The increased CO2 levels in the blood can get so bad that some people develop cyanosis, which is a blue discoloration of the skin, and this is why patients with chronic bronchitis are sometimes referred to as blue bloaters.
What we don't have is any deoxygenated blood escaping into the systemic circulation and causing a baby to appear cyanotic, so we call this acyanotic, which means " not blue" .
When deoxygenated blood mixes into the systemic circulation, it'll often present as cyanosis, a bluish-purple discoloration of the skin, which can be seen in a baby within the first days after birth.
This results in cyanosis in the lower extremities, a blue or purple discoloration of the skin; that's the result of deoxygenated blood mixing with oxygenated blood.