Original article
General thoracic
Unilateral Extrapulmonary Airway Bypass in Advanced Emphysema

https://doi.org/10.1016/j.athoracsur.2009.10.067Get rights and content

Background

Gas trapping in emphysema results in resting and dynamic hyperinflation. We tested the hypothesis that a direct connection between the lung parenchyma and the atmosphere could increase expiratory flow and thereby potentially improve dyspnea through the relief of gas trapping.

Methods

Ex vivo we studied 7 emphysematous lungs and 3 fibrotic lungs (as controls) and measured expiratory flow before and after airway bypass insertion during a forced maneuver in an artificial thorax. Pilot studies were conducted in vivo in 6 patients with advanced emphysema using a size 9 endotracheal tube as a bypass surgically placed through the chest wall into the upper lobe.

Results

In the ex vivo emphysematous lungs the volume expelled during a forced expiratory maneuver increased from 169 to 235 mL (p < 0.05). In the in vivo group 4 patients retained the bypass tube for 3 months or more; total lung capacity was reduced, and the forced expiratory volume in 1 second increased by 23% (mean percent predicted at baseline versus 3 months, 24.4% versus 29.5%).

Conclusions

An extrapulmonary airway bypass increases expiratory flow in emphysema. This may be a useful approach in hyperinflated patients with homogeneous emphysema.

Section snippets

Material and Methods

Two separate studies were undertaken. First, we evaluated the airway bypass ex vivo in human lungs removed during transplantation. Second, we undertook a proof of concept study in 6 patients with advanced homogeneous emphysema. In both cases our ethics committee approved the studies, and patients gave signed informed consent.

Ex Vivo Preclinical Study

The demographic data of the patients participating in study 1 are shown in Table 1. In the patients with emphysematous lungs, the preoperative mean (± standard deviation) FEV1 and forced vital capacity was 22.0% predicted (± 4.8%) and 57.6% predicted (± 5.9%), respectively. In the patients with fibrotic lungs, the preoperative mean (± standard deviation) FEV1 and forced vital capacity was 43.3% predicted (± 5.4%) and 40.9% predicted (± 4.2%), respectively (Mann-Whitney U test, FEV1 emphysema

Comment

In both explanted emphysematous lungs and in patients with hyperinflation as a result of emphysema, an extrapulmonary airway bypass increases the volume expired during a forced maneuver and this approach therefore deserves further evaluation as a treatment in this condition.

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    The Appendix is available only online. To access it, please visit: http://ats.ctsnetjournals.org and search for the article by Moore, Vol. 89, pages 899–906.

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