title: Severe COPD: oxygen prolongs survival.
abstract: More than 15 hours of oxygen per day: prolongs survival.
mesh_terms: D006801:Humans; D010100:Oxygen / Q000627:therapeutic use*; D029424:Pulmonary Disease, Chronic Obstructive / Q000188:drug therapy* / Q000401:mortality
chemical_list: D010100:Oxygen