Efficacy of SLN Block for Chronic Cough

Study Overview
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Brief Summary
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This is a research study to find out if superior laryngeal nerve blocks are an effective way to reduce cough when compared to placebo (a substance without any medical value). Eligibility for the study include the following: age >18, cough history suggestive that the nerve to the voice box is overactive, non-smoker, Patients will be followed over time and assigned to either the treatment or placebo group at random. The treatment would be four superior laryngeal nerve blocks and the placebo would be four saline injections (the inactive substance). Study team will measure if the injection improved cough and ask patients to keep a log of symptoms and fill out questionnaires at each visit. After the four injections, patients will follow up in 3 months to see if cough has returned and if so, how severe the cough is.

Official Title
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Efficacy of Superior Laryngeal Nerve Block for Chronic Cough

Conditions
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Cough, Superior Laryngeal Nerve Block, Neurogenic Cough

Intervention / Treatment
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* Procedure: Superior laryngeal nerve block
* Procedure: Injection of placebo (saline)
* Procedure: Injection of steroid-lidocaine mixture


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: History consistent with neurogenic cough Exclusion of other etiologies (see exclusion criteria) Age ≥ 18 Exclusion Criteria: Current neuromodulating medication use Untreated other etiologies of cough: Current smoker Current ACE/ARB use Abnormal PFTs within 6 months Uncontrolled OSA Abnormal CXR within 6 months RSI > 13 or RFS >11 AND workup positive for GERD (esophagram, 24-hour pH probe, manometry, EGD)

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Steroid-Lidocaine Mixture<br>Will receive numbing injection, which is a mixture of steroid and lidocaine | Procedure: Superior laryngeal nerve block<br>* Injection of either the steroid-lidocaine mixture or placebo through the skin around where the superior laryngeal nerve is located on the neck. The procedure lasts 5 minutes and is done in the clinic.<br>Procedure: Injection of steroid-lidocaine mixture<br>* Superior laryngeal nerve block using 1mg 1:1 triamcinolone 40mg: 1% lidocaine with 1:200000 epinephrine as the injection.<br>|
| Placebo Comparator: Placebo<br>Will receive saline injection as a placebo | Procedure: Superior laryngeal nerve block<br>* Injection of either the steroid-lidocaine mixture or placebo through the skin around where the superior laryngeal nerve is located on the neck. The procedure lasts 5 minutes and is done in the clinic.<br>Procedure: Injection of placebo (saline)<br>* Superior laryngeal nerve block using 1mL of saline as the injection.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in cough severity | Patient will complete the Leicester Cough Questionnaire at each visit. This is a validated survey that measures 3 domains (physical, psychological and social). The total score range is 3-21 and domain scores range from 1-7; a higher score indicates a better quality of life. | Baseline, every two weeks (+/- 1 week) post-treatment (estimated 3 months total) | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Subjective improvement in cough | Patient will state dichotomously yes or no if cough overall improved at each visit. | Every two weeks (+/- 1 week) post-treatment (estimated 3 months total), 3 months post completion of therapy | 
| Daily change in subjective cough severity | Patient will fill out a Visual Analogue Scale measuring cough severity. Patients will be given a log to complete daily after treatment completed and instructed to mark on a line with a X how severe the cough is. The far left of the line will indicate no cough at all, and the far right is indicative of the most severe cough. | Daily after each treatment (estimated 3 months total) | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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superior laryngeal nerve block, chronic cough