Effect of lung inflation on fluid flux in zone 1 lungs.
Because of conflicting data in the literature, we studied the effect of positive-pressure inflation on transvascular fluid filtration in zone 1 lungs. Lungs from New Zealand White rabbits (n = 10) were excised, perfused with saline and autologous whole blood (1:1), ventilated, and continuously weighed. Pulmonary arterial and venous pressures (Pvas) were referenced to the most dependent part of the lung. A change in vascular volume (delta Vvas) and a fluid filtration rate (FFR) were calculated from the change in lung weight that occurred from 0 to 30 s and from 3 to 5 and 5 to 10 min, respectively, after changing alveolar pressure (PA). FFR's and delta Vvas's were measured with Pvas equal to 2 or 10 cmH2O and PA changing from 15 to 30 cmH2O when the lungs were normal and after they were made edematous. When Pvas = 2 cmH2O, increasing PA increased the Vvas and the FFR in both normal and edematous lungs. However, when Pvas = 10 cmH2O, increasing PA only slightly changed the Vvas and reduced the FFR in the normal lungs, and decreased Vvas and markedly decreased the FFR in the presence of edema. Inflating zone 1 lungs by positive pressure has an effect on transvascular fluid flux that depends on the Pvas. The results suggest that the sites of leakage in zone 1 also vary depending on Pvas and PA.
Albert
R K
RK
Medical Service, Veterans Administration Medical Center, Seattle, Washington.
Lamm
W J
WJ
Luchtel
D L
DL
D000818:Animals; D001158:Arteries / Q000502:physiology; D001794:Blood Pressure; D001810:Blood Volume; D066298:In Vitro Techniques; D008168:Lung / Q000098:blood supply / Q000378:metabolism / Q000502:physiology*; D009929:Organ Size; D011654:Pulmonary Edema / Q000378:metabolism / Q000503:physiopathology*; D011817:Rabbits; D014680:Veins / Q000502:physiology; D014882:Water-Electrolyte Balance