Methods: Eleven stable hypoxemic patients with COPD underwent standard rebreathing studies of ventilatory drive (methods of Read and Rebuck and Campbell) and 100% O 2 inhalation for fifteen minutes.

• 并随机让患者室内空气呼吸和吸氧（100%25O2）呼吸各15min，观测每分通气量（VE）、二氧化碳产生量（VCD2）、生理死腔/潮气量（VD/VT）及动脉血气变化。