What is carbon dioxide narcosis in relation to copd?

Carbon dioxide...: Normally, the lungs allow you to inhale oxygen and exhale carbon dioxide. With copd, the lungs are diseased and, as the disease progresses, the patient cannot do this as efficiently, resulting in an increased carbon dioxide level ( when it can't be exhaled!). This increased carbon dioxide level has a similar effect on the brain as narcotics do so it is dubbed "carbon dioxide narcosis".

Cause of death: Carbon dioxide buildup happens as COPD worsens. In an acut exacerbation (sudden worsening), co2 will rapidly accumulate. This can lead to confusion, sedation, and decreased respiratory drive. If not promptly treated it will lead to death.