Pulmonary blood flow distribution has a hilar-to-peripheral gradient in awake, prone sheep

• Published in: Journal of applied physiology (1985) Vol. 82; no. 2; pp. 678 - 685
• Main Authors: Walther, Sten M, Domino, Karen B, Glenny, Robb W, Polissar, Nayak L, Hlastala, Michael P
• Format: Journal Article
• Language: English
• Published: Bethesda, MD Am Physiological Soc 01.02.1997; American Physiological Society
• Subjects: Air breathing; Animals; Biological and medical sciences; Fundamental and applied biological sciences. Psychology; Pulmonary Circulation - physiology; Respiratory system: anatomy, metabolism, gas exchange, ventilatory mechanics, respiratory hemodynamics; Sheep; Space life sciences; Tissue Distribution; Vertebrates: respiratory system; Wakefulness - physiology; Regional blood flow; Gradient; Lung; Respiratory system; Heterogeneity; Vertebrata; Mammalia; Distribution; Sheep; Artiodactyla; Hemodynamics; Ungulata; Gravity
• ISSN: 8750-7587; 1522-1601
• DOI: 10.1152/jappl.1997.82.2.678

Sten M. Walther 2 , Karen B. Domino 1 , Robb W. Glenny 3 , Nayak L. Polissar 3 , and Michael P. Hlastala 2 , 3 Departments of 1  Anesthesiology, 2  Physiology and Biophysics, and 3  Medicine, University of Washington School of Medicine, Seattle, Washington 98195 Received 21 December 1995; accepted in final form 18 October 1996. Walther, Sten M., Karen B. Domino, Robb W. Glenny, Nayak L. Polissar, and Michael P. Hlastala. Pulmonary blood flow distribution has a hilar-to-peripheral gradient in awake, prone sheep. J. Appl. Physiol. 82(2): 678-685, 1997. We examined the pulmonary blood flow distribution with intravenous fluorescent microspheres (15 µm) in nine prone, unanesthetized, lambs. Lungs flushed free of blood were air-dried at total lung capacity and sectioned into ~2-cm 3 pieces. The pieces were weighed, identified by lobe, and assigned spatial coordinates. Fluorescence was read on a spectrophotometer, and signals were corrected for piece weight and normalized to mean flow. Pulmonary blood flow heterogeneity was assessed by using the coefficient of variation of the flow data. The number of pieces (±SD) analyzed were 1,249 ± 150/animal. Heterogeneity of blood flow was 29.5 ± 6.5% (coefficient of variation = SD/mean). Pulmonary blood flow decreased with distance from hilus ( P  < 0.002) but did not change significantly with vertical height. Distance from the hilus was the best predictor of pulmonary blood flow ( R 2  = 0.201) and, together with spatial coordinates and lobe, accounted for 33.7 ± 12.0% of blood flow variability. We conclude that pulmonary blood flow in the awake, prone sheep is distributed with a hilar-to-peripheral gradient but no significant vertical gradient. lung; regional pulmonary blood flow; heterogeneity; gravitational gradient; methods; fluorescence; microspheres; 0161-7567/97 $5.00 Copyright © 1997 the American Physiological Society