Evidence for stretch receptors in pulmonary blood vessels

Summary

1. After publication of a preliminary communication on the subject in 1964, sixty-three more patients have been studied with a view to confirming the previous observations.

2. The analysis of the present data confirms that there was a consistent rise in the pulmonary artery pressure as a result of stretching of anyone of the arterial branches by a balloon.

3. The rise in PA pressure is significantly higher during blocking at the proximal end than at the distal end of a pulmonary artery. It is postulated that there are more stretch receptors at the proximal than at the distal end of a pulmonary artery.

4. There is no significant zonal variation in response to blocking of the pulmonary artery. The slightly higher rise in the mid-zone, however, requires further confirmation as number of mid-zone studies were small.

5. The rise in pressure during blocking is directly related to the inital pulmonary artery pressure. The significance of this is unclear. It may however, be due to increase of musculature in the pulmonary arterioles of those with pulmonary hypertension.