Question

In the movie 'Something the Lord Made', Dr. Alfred Blalock (played by Alan Rickman, aka Severus Snape of the Harry Potter movies) devised a surgical procedure to correct a serious heart defect in children with Blue baby syndrome. Dr. Blalock initiated the medical practice of heart surgeries in an era when no one believed it was possible to do surgery on the heart and have the pateint survive. The surgery was extremely experimental at the time, only the most severe diseases would even be contemplated for such a procedure. The problem was children were born with a severe genetic deformity of the heart that inevitiably led to death. These children have a very narrow pulmonary artery leaving the right ventricle. A defect with the pulmonary valve reduces blood flow at this point. In addition there is a hole in the ventricular septum and blood from the ventricles can pass back and forth between the left and the right ventricles. Knowing what you do about how the blood flows through the heart, explain what effect this deformity would have on the normal functioning of the heart. Think about the effects of mixing oxygenated and deoxygenated blood. Why do they call this blue baby syndrome? There are several causes of BBS, do not give explanations for the others, focus on the condition described here.

Answer 1

The reason this condition is called the blue baby syndrome is because of the bluish/purplish tinge of the skin or mucous membrane. This is because of the the low oxygen saturation of the blood. This phenomenon is called cyanosis.

The pulmonary valve defect means that less blood flows into the lungs for the oxygenation because of a narrowing of the valve of the pulmonary artery (pulmonary stenosis). In addition the intermixing of oxygenated and deoxygenated blood in the ventricles also reduces the amount of blood flowing to the lungs. because the non oxygenated blood flows preferentially into the aorta.

This lack of oxygenation is responsible for the cyanosis (oxygen is what gives blood its red color), and thus called blue baby syndrome.