Pediatric ATI Practice Exam

Which congenital heart condition is associated with cyanosis due to altered blood flow?

1. Ventricular septal defect

2. Atrial septal defect

3. Transportation of great vessels

4. Aortic stenosis

The correct answer is: Transportation of great vessels

Cyanosis in congenital heart conditions often arises from a mixing of oxygenated and deoxygenated blood or from a shunting of blood that bypasses the lungs, resulting in insufficient oxygenation. In the case of transposition of the great vessels, there are two separate circulatory systems: one that is oxygen-poor and another that is oxygen-rich. The aorta and pulmonary artery are switched, which means that blood returning from the body does not go to the lungs to be oxygenated; instead, it is pumped back out to the body in a cycle that does not include the lungs. This leads to significant hypoxemia, or low oxygen levels in the blood, manifesting clinically as cyanosis, particularly noticeable in infants. This contrasts with other conditions such as a ventricular septal defect or an atrial septal defect, where blood shunts left to right typically do not produce cyanosis, as blood continues to become re-oxygenated in the lungs. Aortic stenosis can lead to compromised blood flow, but it does not typically present with cyanosis in the same manner as transposition of the great vessels. Therefore, the mechanism of blood flow alteration in transposition of the great vessels is directly related to the presence of cyan