ABSTRACT
Using a subtraction technique, repeated shunt determinations were successfully performed on 25 patients with a high degree of correlation.
Subject(s)
Radioisotopes/administration & dosage , Humans , Injections, Intravenous , Lung Diseases, Obstructive/diagnostic imaging , Radionuclide Imaging , Subtraction TechniqueABSTRACT
Because the postulated mechanism of high altitude pulmonary edema is inhomogeneous vaconstriction and hyperperfusion of unconstricted vessels, pulmonary blood flow through vessels larger than 10 micron was determined at baseline and during acute hypoxia sufficient to reduce arterial oxygen saturation to 65%. Women demonstrated a uniform response of decreasing such flow, whereas responses in men were highly variable. Hyperperfusion of enlarged vessels during hypoxia is not an acute phenomenon in the majority of subjects and is therefore either unique to some individuals or a sub-acute occurrence.
Subject(s)
Hypoxia/physiopathology , Pulmonary Alveoli/blood supply , Pulmonary Circulation , Acute Disease , Adult , Female , Humans , Male , Technetium Tc 99m Aggregated Albumin , Vascular ResistanceABSTRACT
Eleven patients with cryptogenic fibrosing alveolitis were evaluated for the presence of pulmonary shunting by injection of radiolabelled particles of macroaggregated albumin larger than 10 micron in diameter and by body scanning with a gamma camera. The mean shunt of 9% (SD 2%) in the patients was not significantly different from the mean shunt of 7% (2%) measured in 10 normal controls. These findings suggest that shunting is not an important part of the gas exchange abnormalities noted in such patients.
