Chronic lung diseases cuase chronic general asphyxia (Increased PCO2 and Decreased PO2) due to decreased alveolar ventilation. And it is characterized by:
- respiration is stimulated by both decreased PO2 and increased PCO2
- persistent hypercapnia leads to decreased response of breathing center to CO2 due to increased HCO3- transfer from blood to CSF
- hypoxia is the means for respiratory drive
Hence, if the hypoxic drive is lost due to excessive O2 therapy, respiration stops.