A newborn is receiving care in the neonatal intensive care unit. The patient was born at 36 weeks gestation. Approximately 1 hour after delivery, a 2/6 systolic murmur could be heard at the left upper sternal border. At age 8 hours, the murmur could be heard during both systole and diastole. Examination at age 24 hours revealed no murmur. Which of the following is most likely responsible for the disappearance of this patient's murmur?

Question

A newborn is receiving care in the neonatal intensive care unit.  The patient was born at 36 weeks gestation.  Approximately 1 hour after delivery, a 2/6 systolic murmur could be heard at the left upper sternal border.  At age 8 hours, the murmur could be heard during both systole and diastole.  Examination at age 24 hours revealed no murmur.  Which of the following is most likely responsible for the disappearance of this patient's murmur?

Quizplus · Accepted Answer

Eductional Objective: After birth, pulmonary vascular resistance progressively decreases and systemic vascular resistance progressively increases, resulting in decreased pulmonary pressure and increased systemic pressure.  As the relative pressures in the pulmonary artery and aorta change, the patent ductus arteriosus (PDA) murmur evolves from systolic only to continuous before the PDA closes and the murmur disappears.

A Newborn Is Receiving Care in the Neonatal Intensive Care