title: Effects of oxygen breathing on regional distribution of ventilation and perfusion in hypoxemic patients with chronic lung disease.
abstract: Regional distribution of ventilation and perfusion were measured in 17 hypoxemic and 16 normoxic patients using 13N as tracer. The effect of 100% and 50% O2 breathing was tested. No variation was observed in normoxic patients. In hypoxemic patients, perfusion was not modified significantly during O2 breathing. Poorly-ventilated zones hypoventilated even more during O2 breathing. It is suggested that this effect may have been due to (1) a collapse of some alveoli, (2) a variation in the mechanical properties of the surrounding opened alveoli, or (3) a possible modification in tidal volumes and functional residual capacities during O2 breathing.
mesh_terms: D001784:Blood Gas Analysis; D006801:Humans; D000860:Hypoxia / Q000209:etiology / Q000628:therapy*; D008171:Lung Diseases / Q000150:complications*; D010102:Oxygen Inhalation Therapy; D011652:Pulmonary Circulation; D014692:Ventilation-Perfusion Ratio