title: Ventilation-perfusion inequality during endotoxin-induced pulmonary vasoconstriction in conscious sheep: mechanisms of hypoxia.
abstract: In sheep low-dose endotoxin infusion causes transient thromboxane-mediated pulmonary vaso- and bronchoconstriction. These changes are paralleled by a decrease of arterial PO2. To elucidate the mechanisms of hypoxia we analysed ventilation-perfusion (VA/Q) distributions by the multiple inert gas elimination technique before and after endotoxin infusion in six conscious sheep. We found that hypoxia after endotoxin could be explained by both a VA/Q inequality and a simultaneous decrease in the mixed venous oxygen tension. The latter was due to a decrease of cardiac output. True shunt did not contribute to hypoxia as it was unchanged.
mesh_terms: D000818:Animals; D001986:Bronchial Spasm / Q000209:etiology; D002302:Cardiac Output; D003243:Consciousness; D004731:Endotoxins / Q000633:toxicity; D004926:Escherichia coli; D006976:Hypertension, Pulmonary / Q000209:etiology* / Q000503:physiopathology; D000860:Hypoxia / Q000209:etiology*; D012756:Sheep; D014692:Ventilation-Perfusion Ratio
chemical_list: D004731:Endotoxins