Investigating Diaphragm Thickness and Mobility in Healthy Parous and Nulliparous Volunteers Using RUSI

Study Overview
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Brief Summary
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The purpose of this study is to evaluate the intra-rater and inter-rater reliability of diaphragm thickness and excursion measurements by applying Rehabilitative Ultrasound Imaging (RUSI) in a diverse cohort of healthy women, including nulliparous and parous across varying age groups. The diaphragm, which is primarily a respiratory muscle, is also considered to contribute to spinal stability. Utilizing RUSI, a non-invasive and cost-effective imaging modality, we intend to examine diaphragm parameters. Preliminary evidence highlights a potential link between diaphragm dysfunction and musculoskeletal conditions such as lumbopelvic pain. This research hypothesizes that understanding diaphragm behavior in different pathologies, including postpartum recovery and lower back pain, can contribute to tailored rehabilitation strategies, potentially benefiting a wide range of clinical conditions, and facilitating the assessment of intervention effectiveness. Additionally, this study addresses the lack of research on the diaphragm's role in postpartum rehabilitation and offers novel insights into its reliability, particularly within this demographic.

Detailed Description
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The diaphragm is the main respiratory muscle but is also considered to contribute significantly to trunk stability and posture due to its unique anatomy and coordination with other trunk muscles. Rehabilitative Ultrasound Imaging (RUSI) technique provides a safe, and cost-effective method for assessing diaphragm muscle function. RUSI is employed in musculoskeletal physiotherapy to assess diaphragm thickness or mobility in trunk conditions such as lumbopelvic pain, as a method to investigate rehabilitation effectiveness or as a biofeedback tool for muscle training. Although, the reliability of RUSI measurements for diaphragm thickness and excursion has been previously investigated in healthy populations, individuals with pelvic girdle pain and athletes with lumbopelvic pain, its reliability on postpartum populations has never been researched. Therefore, this study aims to assess the reliability of diaphragm thickness and excursion measurements in healthy women, including nulliparous and parous individuals of varying ages, utilizing RUSI. This reliability study adheres to Ethical considerations and the Helsinki Declaration and is approved by the Research Ethics Committee (R.E.C.) of the University of Patras. The study incorporates a robust quality assurance plan, according to the Internal Review Board of the Research Ethics Committee (R.E.C.) of the University of Patras, including data checks to assess data validation and registry procedures performed by the Data Monitoring Committee of R.E.C. of the University of Patras, as well as site monitoring and auditing, to maintain protocol adherence and data collection integrity. The accuracy, completeness, and representativeness of registry data is assured by the research team, comparing the data to preliminary data published in similar reliability studies. A comprehensive data dictionary is established among the research team, containing detailed variable descriptions, coding information, and normal ranges, ensuring consistency and clarity in data collection. RUSI is performed by two trained physiotherapists (with more than 5 years of clinical experience in musculoskeletal physiotherapy). The physiotherapists received one-day training from a consultant radiologist, specializing in musculoskeletal sonographic imaging, followed by several hours of independent and joint practice between the radiologist and physiotherapists. A convenience sample of adult women coming from around the broader university campus area is invited to participate in the study, via advertisements and university-mediated means (emails, e-platform university announcements etc.). Informed consent is obtained from all participants. Participants undergo an ultrasound assessment in the semi-recumbent position with the Versana Active™ ultrasound system. Anatomical guide points are marked by a surgical skin marker for accuracy, and the 2 trained physiotherapists perform the assessments according to Boussuges et al. (2020) recommendations. Diaphragm thickness is measured using a high-resolution linear transducer in B-mode at the end of a full inspiration and full expiration. Diaphragm excursion is assessed using a high-resolution curvilinear transducer in M-mode during tidal volume diaphragmatic breathing. A two-minute resting interval follows each measurement. During the resting intervals, calipers are placed on the captured images according to literature recommendations and measurements are recorded and saved. Intra-tester and inter-tester reliability are evaluated by taking 3 consecutive measurements per parameter. Operators and subjects are blinded for all measurements taken, by covering measurement tables at the edge of the ultrasound screen. An independent researcher blinded to the subject identity (the identity of the subject on the ultrasound screen is concealed by the operator at the end of the assessment) and the examination procedure is responsible for the extraction, and documentation of all variables in a spreadsheet software. All patient data are stored anonymously/coded in a secure cloud platform accessed only by the research team members. Imputation methods will be applied to address situations where variables are missing, uninterpretable, or inconsistent. Any adverse events will be addressed and documented, while medical consultation will be accessible during patient assessment hours. Any modifications to the study protocol, data collection methods, or other aspects of the study will be reviewed thoroughly among researchers and the Internal Review Board of the R.E.C., and the study protocol as well as study registration will be adjusted accordingly. Statistical analysis of the data will be performed using SPSS software (version 28.0; SPSS Inc, Chicago, IL). Reliability will be calculated using intraclass correlation coefficient (ICC) assessed with a two-way random effect model (ICC2,1) and 95% confidence intervals.

Official Title
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Reliability of Diaphragm Thickness and Excursion Measurements Performed Via Rehabilitative Ultrasound Imaging (RUSI) Across Healthy Parous and Nulliparous Women

Conditions
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Asymptomatic Condition

Intervention / Treatment
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* Diagnostic Test: Diagnostic Ultrasound Imaging of the diaphragm


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Generally healthy women Nulliparous and parous individuals Age between 18 and 60 years Exclusion Criteria: Severe chronic respiratory conditions (e.g., COPD, chronic bronchitis, pulmonary emphysema or fibrosis) Body mass index (BMI) greater than 30 kg/m², which may hinder ultrasound imaging History of major abdominal surgery Pregnancy Neuromuscular disorders that could alter diaphragm morphology and function

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 60 Years

Sexes Eligible for Study
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Female

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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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Reliability Assessment Arm<br>This is a single-arm reliability assessment study. Reliability will be assessed by conducting measurements of diaphragm thickness and excursion on the same participants by the same rater (intra-rater reliability) and by different raters (inter-rater reliability) to evaluate measurement consistency. | Diagnostic Test: Diagnostic Ultrasound Imaging of the diaphragm<br>* In this reliability study, ultrasound imaging will be utilized by trained physiotherapists to assess diaphragm thickness and excursion. Participants will be positioned in a semi-recumbent position, while the scanning area will be marked with a surgical skin marker according to specific anatomical landmarks recommended, to ensure reproducibility of the procedure. Ultrasound probe will be placed at the zone of apposition to visualize the diaphragm through the liver window. Diaphragm thickness will be assessed during both full inhalation and exhalation, capturing images in B-mode to measure distance between the diaphragmatic pleura and peritoneal fascia. Diaphragm excursion will be assessed during tidal volume diaphragmatic breathing, using M-mode to track the craniocaudal displacement of the diaphragm during respiratory cycle. Data obtained will contribute to the evaluation of the reliability of diaphragm thickness and excursion measurements for potential future clinical applications.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Inspiratory Diaphragm Thickness | The thickness of the diaphragm muscle at the end of a full inspiration measured in centimeters (cm). | Measured at full inspiration during the same session (aprox. 10 minutes) | 
| Expiratory Diaphragm Thickness | The thickness of the diaphragm muscle at the end of a full expiration measured in centimeters (cm). | Measured at full expiration during the same session (aprox. 10 minutes) | 
| Diaphragm Excursion | It measures the craniocaudal displacement (movement from top to bottom) of the diaphragm during the respiratory cycle in centimeters (cm). | Measured during quiet, tidal breathing during the same session in a random order (before or after diaphragm thickness) (aprox. 10 minutes) | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Thickening Fraction (Percentage of Thickening) | This metric quantifies the percentage of change in diaphragm thickness during breathing. It is computed by taking the difference between diaphragm thickness at the end of inspiration and diaphragm thickness at the end of expiration, divided by diaphragm thickness at the end of expiration, and then multiplying by 100%. | Thickening fraction is calculated post-assessment by an independent researcher (aprox. 5 minutes) | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Ultrasound, Diaphragm/diagnostic imaging, Rehabilitation, Parity, Validation Study