Experimental lung collapse following deployment of a self-expandable bronchial occluder in a rabbit model

Objectives: Closure of a bronchopleural fistula is required to prevent fatal empyema or aspiration pneumonia. The purpose of this study was to determine the feasibility and efficacy of bronchial occlusion with a self-expandable occluder to induce experimental lung collapse in a rabbit model. Methods: 10 bronchial occluders (wine glass appearance; 8mm in diameter and 15mm in length) were implanted in the native left main bronchi of 10 rabbits via an endotracheal route. We analysed the following: (1) diameters and morphological changes of the bronchial occluders during follow-up; (2) percentage volume of the collapsed lung during follow-up; and (3) complications and gross pathology. 1-day and 2-week follow-up CT scans were routinely obtained. Rabbits were sacrificed 4 weeks after the experiment. Results: In all 10 rabbits, the bronchial occluders were successfully implanted and were completely expanded within 2 weeks. Complete collapse of the left lung occurred in three rabbits on day 1 and in an additional two rabbits 2 weeks following implantation. Two other rabbits maintained the percentage volume of the collapsed lung between 51% and 99% during follow-up; the other three rabbits had <50% during follow-up. Pneumothoraces occurred in nine rabbits, but completely resolved at the 2-week follow-up. Right lung herniation across the midline progressed 2 weeks after occluder implantation. Conclusion: Placement of self-expandable occluders in a rabbit bronchus model was feasible and showed a potential to induce artificial lung collapse. While pneumothoraces were common, they resolved during follow-up.