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Lung Volume Reduction
To investigate whether passive diaphragm stretch after lung volume reduction surgery (LVRS) results in fiber injury, Lewis and colleagues studied the short-term impact of LVRS on diaphragm muscle in hamsters with emphysema induced by intratracheal instillation of pancreatic porcine elastase and control animals. Analysis of diaphragm fiber injury, specific force, and insulin-like growth factor I (IGF-I) expression were assessed 4 days after LVRS. Sarcolemmal rupture was evident in 10.9% of fibers in the LVRS group at Day 1, and reduced to 1.6% in the LVRS group at Day 4. Ultrastructural analysis revealed focal abnormalities involving over one third of fibers in LVRS group animals. IGF-I immunoreactivity was increased in the LVRS group at Day 4, localizing to types IIA and I fibers. These structural changes were associated with marked force deficit in the LVRS group. Thus, short-term effects of LVRS on the diaphragm of emphysematous hamsters included focal sarcolemmal rupture and ultrastructural sarcomeric injury of diaphragm fibers, profound force deficit, and upregulation of IGF-I within diaphragm fibers. The diaphragm fibers most affected were those likely recruited during normal ventilatory behaviors, thus limiting the reserve capacity and function of the ventilatory pump after LVRS. These results suggest a markedly compromised ventilatory pump acutely after LVRS.
Bronchoscopic lung volume reduction achieves collapse of targeted lung regions using a washout solution to disrupt surfactant function and a tissue sealant to prevent reexpansion. Ingenito and coworkers
evaluated this procedure in six sheep with papain-induced emphysema. Features of emphysema included 8% increase in total lung capacity, 66% increase in residual volume, and 76% increase in airway resistance. Bronchoscopic lung volume reduction decreased total lung capacity by 16%, decreased residual volume by 55%, and increased vital capacity by 10%. At autopsy, well organized peripheral scars associated with tissue contraction were observed in 91% of the 36 treated sites. The procedure was tolerated without complications, and there was no evidence of infection, abscess, granuloma formation, or allergic reaction. The authors conclude that bronchoscopic lung volume reduction improved pulmonary function consistently and safely in sheep with experimental emphysema.
Citations 1-2 of 2 total displayed.
Short-term Influences of Lung Volume Reduction Surgery on the Diaphragm in Emphysematous Hamsters
- Michael I. Lewis, Mario Fournier, Xiaoyu Da, Hongmei Li, Zab Mosenifar, Robert J. McKenna, Jr, and Arthur H. Cohen
Am. J. Respir. Crit. Care Med. 170: 753 -759. First published online as doi:10.1164/rccm.200402-181OC
[Abstract]
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Bronchoscopic Lung Volume Reduction Using Tissue Engineering Principles
- Edward P. Ingenito, Robert L. Berger, A. Cortney Henderson, John J. Reilly, Larry Tsai, and Andrew Hoffman
Am. J. Respir. Crit. Care Med. 167: 771 -778. First published online as doi:10.1164/rccm.200208-842OC
[Abstract]
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