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.

会导致下肢发绀，即皮肤变蓝或青紫，是由缺氧和氧合混合造成。

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.

中二氧化碳含量升高可能引起发绀，即皮肤会变蓝，就是为什么慢支又被比做蓝鲱鱼。