title: Main selection criteria for long term oxygen treatment in COPD patients.
mesh_terms: D002245:Carbon Dioxide / Q000097:blood; D006801:Humans; D008134:Long-Term Care; D008173:Lung Diseases, Obstructive / Q000097:blood / Q000628:therapy*; D010102:Oxygen Inhalation Therapy / Q000379:methods*; D010313:Partial Pressure
chemical_list: D002245:Carbon Dioxide