Related Experiment Videos
Perfusion heterogeneity in the pulmonary acinus
N Tanabe1, T M Todoran, G M Zenk
1Department of Anesthesiology, Indiana University School of Medicine, Indianapolis, Indiana 46202-5120, USA.
Journal of Applied Physiology (Bethesda, Md. : 1985)
|April 16, 1998
Summary
Acinar perfusion, the blood flow within lung acini, was studied using fluorescent dye. Contrary to expectations, researchers found that blood flow distribution within these small lung regions is surprisingly uniform.
Area of Science:
- Physiology
- Microcirculation Research
- Pulmonary Blood Flow Dynamics
Background:
- Acinar perfusion distribution is poorly understood due to challenges in resolving blood flow in small lung regions.
- Existing knowledge suggests heterogeneity in arteriolar and capillary blood flow may lead to heterogeneous acinar perfusion.
Purpose of the Study:
- To investigate the distribution of blood flow within the pulmonary acinus.
- To test the hypothesis that heterogeneous arteriolar and capillary flow results in heterogeneous acinar perfusion.
Main Methods:
- Utilized fluorescence microscopy to observe fluorescent dye bolus passage through the subpleural microcirculation of isolated dog lung lobes.
- Recorded and analyzed dye-dilution curves from venular tributary branches draining individual acini.
- Calculated mean appearance times from dye curves to assess perfusion uniformity.
Main Results:
- In most cases, the difference in mean appearance times between venular tributary branches was minimal.
- Dye curves were nearly identical in 43% of observed venular branch pairs (mean appearance-time difference <5%).
- An additional 42% of pairs showed only a 5-10% difference in mean appearance times.
Conclusions:
- Pulmonary acinar perfusion is unexpectedly homogeneous.
- The study challenges the assumption of significant perfusion heterogeneity at the acinar level.
- Findings suggest a more uniform blood supply to the terminal lung units than previously hypothesized.