Neonatal Physiology and Birth Transition Flashcards
6 cards from real NRP practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 Neonatal Physiology and Birth Transition flashcards as text
What is the normal fetal oxygen saturation (SpO2) via pulse oximetry in the minutes immediately after birth for a term infant?
Answer: SpO2 of 60–65% at 1 minute, rising gradually to 85–95% by 10 minutes
NRP provides target SpO2 ranges for the first 10 minutes of life. At 1 minute, 60–65% is normal; it rises gradually as pulmonary circulation is established, reaching 85–95% by 10 minutes.
How does the transition from fetal to neonatal circulation affect systemic vascular resistance?
Answer: SVR increases at birth as the low-resistance placental circuit is removed
Clamping of the umbilical cord removes the low-resistance placental vascular bed, causing systemic vascular resistance to rise. This, combined with falling PVR, reverses the direction of shunting across fetal channels.
What role does surfactant play in neonatal lung transition at birth?
Answer: Surfactant reduces alveolar surface tension, preventing alveolar collapse and facilitating FRC
Surfactant, produced by type II pneumocytes, reduces alveolar surface tension, preventing alveolar collapse (atelectasis) at end-expiration and reducing the work of breathing needed to establish and maintain FRC.
Which cardiovascular change at birth allows the ductus venosus to be bypassed as the umbilical circulation shuts down?
Answer: Umbilical cord clamping stops portal flow through the ductus venosus, causing passive closure
When the umbilical cord is clamped, blood flow from the umbilical vein stops, removing the driving force through the ductus venosus, which then passively closes. This redirects portal blood flow through the hepatic sinusoids.
Which of the following is a key stimulus for the first breath after delivery?
Answer: Cold exposure, tactile stimulation, and chemoreceptor response to rising CO2 and falling O2
The first breath is triggered by multiple stimuli: the sudden change in temperature (cold exposure), tactile stimulation during delivery, and chemoreceptor activation from rising PCO2 and falling PO2 as placental circulation ends.
What is the consequence of a failure to clear lung fluid adequately at birth?
Answer: Transient tachypnea of the newborn (TTN) or respiratory distress requiring positive pressure support
Retained lung fluid interferes with gas exchange and causes respiratory distress, most commonly presenting as transient tachypnea of the newborn (TTN) in term infants, or requiring PPV in those who cannot clear fluid independently.