Question 1

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

Accepted Answer

Endotracheal suctioning in a newborn, especially one born at 28 weeks gestational age, can stimulate the vagus nerve, leading to a reflex bradycardia or apnea due to the immaturity of the respiratory control center in the brain.

Question 2

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

The first breath in a newborn is stimulated by a combination of factors including tactile stimulation (such as drying or touching the baby), stimulation of central chemoreceptors (due to changes in CO2 levels), stimulation of peripheral chemoreceptors (due to changes in O2 levels), and thermal stimuli (the temperature change experienced upon leaving the womb). These factors work together to trigger the newborn's respiratory center to initiate breathing.

Question 3

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, primarily due to surfactant deficiency.

Question 4

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

Accepted Answer

Stimulation of the trigeminal nerve (V cranial nerve) can cause a reflex that decreases respiratory and heart rates, known as the trigeminal cardiac reflex.

Question 5

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 undergoes a transition from fetal to neonatal circulation. This transition is characterized by a decrease in PaCO2 and an increase in PaO2, as the newborn begins to breathe air and establish pulmonary gas exchange. The pH and HCO3- levels also increase slightly as the newborn's body adjusts to the new environment.

Question 6

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 volume, which widens the caliber of extralveolar vessels

Accepted Answer

The reduction in pulmonary vascular resistance following the first breath is due to increased alveolar oxygen pressure, which causes vasodilation; removal of lung fluid, which decreases external pressure on the pulmonary vessels; and an increase in lung volume, which widens the caliber of extralveolar vessels, all contributing to decreased resistance.

Question 7

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. This reflects the lower compliance of neonatal lungs compared to adults, indicating that their lungs are stiffer and require more pressure to fill.

Question 8

What factor causes closure of the foramen ovale?

Accepted Answer

The foramen ovale closes due to increased blood pressure in the left atrium compared to the right atrium after birth, which pushes the septum primum against the septum secundum, closing the foramen ovale and establishing the typical adult circulation pattern.

Question 9

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

Accepted Answer

The NBRC (National Board for Respiratory Care) awards the RRT-NPS credential to registered respiratory therapists who successfully complete the neonatal/pediatric specialty examination. RRT-NPS stands for Registered Respiratory Therapist - Neonatal/Pediatric Specialty.

Question 10

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

Accepted Answer

To initiate the first breath, especially in newborns, a significantly negative intrapleural pressure of approximately -40 cm H2O is required to overcome the surface tension of the fluid-filled alveoli and expand the lungs.

Question 11

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

Accepted Answer

The S:A ratio refers to the Sphingomyelin to Lecithin ratio in the amniotic fluid, which is used to assess fetal lung maturity. A ratio of 2:1 (or 60 in percentage terms) typically indicates mature fetal lungs.

Question 12

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

Accepted Answer

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

Question 13

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 14

Constriction of the ductus arteriosus occurs in response to

Accepted Answer

The ductus arteriosus constricts in response to the increased oxygen levels (PO2) in the blood after birth, as the newborn begins to breathe air.

Question 15

What is the normal respiratory rate of an average newborn?

Accepted Answer

The normal respiratory rate of an average newborn is typically between 35 to 50 breaths per minute. This rate is higher than that of older children and adults due to the smaller lung capacity and higher metabolic rate of newborns.

Quiz 10: Fetal Development and the Cardiopulmonary System