Heterogeneity and matching of ventilation and perfusion within anatomical lung units in rats.
Prior studies exploring the spatial distributions of ventilation and perfusion have partitioned the lung into discrete regions not constrained by anatomical boundaries and may blur regional differences in perfusion and ventilation. To characterize the anatomical heterogeneity of regional ventilation and perfusion, we administered fluorescent microspheres to mark regional ventilation and perfusion in five Sprague-Dawley rats and then using highly automated computer algorithms, partitioned the lungs into regions defined by anatomical structures identified in the images. The anatomical regions ranged in size from the near-acinar to the lobar level. Ventilation and perfusion were well correlated at the smallest anatomical level. Perfusion and ventilation heterogeneity were relatively less in rats compared to data previously published in larger animals. The more uniform distributions may be due to a smaller gravitational gradient and/or the fewer number of generations in the distribution trees before reaching the level of gas exchange, making regional matching of ventilation and perfusion less extensive in small animals.
University of Washington, Seattle, USA. Electronic address: glenny@uw.edu.
Robb W
RW
Glenny
Christian
C
Bauer
Johannes
J
Hofmanninger
Wayne J
WJ
Lamm
Melissa A
MA
Krueger
Reinhard R
RR
Beichel
D000818:Animals; D005456:Fluorescent Dyes; D007091:Image Processing, Computer-Assisted; D008168:Lung / Q000033:anatomy & histology* / Q000098:blood supply* / Q000502:physiology; D008297:Male; D008863:Microspheres; D008953:Models, Anatomic; D011652:Pulmonary Circulation / Q000502:physiology*; D011659:Pulmonary Gas Exchange; D051381:Rats; D017207:Rats, Sprague-Dawley; D012039:Regional Blood Flow; D015656:Respiratory Mechanics / Q000502:physiology*; D014692:Ventilation-Perfusion Ratio
D005456:Fluorescent Dyes
Functional unit of gas exchange; Gas exchange; Imaging; Regional pulmonary blood flow; Regional ventilation; Ventilation–perfusion matching