TY - JOUR
T1 - Micromechanics of alveolar edema
AU - Perlman, Carrie E.
AU - Lederer, David J.
AU - Bhattacharya, Jahar
PY - 2010/1/1
Y1 - 2010/1/1
N2 - The decrease of lung compliance in pulmonary edema underlies ventilator-induced lung injury. However, the cause of the decrease in compliance is unknown.Wetested the hypothesis that in pulmonary edema, the mechanical effects of liquid-filled alveoli increase tissue stress in adjacent air-filled alveoli. By micropuncture of isolated, perfused rat lungs, we established a single-alveolus model of pulmonary edema that we imaged using confocal microscopy. In this model, we viewed a liquid-filled alveolus together with its airfilled neighbor at different transpulmonary pressures, both before and after liquid-filling. Instilling liquid in an alveolus caused alveolar shrinkage. As a result, the interalveolar septum was stretched, causing the neighboring air-filled alveolus to bulge. Thus, the airfilled alveolus was overexpanded by virtue of its adjacency to a liquid-filled alveolus. Confocal microscopy at different depths of the liquid-filled alveolus revealed a meniscus. Lung inflation to neartotal lung capacity (TLC) demonstrateddecreased compliance of the air-filled but not liquid-filled alveolus. However, at near TLC, the airfilled alveolus was larger than it was in the pre-edematous control tissue. In pulmonary edema, liquid-filled alveoli induce mechanical stress on air-filled alveoli, reducing the compliance of air-filled alveoli, and hence overall lung compliance. Because of increased mechanical stress, air-filled alveoli may be susceptible to overdistension injury during mechanical ventilation of the edematous lung.
AB - The decrease of lung compliance in pulmonary edema underlies ventilator-induced lung injury. However, the cause of the decrease in compliance is unknown.Wetested the hypothesis that in pulmonary edema, the mechanical effects of liquid-filled alveoli increase tissue stress in adjacent air-filled alveoli. By micropuncture of isolated, perfused rat lungs, we established a single-alveolus model of pulmonary edema that we imaged using confocal microscopy. In this model, we viewed a liquid-filled alveolus together with its airfilled neighbor at different transpulmonary pressures, both before and after liquid-filling. Instilling liquid in an alveolus caused alveolar shrinkage. As a result, the interalveolar septum was stretched, causing the neighboring air-filled alveolus to bulge. Thus, the airfilled alveolus was overexpanded by virtue of its adjacency to a liquid-filled alveolus. Confocal microscopy at different depths of the liquid-filled alveolus revealed a meniscus. Lung inflation to neartotal lung capacity (TLC) demonstrateddecreased compliance of the air-filled but not liquid-filled alveolus. However, at near TLC, the airfilled alveolus was larger than it was in the pre-edematous control tissue. In pulmonary edema, liquid-filled alveoli induce mechanical stress on air-filled alveoli, reducing the compliance of air-filled alveoli, and hence overall lung compliance. Because of increased mechanical stress, air-filled alveoli may be susceptible to overdistension injury during mechanical ventilation of the edematous lung.
KW - Alveolar edema
KW - Compliance
KW - Fluorescence
KW - Micromechanics
KW - Optical sectioning microscopy
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U2 - 10.1165/rcmb.2009-0005OC
DO - 10.1165/rcmb.2009-0005OC
M3 - Article
C2 - 20118224
AN - SCOPUS:78650630800
SN - 1044-1549
VL - 44
SP - 34
EP - 39
JO - American Journal of Respiratory Cell and Molecular Biology
JF - American Journal of Respiratory Cell and Molecular Biology
IS - 1
ER -