title: Reverse ventilation--perfusion mismatch.
abstract: Patients having lobar airway obstruction or consolidation usually have decreases of both ventilation and perfusion on lung scans. We report three patients in whom hypoxic vasoconstriction was apparently incomplete, resulting in a "reversed" ventilation-perfusion mismatch. Perfusion of the hypoxic lobe on the radionuclide scan was associated with metabolic alkalosis, pulmonary venous and pulmonary arterial hypertension in these patients.
mesh_terms: D005260:Female; D006801:Humans; D008173:Lung Diseases, Obstructive / Q000000981:diagnostic imaging* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D011659:Pulmonary Gas Exchange; D011877:Radionuclide Imaging; D012709:Serum Albumin; D013667:Technetium; D013668:Technetium Tc 99m Aggregated Albumin; D014692:Ventilation-Perfusion Ratio; D014980:Xenon Radioisotopes
chemical_list: D012709:Serum Albumin; D013668:Technetium Tc 99m Aggregated Albumin; D014980:Xenon Radioisotopes; D013667:Technetium