Question 190

Question:

A cardiac catheterization is done in a healthy person. The blood sample withdrawn from the catheter shows 60% oxygen saturation, and the pressure recording shows oscillations from a maximum of 26 mm Hg to a minimum of 14 mm Hg. The catheter tip was located in which of the following areas?

Correct Answer: D.  Pulmonary artery

Blood pressures in the pulmonary artery (choice D) are in the range of 15-30mmHg systolic and 4-12mmHg diastolic, which are pressures that most closely match those found in this patient’s catheterization.
Left atrial (choice C) pressures range from 1-10mmHg, and right atrial (choice E) pressures range from 0-8mmHg. Prior to birth, the ductus arteriosus (choice A) diverts blood from the pulmonary artery to the aorta, and the foramen ovale (choice B) provides a communication between the two atria, equalizing their pressures, and shunting blood from the pulmonary circulation to the systemic circulation.