Which of the following is the main factor for the ductal closure postnatally
Increase in paial pressure of oxygen (PaO2)
Increase in systemic vascular resistance
Increase in circulating prostaglandin levels
Decrease in pulmonary venous resistance
Oxygen is the most impoant controlling ductal closure. Note: Gestational age also appears to play an impoant role; the ductus of a premature infant is less responsive to oxygen, even though its muscular is developed. Hence, patent ductus aeriosus (PDA) is more common in premature infants. Ref: Nelson textbook of pediatrics 21st edition Pgno: 2345
C.V.S