title: [Inert gas study of heliox gas exchange in patients with COPD].
abstract: Ventilation and perfusion distributions were measured in the patients with COPD breathing room air and normoxic helium-oxygen mixture (heliox) successively, using the multiple inert gas method. The D (A-a) O2 were calculated from ideal alveolar gas (Ai) and with West's gas mean model (A). Measured PaO2 and predicted PaO2 were compared during room air and heliox breathing. There were no change in overall distributions and in D (Ai-a) while D (A-a) O2 increase significantly during heliox breathing and the predicted PaO2 were significantly higher than the measured PaO2. Heliox breathing does not seem to change parallel heterogeneity in COPD. These results suggest an impairment of series heterogeneity and O2 diffusion during heliox breathing.
mesh_terms: D006371:Helium / Q000494:pharmacology*; D006439:Hemodynamics; D006801:Humans; D008173:Lung Diseases, Obstructive / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D005741:Noble Gases; D010100:Oxygen / Q000494:pharmacology*; D010313:Partial Pressure; D011659:Pulmonary Gas Exchange / Q000187:drug effects*; D012121:Respiration, Artificial; D014692:Ventilation-Perfusion Ratio
chemical_list: D005741:Noble Gases; D006371:Helium; C038949:heliox; D010100:Oxygen
vernacular_title: Etude par les gaz inertes des échanges gazeux en héliox chez les malades atteints de BPCO.