title: Timing and magnitude of the postural effect on the distribution of pulmonary blood flow.
abstract: The magnitude and timing of the effects of postural change on pulmonary blood flow distribution were studied in dogs by means of computed tomography (CT) and radioactive microspheres. A change in the mean attenuation values was demonstrated by CT in the anterior and posterior lung zones after change from the supine to the prone position. Similarly, a significant shift in blood flow distribution, as measured by microspheres, occurred rapidly, within 1 minute of the time of change from upright to supine position. These data confirm the importance of gravity in determining blood flow distribution in the lungs and demonstrate that maximum readjustments occur within 1 minute after postural change.
mesh_terms: D000818:Animals; D004285:Dogs; D006112:Gravitation; D008168:Lung / Q000000981:diagnostic imaging; D008863:Microspheres; D011187:Posture; D011652:Pulmonary Circulation; D011868:Radioisotopes / Q000008:administration & dosage; D011877:Radionuclide Imaging; D013997:Time Factors; D014057:Tomography, X-Ray Computed
chemical_list: D011868:Radioisotopes