P243 Assessing the Effect of pH on Citric Acid Cough Challenges in Chronic Cough Patients and Healthy Volunteers

Introduction

Citric acid has been used for over 6 decades in cough challenge studies, however despite this, the mechanism of its tussive effect is still not fully understood. We assessed the cough response to citric acid solutions, at different levels of acidity (pH) to determine what role this plays in the induction of cough. Healthy volunteers and chronic cough patients were compared.

Methods

20 chronic cough patients and 20...