title: [Effect of low lung volume ventilation on the relative proportions of carbon monoxide partial ductances (author's transl)].
abstract: Lacoste has shown the interest of determination of overall ductance of CO and partial expired alveolar ductance and arterio-alveolar partial ductances in the assessment of the efficacy of gaseous exchanges in the lung. DuCO was, by definition, the product : DuACO X DuaCO, the increase in partial ductance may theoretically compensate reduction in the other, the overall ductance then remains normal. This theory was verified studying the effects of low lung volume ventilation. Under these conditions, the dead space series becomes reduced and the DuACO should increase at the same rate, for ventilation occurs at the level of the closing volume. The inspired air is then directed preferentially towards the lung apices. These artificial changes in distribution of ventilation should produce a reduction in DuaCO. The measurements carried out confirmed these theories during low lung volume ventilation ; whereas the differences observed in overall ductance were not significant, those observed on partial ductance were very definitely significant. It appears that isolated measurement of overall ductance is insufficient and may lead to misdiagnosis of a change in the lung exchanges.
mesh_terms: D000328:Adult; D002248:Carbon Monoxide / Q000097:blood / Q000378:metabolism*; D006801:Humans; D011650:Pulmonary Alveoli / Q000378:metabolism; D011653:Pulmonary Diffusing Capacity
chemical_list: D002248:Carbon Monoxide
vernacular_title: Retentissement d'une ventilation à bas volume pulmonaire sur la proportion relative des ductances partielles à l'oxyde de carbone