Neonatology Week 3 Flashcards
Q: How is fetal circulation different from adult circulation?
A: In fetal circulation, gas exchange occurs in the placenta, not the lungs. The fetus does not breathe in utero, so the placenta supplies oxygen and nutrients via the umbilical vein.
Q: What is the role of the umbilical vessels?
A: The single umbilical vein carries oxygenated blood to the fetus, while the two umbilical arteries carry deoxygenated blood back to the placenta for re-oxygenation.
Q: What is the function of the ductus venosus?
A: It bypasses the liver, connecting the umbilical vein to the inferior vena cava, allowing most blood to go directly to the heart.
Q: What does the foramen ovale do in fetal circulation?
A: It is an opening between the right and left atrium, allowing oxygenated blood to bypass the lungs and flow from the right to the left atrium.
Q: What is the function of the ductus arteriosus?
A: It connects the pulmonary artery to the aorta, bypassing the fluid-filled lungs by shunting blood away from them.
Q: How does oxygenated blood flow in the fetus?
A: Oxygenated blood from the placenta flows through the umbilical vein, bypasses the liver via the ductus venosus, enters the right atrium, and passes through the foramen ovale to the left atrium, then to the aorta, supplying the heart, brain, and body.
Q: How does deoxygenated blood return to the placenta?
A: Deoxygenated blood is carried through the umbilical arteries back to the placenta for re-oxygenation.
Q: What is meconium aspiration and how is it treated?
Meconium aspiration occurs when a baby inhales amniotic fluid mixed with meconium (baby’s first stool) due to stress in the womb or after birth, leading to blocked airways and respiratory distress.
It occurs in 5-10% of births, often in post-term infants or when fetal distress happens during labor.
Treatment:
• Wipe away meconium from the nose or mouth.
• Use gentle suction with a bulb syringe for the oro/nasopharynx if needed.
• Turn the head to the side if meconium is copious to allow gravity to help.
• Always suction the mouth before the nose to reduce aspiration risk.
• Avoid vigorous suctioning, as it can cause apnea or bradycardia.
Q: What is apnea in newborns and how is it classified?
• Primary apnea: The absence of spontaneous breathing after birth, often self-limiting and reversible with minimal resuscitation efforts.
• Secondary apnea: Apnea lasting longer than 20 seconds, which can be caused by:
• Difficult labor
• Airway obstruction
• Hypoglycemia
• Respiratory muscle weakness
• Narcotics or CNS depressants (avoid Narcan if drug abuse is suspected due to the risk of withdrawal).
Q: What is hypovolemia in newborns and how is it recognized?
Hypovolemia occurs due to dehydration, hemorrhage, sepsis, or trauma, leading to poor blood volume and circulation.
Signs:
1. Failing the “look test” with symptoms of hypoperfusion:
Mottled, pale, cool skin
Lethargy
Poor muscle tone
2. Fontanelles:
Newborns have two soft spots on the head: one anterior and one posterior, both closing by 18 months.
Sunken fontanelles may indicate hypovolemia.
Bulging fontanelles may suggest increased intracranial pressure (ICP).
Q: What is hypoglycemia in newborns and how is it treated?
Risk factors:
• Apnea
• Preeclampsia/eclampsia
• Smaller babies or twins
• Signs and symptoms:
• Seizures
• Pale skin
• Poor muscle tone
• Lethargy
• Apnea
Treatment: glucagon 0.5mg IM. Max 2 doses every 20 mins
The difference between simple and complex heart defects in newborns
Simple heart defects: Structural heart issues that are typically less severe and may resolve on their own or with minimal treatment.
Complex heart defects: More serious heart abnormalities that usually involve multiple defects and require surgery or intensive medical care.
Q: What is an atrial septal defect?
A: A hole in the wall between the left and right atrium, causing blood to flow from the left atrium to the right atrium. It’s a simple congenital heart defect that may close on its own as the child grows.
Q: What is a ventricular septal defect?
A: A hole in the wall between the left and right ventricles, causing blood to mix between the ventricles. Large defects can make the heart and lungs work harder, possibly leading to fluid buildup in the lungs.
Q: What is patent ductus arteriosus?
A: A condition where the ductus arteriosus (connection between the aorta and pulmonary artery) doesn’t close after birth, allowing blood to flow abnormally. Small openings often close on their own.
