Description of Bullous Emphysema Using Lung Ultrasound and Comparison to the Characteristics of Pneumothorax

Study Overview
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Brief Summary
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Chronic Obstructive Pulmonary Disease (COPD) is a frequent disease affecting a growing number of adults in the world which is responsible for a large public health burden through heavy morbidity and mortality. Emphysema is one of a wide spectrum of pulmonary complications linked to COPD, defined as the abnormal permanent enlargement of the airspaces distal to the terminal bronchioles accompanied by destruction of the alveolar wall. Disease progression is correlated to worsening and enlargement of emphysema lesions, sometimes conflating in sizeable bullae, deleterious to normal mechanical pulmonary function. Bullous emphysema (BE) is sometimes eligible to invasive curative treatment through surgery or interventional bronchoscopy. Diagnosis of BE relies on computerized tomodensitometry (CT), the gold-standard for evaluating pulmonary parenchyma. However, CT is not always available, and bullous emphysema can present as pneumothorax on chest radiography. The practice of lung ultrasound is currently growing in respiratory medicine and emergency departments owing to an increasing amount of evidence showcasing its reliability as a diagnostic tool, most notably for pneumothorax and other pleural diseases. Despite BE having been reported to present similarly to pneumothorax in ultrasound, its characteristics have not yet been precisely described. The primary aim of this study is to describe BE using lung ultrasound. Participants with known BE on CT will undergo a simple ultrasound examination. The secondary aim is to compare the characteristics of BE to those of pneumothorax using lung ultrasound. To achieve this, a second group of participants with currently treated pneumothorax will also undergo lung ultrasound.

Official Title
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Lung Ultrasound Characterization of Bullous Emphysema

Conditions
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Pulmonary Emphysema

Intervention / Treatment
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* Diagnostic Test: Lung ultrasound
* Diagnostic Test: Chest radiography
* Diagnostic Test: Pulmonary function tests
* Other: Clinical examination


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Bullous emphysema group Consultation or scheduled hospitalization in a Pulmonary Medicine department Past medical history of emphysema on computerized tomodensitometry dating less than two years Bullous emphysema with subpleural contact of two or more intercostal spaces on tomodensitometry Pneumothorax group Hospitalized in a Pulmonary Medicine department for the treatment of a pneumothorax Patent pneumothorax visible on chest x-ray dating less than 24 hours Exclusion Criteria: Bullous emphysema group Current pneumothorax Past medical history of pleurodesis or pleural thickening homolateral to the bullous emphysema All patients Organ failure (hemodynamic, neurological, respiratory) Recent thoracic surgery dating less than 7 days with subcutaneous emphysema Minor participant or otherwise deprived of their freedom or their ability to consent freely No affiliation to social security

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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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Bullous emphysema<br>Participants with known bullous emphysema will undergo lung ultrasound according to standard of care clinical practice during a regular follow-up consultation or scheduled hospitalization. | Diagnostic Test: Lung ultrasound<br>* Non-invasive external ultrasonography of the chest wall<br>Diagnostic Test: Pulmonary function tests<br>* Pulmonary function evaluation as part of routine care for emphysematous patients<br>Other: Clinical examination<br>* Standard clinical examination performed by investigating physician<br>|
| Pneumothorax<br>Participants hospitalized in pulmonary medicine units for the treatment of a pneumothorax will undergo lung ultrasound according to standard of care clinical practice. | Diagnostic Test: Lung ultrasound<br>* Non-invasive external ultrasonography of the chest wall<br>Diagnostic Test: Chest radiography<br>* Chest radiography to search for visible pleural edge, synonym with persistent pneumothorax<br>Other: Clinical examination<br>* Standard clinical examination performed by investigating physician<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Prevalence of various ultrasound signs in the bullous emphysema group, according to a predetermined sonographic evaluation form, following a standardized segmentation of the chest | The following sonographic signs will be investigated : Pleural sliding (presence/absence) Z lines (presence/absence) A line visibility increase (presence/absence) B line (number per field) pulmonary pulse (presence/absence) lung-point (presence/absence) intercostoaeric line thickness (in mm) For qualitative signs, the investigators will present proportions Quantitative signs will be reported using means, medians and standard-deviations | 2 years | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Prevalence of various ultrasound signs in the pneumothorax group, according to a predetermined sonographic evaluation form, following a standardized segmentation of the chest | The following sonographic signs will be investigated : Pleural sliding (presence/absence) Z lines (presence/absence) A line visibility increase (presence/absence) B line (number per field) pulmonary pulse (presence/absence) lung-point (presence/absence) intercostoaeric line thickness (in mm) For qualitative signs, the investigators will present proportions Quantitative signs will be reported using means, medians and standard-deviations | 2 years | 
| Statistical comparison of ultrasound characteristics of bullous emphysema and pneumothorax | Calculation of sensitivity values of lung ultrasound for bullous emphysema for each sonographic sign. Study design prohibits calculation of specificity. A quantitative discrete score will be constructed by enumerating signs which are positive in favor of bullous emphysema, able to discriminate between both diseases. AUC will be calculated. An AUC < 0.75 will be considered as insufficient for establishing lung ultrasound as a diagnostic test for bullous emphysema. An AUC > 0.75 would prompt further studies. | 2 years | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Lung ultrasound