Longitudinal distribution of pulmonary vascular compliance in dogs.
The longitudinal distribution of pulmonary vascular compliance was evaluated in isolated canine lung lobes using arterial-(AO), venous-(VO), and double-occlusion (DO) techniques. Total vascular compliance (Ctau) was separated into pulmonary arterial (Ca) and venous compliance (Cv) in lumped model of pulmonary circulation. Under constant pulmonary venous pressure (Pv) at 5 mmHg, blood inflow to the lobe (Q) was gradually increased by changing pulmonary arterial pressure (Pa) from 10 to 22 mmHg at 4 mmHg ranges. Changes in vascular blood volume (deltaV) with each increment in Q were determined by decreased reservoir blood volume of perfusion system. DO was performed at each level of Q and allowing all vascular pressures to equilibrate at the same static pressure (Ps), which was equal to the compliance-weighted average pressure in the circulation. Ctau was obtained from the slope of the relationship between Ps and deltaV. When Pa and Pv were 14 and 5 mmHg, AO, VO, and DO were performed to measure pressures at Ca (Pca) and Cv (Pcv) and Ps. The arterial-to-venous compliance ratio (Ca/Cv) was evaluated using Pca, Pcv, and Ps measurements. Ctau was 0.113 +/- 0.012 ml/kg/mmHg. Ca/Cv was 0.30. Ca and Cv were 0.026 +/- 0.013 and 0.087 +/- 0.007 ml/kg/mmHg, respectively. These data demonstrated the usefulness of AO, VO, and DO techniques in evaluating the longitudinal distribution of compliance in canine pulmonary vasculature.
Kobayashi
K
K
Research Laboratory in Veterinary Medical Teaching Hospital, School of Veterinary Medicine, Nippon Veterinary and Animal Science University, Tokyo, Japan.
Washizu
M
M
Kondo
M
M
Matsukura
Y
Y
Motoyoshi
S
S
Miyasaka
K
K
Takata
M
M
D000818:Animals; D001794:Blood Pressure; D004285:Dogs; D008168:Lung / Q000098:blood supply / Q000502:physiology*; D008955:Models, Cardiovascular; D011651:Pulmonary Artery / Q000502:physiology*; D011652:Pulmonary Circulation; D011667:Pulmonary Veins / Q000502:physiology*