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.
血中二氧化碳含量升高可能引起发绀,即患者的皮肤会变蓝,这就是为什么慢支患者又被比做蓝鲱鱼。

![Percentage of females smoking tobacco as of the late 1990s early 2000sPercentage of males smoking tobacco as of the late 1990s early 2000s. Note the scales used for females and males differ.[22]](/uploads/202501/01/Female_Smoking_by_Country3909.png)
