Normal Newborn: Adaptation & Assessment Flashcards
Newborn Adaptations
The first, most important task in newborn adaptation is the ___ ?
initiation of respiration
Development of the Lungs
?
* Alveoli produce ___ that expand the alveoli & assist in lung development
* As the fetus nears term, the production of ___ decreases
* During labor, the fluid begins to move into the interstitial space where it is absorbed
> Absorption is accelerated by labor, delayed w/cesarean births
* At birth, only about ___% of the original amount of fluid remains
Fetal Lung Fluid
35%
* Complications like HTN, placental insufficiency, maternal infection, & rupture of membranes greater than 48 hours may cause accelerated fetal lung maturity
?
* Reduces surface tension in the alveoli
> Without it, the alveoli collapse as the infant exhales, & needs to be re-expanded w/each breath
* Secretion increases during labor & immediately after birth
> Usually sufficient by ___ to ___ weeks gestation
* DM & gestational DM can delay ___ production
* Steroids may be given to women who are in preterm labor to help increase production & lung maturation
Surfactant (a combination of lipoproteins)
34-36 weeks
What causes respirations to initiate?
Chemical Factors
* ___ respond to changes in blood chemistry
* Stimulates the respiratory center in the ___, stimulating a forceful contraction of the diaphragm & air enters the lungs
* Does not occur if prolonged hypoxia (CNS depression)
Chemoreceptors
medulla
Mechanical Factors (Vaginal deliveries only)
* Fetal chest is compressed by the birth canal, forcing fluid out of the lungs
* At birth, chest recoils & brings air into the lungs, making 1st breath easier
Thermal Factors
* Sensors in the skin respond to the sudden change in temperature, sending impulses to stimulate respiratory center of the brain & breathing
Sensory Factors
* Tactile stimulation from birth & care following stimulate skin sensors
Maintaining Respiration
* Surfactant allows the alveoli to remain partially open
> Subsequent breaths require less effort
* As the infant cries, pressure within the lungs increase causing the remaining fetal lung fluid to move into the interstitial space to be reabsorbed
> Complete absorption may take as long as 24 hours
> Lungs may sound moist when first auscultated, but clear a short time later
Cardiovascular Adaptations: Fetal Circulation
* Ductus Venosus
* Foramen Ovale
* Ductus Arteriosus
?
About 1/3 of blood is directed away from the liver
Near the end of pregnancy the liver needs more perfusion, so blood flow is increased
Ductus Venosus
?
* Connects the pulmonary artery w/the aorta
* Only 10-12% of blood entering the pulmonary artery travels to the lungs, the remainder passes through the ___
* Patency is maintained by ___ from the placenta & the low oxygen content of the blood
Ductus Arteriosus
ductus arteriosus
prostaglandins
?
* Flap in the septum of the right & left atria of the heart
* 50-60% of blood from R atrium moves through the ___ to the L atrium
Foramen Ovale
foramen ovale
Cardiovascular Adaptation: Neonatal Circulation
After birth, the fetal shunts close & the pulmonary vessels dilate
?
Closes shortly after birth; permanently closes 1-2 weeks after birth
closure of the Ductus Venosus
?
Closes at about 72 hours of life, & permanently closes within 1-2 weeks
closure of the Ductus Arteriosus
* If it does not close = patent ductus arteriosus (PDA) & may need surgical intervention
?
Because the ___ opens only from right to left, when the pressures in the left atrium increases it closes; permanently closes within 7 months
Conditions such asphyxia & persistent pulmonary HTN can cause the ___ to reopen
closure of the Foramen Ovale
foramen ovale
* Can see adults w/PFO (patent foramen ovale)
Neurologic Adaptations: Thermoregulation
Methods of Heat Loss
* Evaporation
* Conduction
* Convection
* Radiation
Nonshivering Thermogenesis
Cold Stress
?
Is the transfer of heat to cooler objects that are not in direct contact w/the infant
* Do not place cribs near windows/open doors
Radiation
?
Is the transfer of heat from infant to cooler surrounding air
> e.g. incubator use
Convection
?
Is air-drying of the skin
Evaporation
?
Is the movement of heat away from the body that occurs when newborns come into direct contact w/objects that are cooler than their skin
Conduction
?
Increases O2 needs, decreases surfactant production; makes it harder to breathe, causing respiratory distress
> Can lead to hypoglycemia ⇒ metabolic acidosis, increased risk of jaundice
Cold Stress
?
Brown fat protects the heart & kidneys & is metabolized to produce heat
* A decrease in core temperature will not occur until this is no longer active
Nonshivering thermogenesis
Thermoregulation
* The rate of heat loss in a newborn is four times greater than that of adults
* Because preterm infants do not hold a flexed position like the term neonate, they are more susceptible to heat loss
Neutral Thermal Environment
* Where the infant can maintain a stable body temperature with minimal oxygen need & without an increase in metabolic rate
Called the ___ ?
* Healthy, unclothed full-term newborns: ___ to ___ °F
* Dressed infant: ___ to ___ °F
thermoneutral zone
- 6 - 92.3 °F
- 2 - 80.6 °F
Hematologic Adaptations
Term newborn blood volume = ___ to ___ mL/kg
Blood Values in the Newborn
* RBC’s: 4.8 - 7.1 million/microliter
* Hgb: 15-24 g/dL
* HCT: ___ to ___ %
* Leukocytes: ___ to ___ thousand/mm3
Average neonate weight 3 kg
80-100 mL/kg
44-70%
9.1-34
Risk of Clotting Deficiencies
* Newborns have low levels of Vitamin K
* Most newborns receive an intramuscular administration of Vitamin K within 12 hours of birth to reduce the risk of hemorrhagic diseases
> Especially important if there was any kind of operative vaginal delivery, i.e. vacuum or forceps use that could cause intracranial damage & bleeding
* Maternal rx’s like phenytoin, phenobarbital, & anti-tuberculosis drugs taken during pregnancy can interfere w/clotting abilities in the newborn
