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Pulmonary arterial distension does not cause pulmonary vasoconstriction
Journal of Applied Physiology (Bethesda, Md. : 1985)
|August 1, 1986
Summary
Pulmonary artery distension did not cause vasoconstriction in dogs. Researchers suspect previous findings of pulmonary vasoconstriction may have been due to undetected arterial obstruction.
Area of Science:
- Cardiovascular Physiology
- Pulmonary Circulation Research
Background:
- Pulmonary artery distension via balloon has been anecdotally linked to pulmonary vasoconstriction.
- The underlying mechanism for this proposed pressor response remains unclear.
Purpose of the Study:
- To investigate and confirm the pressor response attributed to pulmonary artery distension.
- To elucidate the potential mechanisms driving pulmonary vasoconstriction following arterial distension.
Main Methods:
- Anesthetized open-chest dogs underwent controlled blood flow and gas composition using a pump oxygenator.
- Retrograde balloon inflation was confined to the left main pulmonary artery, with left lobar arterial branches ligated.
- Systemic and pulmonary pressures were recorded; alveolar hypoxia served as a control for pulmonary vasoreactivity.
Main Results:
- Pulmonary artery distension did not induce significant changes in lung perfusion pressure.
- Hypoxic pressor responses were observed, confirming pulmonary vasoreactivity independent of arterial distension.
- Silicone casts revealed limitations in balloon placement to avoid unintentional arterial obstruction.
Conclusions:
- The study did not support the conclusion that pulmonary artery distension causes vasoconstriction.
- Increased perfusion pressures reported in prior studies may be attributable to undetected obstruction of major arterial branches.