Original article: general thoracic
Bronchial fenestration improves expiratory flow in emphysematous human lungs

Presented at the Thirty–eighth Annual Meeting of The Society of Thoracic Surgeons, Fort Lauderdale, FL, Jan 28–30, 2002.
https://doi.org/10.1016/S0003-4975(02)04553-8Get rights and content

Abstract

Background

The crippling effects of emphysema are due in part to dynamic hyperinflation, resulting in altered respiratory mechanics, an increased work of breathing, and a pervasive sense of dyspnea. Because of the extensive collateral ventilation present in emphysematous lungs, we hypothesize that placement of stents between pulmonary parenchyma and large airways could effectively improve expiratory flow, thus reducing dynamic hyperinflation.

Methods

Twelve human emphysematous lungs, removed at the time of lung transplantation, were placed in an airtight ventilation chamber with the bronchus attached to a tube traversing the chamber wall, and attached to a pneumotachometer. The chamber was evacuated to −10 cm H2O pressure for lung inflation. A forced expiratory maneuver was simulated by rapidly pressurizing the chamber to 20 cm H2O, while the expiratory volume was continuously recorded. A flexible bronchoscope was then inserted into the airway and a radiofrequency catheter (Broncus Technologies) was used to create a passage through the wall of three separate segmental bronchi into the adjacent lung parenchyma. An expandable stent, 1.5 cm in length and 3 mm in diameter, was then inserted through each passage. Expiratory volumes were then remeasured as above. In six experiments, two additional stents were then inserted and forced expiratory volumes again determined.

Results

The forced expiratory volume in 1 second (FEV1) increased from 245 ± 107 mL at baseline to 447 ± 199 mL after placement of three bronchopulmonary stents (p < 0.001). With two additional stents, the FEV1 increased to 666 + 284 mL (p < 0.001).

Conclusions

Creation of extra-anatomic bronchopulmonary passages is a potential therapeutic option for emphysematous patients with marked hyperinflation and severe homogeneous pulmonary destruction.

Section snippets

Material and methods

Freshly explanted human lungs from recipients undergoing lung transplantation for emphysema were studied ex vivo. Patient consent was obtained. During explantation, the surgeon paid particular attention to avoid injury of the lungs and thus avoid air leakage from the surface during subsequent testing. The lungs were placed in ice-cold saline, taken immediately to the laboratory, and placed in an airtight ventilating chamber for measurement of forced expiratory flow and volume according to a set

Results

We attempted to study 18 lungs, but in six the air leakage from the surface was less than 400 cc/min and they were not used. The data from the remaining 12 lungs form the basis for this report. In these lungs, the rate of air leakage on inflation to −10 cm of water pressure was an average of 125 cc/min (range 0 to 400 cc). Five of the last six lungs used had no air leakage whatsoever. The repeat measurements of expiratory flow and volume were very reproducible for each lung, with a mean

Comment

In 1930 Van Allen and colleagues [6] obstructed sublobular bronchi in canine lungs and noted no collapse distal to the obstruction. They used the term “collateral inspiration” to explain how “gases may enter one lobule from another in the lung without resorting to known anatomical pathways” [6]. Hogg and associates [4] demonstrated that resistance to collateral airflow in postmortem emphysematous human lungs was low in comparison to normal lungs. They concluded that collateral channels may be

Acknowledgements

The authors acknowledge the expert technical assistance provided by Kathryn Fore, Laura Martini, and Dennis Gordon. This work was supported in part by National Institutes of Health grant R01 (HL62194).

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