Abstract
Introduction
The mechanics of inhaled antibiotics in obstructed airways are not well known. It is possible that local areas with concentration below the minimal inhibitory concentration (10xMIC90, 128µg/ml for P. Aeruginosa) exist, causing undertreated parts of the lung. To optimize inhaled therapy, knowledge about antibiotic concentrations throughout the lung should be known. Local deposition characteristics of inhaled Aztreonam lysine (AZLI) were simulated using Functional Respiratory Imaging.
Methods
Airways and lungs were segmented from a retrospective dataset of 40 in- and expiratory CT-scans of children with cystic fibrosis (CF) between 5 and 17 years. FRI simulations were performed that simulated the nebulisation of 75mg AZLI through PARI eFlow® with minimal/median/maximal reported aerodynamic diameters (MMAD) and different thicknesses of airway surface liquid (ASL). Figure 1 shows local concentrations in the central airways and lung.
Results
In Figure 2, it is shown how many lobes are being undertreated.
Conclusion
Parts of the CF-lung receive concentrations < 10xMIC90 with inhaled antibiotics, such as AZLI.
- © 2013 ERS
