Journal of Applied Physiology, Vol 68, Issue 5 1838-1843, Copyright © 1990 by American Physiological Society
Micropuncture pressure in small arteries or veins of perfused rabbit lungs
M. Onizuka, L. Wagner, G. Nicolaysen and N. C. Staub
Cardiovascular Research Institute, San Francisco, California.
Until now, direct micropuncture measurements of vascular pressure in lung
have been limited to small vessels less than 100 microns on the pleural
surface. On the other hand, direct pressure measurements using small
catheters (less than 1-mm OD) in pulmonary vessels have been limited to
those greater than 1.2 mm. We measured pressure in intermediate-sized
microvessels (300-700 microns) using the micropuncture method in isolated
perfused rabbit lungs. These microvessels are located 2 or 3 mm beneath the
pleura. We exposed them by microsurgery and punctured the relatively
thick-walled vessels with specially configured micropipettes. We exposed
one pulmonary microvessel in each rabbit lung by microsurgery on the left
middle lobe. In 15 rabbit lungs we measured pressure in a total of six
small arteries (275- to 470-microns diam) and nine small veins (300- to
700-microns diam) under high zone 3 conditions, near the zone 2/3 boundary.
We found approximately 35% of the total pulmonary vascular pressure drop in
arteries greater than 275-microns diam and 7% in veins greater than
300-microns diam. In veins greater than 500-microns diam, there was no
measurable pressure drop. After the measurements, we froze the lung and
confirmed that there was no detectable interstitial or alveolar edema in
the cross sections of the punctured site. Our data are compatible with
those of other investigators who have used isolated perfused rabbit lungs
under similar experimental conditions.
