The fetal lungs are collapsed, and blood passes from the right atrium directly into the left atrium through the foramen ovale: an open conduit between the paired atria, or through the ductus arteriosus: a shunt between the pulmonary artery and the aorta.
By Deborah Leader, RN. Updated January 21, 2016. Hypercapnia is a condition that occurs when there is too much carbon dioxide in the blood. While it is sometimes caused by things such as hypoventilation or a narcotic drug overdose, a much more common cause is COPD. If you have COPD, it's important to know the hypercapnia symptoms, as well as the treatments available.
1 Arterial blood gases or venous blood gases must be checked to determine the arterial blood pH and confirm the diminution of bicarbonate. 2  pH and pCO 2 values must be interpreted carefully and a judgement made as to whether this is a pure metabolic acidosis or a mixed acid-base disorder.