Currently, there are no clinical tools for the precise measurement of airways during bronchoscopy. Placement of a non-stent based Intra-Bronchial Valve system (IBV) for the treatment of emphysema may be facilitated by measurements of targeted airways.
To assess the effectiveness of a balloon catheter system to determine segmental airway diameter for selecting valve sizes using an ex-vivo human lung model.
Three sets of fresh, intact ex-vivo human lungs were placed into an artificial thorax and cycled with pressures corresponding to tidal breathing. A prototype compliant balloon catheter, purged of air, was inflated with saline into templates of known diameters for calibration. In selected segments of the airways, the catheter was placed bronchoscopically and the balloon inflated to volumes corresponding to 1 mm increments to just occlude the lumen. Corresponding valves were implanted into the appropriate airways. The fit of these devices was evaluated bronchoscopically.
Thirty-six measurements (12 per each set of lungs) were used to select appropriate valve sizes for implantation. The first set of lungs had 100% correlation between the measurements taken and the IBV selected. The second and third set of lungs had a correlation of 92% and 83%, respectively. The cumulative correlation amongst all 3 sets was 92%. In the areas where the fit was not adequate, additional balloon measurements were not required because discrepancies were minimal and removal/replacement of the devices was simple. Upon completion, 100% of the devices fit the airways.CONCLUSIONS: In these experiments, a calibrated balloon catheter for bronchoscopic airway measurement was a useful tool for selecting the appropriate valve sizes for implant. The IBV system has been designed for easy valve removal and replacement if the fit is not appropriate.
A reliable method for sizing airways is desirable in determining the appropriate valve size for implantation.
M. Park, Spiration Inc., Industry, discussion of product research or unlabeled uses of product.