Protocol for a double-blind crossover randomised controlled trial to investigate inhalation CHallenge to assess Inducible Laryngeal Obstruction (CH-ILO)

This paper describes the design of a randomized, double-blind, single center, crossover study that will evaluate the use of citric acid as an inhalation agent for inducing laryngeal obstruction in 10 patients with confirmed inducible laryngeal obstruction. For comparative purposes, the study will also enroll 10 patients with refractory chronic cough and 10 healthy control subjects. A Vitalograph VitaloJAK cough monitor will be worn by study participants during each inhalation challenge test, to verify the number of coughs evoked in the 15-second period following inhalation.