title: Effect of dehydration on interstitial pressures in the isolated dog lung.
abstract: We have determined the effect of dehydration on regional lung interstitial pressures. We stopped blood flow in the isolated blood-perfused lobe of dog lung at vascular pressure of approximately 4 cmH2O. Then we recorded interstitial pressures by micropuncture at alveolar junctions (Pjct), in perimicrovascular adventitia (Padv), and at the hilum (Phil). After base-line measurements, we ventilated the lobes with dry gas to decrease extravascular lung water content by 14 +/- 5%. In one group (n = 10), at constant inflation pressure of 7 cmH2O, Pjct was 0.2 +/- 0.8 and Padv was -1.5 +/- 0.6 cmH2O. After dehydration the pressures fell to -5.0 +/- 1.0 and -5.3 +/- 1.3 cmH2O, respectively (P less than 0.01), and the junction-to-advential gradient (Pjct-Padv) was abolished. In a second group (n = 6) a combination of dehydration and lung expansion with inflation pressure of 15 cmH2O further decreased Pjct and Padv to -7.3 +/- 0.7 and -7.1 +/- 0.7 cmH2O, respectively. Phil followed changes in Padv. Interstitial compliance was 0.6 at the junctions, 0.8 in adventitia, and 0.9 ml.cmH2O-1.100 g-1 wet lung at the hilum. We conclude, that perialveolar interstitial pressures may provide an important mechanism for prevention of lung dehydration.
authors: St. Luke's-Roosevelt Hospital Center, Columbia University, New York, New York 10019.
authors: M R
authors: MR
authors: Glucksberg
authors: J
authors: J
authors: Bhattacharya
mesh_terms: D000818:Animals; D001992:Bronchoalveolar Lavage Fluid; D003681:Dehydration; D004285:Dogs; D008168:Lung / Q000502:physiology*; D008176:Lung Volume Measurements; D011312:Pressure; D011650:Pulmonary Alveoli / Q000378:metabolism; D011669:Pulmonary Wedge Pressure; D013500:Surface Tension; D013997:Time Factors