Ventilation and Perfusion in the Respiratory System

University of California, San Diego (Other)
Overall Status
Enrolling by invitation ID

Study Details

Study Description

Brief Summary

Respiratory failure occurs when the lung fails to perform one or both of its roles in gas exchange; oxygenation and/or ventilation. Presentations of respiratory failure can be mild requiring supplemental oxygen via nasal cannula to more severe requiring invasive mechanical ventilation as see in acute respiratory distress syndrome (ARDS).It is important to provide supportive care through noninvasive respiratory support devices but also to minimize risk associated with those supportive devices such as ventilator induced lung injury (VILI) and/or patient self-inflicted lung injury (P-SILI). Central to risk minimization is decreasing mechanical stress and strain and optimizing transpulmonary pressure or the distending pressure across the lung, minimizing overdistention and collapse. Patient positioning impacts ventilation/perfusion and transpulmonary pressure. Electrical impedance tomography (EIT) is an emerging technology that offers a noninvasive, real-time, radiation free method to assess distribution of ventilation at the bedside. The investigators plan to obtain observational data regarding distribution of ventilation during routine standard of care in the ICU, with special emphasis on postural changes and effects of neuromuscular blockade, to provide insight into ventilation/perfusion matching, lung mechanics in respiratory failure, other pulmonary pathological processes.

Condition or Disease Intervention/Treatment Phase
  • Device: Electrical Impedance tomography
  • Other: Lung mechanics and gas exchange

Study Design

Study Type:
Anticipated Enrollment :
20 participants
Observational Model:
Time Perspective:
Official Title:
Ventilation and Perfusion in the Respiratory System
Actual Study Start Date :
Aug 19, 2021
Anticipated Primary Completion Date :
Jul 1, 2024
Anticipated Study Completion Date :
Jul 1, 2024

Arms and Interventions

Arm Intervention/Treatment
Respiratory failure

Device: Electrical Impedance tomography
Patients will be monitored with electrical impedance tomography during routine care with special attention to effects of neuromuscular blockade and postural changes.

Other: Lung mechanics and gas exchange
Patient lung mechanics and gas exchange will be monitored during routine clinical care, with specific attention to postural changes and use of neuromuscular blockade.

Outcome Measures

Primary Outcome Measures

  1. Distribution of ventilation [change from baseline at 15 minutes and 1 hour]

    Regional ventilation distribution differences measured through electrical impedance tomography (EIT)

Secondary Outcome Measures

  1. Lung mechanics [Baseline, then at 15 minutes and 1 hour]

    Lung compliance

  2. Oxygenation [Up to 48 hours]

    Oxygen saturation measured by pulse oximetry (SpO2) and fraction of inspired oxygen (FiO2) as well as arterial blood gas partial pressure of oxygen (PaO2). Results will be reported as either PaO2/FiO2 ratio or SpO2/FiO2 ratio (depending on availability of arterial blood gas measurements)

  3. Blood Gas Partial Pressure of Carbon Dioxide (PaCO2) (mmHg) [Up to 48 hours]

    Partial pressure of carbon dioxide (PaCO2) (mmHg)

  4. Blood Gas pH [Up to 48 hours]

    Blood Gas pH

Other Outcome Measures

  1. In-hospital Mortality [Up to 28 days]

    Mortality at 28 days after study enrollment

  2. ICU Mortality [Up to 28 days]

    ICU Mortality

  3. Ventilator-free days [Up to 28 days]

    Ventilator-free days

  4. Ventilator associated pneumonia [Up to 28 days]

    Incidence of ventilator associated pneumonia

Eligibility Criteria


Ages Eligible for Study:
18 Years and Older
Sexes Eligible for Study:
Accepts Healthy Volunteers:
Inclusion Criteria:
  • 18 years or older

  • admitted to UC San Diego La Jolla or Hillcrest Campus Intensive Care Units

  • Patient requiring supplemental oxygen (including but no limited to nasal cannula, high flow devices, noninvasive positive pressure ventilation or mechanical ventilation

Exclusion Criteria:
  • <18 years

  • Chest wall, anatomical, physical abnormalities, skin integrity issues precluding placement of electrode belt in direct contact with skin

  • Patient is too unstable to position the belt/electrodes or tolerate head of bed changes

  • Confirmed or suspected intracranial bleed, stroke, edema

  • Active implants (i.e. implantable electronic devices such as pacemakers, cardioverter defibrillators, 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

Contacts and Locations


Site City State Country Postal Code
1 University of California San Diego Health La Jolla California United States 92037

Sponsors and Collaborators

  • University of California, San Diego


  • Principal Investigator: Alex Pearce, MD, University of California, San Diego

Study Documents (Full-Text)

None provided.

More Information


None provided.
Responsible Party:
Alex Pearce, Principal Investigator, University of California, San Diego Identifier:
Other Study ID Numbers:
  • 210285
First Posted:
Oct 18, 2021
Last Update Posted:
Oct 18, 2021
Last Verified:
Oct 1, 2021
Individual Participant Data (IPD) Sharing Statement:
Plan to Share IPD:
Studies a U.S. FDA-regulated Drug Product:
Studies a U.S. FDA-regulated Device Product:
Additional relevant MeSH terms:

Study Results

No Results Posted as of Oct 18, 2021