hearts may become compromised when shunts close. o Cardiovascular Highlights
 The status of the cardiopulmonary system may be measured by evaluating the heart rate, blood pressure, and presence or absence of murmurs
 The normal heart rate is 120 to 160 beats per minute
 Normal capillary refill is 2-3 seconds

Hematopoietic Adaptations o Physiologic Anemia of Infancy
 Normal Newborn has higher hgb & hct with larger RBCs than older children or adults
 Transient increase in hgb & hct occurs
 If placental to infant transfusion occurred

Low oral intake & diminished extracellular fluid volume
 Hemoglobin level declines over the first 2-3 months of life

Cessation of erythropoiesis with SaO2 increase at birth

Expansion of blood volume accompanying rapid growth
 At 2-3 months of age erythropoiesis resumes o Factors Affecting Blood Volume
 Blood volume is approximately 80-85 ml/kg of body weight

Delayed cord clamping

Gestational age

Prenatal and/or perinatal hemorrhage

Site of the blood sample o Leukocytosis
 Increased neutrophil production results from the stress of birth
 By 2 weeks neutrophils decrease to 35% of total WBC count
 Lymphocytes become predominant and WBC total decreases o Highlights on Hematopoietic System
 See page 570 Table 23-2
 Normal Term Newborn Blood Values
 Blood values in the newborn are modified by several factors, such as site of the blood sample, gestational age, prenatal and/or perinatal hemorrhage, and the timing of the clamping of the umbilical cord

Temperature Regulation o Heat Loss from Body Surface to Environment *see pg 572 Figure 23-5*
 Convection


The loss of heat from the warm body surface to the cooler air currents. Examples: air conditioned rooms, air currents with a terperature below the infant’s skin temperature, oxygen by mask, and removal from an incubator for procedures.
 Radiation

When heat transfers from the body surfact to cooler surfaces and objcts not in direct contact with the body. Examples: the walls of a room or an iancubator; placing cold objects onto the incubator or near the infant in the radiant warmer
 Evaporation

The loss of heat when water in converted to a vapor. Example: a newborn wet with amniotic fluid and blood, during baths.
 Conduction

The loss of heat to a cooler surface by direct skin contact. Example chilled hands, cool scales, cold exam tables, a cold stethoscope o Thermoregulation
 Thermoregulation occurs when oxygen consumption and metabolic activity are minimal

The baby isn’t having to burn up their fat to warm themselves
 Newborns transfer heat from internal core to the body surface o Thermal Neutral Zone
 Thermal Neutral Zone: Environmental temperature range where the internal body temperature is maintained and the rate of O2 consumption and metabolism are minimal

The room is the right temperature so that they don’t have to burn fat to warm themselves
 Newborns require higher environmental temperatures for their thermal neutral zone o Nonshivering Thermogenesis
 Unique to Newborns
 Occurs to provide heat in the cold-stressed newborn
 Regulated by the sympathetic nervous system
 Brown fat is metabolized to generate heat
 Brown fat is unique to the newborn, it’s brown because it’s so highly vascular, it transfers the heat it’s holding to the baby o Rationale for Increased Heat Loss
 Decreased subcutaneous fat
 Thin epidermis
 Blood vessels close to the skin o Hazards of Cold Stress
 Increased O2 consumption

Respiratory distress
 Use of glycogen stores

Hypoglycemia
 Metabolizing brown fat
 Decreased surfactant production
 Metabolic acidosis o Byproduct of burning fat to keep warm o Eventually leads to respiratory acidosis

Jaundice o Highlights of Temperature Regulation
 Heat conservation is enhanced by flexed posture because the skin’s surface area exposed to the environment is decreased

They ball up or whatever, this reduces surface area, pull their arms in and what not

Flexed posture isn’t heat loss or the inability to lose heat, it has to do with conserving their heat or keeping it in!

 Evaporation is the primary heat loss mechanism in newborns who are wet
 Excessive heat loss occurs from radiation and convection because of the newborn’s larger surface area compared with weight
 The primary source of heat in the cold-stressed newborn is brown adipose tissue
 Important to keep baby warm because if it is cold stressed it can send them into acidosis (metabolic and respiratory), can cause hypoglycemia

Hepatic Adaptation o Newborn Liver Functions
 Iron storage and RBC Production

As RBCs are destroyed after birth, the iron is stored in the liver until needed for new RBC production o Infant has iron stores from mother for about 5 months o After 5 months, will need iron supplement to prevent anemia
 Carbohydrate metabolism
 Glucose is supplied by the placenta until birth

Newborn carbohydrate reserves are limited

Metabolic fuel sources are consumed by the work of breathing, heat production, and activation of muscle tone

Glucose is main source of energy in the first 4 to 6 hours

As stores of glycogen and blood glucose decrease the newborn changes to fat metabolism
 Conjugation of bilirubin

Unconjugated bilirubin is a breakdown product of destroyed RBC’s - indirect bilirubin o Unconjucated is lipid soluble, and we can’t get these out of our body. Conjugated is water soluble, so we can get rid of it

Conjugation of bilirubin must occur for elimination to occur (conversion of yellow lipid soluble pigment into water-soluble pigment) - direct bilirubin.

The newborn’s liver must conjugate bilirubin after birth
 Coagulation

Coagulation factors II, VII, IX, and X are synthesized in the liver and are activated by Vitamin K o Vit K is made in our bodies by bacteria in the intestines, when the baby is born their gut is sterile, they don’t have the ability to make vit K so we give it to them, if they don’t get it they may have bleeding problems

There is an absence of normal flora to synthesize Vitamin K in the newborn gut

Vitamin K given IM at birth to prevent potential bleeding problems o Jaundice
 Jaundice is a yellowish coloration of the skin and sclera of the eyes that develops from deposit of the yellow pigment Bilirubin in tissues.
 3 Types of Jaundice in the Newborn

Physiologic o Occurs after the first 24 hour of life o Bilirubin level does not exceed 5 mg/dl/day or 15 mg/dl in first week of life
 Normal bilirubin level is 1-2.2 ish… o Bilirubin peaks at 3 to 5 days o Occurs not from pathology but as a normal biologic response of the newborn to
 Hemolysis of excessive erythrocytes
 Short RBC life

Pathologic o Occurs in the first 24 hours o Caused by excessive destruction of RBCs, infection, or maternal-fetal blood incompatibilities

o Bilirubin rises rapidly in response to the disease process and can cause significant problems

Breastfeeding o Occurs when bilirubin rises about the fourth day after mature breast milk comes in
(higher concentration of fatty acids in the breast milk) o Peaks at 2 to 3 weeks of age o Occurs in response to breastmilk’s higher concentration of free fatty acids which compete with bilirubin for binding sites o Interruption of breastfeeding for 24 hours is usually recommended
 Nursing Care for Jaundice

Maintain skin temp at 97.8F (36.5C)

Encourage early feeding to promote intestinal elimination and bacterial colonization and provide caloric intake

Keep newborn well hydrated and promote intestinal elimination o Because it’s under a light (phototherapy), it’s like when you’re out in the sun all day

Phototherapy if bilirubin exceeds normal for age level

Gastrointestinal Adaptations o Characteristics
 The full-term newborn can digest simple carbohydrate, proteins, and fats
 Stomach capacity of about 50-60 ml and empties 2 to 4 hours after feeding
 Cardiac sphincter and stomach’s neural control are immature

Regurgitation (sometimes excessive) may be noted in the first few days. Should be small amount and decrease o Growth and Development
 Postnatal growth should parallel intrauterine growth (30 g/day) (or an ounce)
 Requires 120 cal/kg/day
 Initial weight loss of 5-10% is normal

Say you have a baby that weighs 6lb 8oz you would convert it all to oz or grams then take away the 5-10%.... She will have a question like this on the test! o Elimination
 First bowel movements occur within 24 hours and consist of meconium

Meconium thick black or dark green stool that is formed in utero from amniotic fluid, intestinal secretions, and mucosal cells.
 Transitional stools replace meconium gradually

Thin brown to green consisting of meconium and fecal material o Breast/Formula Feeding *see pg 578 Figure 23-8*
 Breast Milk Stools

Yellow-gold or green

Soft or mushy

More frequent at first
 Formula Milk Stools

Paler yellow than breast

Formed or pasty

Frequency varies o Urinary Adaptations
 Info
 Newborns are less able to concentrate urine because the renal tubules are short and narrow.
 The effect of excessive insensible water loss or restricted fluid intake is unpredictable
 Characteristics

Concentrating and dilutional limitations of renal function due to:

o Decreased rate of glomerular flow o Limited excretion of solutes
 We have to be careful with drugs that are nephrotoxic because they can’t excrete them as well o Limited ability to concentrate urine

Must monitor fluid therapy to prevent dehydration or over-hydration
 Urinary Functions

Many newborns void immediately after birth & voiding should be noted o 93% void in 24 hours; 98% void by 48 hours

Bladder capacity 6 to 44 ml of urine o First 48 hours urine output=15 ml/day o Urine output should then increase to 25ml/kg/day
 Urinary Values

Normal early urine may be cloudy due to mucous or have pink staining on diaper due to urates

Female infants may have pseudomenstruation o A bloody discharge in response to withdrawal of maternal hormones

Immunologic Adaptations o Characteristics
 Newborn immune system not fully activated
 Lack of inflammatory response results in subtle non-specific signs/symptoms of infection
 Poor hypothalamic response to pyrogens

Fever not a reliable indicator of illness

Sick newborn more likely to be hypothermic o IgG
 Crosses placenta and confers passive immunity to infant in response to maternal illness or immunization
 Transferred during 3 rd trimester giving newborn passive immunity to tetanus, diphtheria, smallpox, measles, mumps, polio, and other bacterial or viral diseases
 Variable duration of immunity from 4 weeks to 8 months so immunizations are begun at 2 months to develop active acquired immunity o IgA
 Provides protection on secreting surfaces such as respiratory tract, gastrointestinal tract, and eyes
 Does not cross the placenta
 Colostrum is high in IgA possibly providing passive immunity to breastfed newborns o IgM
 Produced in response to blood group antigens, gram-negative enteric organisms, and some viruses in the expectant mothers.
 Does not normally cross the placenta accounting for the newborn’s susceptibility to gram-negative enteric organisms (i.e. E. Coli)
 Elevated levels at birth indicate placental leaks or antigenic stimulation in utero (i.e. TORCH or syphilis)

TORCH stands for several different infections, like T is toxoplasmosis, H is for herpes, etc.
 If you see an elevated IgM in the newborn it is bad because it means it was exposed
 Neurologic and Sensory-Perceptual Functioning o Characteristics
 Newborn brain is ¼ adult size and myelination of nerve fibers is incomplete
 The brain and nervous system structures mature in a predictable order
 Partially flexed extremities with legs near the abdomen with random, uncoordinated movements of the extremities
 Eyes – able to fixate on faces/objects and blinks reflexively to bright light
 Growth progresses in cephalo-caudal manner (head-to-toe)
 Muscle tone is symmetrical and hypertonic
 Predictable reflexes are present

 Displays some complex behavioral patterns – hand to mouth demonstrates motor coordination and selfquieting
 The First Period of Reactivity

Lasts for 30 minutes after birth.

Newborn is alert and eager to breastfeed

May have tachycardia/tachypnea; mildly increased respiratory effort

Sleep phase then lasts up to 4 hours
 Second Period of Reactivity

Awake/alert for 4 to 6 hours
 Increased heart and respiratory rates

Apnea and bradycardia may occur

Color fluctuations

Increased respiratory and gastric mucous and may gag, choke, or regurgitate

Gastrointestinal tract becomes more active o Behavioral States
 Sleep States

Deep or quiet sleep-eyes closed with no movement; regular breathing; subdued startles; 35-45% of total sleep

Active REM sleep- eyes closed with eye movements visible; irregular breathing; irregular sucking; startles responsively to environmental or internal stimuli; 45-50% of total sleep
 Alert States

Drowsy or semi-drowsy

Active awake

Hyper alert/Crying
 Behavioral Capacities
 Important to support infant in achieving a robust sleep or quiet alert state for optimum growth, development, and bonding
 Habituation: Ability to process and respond to visual and auditory stimulation, then with repeated stimulation the newborn’s response diminishes

Orientation: Ability to alert to, follow, and fixate on complex visual stimuli. Useful in becoming familiar with family, friends, and surroundings

Self-quieting: Ability to quiet and comfort self
 Sensory Capacities

Auditory: Responds with increased heart rate, startle, or alerting. May search for the source

Olfactory: Newborns can select people by smell; mom’s breastmilk

Tactile: Sensitive to being touched, cuddled, and held

Taste and Sucking: Responds differently to varying tastes. Breastfeeding produces different kind of sucking than bottle-feeding