Assessing Lung Inhomogeneity During Ventilation for Acute Hypoxemic Respiratory Failure

NCT ID: NCT03589482

Last Updated: 2023-11-21

Basic Information

• Recruitment Status: COMPLETED
• Clinical Phase: NA
• Total Enrollment: 20 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2019-03-01
• Study Completion Date: 2021-08-31

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.

Detailed Description

Patients participating in this physiological cross-over randomized trial will undergo a series of PEEP maneuvers designed to assess lung recruitability, PEEP responsiveness, and optimal PEEP. EIT imaging and esophageal manometry will be employed throughout the protocol to quantify the effect of PEEP on lung function. Patients will be randomized to be ventilated at PEEP levels supplied by the ExPRESS strategy or by the EIT hyperdistention/collapse algorithm. The biological response will be assessed by measuring serum cytokines.

Conditions

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

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: PARALLEL
• Primary Study Purpose: TREATMENT
• Blinding Strategy: NONE

Study Groups

EIT algorithm

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.

Group Type: EXPERIMENTAL

Electrical Impedance Tomography

Intervention Type: 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.

ExPRESS algorithm

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.

Group Type: ACTIVE_COMPARATOR

ExPRESS-derived PEEP level

Intervention Type: OTHER

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

Interventions

Electrical Impedance Tomography

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.

Intervention Type: DEVICE

ExPRESS-derived PEEP level

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

Intervention Type: OTHER

Eligibility Criteria

Inclusion Criteria

• 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

Exclusion Criteria

• 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

• Minimum Eligible Age: 18 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: No

Sponsors

University Health Network, Toronto

OTHER

Sponsor Role: lead

Responsible Party

Responsibility Role: SPONSOR

Principal Investigators

Ewan Goligher, MD, PhD

Role: PRINCIPAL_INVESTIGATOR

University Health Network, Toronto

Locations

University Health Network

Toronto, Ontario, Canada

Countries

Canada

References

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.

Reference Type: DERIVED

PMID: 33784416 (View on PubMed)

Other Identifiers

17-6226

Identifier Type: OTHER

Identifier Source: secondary_id

18-6091

Identifier Type: -

Identifier Source: org_study_id