What would happen if oxygen rich blood mixed with carbon dioxide rich blood?

If oxygen-rich blood mixes with carbon dioxide-rich blood, the overall oxygen content of the mixed blood would decrease, resulting in less efficient oxygen delivery to tissues. This can happen in conditions like congenital heart defects, where blood flows improperly between the heart's chambers. The body may experience symptoms of hypoxia, such as fatigue, confusion, and diminished physical performance, as tissues receive inadequate oxygen for their metabolic needs.