Ventilation and Perfusion in the Respiratory System

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.

Study Overview

• Status: Completed
• Conditions: Critical Illness; Respiratory Failure; Pulmonary Disease; Ventilator-Induced Lung Injury; Respiratory Distress Syndrome, Adult
• Intervention / Treatment: Device: Electrical Impedance tomography; Other: Lung mechanics and gas exchange

• Study Type: Observational
• Enrollment (Actual): 16

Contacts and Locations

Study Locations

• United States
  • California
    • La Jolla, California, United States, 92037
      • University of California San Diego Health

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No

• Sampling Method: Non-Probability Sample

Study Population

Human subjects admitted to the UC San Diego La Jolla Campus and Hillcrest Campus Intensive Care Units who are admitted with a pathologic condition requiring supplemental oxygen (including but not limited to nasal cannula, high flow devices), noninvasive positive pressure ventilation, mechanical ventilation.

Description

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

Study Plan

How is the study designed?

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort

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.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Distribution of ventilation	Regional ventilation distribution differences measured through electrical impedance tomography (EIT)	change from baseline at 15 minutes and 1 hour

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Lung mechanics	Lung compliance	Baseline, then at 15 minutes and 1 hour
Oxygenation	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)	Up to 48 hours
Blood Gas Partial Pressure of Carbon Dioxide (PaCO2) (mmHg)	Partial pressure of carbon dioxide (PaCO2) (mmHg)	Up to 48 hours
Blood Gas pH	Blood Gas pH	Up to 48 hours

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
In-hospital Mortality	Mortality at 28 days after study enrollment	Up to 28 days
ICU Mortality	ICU Mortality	Up to 28 days
Ventilator-free days	Ventilator-free days	Up to 28 days
Ventilator associated pneumonia	Incidence of ventilator associated pneumonia	Up to 28 days

Collaborators and Investigators

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

Study record dates

Study Major Dates

• Study Start (Actual): August 19, 2021
• Primary Completion (Actual): December 18, 2023
• Study Completion (Actual): December 18, 2023

Study Registration Dates

• First Submitted: September 9, 2021
• First Submitted That Met QC Criteria: October 5, 2021
• First Posted (Actual): October 18, 2021

Study Record Updates

• Last Update Posted (Estimated): December 10, 2024
• Last Update Submitted That Met QC Criteria: December 5, 2024
• Last Verified: December 1, 2024

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Wounds and Injuries; Pathologic Processes; Disease Attributes; Respiratory Tract Diseases; Lung Diseases; Respiration Disorders; Infant, Premature, Diseases; Infant, Newborn, Diseases; Thoracic Injuries; Respiratory Distress Syndrome; Respiratory Distress Syndrome, Newborn; Respiratory Insufficiency; Critical Illness; Lung Injury; Ventilator-Induced Lung Injury; Acute Lung Injury
• Other Study ID Numbers: 210285

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED
• IPD Plan Description: Reasonable requests for IPD will be considered by the investigators

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No