PURPOSE: Bronchoscopic implantation of Beacon® transponders (Calypso® Medical, Seattle, WA) into peripheral airways of canine lung is feasible. We compared pneumothorax rates following bronchoscopic implantation into canine lung for catheters preloaded with Beacon transponders and catheters with preloaded spherical gold markers. We also measured the force required for both preloaded catheter types to puncture a thin plastic membrane.
METHODS: Following Animal Care and Use Committee approval, five mongrel dogs (weight = 20.3 ± 1.4 kg) were anesthetized, intubated, and ventilated (pressure support 0 to 20 cm H2O). Three cylindrical Beacon transponders (1.8 mm × 8.5 mm) were inserted into the tip of a plastic catheter passed through the 2.6 mm working channel of a flexible bronchoscope (Olympus® America Inc., Melville, NY), and implanted using an inner wire releasing plunger into sub-segmental bronchi of a single lobe. This procedure was repeated for three spherical gold markers (diameter 2.0 mm) in the opposite lung using a new catheter. Fluoroscopy was used to document puncture of the visceral pleura.These catheters were again loaded, five with Beacon transponders and five with gold spheres, and tested with a force measuring instrument (Lloyd Instruments, Fareham, Hants, UK) to determine the force required to puncture a 0.025 mm thick polyethylene membrane.
RESULTS: Puncture of the visceral pleura occurred following bronchoscopic implantation of 0/15 Beacon transponders in 0/5 dogs and 3/15 gold spheres in 2/5 dogs (p = NS), one dog developed a pneumothorax. The force required to puncture a membrane was 3.21 ± 0.38 N for Beacon transponder and 2.09 ± 0.28 N for gold sphere catheters (p < 0.0001).
CONCLUSION: Bronchoscopic implantation using preloaded spherical gold marker catheters may lead to a higher rate of pneumothorax when compared to implantation using blunted, cylindrical shape preloaded Beacon transponder catheters. The force required to puncture a thin polyethylene film was 1/3 less using a gold sphere catheters compared to Beacon transponder catheters.
CLINICAL IMPLICATIONS: Shape of a fiducial marker catheter tip may impact the risk of pneumothorax following implantation.
DISCLOSURE: Martin Mayse, Consultant fee, speaker bureau, advisory committee, etc. Consultant, Calypso Medical Technologies, Inc.; Product/procedure/technique that is considered research and is NOT yet approved for any purpose, Implantation of electromagnetic transponders in the lung.