Experimental Pilot Study of a Novel Endobronchial Drug Delivery Catheter

An endobronchial infusion catheter introduced through a flexible bronchoscope channel has not been previously described. The aim of this study was to evaluate the technical feasibility of a new device.

Four porcine models underwent bronchoscopy with the infusion catheter. In the first experiment, methylene blue was injected into airway in volumes of 0.1, 0.3, or 1.0 mL into 2 animals. One animal was killed at 1 hour and the other at 24 hours after the procedure and gross dye diffusion was visually assessed. In the second experiment, a mixture of 80% sterile normal saline and 20% contrast media was injected into the airway in volumes of 0.3, 1.0, and 3.0 mL into 2 animals. One animal was killed at 7 days and the other at 20 days. Histologic evaluations were performed according to a bronchial damage scoring system.

There was no perioperative morbidity. In the first experiment, infusion volumes of 0.1, 0.3, and 1.0 mL resulted in dye surrounding 67%±29%, 55%±17%, and 80%±20% of the infusion-site circumference, and longitudinal distribution of 4.0±1.7, 8.1±4.1, and 18.0±3.0 mm each, respectively. In the second experiment, infusion of 0.3 to 3.0 mL resulted in mild injury, inflammation, and hemorrhage/fibrin/thrombus at 7 and 20 days after surgery.

Endobronchial infusion of dye and contrast media by the endobronchial drug delivery catheter showed that the media spread in a dose-dependent manner macroscopically and histologically. Further investigation will be required to assess the catheter as a new tool for localized drug delivery into the airway.