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Mechanical interactions between air‐filled and liquid‐filled pulmonary alveoli
Author(s) -
Perlman Carrie E.,
Bhattacharya Jahar
Publication year - 2006
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.20.4.a747
Subject(s) - alveolar wall , calcein , chemistry , pulmonary alveolus , lung , alveolar epithelium , anatomy , distension , pathology , biology , medicine , respiratory disease , biochemistry , membrane
In the partially edematous lung, mechanical ventilation over‐distends air‐filled alveoli. However, relevant alveolar mechanics are not defined. To determine mechanics of juxtaposed air‐ and liquid‐filled alveoli, we blood‐perfused (10 ml/min) isolated rat lungs at baseline alveolar (Palv), left atrial and pulmonary artery pressures of 5, 3 and 10 cmH 2 O, respectively. By alveolar micropuncture, we loaded alveolar wall epithelium with calcein. In 2 μm‐thick optical sections viewed by confocal microscopy at a fixed subpleural depth (15 μm), calcein fluorescence defined alveolar margins. At baseline, alveolar diameter (D A ) was 98±9 μm (mean±SE; n=4). In pairs of juxtaposed alveoli, we microinjected buffer to liquid‐fill one alveolus. Consequently, D A increased by 5±1% (P<0.05) in the air‐filled alveolus, but decreased by 4±1% in the liquid‐filled alveolus. Increasing Palv to 15 cmH 2 O further increased D A by 6±2% (P<0.05) in the air‐filled alveolus, but restored D A to baseline in the liquid‐filled alveolus. Hence, when air‐ and liquid‐filled alveoli are juxtaposed, lung expansion imposes excessive distension on the air‐filled alveolus. Interactions between air‐ and liquid‐filled alveoli may determine proneness to alveolar injury during mechanical ventilation of edematous lungs (Support: HL 80878, HL64896).