PT - JOURNAL ARTICLE AU - I. Rivolta AU - V. Lucchini AU - M. Rocchetti AU - F. Kolar AU - F. Palazzo AU - A. Zaza AU - G. Miserocchi TI - Interstitial pressure and lung oedema in chronic hypoxia AID - 10.1183/09031936.00066710 DP - 2010 Jan 01 TA - European Respiratory Journal PG - erj00667-2010 4099 - http://erj.ersjournals.com/content/early/2010/08/06/09031936.00066710.short 4100 - http://erj.ersjournals.com/content/early/2010/08/06/09031936.00066710.full AB - We evaluated how the increase in lung interstitial pressure correlates with the pulmonary vascular response to chronic hypoxia.In control and hypoxic (30days, 10%O2) Wistar male rats, we measured: pulmonary interstitial pressure, cardiac and hemodynamic parameters by echocardiography, and performed lung morphometry on tissue specimens fixed in situ.In control animals, pulmonary interstitial pressure, air/tissue volume ratio and capillary vascularity index in the air-blood barrier were respectively: −12±2.03cmH2O, 3.9 and 0.43. After hypoxia exposure, the corresponding values of these indexes in apparently normal lung regions, were: 2.6±1.7cmH2O, 3.6, and 0.5. In oedematous regions the corresponding values were: 12±4cmH2O, 0.4 and 0.3. Furthermore, in normal regions the density of precapillary vessels (diameter range ∼50–200 μm) increased and their thickness/internal diameter ratio decreased, while opposite results were found in oedematous regions. Pulmonary artery pressure increased in chronic hypoxia relative to control (39.8±5.9 vs 26.2±2.2 mmHg).Heterogeneity in local lung vascular response contributes to developing pulmonary hypertension in chronic hypoxia. In oedematous regions the decrease in capillary vascularity correlated to the remarkable increase in interstitial pressure and morphometry of the precapillary vessels suggested an increase in vascular resistance; the opposite was true in apparently normal regions.