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Avalanches and power-law behaviour in lung inflation
B Suki1, A L Barabási, Z Hantos
1Department of Biomedical Engineering, Boston University, Massachusetts 02215.
Nature
|April 14, 1994
Summary
Peripheral airways can close during exhalation and may not reopen properly in lung disease, hindering gas exchange. This study reveals that airway reopening follows power-law distributions, suggesting a self-organized critical system governs lung inflation.
Area of Science:
- Pulmonary physiology
- Complex systems science
- Biophysics
Background:
- Peripheral airway closure during exhalation is a significant issue in lung diseases, impairing gas exchange.
- Understanding the mechanisms of airway reopening is crucial for developing effective ventilation strategies.
Purpose of the Study:
- To investigate the physical mechanisms governing the reinflation of collapsed peripheral airways.
- To characterize the dynamics of terminal airway opening during lung inflation.
Main Methods:
- Measurements of terminal airway resistance (Rt) were performed during the inflation of isolated dog lungs.
- Analysis of the probability distributions of jump sizes and time intervals during inflation.
Main Results:
- Terminal airway resistance (Rt) decreased in discrete jumps when lungs were inflated at a constant flow.
- The probability distributions of jump sizes and time intervals exhibited power-law behavior over two decades.
- A model of airway inflation incorporating 'avalanches' of openings quantitatively matched experimental results.
Conclusions:
- Airway reopening dynamics, characterized by power-law distributions, suggest a self-organized critical phenomenon.
- Avalanches of airway openings, driven by threshold dynamics in a branching structure, govern the recruitment of terminal airspaces.
- These findings offer insights into lung mechanics and potential therapeutic targets for respiratory conditions.