PURPOSE: We sought to (1) determine whether bronchoscopic ablation therapy results in systemic gas emboli and to (2) correlate their presence with the rate of gas flow used in conjunction with endobronchial/tracheal thermal ablation with Argon Plasma Coagulation (APC) or a fiber delivering CO2 laser power.
METHODS: CO2 laser delivered through a Photonic Bandgap Fiber (PBF) and APC were applied in the trachea and mainstem bronchi of 6 anesthesized sheep at varying dosages and gas flow rates. Direct epicardial echocardography was used to obtain a four-chamber view and detect gas emboli.
RESULTS: The presence of gas flow accompanying APC (0.5lit/min) and CO2 laser through a PBF with forward flow (2lit/min) correlated significantly with the appearance of gas bubbles in the atria. Bubbles were visualized in the right atrium when ablation was performed in the trachea, and in the left atrium when ablation was performed in the bronchi. A definite dose response was observed between the gas flow rate and the amount of bubbles seen. When CO2 laser was delivered through a PBF with zero flow (ZF) to the trachea or bronchi no bubbles were observed.
CONCLUSION: Bronchoscopic thermal ablation therapy in conjunction with gas flow is associated with gas emboli in this animal model. Ablation therapy with gas flow when performed in the trachea results in emboli to the right heart and when performed in the bronchi results emboli to the left heart. Ablational therapy delivered without gas flow is associated with significantly fewer embolic episodes. Bleeding and constant positive pressure ventilation during thermal ablation with gas flow were independent risk factors for emboli.
CLINICAL IMPLICATIONS: Treatment modalities utilizing gas flow in conjunction with thermal ablation in the airway, including the APC and gas cooled Nd:YAG, are established standards of care. An animal model for studying the risk of gas emboli has been established. A new tool enabling CO2 laser administration through a PBF with zero forward flow is associated with reduced risk of gas embolism.
DISCLOSURE: David Feller-Kopman, No Product/Research Disclosure Information; Other This study was funded by Omniguide, Inc.