Nursing 323: Newborn Physiologic Adaptations

Physiologic Adaptations of the Newborn at Birth

• Chapters 22, 23, and 24 discusses the physiologic adaptations of newborns, used for Nursing 323

Learning Outcomes

• The major physiologic changes that occur as the newborn transitions to extrauterine life are examined
• Determines the primary challenges faced by the newborn during transition to extrauterine life
• Describes the three behavioral patterns that newborns progress through following birth
• Describes interventions that meet the immediate needs of the term newborn
• Describes characteristics that contribute to newborn heat loss after birth
• Distinguishes common variations that can be noted during a newborn's physical assessment
• Discusses the discharge planning education needed for the family with a newborn

Immediate Care After Birth

• Initial assessment is completed in the delivery area
• Maintain a patent airway and respirations
• Apgar scores are assigned
• Vital signs are obtained and monitored
• Thermoregulation is maintained
• An ID band is placed on infant, parents, and includes a security tag
• A 3 vessel umbilical cord is assessed
• Footprints are taken
• Measurements and weight are recorded
• Promotion of bonding occurs
• Documentation is completed

APGAR Score

• Two points are allotted to the following areas at 1 and 5 minutes after birth, and repeated at 10 minutes if warranted
• A = appearance (color)
• P = Pulse (Heart rate)
• G = grimace (reflex irritability)
• A = activity (muscle tone)
• R = respiratory (respiratory effort)

Respiratory System

• Initiation of respirations adjusts from a fluid-filled intrauterine environment to a gaseous extrauterine environment
• Surfactant reduces surface tension, preventing alveolar collapse
• Respirations occur at a rate of 30 to 60 breaths per minute, irregular, shallow, unlabored with short periods of apnea if less than 15 seconds; symmetrical chest movements

Cardiovascular System

• Heart Rate ranges from 110-160 beats per minute
• Apical pulse for one full minute
• Blood pressure should measure 60-80 mmHg systolic and 40-50 mmHg diastolic
• Delayed umbilical cord clamping increases blood volume and blood pressure

Newborn Temperature Regulation

• Thermoregulation involves maintaining a balance between heat loss and production
• Newborns are predisposed to heat loss because of:
• Thin skin with blood vessels close to the surface
• Large body surface area relative to body weight
• Lack of subcutaneous fat, limiting their ability to conserve heat by changing posture
• Lack of shivering ability; limited stores of glucose, glycogen, and fat

Mechanisms of Heat Exchange

• Conduction is the transfer of heat when two objects are in direct contact with each other
• Convection is the flow of heat from the body surface to cooler surrounding air or to air circulating over a body surface
• Evaporation is heat loss when liquid is converted to a vapor
• Radiation is the loss of body heat to cooler, solid surfaces in close proximity, not in direct contact

Transition to Extrauterine Life Thermoregulation

• Neutral thermal environment (NTE) maintains body temperature without an increase in metabolic rate or oxygen consumption
• Brown adipose tissue: Brown fat helps with heat exchange
• Cold stress is ineffective thermoregulation
• Factors that negatively affect thermoregulation include:
• Decreased subcutaneous fat and large body surface
• Decreased brown fat in preterm infants

Signs of Cold Stress

• Low temperature
• Weak cry
• Decreased tone, lethargy
• Respiratory distress
• Cool, mottled skin
• Poor feeding
• Hypoglycemia
• Thermal neutral environment is important for successful transition, especially in SGA and preterm newborns

Renal System

• There is a limited ability to concentrate urine and reduced glomerular filtration rate
• This makes newborns susceptible to dehydration and fluid overload
• Affects ability to excrete drugs
• Many newborns void right after birth
• Typically, void within 24 hours of birth
• For the first 2 days, they void 2-6 times/day
• Then increases to 6 to 8 times /day
• Pseudomenstruation results from withdrawal of maternal hormones that happen only once in female neonates
• "Brick dust spots" are urates, which are normal, and may be seen on a diaper

Gastrointestinal System

• The GI system is still immature but can transport nutrients
• Bowel sounds are audible a short time after birth
• Newborn needs to adapt to bacterial colonization of the gut
• Dependent on nutrition required for production of Vitamin K
• Regurgitation of feeding is common due to an immature cardiac sphincter and nervous control of stomach, leading to regurgitation
• Do not overfeed, needs to be burped often
• Weight gain
• A typical 5-10% weight loss happens in the first week

Characteristics of Newborn Stools

• Meconium is passed within 24 to 48 hours
• It is greenish-black and viscous
• Transitional stools pass by day 3
• Greenish-brown to yellow-brown in color
• Thin, less sticky than meconium
• Milk Stools should be present by day 4
• Breast-fed newborns have yellow/gold, mustard/cottage cheese that has a sour milk smell
• Formula-fed newborns have pale yellow to light brown stools
• Firmer consistency, unpleasant odor

Hepatic System

• The liver assumes the function of the placenta
• Important for iron storage
• If maternal iron intake is adequate, the newborn should have enough iron stored in the liver to last the first 6 months
• Carbohydrate metabolism
• Glucose is essential fuel for brain metabolism, is the main source of energy for the first few hours after birth
• The liver releases glucose from glycogen stores for the first 24 hours
• Initiate early feedings to help stabilize glucose levels

Hypoglycemia

• Issues during transition with glucose regulation
• Impaired ability to generate glucose from glycogen stores
• Slower postnatal glucose increase
• Increased glucose utilization
• Risk Factors for Hypoglycemia:
• Maternal: Diabetic, multiples, obesity
• Fetal/Neonatal: Hypothermia, birth weight variations, stress, sepsis

Hypoglycemia Signs

• Irritability
• Tremors/jitteriness
• High-pitched cry
• Lethargy/floppiness/hypotonia
• Cyanosis
• Apnea/Tachypnea
• Hypothermia/temperature instability
• Poor Feeding

Bilirubin Synthesis

• This is an imbalance in the rate of bilirubin production and elimination
• A total serum bilirubin level over 5 mg/dL
• Two types of jaundice:
• Physiologic jaundice occurs within the 3rd to 4th day of life and is considered benign
• Pathologic jaundice occurs within the first 24 hours of life
• Kernicterus result from Total Bilirubin over 20 mg/dl, is irreversible
• Crosses the blood-brain barrier
• Causes permanent impaired neurological function from Rh isoimmunization and or ABO incompatibility
• Nursing assessment :
• Monitor skin and sclera, early and frequent feedings, possible phototherapy
• Check and monitor bilirubin levels

Phototherapy

• Reduces bilirubin by converting it to a water-soluble form
• Nursing care includes:
• Skin care and eye protection
• Hydration with frequent feedings
• Thermoregulation
• Education
• Interpret all bilirubin levels according to the infant's age in hours
• Side effects include:
• Increased insensible water loss
• Decreased maternal-newborn interaction
• Lack of visual sensory input

Immune System

• The newborn immune system is immature and does not readily respond to infections
• Hypothermia may be a sign of infection in first days of life
• Temperature of less than 36.5-37.5℃ / 97.7-99.5°F
• Passive acquired immunity involves the transfer of antibodies from the mother to the fetus
• IgG antibodies cross the placenta, giving the neonate protection against infection for up to 2 months
• Colostrum is high in IgA
• Active Acquired immunity involves immunizations, beginning at 2 months of age

Neonatal Assessment Continued

• Growth follows cephalo-caudal to proximo-distal patterns
• Reflexes includes:
• Sucking and rooting
• Palmer grasp
• Tonic neck (fencer position)
• Moro
• Stepping
• Babinski

Sensory Behaviors

• Acute senses of hearing, smell, and taste are well developed
• The newborn is able to distinguish mothers breast milk, sweet and sour tastes by 72 hours
• Touch-sensitive
• Response to environmental stimuli: temperament, habituation, consolability and cuddliness, and irritability and crying

Medications

• Erythromycin ophthalmic ointment at 0.5%
• Prevents against STDs like Chlamydia and Gonorrhea
• Mandatory antibiotic ointment and prevents ophthalmia neonatorum caused by Neisseria gonorrhoeae or Chlamydia trachomatis
• Can cause blindness
• Apply 1-2 cm ribbon of ointment to the lower conjunctival sac of each eye
• Vitamin K at 0.5 to 1 mg IM should be administered within one hour after birth
• Prevents hemorrhagic disorders
• Vitamin K is not produced by the GI tract of newborns until day 7, but is produced by the colon when bacteria form after formula or breast milk
• Hepatitis B protects against hepatitis B
• Parents sign informed consent
• Dosage occurs at birth, one month, and 6 months
• Do not administer both IM injections into same site

Newborn Vital Signs

• Temperature should measure 97.7- 99.5 F (36.5-37.5)
• Heart Rate: 120-160 bpm
• Respirations: 30-60 breaths/minute at rest
• Blood Pressure: 50-75 mm Hg systolic, 30-45mmHg diastolic
• Perform pain assessments using the Neonatal Infant Pain Scale (NIPS)

Immediate Care After Birth Measurements

• Birth weight: 2500-4000 grams
• Length: 46-54 cm (19-21 inches)
• Head Circumference: 33-35 cm (13-14 inches)
• Chest Circumference: 30.5-33 cm (12-13 inches)
• Abdominal Circumference
• Neurologic Assessment

Physical Maturity Assessment: Ballard

• Determines the newborn's gestational age by looking at physical and neuromuscular maturity
• Skin texture
• Lanugo
• Plantar creases
• Breast tissue
• Eyes and ears
• Genitals

Care Management

• Use of Laboratory and diagnostic tests, which include:
• Universal newborn screening
  • PKU should be tested 24-48 hours after feeding
• Newborn hearing screening
• Critical congenital heart disease

Circumcision

• Removal of the foreskin of the penis
• Contraindications include:
• Preterm neonate
• Genitourinary defect such as hypospadius
• Bleeding disorder, baby is not getting vitamin K
• Compromised neonate with a respiratory distress syndrome
• Risks: hemorrhage, infection, pain, adhesions
• Benefits: Reported decrease UTI,STI's-including HIV; penile cancer and cervical cancer in female partner

Circumcision Types and Post Procedure

• Procedure: AAP recommends analgesia, nerve block, topical, concentrated oral sucrose, and pacifier
• Types of circumcisions:
• Mogen clamp- wound covered with sterile petroleum gauze to prevent bleeding, infection
• Plastibell- falls off 5-7 days plastibell, no petroleum gauze used
• Post procedure
• Assess bleeding every 15 to 30 minutes for first hour then every hour for 4 to 6 hours
• Note first voiding, assess for signs infection
• Prescribe acetaminophen 10-15 mg/kg every 4 to 6 hours for 24 hours post procedure
• Caution maximum dose of 30-45 mg/kg/day

Discharge Planning

• Covers newborn care, bathing, cord care, feeding, temperature, and positioning
• Offers swaddling assistance
• Discusses SIDS
• Examines sleep/activity
• Reviews safety with infant car seat, must be rear facing in the back seat until age 2
• Includes a Bilirubin screen
• Covers newborn screen, PKU- 24 to 48 hours after protein feeding, hearing, and congenital cardiac issues
• Plans for follow up care with Pediatrician, 1-2 weeks post discharge
• Covers when to call Pediatrician and signs of illness

Summary

• Identifies the assessments performed during the immediate newborn period
• Describes interventions that meet the immediate needs of the term newborn
• Defines the key laboratory and newborn screening tests conducted in the newborn period
• Distinguishes common variations that can be noted during a newborn's physical assessment
• Explores the discharge needs for the neonate
• Examines the major physiologic changes that occur as the newborn transitions to extrauterine life
• Determines the primary challenges faced by the newborn during transition to extrauterine life
• Describes the three behavioral patterns that newborns progress through following birth