Inhalation challenge to assess Inducible Laryngeal Obstruction

  • Research type

    Research Study

  • Full title

    Inhalation challenge to assess Inducible Laryngeal Obstruction



  • Contact name

    Faye O'Keeffe

  • Contact email


  • Sponsor organisation

    Research and Development Directorate

  • ISRCTN Number


  • Duration of Study in the UK

    2 years, 0 months, 1 days

  • Research summary

    Inducible laryngeal obstruction(ILO) is when the voice box(larynx) closes and obstructs breathing. The closure is usually sudden and often happens in response to a trigger. This causes breathing difficulties, which are reversible, but can be severe meaning patients can present to Emergency Departments and intensive care units.

    No standard test has been established to diagnose ILO and this study aims to develop a reproducible assessment. Patients report similar triggers for ILO and idiopathic chronic cough(ICC). Based upon our work with ICC we suspect citric acid(CA) will be a reliable trigger to provoke ILO. In order to see if this is correct, we are looking at changes in laryngeal opening during inhaling CA compared to a control solution and comparing this between people who cough, have ILO and a healthy control group.

    We want to recruit 20 ILO, 20 ICC patients and 20 healthy volunteers. Each participant will attend a hospital visit on two occasions over a 7 day period and then receive a telephone follow-up 7 days later.

    On the first two visits participants will be asked to complete a standard cough challenge(where an increasing amount of challenge solution is inhaled through a mouth piece) at the same time as having a laryngoscopy(a small flexible tube passed through a nostril to rest just above the voice box). Participants will wear two bands around their chest to monitor breathing movements and a microphone to record sounds. The challenge agent given on each visit will be determined by randomisation and the person doing the test and the participant will not know which is being administered. Before and after the challenge simple breathing tests and questionnaires will be completed. After each dose challenge questions will be asked about throat and breathing symptoms. A routine telephone consultation 7 days later will check general wellbeing.

  • REC name

    North West - Haydock Research Ethics Committee

  • REC reference


  • Date of REC Opinion

    11 Apr 2019

  • REC opinion

    Further Information Favourable Opinion

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