In an animal study, 21 valves were inserted into the upper lobes of five healthy swine. After 4 to 6 days, bronchoscopy and fluoroscopy confirmed proper positioning of the valves. One valve in each of the four swine was easily removed and replaced bronchoscopically. No complications were observed. At thoracotomy 4 to 6 days after valve insertion, visual confirmation of volume reduction was observed. so
The umbrella-shaped valve with the convex side distally is designed to allow mucus and air to escape from the targeted bronchus while preventing air from entering the bronchus. The intent is to limit ventilation to emphysematous regions of lung, allowing better ventilation of healthier regions, while allowing mucus to escape from the treated region to avoid postobstructive pneumonia. Human trials are pending.
Bronchoscopic occlusion of bronchi to treat bronchopleural fistulae has been reported. Twenty-three patients with emphysema and bronchopleural fistula were treated with endoscopic Watanabe spigots (EWSs; Fig 6) [Novatech; Plan deGrasse, France] during 2000 and 2001. Ninety-one spigots were inserted in 23 patients. Upper-lobe collapse was seen in two patients who had their whole upper lobe occluded. Complications reported were pneumonia (n = 2) and dyspnea (n = 1). A patient with emphysema and giant bullae was treated with the EWS. The bullae became larger following insertion of the EWS, presumably due to collateral ventilation with impaired exhalation from the occluded bronchus. One-way valve devices described previously avoid this complication.
Based on the favorable results from LVRS, In-genito et al theorized that collapse of emphysematous regions of lung via fiberoptic methods consisting of surfactant washout and fibrin-based glue instillation could achieve results similar to LVRS. This hypothesis was tested on 12 sheep with emphysema induced by four weekly papain inhalations.
Figure 6. EWS consisting of 5 mm, 6 mm, and 7 mm in diameter silicon plugs.