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 The blood sample withdrawn from the catheter shows 60% oxygen saturation, and the pressure recording shows oscillations from a maximum of 26 mm Hg to a minimum of 14 mm Hg.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?
1.Ductus arteriosus
2.Foramen ovale
3.Left atrium
3.Pulmonary artery
4.Right atrium
Correct answer
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.