Pulmonary interstitial pressure in intact in situ lung: Transition to interstitial edema

G. Miserocchi, D. Negrini, M. Del Fabbro, D. Venturoli

Research output: Contribution to journalArticlepeer-review

Abstract

In anesthetized rabbits (n = 25) subject to slow intravenous saline loading (0.4 ml · min-1 · kg-1) for 3 h, we measured pulmonary interstitial pressure (Pip) in intact in situ lungs with glass micropipettes inserted directly into the lung parenchyma via a 'pleural window.' Measurements were done in apneic animals at the end-expiratory volume with O2 delivered in the trachea. Pip was -10 ± 1.5 (SD) cmH2O in control and increased to 0.6 ± 3.8 and 5.7 ± 3.3 cmH2O at 66 and 180 min, respectively. The wet-to-dry weight ratio (W/D) of the lung was 5.04 ± 0.2 in the control group and 5.34 ± 0.7 180 min (+6%); the corresponding W/D for intercostal muscles were 3.25 ± 0.03 and 4.19 ± 0.5 (+28%). Pulmonary interstitial compliance was 0.47 ml · mmHg-1 · 100 g wet wt-1. Pulmonary arterial and left atrial pressures were 18.4 ± 2 and 3 ± 1 cmH2O in control and increased to 19.5 ± 2.9 and 4.6 ± 1.7 cmH2O at 180 min, respectively. Aortic flow (cardiac output) increased from 103 ± 35 to 131 ± 26 ml/min; pulmonary resistance fell from 0.17 ± 0.06 to 0.14 ± 0.05 cmH2O · min · ml-1 (-18%), suggesting that the increase in Pip did not limit blood flow. The pulmonary capillary-to-interstitium filtration pressure gradient decreased sharply from a control value of 10 cmH2O to 0 cmH2O within 60 min because of the increase in Pip and remained unchanged for ≤180 min. Data suggest that the pulmonary interstitial matrix can withstand fluid pressures above atmospheric, preventing the development of pulmonary alveolar flooding.

Original languageEnglish
Pages (from-to)1171-1177
Number of pages7
JournalJournal of Applied Physiology
Volume74
Issue number3
Publication statusPublished - 1993

Keywords

  • alveolar stability
  • micropuncture
  • pulmonary compliance
  • pulmonary microvascular stability

ASJC Scopus subject areas

  • Physiology
  • Endocrinology
  • Orthopedics and Sports Medicine
  • Physical Therapy, Sports Therapy and Rehabilitation

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