Ivacaftor for Acquired CFTR Dysfunction in Chronic Rhinosinusitis (EDSPD Protocol)

The equipment \& conditions for measuring bioelectric changes across the sinus mucosa are based on the standard NPD protocol, including use of agar-filled PE90 tubing for the probing electrode and limiting perfusion solutions to Ringer, Ringer + amiloride (100 µM), chloride-free gluconate with amiloride + isoproterenol (10 µM). The potential difference will be monitored in actively inflamed areas as judged by endoscopy in comparison to an agar-filled reference butterfly electrode placed in the volar aspect of the forearm. A stable potential with the mean value of a 10-s scoring interval after perfusion of each solution will be recorded by a blinded investigator.