Inhaled Nitric Oxide (iNO) in Idiopathic Pulmonary Fibrosis (IPF).
Status:
Not yet recruiting
Trial end date:
2023-08-30
Target enrollment:
Participant gender:
Summary
Idiopathic Pulmonary Fibrosis (IPF) is a progressive lung disease marked by reduced exercise
capacity and activity-related breathlessness (commonly termed dyspnea). Our previous work has
shown that dyspnea during exercise is associated with an increased drive to breathe
(inspiratory neural drive; IND). However, little work has been done to understand the
mechanisms of exertional dyspnea in patients with mild IPF. The objectives of this study are
to compare the acute effects of inhaled nitric oxide to placebo on ventilatory efficiency
(VE/VCO2), and IND at rest and during a standard cardiopulmonary exercise test (CPET). Twenty
patients with diagnosed IPF with mild (or absent) mechanical restriction and 20 healthy age-
and sex-matched controls will be recruited from a database of volunteers and from the
Interstitial Lung Disease and Respirology clinics at Hotel Dieu Hospital. Participants with
cardiovascular, or any other condition that contributes to dyspnea or abnormal
cardiopulmonary responses to exercise will be excluded. After giving written informed
consent, all participants will complete 7 visits, conducted 2 to 7 days apart. Visit 1
(screening): medical history, pulmonary function testing and a symptom limited incremental
CPET. Visit 2: Standard CT examination conducted at KGH Imaging. Visit 3: assessment of
resting chemoreceptor sensitivity, followed by a symptom limited incremental CPET to
determine peak work rate (Wmax). Visits 4 & 5 (run-in): familiarization to standardized
constant work rate (CWR) CPET to symptom limitation at 75% Wmax. Visits 6 & 7 (Randomized &
Blinded): CWR CPET to symptom limitation while breathing a gas mixture with either 1) 40 ppm
iNO or 2) placebo [medical grade normoxic gas, 21% oxygen]. The proposed work has the
potential to provide important physiological insights into the underlying mechanisms of
heightened dyspnea, as well as examine therapeutic avenues to improve quality of life in
patients with IPF.