The nurse assessing a premature newborn infant auscultates a continuous machinery-like murmur.
This finding is associated with which congenital heart defect?
A.
Pulmonary stenosis
B.
Patent ductus arteriosus
C.
Ventricular septal defect
D.
Coarctation of the aorta
The correct answer and Explanation is :
The continuous machinery-like murmur described in the assessment of a premature newborn infant is associated with Patent Ductus Arteriosus (PDA).
Explanation:
Patent Ductus Arteriosus (PDA) is a congenital heart defect where the ductus arteriosus, a blood vessel connecting the pulmonary artery and the aorta, fails to close after birth. Normally, this vessel closes shortly after birth to separate the fetal and postnatal circulatory systems. When it remains open, it allows blood to flow from the aorta into the pulmonary artery, creating a continuous abnormal blood flow.
The continuous murmur, often described as machinery-like, is characteristic of PDA and is best heard best in the left infraclavicular region. This sound is produced by the continuous flow of blood from the high-pressure aorta into the lower-pressure pulmonary artery through the patent ductus arteriosus.
Other congenital heart defects present with different types of murmurs:
- Pulmonary stenosis (A) is typically associated with a systolic ejection murmur due to the obstruction of blood flow from the right ventricle into the pulmonary artery.
- Ventricular septal defect (C) usually causes a holosystolic (or pansystolic) murmur, which is a continuous sound throughout systole, due to the flow of blood from the left ventricle to the right ventricle through the defect.
- Coarctation of the aorta (D) generally presents with differences in blood pressure and diminished pulses in the lower extremities compared to the upper body but does not typically cause a continuous murmur.
Premature infants are particularly susceptible to PDA due to their immature organ systems and incomplete closure of the ductus arteriosus, making the identification of this continuous murmur an important clinical finding for diagnosis and management.