physiologic and adaptation of newborn

NRS 400

What is the first 6–8 hours after birth considered?

A period of instability requiring close monitoring and assessment.

What are the three stages of transition to extrauterine life?

Transition/period of reactivity; decreased responsiveness; second period of reactivity.

When does the first transition/period of reactivity occur?

During the first 30 minutes after birth.

What characterizes the first period of reactivity?

The newborn is alert; it is a good time for breastfeeding and skin-to-skin.

How long does decreased responsiveness last?

About 60–100 minutes.

What is the newborn like during decreased responsiveness?

Sleepy or decreased in activity/responsiveness.

When does the second period of reactivity occur?

Between 2 and 8 hours after birth.

How long can the second period of reactivity last?

About 10 minutes to several hours.

What did the placenta provide for the fetus in utero?

Oxygen and nutrients.

What major change occurs when the cord is clamped and cut?

The baby must adapt and take over functions previously supported by the placenta.

What is the most critical physiologic respiratory adaptation in the newborn?

Establishment of effective respirations.

What four types of factors initiate newborn respirations?

Chemical, mechanical, thermal, and sensory factors.

What chemical changes occur during labor that help initiate respirations?

Oxygen decreases and CO2 increases.

What happens to prostaglandins with cord clamping according to the lecture?

They decrease.

What mechanical factors help initiate newborn respirations?

Chest compression during vaginal delivery followed by chest expansion after birth.

What thermal factor helps initiate newborn respirations?

The newborn enters an environment with a much lower temperature.

What sensory factor helps initiate newborn respirations?

A catecholamine surge shortly before labor stimulates lung-fluid clearance and increases surfactant release.

What is the normal newborn respiratory rate?

30–60 breaths/min.

How long should a newborn's respiratory rate be counted?

One full minute.

Are newborns primarily nose breathers?

Yes.

What is periodic breathing in a newborn?

Breathing that can include shallow and irregular breaths.

Why can nasal obstruction be significant in a newborn?

Newborns are nose breathers, so narrowing or obstruction can affect breathing.

If suctioning a newborn's airway is needed, what should be suctioned first?

The mouth, then the nose.

What should you observe in the newborn's chest and abdomen during inspiration?

Both should rise with inspiration.

Why are newborn breath sounds often louder?

The newborn has a thin chest wall.

What breath sounds are expected over most areas of a newborn's lungs?

Clear breath sounds over most areas.

Why can occasional rales occur during the first two hours?

They can occur during the early transition period.

Are diminished breath sounds normal in a newborn?

No. The lecture states they are always abnormal.

What respiratory rate is a sign of respiratory distress if the newborn is not crying?

Greater than 60 breaths/min.

What can respirations under 30/min indicate in a newborn?

CNS depression.

What abnormal breath sounds may indicate newborn respiratory distress?

Rhonchi/rales (crackles), wheezes, and expiratory grunts.

What is the difference between central cyanosis and acrocyanosis in newborn assessment?

The lecture identifies both as important to distinguish; central cyanosis is abnormal, while blue hands/feet can be a normal immature vascular finding.

What is apnea?

A period in which the newborn stops breathing; the lecture lists apnea as a sign requiring attention.

What are signs of newborn respiratory distress besides abnormal rate or sounds?

Nasal flaring, retractions, chin tug/head bobbing, seesaw respirations, and grunting.

What types of retractions may be seen with newborn respiratory distress?

Intercostal, subcostal, and supraclavicular retractions.

What is chin tug/head bobbing a sign of?

Respiratory distress.

What are seesaw respirations?

A sign of respiratory distress listed in the lecture.

A newborn has a respiratory rate of 65 while crying. Does the lecture identify this as automatically abnormal?

No. The respiratory distress criterion given is >60 without crying.

Crackles/rales 30 minutes after birth: is this necessarily abnormal according to the lecture?

No. Occasional rales can be common during the first two hours.

Why does chest compression during birth help the newborn?

It clears some secretions from the airways.

Why is the first breath important for cardiovascular adaptation?

Chest expansion triggers pressure changes that transition circulation from fetal to neonatal patterns.

What two other factors are important in cardiovascular transition?

Temperature shifts and cutting the umbilical cord.

What happens to blood flow to the newborn lungs after birth?

It increases.

What happens to left atrial pressure as pulmonary blood flow increases?

Left atrial pressure increases.

What happens to the foramen ovale as left atrial pressure increases?

It closes.

What happens to the ductus arteriosus as PO2 increases?

It closes.

What can cause cardiovascular problems during newborn transition?

Failure to transition from fetal to neonatal circulation pathways or structural defects.

What is an example of failure to transition from fetal circulation pathways?

Patent ductus arteriosus (PDA).

What is an example of a structural cardiovascular defect in the newborn?

Coarctation of the aorta.

How should a newborn pulse be assessed?

Apically, for one full minute.

When should a newborn pulse be assessed?

At rest or when alert, but not crying.

What pulse range does the lecture give from sleeping to crying?

About 85 bpm when sleeping to 180 bpm when crying.

What is the typical newborn heart-rate range given in the lecture?

110–160 bpm.

When should an abnormal newborn pulse finding be reevaluated?

Within 30 minutes, or sooner if the infant's activity changes.

What murmur can be common during the first several days?

A systolic ejection murmur.

What can contribute to a systolic ejection murmur in the first several days?

A patent foramen ovale (PFO) or patent ductus arteriosus (PDA).

When may an echocardiogram be used according to the lecture?

PRN when indicated by cardiac assessment.

Which pulses should be assessed in the arms and legs?

Brachial and femoral pulses.

What should brachial and femoral pulses be like?

Present and equal bilaterally and between upper and lower extremities.

What is the average newborn systolic BP listed?

60–80 mmHg.

What is the average newborn diastolic BP listed?

40–50 mmHg.

When is further diagnostic testing indicated based on upper vs. lower extremity systolic BP?

If upper-extremity SBP is more than 10 mmHg higher than lower-extremity SBP.

After respirations and circulation are established, what becomes the most critical factor for newborn survival?

Heat regulation.

What is thermoregulation?

Maintaining a balance between heat production and heat loss.

Why are newborns at increased risk for heat loss?

Thin subcutaneous fat, superficial blood vessels, environmental temperature changes, blood-temperature changes, and a large body-surface-area-to-body-mass ratio.

What type of fat is important for newborn non-shivering thermogenesis?

Brown fat.

Do newborns shiver to generate heat?

No. The lecture states newborns do not shiver.

How do newborns perform non-shivering thermogenesis?

By metabolizing brown fat.

What happens to oxygen and glucose consumption during thermogenesis?

They increase.

What is one characteristic of brown fat compared with white fat?

It can be broken down into glycogen more easily.

How is brown fat supplied compared with white fat?

It has a richer vascular and nerve supply.

In which newborns is brown fat most abundant?

Term newborns.

Where is brown fat located?

Around the kidneys, adrenal glands, mediastinum, subscapular area, axillary area, and nape of the neck.

When does brown fat accumulate most rapidly?

During the last part of the third trimester; amount increases with gestation.

What percentage of a term infant's total body weight can brown fat account for?

About 2–7%.

What does brown fat produce?

Heat in core regions of the body.

What happens to brown-fat reserves during cold stress?

They are rapidly depleted.

Are brown-fat stores replaced once used?

No, according to the lecture.

What is convection heat loss?

Flow of body heat from the body surface to cooler ambient air.

What is an example of convection heat loss?

A baby in a cool room.

What is conduction heat loss?

Loss of body heat to cooler surfaces in direct contact.

What is an example of conduction?

Placing the baby on a scale.

What is radiation heat loss?

Loss of body heat to a cooler solid surface that is not in direct contact but is nearby.

What is an example of radiation?

A baby being near a window.

What is evaporation heat loss?

Heat loss when liquid is converted to vapor.

What is an example of evaporation?

A baby after a bath.

Drying an infant quickly after birth primarily prevents which heat-loss mechanism?

Evaporation.

Why does drying a newborn help prevent heat loss?

It removes moisture that could evaporate and carry heat away.

What type of heat loss is reduced by placing a newborn in a prewarmed crib or skin-to-skin with the mother?

Conduction.

What type of heat loss is reduced by placing the crib away from windows?

Radiation.

What type of heat loss is reduced by keeping the room warm and at a constant temperature?

Convection.

What happens to respiratory rate during cold stress?

It increases in response to increased oxygen needs.

What happens to BMR during cold stress?

It increases.

What happens to glucose consumption during cold stress?

It increases.

What happens to tissue perfusion during cold stress?

It decreases.

Where is oxygen and energy diverted during cold stress?

Away from brain cells, cardiac function, and growth and toward thermogenesis for survival.

What acid-base problems can result from cold stress?

Respiratory and metabolic acidosis.

What happens to unbound bilirubin during cold stress?

It increases.

What glucose problem can result from cold stress?

Hypoglycemia.

What is the newborn axillary temperature range given in the lecture?

97.8–99.5°F (36.5–37.5°C).