NRP Neonatal Physiology and Birth Transition 2

Question 1

What is the normal fetal oxygen saturation (SpO2) via pulse oximetry in the minutes immediately after birth for a term infant?

Accepted Answer

SpO2 of 60–65% at 1 minute, rising gradually to 85–95% by 10 minutes

Answer

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.

Question 2

How does the transition from fetal to neonatal circulation affect systemic vascular resistance?

Accepted Answer

SVR increases at birth as the low-resistance placental circuit is removed

Answer

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.

Question 3

What role does surfactant play in neonatal lung transition at birth?

Accepted Answer

Surfactant reduces alveolar surface tension, preventing alveolar collapse and facilitating FRC

Answer

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.

Question 4

Which cardiovascular change at birth allows the ductus venosus to be bypassed as the umbilical circulation shuts down?

Accepted Answer

Umbilical cord clamping stops portal flow through the ductus venosus, causing passive closure

Answer

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.

Question 5

Which of the following is a key stimulus for the first breath after delivery?

Accepted Answer

Cold exposure, tactile stimulation, and chemoreceptor response to rising CO2 and falling O2

Answer

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.

NRP - Neonatal Resuscitation Program Practice Test

NRP - Neonatal Resuscitation Program Practice Test

NRP Neonatal Physiology and Birth Transition 2