title: Intrapulmonary shunt is not increased by 100% oxygen ventilation in acute respiratory failure.
abstract: Increase of shunt has been demonstrated during short periods of pure oxygen breathing, mostly in patients with mild acute respiratory failure (ARF). Twenty patients with a large range of venous admixture (12 to 63%) were studied when FIO2 was increased from maintenance to one. Intrapulmonary shunt was measured with both the conventional oxygen method [QS/QT (O2)] and the multiple inert gas elimination technique [QS/QT (IG)]. Mean venous admixture decreased from 29 to 24% when FIO2 was increased and QS/QT (IG) remained unaltered. The pattern of blood flow distribution remained similar in both conditions, even in the eleven patients with ARF secondary to bacterial pneumonia and who had a low V/Q mode, highly liable to collapse with 100% oxygen. As no increase in shunt was documented in these patients, reluctance to measure shunt during 100% oxygen breathing should be re-evaluated.
authors.forename: F
authors.initials: F
authors.lastname: Lemaire
authors.forename: D
authors.initials: D
authors.lastname: Matamis
authors.forename: N
authors.initials: N
authors.lastname: Lampron
authors.forename: B
authors.initials: B
authors.lastname: Teisseire
authors.forename: A
authors.initials: A
authors.lastname: Harf
mesh_terms: D000208:Acute Disease; D000328:Adult; D000368:Aged; D001158:Arteries; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D005741:Noble Gases; D010100:Oxygen / Q000008:administration & dosage* / Q000097:blood; D011659:Pulmonary Gas Exchange; D012121:Respiration, Artificial; D012131:Respiratory Insufficiency / Q000503:physiopathology* / Q000628:therapy; D014680:Veins
chemical_list: D005741:Noble Gases; D010100:Oxygen