Healthy Volunteers Only
Conditions
Keywords
obesity, electrical impedance tomography, computed tomography, esophageal manometry, airway geometry
Brief summary
This study investigates how body fat distribution affects airway closure and lung mechanics in healthy adults. Using Electrical Impedance Tomography (EIT), esophageal manometry, and computed tomography (CT), we aim to characterize how varying BMI and fat topography influence regional ventilation and airway collapse in supine and prone positions. Healthy volunteers with a range of BMIs will undergo a 2-hour imaging session with noninvasive and minimally invasive monitoring.
Detailed description
This physiological research study explores the relationship between body habitus, fat distribution, and mechanical responses of the lung to the prone and supine position. In a prospective, single-center, physiological, crossover study, study subjects (n=20) will be recruited among healthy volunteers across BMI categories. Lung function will be assessed in the supine and prone position (maintained for 15 min). Intrathoracic pressure (ITP) will be measured using esophageal manometry. Airway opening pressure (AOP) will be measured by as the airway pressure (non-invasively applied through a mask) needed to match ITP. Regional ventilation will be measured in both positions using electrical impedance tomography. Subjects will then transfer to the computed tomography (CT) scanner, where supine and prone images will be acquired during breath holds after normal expiration and after full inspiration. CT scans will then be analyzed for the quantification of lung volumes, thoracic adipose mass and airway geometry.
Interventions
PROCEDUREBody positioning
Each subject will breathe in both the supine and prone positions, randomly applied for 15 minutes each. The procedure will be performed twice: once for the assessment of respiratory physiology, and once for computed tomography acquisition.
Sponsors
National Institutes of Health (NIH)
Maurizio F. Cereda, MD
Study design
Allocation
NA
Intervention model
SINGLE_GROUP
Primary purpose
DIAGNOSTIC
Masking
NONE
Intervention model description
In a prospective, single-center, physiological, crossover study, the investigators will recruit 20 healthy volunteers across four standard body mass index categories (normal weight, overweight, class I obesity, class II/III obesity).
Eligibility
Sex/Gender
ALL
Age
18 Years to 80 Years
Healthy volunteers
Yes
Inclusion criteria
• Healthy subjects older than 18 years and younger than 80.
Exclusion criteria
* Pre-existing cardiopulmonary disease * history of tobacco or ecigarette smoking
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Lung volumes | Day 1, 15 minutes after breathing in the supine and in the prone position | Lung volumes will be measured from quantitative analysis of CT scans obtained in the supine and in the prone position. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Thoracic adiposity | Day 1 | Thoracic adipose tissue will be quantified from analysis of computed tomography images as area of adipose tissue (cm\^2) at multiple vertebral levels. |
Other
| Measure | Time frame | Description |
|---|---|---|
| Intrathoracic pressure (ITP) | Day 1, after 15 minutes in the supine and prone positions. | ITP (cmH2O) will be measured as the pressure in the esophagus at the end of expiration. This will be obtained through a thin balloon mounted catheter placed in the distal esophagus through a nostril. |
| Airway opening pressure (AOP) | Day 1, after 15 minutes in supine and prone position | AOP (cmH2O) will be measured as the airway pressure that matches ITP during the graded application of positive airway pressure through a face mask. |
| Regional ventilation | Day 1, after 15 minutes in the supine or prone position | Changes in EIT-derived measurements of regional ventilation with PEEP titration and prone positioning. EIT regional ventilation is measured as percentage of total ventilation in each examined lung region. |
| Age | Day 1 | Age will be measured in years and obtained during subject interview |
| Height | Day 1 | Body height will be measured in meters and will be aggregated with body weight to yield body mass index (BMI) in kg/m\^2. |
| Weight | Day 1 | Body weight will be measured in kg and will be aggregated with height to yield body mass index (BMI) in kg/m\^2 |
| Thoracic circumference | Day 1 | Thoracic circumference will be measured in cm using a tape ruler placed at nipple level. |
| Abdominal circumference | Day 1 | Abdominal circumference will be measured in cm using a tape ruler at the level of the umbilicus. |
| Hip circumference | Day 1 | Hip circumference will be measured in cm using a tape ruler placed around the widest portion of the hips. |
| Medical history | Day 1 | During subject interview, the presence of the following conditions will be recorded: hypertension, diabetes, asthma. |
| Airway diameters | Day 1, after 15 minutes in the supine and prone positions | CT scans will be digitally processed for the identification of airway branches down to the 4th bronchial generation. Bronchial cross sectional areas will then be measured (mm\^2) and compared between body positions. |
Contacts
Primary ContactMaurizio Cereda, MD
Backup ContactLorenzo Berra, MD
Outcome results
None listed