Abstract
The main bronchi of excised dog lobes were obstructed with beads, 5 to 6cm from their origin so that they did not communicate with the peripheral air spaces.Both pulmonary artery and vein were cannulated and both pulmonary vascular pressures were controlled. With the lobe held at constant transpulmonary pressure, bronchial pressurevolume curves were studied during acute pulmonary vascular engorgement. The bronchial compliance was reduced at higher vascular pressure and the effect of vascular engorgement on the bronchial collapsibility was larger at higher transpulmonary pressure: bronchial compliance at vascular pressure 10cm H2O were 70, 84, 98, and 100% of the bronchial compliance at vascular pressure-40cm H2O at transpulmonary pressure 20, 10, 5, and 0cm H2O, respectively. We concluded that vascular engorgement increased parenchymal radial traction to the bronchi when the bronchi reduced its diameter, although it appeared that vascular engorgement resulted in little change in the lung elastic recoil pressure.
