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 ~ 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 < 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.
|Original language||English (US)|
|Number of pages||7|
|Journal||Journal of Applied Physiology|
|State||Published - Jan 1 1989|
ASJC Scopus subject areas
- Physiology (medical)