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Ventilation heterogeneity does not change following pulmonary microembolism.
J Y Tsang1, D Frazer, M P Hlastala
1University of British Columbia Pulmonary Research Laboratory, St. Paul's Hospital, Vancouver, British Columbia, Canada V6Z 1Y6. jtsang@interchange.ubc.ca
Journal of Applied Physiology (Bethesda, Md. : 1985)
|February 5, 2000
Summary
Pulmonary microembolism did not significantly increase ventilation heterogeneity (VH) in dogs. The acinar component, not the conductive component, dominates VH, suggesting distal airways are primarily affected.
Area of Science:
- Pulmonary physiology
- Respiratory system mechanics
- Microcirculation
Background:
- Ventilation heterogeneity (VH) quantifies uneven air distribution in the lungs.
- VH can be partitioned into conductive and acinar components.
- Embolic injury is a potential cause of altered lung ventilation.
Purpose of the Study:
- To investigate the impact of pulmonary microembolism on ventilation heterogeneity.
- To determine if embolic injury causes a redistribution of ventilation.
- To partition ventilation heterogeneity into conductive and acinar components after embolic injury.
Main Methods:
- Multiple-breath helium washout technique was used.
- Ventilation heterogeneity (VH) was measured as the normalized slope of the phase III alveolar plateau (Sn(III)).
- Mongrel dogs underwent repeated infusions of polystyrene beads (250 or 1,000 microm) or saline control.
Main Results:
- Repeated embolic injury did not significantly increase total VH.
- The acinar component accounted for over 90% of total VH.
- The conductive component of VH remained constant and was a minor contributor.
Conclusions:
- Pulmonary microembolism does not lead to significant redistribution of ventilation.
- Acinar ventilation heterogeneity is the predominant component.
- The study provides quantitative insights into lung ventilation dynamics post-embolic injury.
Keywords:
Non-programmatic