Question 1

What of the following factors cause a reduction in the pulmonary vascular resistance following the first breath?
I.Increased alveolar pressure of oxygen
II.Removal of lung fluid which reduces pressure on pulmonary vessels
III.Increase in lung volumewhich widens the caliber of extralveolar vessels

Accepted Answer

All three factors contribute to the reduction in pulmonary vascular resistance following the first breath. Increased alveolar oxygen pressure causes vasodilation of the pulmonary vessels, removal of lung fluid decreases external pressure on the vessels, and an increase in lung volume during inspiration widens the extralveolar vessels, all of which decrease resistance.

Question 2

Constriction of the ductus arteriosus occurs in response to

Accepted Answer

The ductus arteriosus constricts in response to increased oxygen levels (PO₂) in the newborn's blood after birth.

Question 3

Which of the following nerves,when stimulated,causes a decrease in the respiratory and heart rates of the newborn?

Accepted Answer

The answer of Which of the following nerves,when stimulated,causes a...

Question 4

What would you conclude regarding a fetus' lung maturity if the S:A ratio equaled 60?

Accepted Answer

The S:A ratio, or surfactant to albumin ratio, is used to assess fetal lung maturity. A ratio of 60 indicates fetal lung maturity, as higher ratios generally suggest sufficient surfactant production for adequate lung function outside the womb.

Question 5

What does the presence of phosphatidyglycerol (PG)in the amniotic fluid indicate?

Accepted Answer

Phosphatidylglycerol (PG) in the amniotic fluid is a marker of fetal lung maturity, indicating a lower risk of the newborn developing respiratory distress syndrome.

Question 6

What is the normal tidal volume and TLC of an average newborn?

Accepted Answer

The normal tidal volume for a newborn is around 15 mL and the total lung capacity (TLC) is around 155 mL. Options B, C, and D have much higher tidal volumes and TLC values, which are not typical for newborns.

Question 7

What response would be expected if a newborn of 28 weeks gestational age received endotracheal suctioning?

Accepted Answer

Endotracheal suctioning is a procedure done to clear the airway of mucus and secretions, but it can also stimulate the vagus nerve which can result in a decrease in heart rate and even apnea. In a newborn of 28 weeks gestational age who is already at high risk for respiratory distress syndrome and apnea, endotracheal suctioning can exacerbate these issues and result in bradypnea or apnea.

Question 8

What is the average value for airway resistance in a newborn?

Accepted Answer

The answer of What is the average value for airway...

Question 9

If a registered repiratory therapist succesfully completes the NBRC's neonatal/pediatric specialty credential,what credential would be awarded?

Accepted Answer

The NBRC's neonatal/pediatric specialty credential is RRT-NPS. This credential is awarded to registered respiratory therapists who have successfully completed the examination in neonatal/pediatric respiratory care.

Question 10

What intrapleural pressure must be generated to initiate the first breath?

Accepted Answer

To initiate the first breath, an intrapleural pressure of -40 cm H2O must be generated. This is significantly more negative than the typical intrapleural pressures required during normal breathing due to the need to overcome the surface tension of the fluid in the alveoli and expand the lungs for the first time.

Question 11

What factor causes closure of the foramen ovale?

Accepted Answer

The closure of the foramen ovale is caused by increased blood pressure in the left atrium, which eventually exceeds the pressure in the right atrium and forces the septum primum to fully close the foramen ovale. This is due to the fact that during fetal development, the right atrium has higher pressure than the left atrium, which allows blood to flow from the right atrium to the left atrium through the foramen ovale. However, after birth, the pressure in the left atrium increases due to the return of oxygenated blood from the lungs, causing the closure of the foramen ovale. Increased PCO₂ or PO₂ levels in arterial blood do not directly affect the closure of the foramen ovale.

Question 12

During the first 72 hours in the life of a healthy newborn,what changes would be expected in arterial blood gases?
I.pH would increase
II.PaCO₂ would decrease
III.HCO₃- would increase
IV.PaO₂ would increase

Accepted Answer

During the first 72 hours of life, a healthy newborn's arterial blood gases undergo several changes as the baby adapts from a fetal to a neonatal circulation. The pH increases as the initial mild acidosis from birth is corrected. PaCO₂ decreases as the newborn begins to breathe air, eliminating carbon dioxide more effectively. PaO₂ increases as the lungs expand and the baby starts breathing oxygen from the air, improving oxygenation. HCO₃- (bicarbonate) levels may initially decrease as part of the compensation for the respiratory changes and the correction of acidosis, not increase, which is why option III is not expected.

Question 13

Which of the following factors contribute to stimulate the first breath?
I.Tactile stimulation
II.Stimulation of central chemoreceptors
III.Stimulation of peripheral chemoreceptors
IV.Thermal stimuli

Accepted Answer

All listed factors contribute to stimulating the first breath in a newborn. Tactile stimulation occurs during delivery and handling; central chemoreceptors respond to changes in CO2 levels; peripheral chemoreceptors respond to oxygen levels; and thermal stimuli occur due to the temperature change when the baby leaves the womb.

Question 14

What is the most common cause of respiratory failure in preterm infants?

Accepted Answer

Respiratory distress syndrome (RDS) is the most common cause of respiratory failure in preterm infants. This is due to the immature lungs of preterm infants, which lack adequate surfactant production, leading to alveolar collapse and impaired gas exchange.

Question 15

What is the average lung compliance of a neonate?

Accepted Answer

The average lung compliance of a neonate is approximately 0.005 L/cm H2O, which is equivalent to 5 mL/cm H2O.

Quiz 10: Fetal Development and the Cardiopulmonary System

What of the following factors cause a reduction in the pulmonary vascular resistance following the first breath? I.Increased alveolar pressure of oxygen II.Removal of lung fluid which reduces pressure on pulmonary vessels III.Increase in lung volumewhich widens the caliber of extralveolar vessels