Distribution of Ventilation, Respiratory Drive and Gas Exchange: Measurements and Monitoring

NCT05462600 | Enrolling By Invitation

• 1 other identifier: 801980
• Study Type: observational
• Target: 40
• Locations: 1 country
• Sites: 1

Brief Summary

Respiratory physiology involves a complex interplay of elements including control of breathing, respiratory drive, pulmonary mechanics, distribution of ventilation and gas exchange. Body position may also play an important role in respiratory mechanics. While effective methods exist for measuring these variables, they are typically measured in isolation rather than in combination. In pulmonary disease, decreasing mechanical stress and strain and optimizing transpulmonary pressure or the distending pressure across the lung, minimizing overdistention and collapse are central to clinical management. Obesity has a significant impact on pulmonary mechanics and is a risk factor for obstructive sleep apnea (OSA). However, our understanding of these elements is limited even in the general population. The investigators plan to use various validated methods to assess control of breathing, respiratory drive, distribution of ventilation and gas exchange to obtain a better understanding of underlying physiologic signatures in patients with and without obesity and the role of posture/position, with a secondary analysis comparing participants with and without obstructive sleep apnea.

Conditions

Pulmonary Disease; Respiratory System Abnormalities; OSA; Respiratory Failure

Outcome Measures

Primary Outcomes (4)

• Distribution of ventilation

  Change in regional ventilation distribution (ventral/dorsal) measured through electrical impedance tomography (EIT)

  3 hours

• Respiratory drive

  Respiratory drive differences will be measured by mean desaturation (change from baseline percent oxygen saturation) following breath-hold maneuvers

  3 hours

• Respiratory drive

  Respiratory drive differences will be assessed by the duration of maximal breath-hold (seconds)

  3 hours

• Respiratory drive

  Respiratory drive will also be assessed by measurement of occlusion pressure (cm H2O) at 100 ms (P0.1) after the initiation of an inspiratory effort against a closed circuit.

  3 hours

Secondary Outcomes (3)

• Pulmonary mechanics

  3 hours

• Dead space fraction

  3 hours

• Ventilatory ratio

  3 hours

Study Arms (2)

BMI>24.9 kg/m2

Other: Position change

BMI 18-24.9 kg/m2

Other: Position change

Interventions

Position change OTHER

Distribution of ventilation, respiratory drive, pulmonary mechanics and gas exchange will be measured in 3 unique positions: prone, head of bed (HOB) flat (i.e. 0 degrees) and HOB elevated (i.e. 30 degrees).

BMI 18-24.9 kg/m2; BMI>24.9 kg/m2

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)
• Sampling Method: Non-Probability Sample

Study Population

Investigators will enroll 20 subjects with BMI 18.5-24.9 and 20 subjects with BMI 25 or more. The detailed inclusion criteria for subjects are listed below.

You may qualify if:

• years or older
• Non-smokers

You may not qualify if:

• \<18 years old
• Significant history of pulmonary disease
• Chest wall, anatomical, physical abnormalities, skin integrity issues precluding placement of electrode belt in direct contact with skin
• Skin integrity issues precluding placement of nose clips, or transcutaneous carbon dioxide monitoring
• Inability to form a seal around a mouthpiece
• Known esophageal strictures, webs, or varices (if esophageal manometry to be included)
• Known platelet count \< 100,000 (if esophageal manometry to be included)
• On therapeutic anticoagulation (if esophageal manometry to be included)
• Known multidrug resistant (MDR) pulmonary infection
• Non-English language speakers
• Chronic hypoxemic respiratory failure
• Confirmed or suspected intracranial bleed, stroke, edema
• Active implants (i.e. implantable electronic devices such as pacemakers, cardioverter defibrillators or neurostimulators) or if device compatibility is in doubt
• Pregnant or lactating patients as safety and efficacy for use of EIT in such cases has not been verified

Sponsors & Collaborators

• University of California, San Diego: lead

Study Sites (1)

University of California San Diego Health

La Jolla, California, 92037, United States

Location

MeSH Terms

Conditions

Lung Diseases; Respiratory System Abnormalities; Respiratory Insufficiency

Condition Hierarchy (Ancestors)

Respiratory Tract Diseases; Congenital Abnormalities; Congenital, Hereditary, and Neonatal Diseases and Abnormalities; Respiration Disorders

Study Officials

• Alex Pearce

  University of California, San Diego

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: observational
• Observational Model: COHORT
• Time Perspective: PROSPECTIVE
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Principal Investigator

Study Record Dates

• First Submitted: June 30, 2022
• First Posted: July 18, 2022
• Study Start: July 19, 2022
• Primary Completion (Estimated): December 30, 2026
• Study Completion (Estimated): December 30, 2026
• Last Updated: April 11, 2025

Record last verified: 2024-06

Locations

US (1)