Assessing Lung Inhomogeneity During Ventilation for Acute Hypoxemic Respiratory Failure

NCT03589482 | Completed

• 2 other identifiers: 18-609117-6226
• Study Type: interventional
• Target: 20
• Locations: 1 country
• Sites: 1

Brief Summary

Mechanical ventilation can cause damage by overstretching the lungs, especially when the lungs are collapsed or edematous. Raising ventilator pressures can reduce lung collapse and this can prevent overstretching from mechanical ventilation. It remains uncertain how much pressure (PEEP - positive end-expiratory pressure) should be used on the ventilator and how to identify patients who will benefit from higher ventilator pressures vs. lower ventilator pressures. The investigators are using a unique new imaging technology, electrical impedance tomography (EIT), to study this problem and to determine the safest and most effective ventilator pressure level. The results of this study will inform future trials of higher vs. lower PEEP strategies in mechanically ventilated patients.

Conditions

Acute Respiratory Distress Syndrome; Mechanical Ventilation Pressure High; Hypoxemic Respiratory Failure

Outcome Measures

Primary Outcomes (1)

• Intratidal ventilation heterogeneity

  A measure of variation in the distribution of ventilation throughout the lung as detected by electrical impedance tomography

  Assessed after completion of 3 hours on randomized strategy (EIT vs ExPRESS)

Secondary Outcomes (3)

• Difference in the optimal PEEP levels identified by several different PEEP titration strategies

  Assessed immediately after completion of decremental PEEP titration procedure

• Change in ratio of partial pressure of oxygen (PaO2) to inspired fraction of oxygen (FiO2) ratio following a standardized increased in PEEP

  Assessed 10 minutes after step PEEP increase from 6-8 to 16-18 cm H2O

• Respiratory mechanics (transpulmonary driving pressure)

  Assessed after completing 3 hours on the randomized PEEP strategy (EIT vs ExPRESS)

Study Arms (2)

EIT algorithm

EXPERIMENTAL

Patients randomized to this arm will be ventilated at the PEEP level selected by the EIT algorithm, which selects a PEEP at which both collapse and hyperdistention are minimized.

Device: Electrical Impedance Tomography

ExPRESS algorithm

ACTIVE COMPARATOR

Patients randomized to this arm will be ventilated at the PEEP level selected by the ExPRESS algorithm, which is a method that targets a tidal volume of 6 ml/kg predicted body weight and then titrates PEEP until plateau airway pressure reaches 28 cm H2O.

Other: ExPRESS-derived PEEP level

Interventions

Electrical Impedance Tomography DEVICE

Electrical impedance tomography (EIT) is a new technique that enables real-time visualization of the distribution of ventilation at the bedside. This technique allows clinicians and investigators to immediately determine how applying higher or lower PEEP levels affect stress and strain in the lung. The investigators propose to apply this new technique to test a strategy for finding the optimal level of PEEP that prevents lung injury and improves outcomes in critically ill patients.

EIT algorithm

ExPRESS-derived PEEP level OTHER

The ExPRESS algorithm is a traditional approach to selecting PEEP based on respiratory mechanics.

ExPRESS algorithm

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Acute (≤7 days) hypoxemia with PaO2:FiO2 ratio less than or equal to 200 mm Hg
• Oral endotracheal intubation and mechanical ventilation
• Bilateral airspace opacities on chest radiograph or CT

You may not qualify if:

• Contraindication to EIT electrode placement (burns, chest wall bandaging limiting electrode placement)
• Contraindication to esophageal catheter placement (recent upper GI surgery, actively bleeding esophageal varices)
• Respiratory failure predominantly due to cardiogenic cause or fluid overload
• Ongoing hemodynamic instability (requiring 2 vasopressor agents by continuous infusion AND rising vasopressor infusion rate requirements in the previous 8 hours)
• Ongoing ventilatory instability (P/F \< 70 mm Hg, pH \< 7.2; ventilator driving pressures, PEEP, or FiO2 increasing by more than 25% in previous 30 minutes)
• Intracranial hypertension (suspected or diagnosed by medical team)
• Known or suspected pneumothorax recognized within previous 72 hours
• Bronchopleural fistula
• Bridge to lung transplant
• Recent lung transplantation (within previous 6 weeks)
• Attending physician deems the transient application of high airway pressures (\>40 cm H2O) to be unsafe

Sponsors & Collaborators

• University Health Network, Toronto: lead

Study Sites (1)

University Health Network

Toronto, Ontario, M5G 2N2, Canada

Location

Related Publications (1)

• Santa Cruz R, Villarejo F, Irrazabal C, Ciapponi A. High versus low positive end-expiratory pressure (PEEP) levels for mechanically ventilated adult patients with acute lung injury and acute respiratory distress syndrome. Cochrane Database Syst Rev. 2021 Mar 30;3(3):CD009098. doi: 10.1002/14651858.CD009098.pub3.

  PMID: 33784416 DERIVED

MeSH Terms

Conditions

Respiratory Distress Syndrome; Respiratory Insufficiency

Condition Hierarchy (Ancestors)

Lung Diseases; Respiratory Tract Diseases; Respiration Disorders

Study Officials

• Ewan Goligher, MD, PhD

  University Health Network, Toronto

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: NONE
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: April 6, 2018
• First Posted: July 18, 2018
• Study Start: March 1, 2019
• Primary Completion: March 31, 2021
• Study Completion: August 31, 2021
• Last Updated: November 21, 2023

Record last verified: 2020-08

Data Sharing

• IPD Sharing: Will not share

Locations

CA (1)