A 2-week-old newborn is brought to the physician for a follow-up examination. He was born at term and the pregnancy was uncomplicated. His mother says he has been feeding well and passing adequate amounts of urine. He appears healthy. He is at the 60th percentile for length and 40th percentile for weight. His temperature is 37.3°C (99.1°F), pulse is 130/min, respirations are 49/min and blood pressure is 62/40 mm Hg. A grade 5/6 holosystolic murmur is heard over the left lower sternal border and a thrill is present at the same location. Echocardiography shows a 3-mm membranous ventricular septal defect. Compared to an unaffected child, which of the following changes in oxygen saturation would be expected in this patient?

Question

A 2-week-old newborn is brought to the physician for a follow-up examination. He was born at term and the pregnancy was uncomplicated. His mother says he has been feeding well and passing adequate amounts of urine. He appears healthy. He is at the 60th percentile for length and 40th percentile for weight. His temperature is 37.3°C (99.1°F), pulse is 130/min, respirations are 49/min and blood pressure is 62/40 mm Hg. A grade 5/6 holosystolic murmur is heard over the left lower sternal border and a thrill is present at the same location. Echocardiography shows a 3-mm membranous ventricular septal defect.   Compared to an unaffected child, which of the following changes in oxygen saturation would be expected in this patient?

Quizplus · Accepted Answer

Eductional Objective: A ventricular septal defect, classically characterized by a harsh, holosystolic murmur at the left lower sternal border, causes left-to-right shunting of oxygenated blood from the left ventricle to the right ventricle.  Therefore, right ventricular oxygen saturation is increased compared to normal.

A 2-Week-Old Newborn Is Brought to the Physician for a Follow-Up