TY - JOUR
T1 - Regional expansion of oleic acid-injured lungs
AU - Martynowicz, Marek A.
AU - Minor, Thomas A.
AU - Walters, Bruce J.
AU - Hubmayr, Rolf D.
PY - 1999
Y1 - 1999
N2 - It has been suggested that dependent regions of an injured lung are collapsed and subject to cyclic reopening and collapse during mechanical ventilation. To test this hypothesis, we measured both temporal and spatial heterogeneity of lobar expansion in oleic acid (OA)-injured dogs. Regional volumes were measured in nine dogs (seven supine and two prone) during closed loop sinusoidal oscillations of the lungs before and after OA injury using the parenchymal marker technique. In contrast to computer tomography, the parenchymal marker technique provides absolute measures of regional tissue dimensions as opposed to relative measures of regional air to liquid content. The experiments generated three major findings: (1) OA injury did not lead to the collapse of dependent lung units at FRC, (2) OA injury did not steepen the vertical gradient in regional lung volumes at FRC, and (3) during sinusoidal oscillation of the OA-injured lungs from FRC, dependent regions did not undergo cyclic reopening and collapse. On the basis of these results, we propose an alternative mechanism for the topographic variability in regional impedances and lung expansion after injury, namely liquid and foam in conducting airways.
AB - It has been suggested that dependent regions of an injured lung are collapsed and subject to cyclic reopening and collapse during mechanical ventilation. To test this hypothesis, we measured both temporal and spatial heterogeneity of lobar expansion in oleic acid (OA)-injured dogs. Regional volumes were measured in nine dogs (seven supine and two prone) during closed loop sinusoidal oscillations of the lungs before and after OA injury using the parenchymal marker technique. In contrast to computer tomography, the parenchymal marker technique provides absolute measures of regional tissue dimensions as opposed to relative measures of regional air to liquid content. The experiments generated three major findings: (1) OA injury did not lead to the collapse of dependent lung units at FRC, (2) OA injury did not steepen the vertical gradient in regional lung volumes at FRC, and (3) during sinusoidal oscillation of the OA-injured lungs from FRC, dependent regions did not undergo cyclic reopening and collapse. On the basis of these results, we propose an alternative mechanism for the topographic variability in regional impedances and lung expansion after injury, namely liquid and foam in conducting airways.
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U2 - 10.1164/ajrccm.160.1.9808101
DO - 10.1164/ajrccm.160.1.9808101
M3 - Article
C2 - 10390408
AN - SCOPUS:0032807266
SN - 1073-449X
VL - 160
SP - 250
EP - 258
JO - American journal of respiratory and critical care medicine
JF - American journal of respiratory and critical care medicine
IS - 1
ER -