Clinical Trial: Specificity of Dyspnoea Relief With Inhaled Furosemide

Study Status: Completed
Recruit Status: Completed
Study Type: Interventional

Official Title: Specificity of Dyspnoea Relief With Inhaled Furosemide

Brief Summary: This study evaluates the effect of inhaled furosemide on different types of breathlessness relief in healthy volunteers. Each volunteer inhaled mists of either furosemide or a control substance on 3 occasions per day on 2 separate days. On one day they performed one breathlessness test which creates an 'urge to breathe' known as air hunger (AH) and the other day they performed a breathlessness test which increases the sense of work/effort (WE) of breathing. The study is double blinded so neither the volunteer or the research knows which mist is being inhaled.

Detailed Summary:

This is a double-blind, placebo-controlled trial. 16 healthy volunteers will attend 4 sessions. After 2 practice sessions subjects will undergo 2 test days where they will be made to feel 'air hunger' (hypercapnia with constrained ventilation) before and after mist inhalations on one day and sense of breathing 'effort' (raised ventilation with external resistive load) before and after mist inhalations on the second test day. The mist will either be furosemide or a placebo (saline) mist.

The urge to urinate from systemic absorption from the lungs will be accounted for by a concomitant administration of intravenous furosemide when saline is inhaled.

Furosemide is a prescription drug which makes kidneys produce more urine. When administered by inhalation as an aerosol it has direct action in the lungs which sensitises slowly adapting stretch receptors which is believed to account for the relief of dyspnoea previously reported with inhaled furosemide.

Vagal afferents from the pulmonary stretch receptors are known to be involved in relief of air hunger but it is not known if they will also relieve the sense of breathing effort. Relief of breathlessness will be measured and compared between the two trial days to see if furosemide specifically relieves the 'air hunger' type of breathlessness and not the 'effort' type of breathlessness.


Sponsor: Oxford Brookes University

Current Primary Outcome: Visual analogue scale for breathlessness type [ Time Frame: 20minutes ]

The visual analogue scale (VAS) is from 0 (no breathlessness) to 100 (maximal breathlessness willing to tolerate). The VAS is measure every 15-20 seconds during each experimentally induced breathing test. Each breathing test is performed before and after each mist inhalation. Total of 6 breathing tests. The final minute of a 4 minute steady state breathing test is analysed.


Original Primary Outcome: Same as current

Current Secondary Outcome:

Original Secondary Outcome:

Information By: Oxford Brookes University

Dates:
Date Received: August 24, 2016
Date Started: October 2015
Date Completion:
Last Updated: August 24, 2016
Last Verified: August 2016