Cyanosis occurs in children with tetralogy of Fallot because:
A) more carbon dioxide is present in the circulating blood.
B) a large amount of hemoglobin in the general circulation is unoxygenated.
C) the pulmonary circulation is overloaded and congested.
D) the circulation is sluggish (slow) throughout the system.

Question

Quizplus · Accepted Answer

Cyanosis in tetralogy of Fallot is due to a right-to-left shunt caused by a ventricular septal defect and pulmonary stenosis, leading to unoxygenated blood entering the systemic circulation.

Cyanosis Occurs in Children with Tetralogy of Fallot Because