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Increased extra‐alveolar vessel permeability decreases dynamic compliance in intubated rats
Author(s) -
Lowe Kevin Michael,
King Judy,
Stevens Troy
Publication year - 2007
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.21.5.a557-a
Subject(s) - hypoxemia , medicine , compliance (psychology) , pulmonary gas pressures , lung , anesthesia , sildenafil , ards , alveolar wall , pulmonary compliance , psychology , social psychology
Microscopy of lungs from patients with ARDS (acute respiratory distress syndrome) show fluid accumulations in both the interstitium surrounding extra‐alveolar vessels and in the alveolar compartment. However, the pathophysiologic effects of fluid collections outside the alveolar compartment are unknown. Our work shows that extra‐alveolar fluid accumulations decrease dynamic compliance without causing hypoxemia. In intubated and paralyzed rats, we increase the permeability of extra‐alveolar vessels by stimulating store operated calcium release with intravenous thapsigargin (70 to 700nM). Light micrographs of lungs from these rats reveal that thapsigargin induces extra‐alveolar vessel cuffing but does cause fluid to accumulate in the alveolar compartment. Assessment of respiratory mechanics and arterial blood gases demonstrates that thapsigargin decreases dynamic compliance in a dose dependent manner, but does not cause hypoxemia. Rolipram (10μM) treatment prior to thapsigargin (700nM) removes peri‐vascular cuffing and reverses the thapsigargin induced decrease in dynamic compliance. Intravenous sildenafil (2μM) alone did not change dynamic compliance, however, pre‐treatment with sildenafil did attenuate (50%) the thapsigargin induced decrease in dynamic compliance. Therefore, extra‐alveolar vascular cuffs reduce dynamic compliance without causing hypoxemia.