Phrenic Nerve Conduction Study to Diagnose Unilateral Diaphragmatic Paralysis

Study Overview
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Brief Summary
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The study aims as the principal objective to compare two approaches to diagnosis unilateral diaphragmatic paralysis: transdiaphragmatic pressure (Pdi) measurement versus phrenic nerve conduction (NPC) study. The secondary objective of the study is the strengths and weaknesses of different tests. Diagnostic threshold values.

Detailed Description
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Inpatient patients in Raymond Poincaré hospital are informed of the utilization of their data retrospectively by the hospital's welcome booklet and reports of patients' hospitalization. Period of date collected: November 2015 to June 2018. The reference standard was the diagnosis established during a multidisciplinary meeting held during patient management involving a neurologist, an electrophysiologist, a pulmonologist, and a respiratory physiologist. The medical history, physical findings, and all available investigations including imaging studies, ENMG, lung function tests, and Pdi measurement were considered during the meeting.

Official Title
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Phrenic Nerve Conduction Study to Diagnose Unilateral Diaphragmatic Paralysis

Conditions
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Unilateral Diaphragmatic Paralysis

Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patient ≥ 18 years; Available data of Pdi and PNC; Suspected unilateral diaphragmatic paralysis. Exclusion Criteria: Abnormalities in thoracic wall which susceptible to modify the investigation's results; Scoliosis; Pleural effusion.

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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No

Study Plan
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How is the study designed?
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What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Diaphragm evaluation-compound muscle action potential | Right and left diaphragm compound muscle action potential (CMAP) : CMAP of Right and left diaphragm were elicited by transcutaneous electrical stimulation of phrenic nerves at the posterior edge of the sternocleido mastoid muscle. They are recorded with two surface electrodes positioned in the eighth intercostal space. The intensity of electrical stimulation was increased until no additional increment in diaphragm CMAP was observed. CMAP amplitude of 300µV or greater and latencies of 9 milliseconds or less were considered normal. | at 1 month | 
| Diaphragm evaluation-transdiaphragmatic pressure | Transdiaphragmatic pressure (Pdi) was computed as the difference between gastric and esophageal pressure. Pdi was considered normal when magnetic stimulation of both phrenic nerves induced a Pdi change (Pdi Twitch) above 18 cmH2O and unilateral stimulation of each nerve induced a Pdi change (unilat-Pdi Twitch) above 4 cmH2O and ratio of the two unilat-Pdi Twitch > 0.5. and < 2. | at 1 month | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Spirometry | Spirometry will be performed in the upright and supine positions. Upright vital capacity (VC) was reported as % predicted value and the difference between upright and supine VC (VC) as % upright value (normal value > 75%). | 1 month | 
| Lung volume measurements | Lung volume measurements will be performed in the upright and supine positions. Upright vital capacity (VC) was reported as % predicted value and the difference between upright and supine VC (VC) as % upright value (normal value > 75%). | 1 month | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Unilateral Diaphragmatic Paralysis, Diagnose, Phrenic Nerve