title: A new oxygen cannula system using intermittent-demand nasal flow.
abstract: A new cannula with a system of intermittent nasal flow was evaluated and compared with a standard constant-flow nasal cannula in 15 patients with chronic obstructive pulmonary disease. The intermittent-demand cannula released oxygen only when a negative pressure was detected in the nose (negative mode) or when a a positive pressure ceased to be detected in the nose (positive mode). At rates of flow varying from 0.63 to 5.60 L/min, the continuous-flow mode used 9 percent more oxygen than the negative mode and 31 percent more oxygen than the positive mode to achieve comparable improvement in arterial oxygen tension. The system using the intermittent-demand cannula was sensitive and reliable in over 150 hours of testing.
mesh_terms: D000328:Adult; D000368:Aged; D002245:Carbon Dioxide / Q000097:blood; D005260:Female; D006801:Humans; D008173:Lung Diseases, Obstructive / Q000097:blood / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000097:blood; D010102:Oxygen Inhalation Therapy / Q000191:economics / Q000295:instrumentation*
chemical_list: D002245:Carbon Dioxide; D010100:Oxygen