The Influence of Posture on Airway Diameter, Resistance and Airflow Distribution in Healthy Subjects

NCT ID: NCT01893697

Last Updated: 2015-05-28

Basic Information

• Recruitment Status: COMPLETED
• Total Enrollment: 5 participants
• Study Classification: OBSERVATIONAL
• Study Start Date: 2013-04-30
• Study Completion Date: 2014-09-30

Brief Summary

FRI could give the opportunity to investigate the possible effect of a lateral posture on airway diameter and airflow distributions. This physiological study in healthy subjects may help to identify the role of positioning as an aid in airway clearance techniques for patients with respiratory diseases.

Detailed Description

Many respiratory diseases require a physiotherapeutic treatment that focusses on clearance of excessive mucus from the airways.

The underlying physiological hypothesis why those mucus clearance techniques are effective is based on the development of an optimal expiratory airflow velocity that applies shearing forces on the mucus at the inner surface of the airway. These shearing forces eventually lead to displacement of mucus to the central airways were it could be evacuated.To accomplish optimal velocity with the same expiratory airflow, it is necessary to decrease the airway diameter and hence increase in the airflow velocity. In other words, the airway diameter and resistance are important factors to take into account in mucus clearance techniques.

In many mucus clearance techniques, postural position is used to facilitate this clearance. Clinical trials in patients with chronic obstructive pulmonary disease (COPD) and cystic fibrosis where they combined clearance techniques with different postural positions showed to be effective.

The influence of posture has been evaluated in the lateral decubitus position and resulted in a greater clearance of mucus in the depended lung. The authors suggested that this may be due to a better deflation of the depended lung that is favored by 3 forces: gravity, mediastinum weight and pressure of abdominal viscera on the infra lateral lung. Deflation of this lung leads not only to a decrease in lung volume, but also results in a decrease in airway diameter. Nevertheless, it is not known to what extend this decrease in diameter occurs in a lateral position. Furthermore, an optimal expiratory flow must be retained in the underlying lung at lower lung volumes. These regional changes in the underlying lung cannot be measured by for example classic lung function tests since these test are not sensitive enough. Indeed, Washko et. al. found no significant changes of overall residual volume (RV), total lung capacity (TLC) and vital capacity (VC) between the different positions in healthy subject.

However, Functional respiratory imaging (FRI) is able to assess the regional changes in healthy subjects. This 3D imaging technique in combination with computational fluid dynamics (CFD) is accurate in calculating regional changes such as airway diameter, volume and resistance. In addition, repetitive FRI measures are able to assess lobar expansion, which is an indirect measure of airflow distribution in a specific part of the lung.

Conditions

Healthy Participants

Study Design

• Observational Model Type: CASE_CROSSOVER
• Study Time Perspective: PROSPECTIVE

Study Groups

Healthy Participants

HRCT scan in a specific postural position

HRCT scan in a specific postural position

Intervention Type: OTHER

HRCT Scan taken in supine and lateral position

Interventions

HRCT scan in a specific postural position

HRCT Scan taken in supine and lateral position

Intervention Type: OTHER

Eligibility Criteria

Inclusion Criteria

1. Men or female patients age > 18

2. No respiratory disease in the days prior to the enrollment

3. Able to perform a lung function tests

4. Motivated to participate.

5. Written informed consent from the subject prior to the participation

Exclusion Criteria

1. Serious co-morbidity which would interfere with the examinations

2. One or multiple CT scans of the chest during the last year.

3. Deformities or complications preventing patients to maintain side lying position during the scanning procedure

• Minimum Eligible Age: 18 Years
• Maximum Eligible Age: 40 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: Yes

Sponsors

University Hospital, Antwerp

OTHER

Sponsor Role: lead

Responsible Party

Wilfried De Backer

Prof. Dr. W De Backer

Responsibility Role: PRINCIPAL_INVESTIGATOR

Principal Investigators

Wilfried De Backer, MD PhD

Role: PRINCIPAL_INVESTIGATOR

University Hospital, Antwerp

Locations

UZA

Antwerp, Edegem, Belgium

Countries

Belgium

References

Ides KM, De Backer WA, Lanclus M, Leemans G, Dierckx W, Lauwers E, Vissers D, Steckel J, De Backer JW. The effect of posture on airflow distribution, airway geometry and air velocity in healthy subjects. BMC Pulm Med. 2022 Dec 15;22(1):477. doi: 10.1186/s12890-022-02276-5.

Reference Type: DERIVED

PMID: 36522658 (View on PubMed)

Other Identifiers

RESPT_2013_01

Identifier Type: -

Identifier Source: org_study_id