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

Respiratory Failure Clinical Trial

Official title:

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

Clinical Trial Details — Status: Enrolling by invitation

Administrative data

• NCT number: NCT05462600
• Other study ID #: 801980
• Status: Enrolling by invitation
• Start date: July 19, 2022
• Est. completion date: June 30, 2025

Study information

• Verified date: May 2023
• Source: University of California, San Diego
• Contact: n/a
• Is FDA regulated: No
• Study type: Observational

Clinical Trial 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.

Recruitment information / eligibility

• Status: Enrolling by invitation
• Enrollment: 40
• Est. completion date: June 30, 2025
• Est. primary completion date: June 30, 2024
• Accepts healthy volunteers: Accepts Healthy Volunteers
• Gender: All
• Age group: 18 Years and older

Eligibility

Inclusion Criteria:

• 18 years or older
• Non-smokers

Exclusion Criteria:

• <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

Related Conditions & MeSH terms

• OSA
• Pulmonary Disease
• Respiratory Failure
• Respiratory Insufficiency
• Respiratory System Abnormalities

Intervention

Other:
• Position change
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).

Locations

Country	Name	City	State
United States	University of California San Diego Health	La Jolla	California

Sponsors (1)

Lead Sponsor	Collaborator
University of California, San Diego

Country where clinical trial is conducted

United States, 

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	Distribution of ventilation	Change in regional ventilation distribution (ventral/dorsal) measured through electrical impedance tomography (EIT)	3 hours
Primary	Respiratory drive	Respiratory drive differences will be measured by mean desaturation (change from baseline percent oxygen saturation) following breath-hold maneuvers	3 hours
Primary	Respiratory drive	Respiratory drive differences will be assessed by the duration of maximal breath-hold (seconds)	3 hours
Primary	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	Pulmonary mechanics	Pulmonary mechanics will be measured by transpulmonary pressure (cmH2O)obtained from esophageal manometry (transpulmonary pressure= airway pressure- esophageal pressure)	3 hours
Secondary	Dead space fraction	Dead space fraction will be calculated by partial pressure arterial/transcutaneous CO2 (PCO2) minus partial pressure of CO2 in mixed expired gas divided by the partial pressure of arterial/transcutaneous CO2	3 hours
Secondary	Ventilatory ratio	Ventilatory ratio will be calculated as measured minute ventilation multiplied by the measured partial pressure of PCO2 divided (transcutaneous) by the predicted minute ventilation based on ideal body weight multiplied by the ideal PaCO2	3 hours