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.

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.

Inclusion Criteria

• Healthy subjects older than 18 years and younger than 80.

Exclusion Criteria

• Pre-existing cardiopulmonary disease
• history of tobacco or ecigarette smoking