Obesity
Conditions
Keywords
closing volume, expiratory flow limitation, obesity, orthopnea
Brief summary
The purpose of this study is to study the role of closing volume as a determinant of orthopnea in stable obese subjects. The investigators hypothesized that: (1) increase in closing volume in supine position would be greater in orthopneic than in non-orthopneic subjects, and (2) the relationship of change in closing volume to change in dyspnea with position would be dependent on expiratory flow limitation in the sitting position. In stable obese subjects, in sitting and supine positions, the investigators measured Borg dyspnea score, static lung volumes, expiratory flow limitation, and single-breath nitrogen expiration test, from which the investigators determined closing volume and closing capacity, slope of phase III, and opening capacity. Orthopnea was defined as any increase in the Borg score in the supine position from its value in the sitting position
Interventions
OTHERSupine
measurements after 30 minutes in complete supine position
Sponsors
Hospices Civils de Lyon
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
DIAGNOSTIC
Masking
NONE
Eligibility
Sex/Gender
ALL
Age
20 Years to 60 Years
Healthy volunteers
No
Inclusion criteria
* obese (BMI ≥ 30) * stable condition * 20 \< Age \< 60 years
Exclusion criteria
* other respiratory disorder (COPD) * left cardiac insufficiency
Design outcomes
Primary
| Measure | Time frame |
|---|---|
| closing volume by nitrogen washout method | 30 minutes after changing position (hour 2) |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| static lung volumes by plethysmography | 30 minutes after changing position (hour 2) | static lung volumes are composed of vital capacity, FEV1, inspiratory capacity, and reserve expiratory volume and are measured by plethysmography |
| expiratory flow limitation by NEP test | 30 minutes after changing position (hour 2) | NEP test |
Countries
France
Outcome results
None listed