PEEP-induced Effects on Respiratory dRivE and EFfort

Official title

Unraveling PEEP-induced Effects on Respiratory dRivE and EFfort in Acute Hypoxemic Respiratory Failure: the REEF Study

Overview

Rationale: In patients with acute hypoxemic respiratory failure (AHRF), preserving spontaneous breathing during mechanical ventilation offers physiological benefits, but also carries risks. While spontaneous breathing improves gas exchange and limits diaphragm atrophy, strong inspiratory efforts may worsen lung and diaphragm injury. Balancing these factors requires refined and tailored strategies, such as the modulation of PEEP. However, the impact of PEEP on neural respiratory drive and inspiratory effort is very heterogenous, and these two entities have only been studied separately in limited subsets of patients and healthy subjects. Additionally, it remains unclear whether the major determinant of PEEP-induced changes in respiratory drive and effort is represented by variations in diaphragm geometry, lung compliance, or by the presence of expiratory muscles recruitment, which may counteract its effect. Objective: The primary objective is to determine the effect of PEEP on diaphragm neuromechanical efficiency (i.e. an index of neural respiratory drive and inspiratory effort) in patients with acute hypoxemic respiratory failure during invasive assisted mechanical ventilation. The secondary objective is to determine the major physiological contributors to PEEP-mediated changes in diaphragm neuromechanical efficiency. Study design: Prospective, physiological study. Study population: Invasively mechanically ventilated adult patients admitted to the ICU. Intervention: For each patient, six different PEEP levels (15-12-10-8-5-2 cmH2O) will be tested during a decremental PEEP trial. During each step, neural respiratory drive, inspiratory effort, expiratory muscle activity, lung inflation pattern through electrical impedance tomography, respiratory muscle geometry and function through ultrasound and surface EMG, gas exchange and hemodynamics data will be collected. Main study parameters/endpoints: The primary outcome of the study will be the evaluation of PEEP-mediated changes in diaphragm neuromechanical efficiency (NME).

Interventions

• Other PEEP level changes
  For each patient, six different PEEP levels (15-12-10-8-5-2 cmH2O) will be tested during a decremental PEEP trial. During each step, neural respiratory drive, inspiratory effort, expiratory muscle activity, lung inflation pattern through electrical impedance tomography, respiratory muscle geometry and function through ultrasound and surface EMG, gas exchange and hemodynamics data will be collected.

Primary outcome measures

• PEEP-related changes in diaphragm neuromechanical efficiency (NME) [Time frame: Measurements will be conducted throughout the protocol at each of the 6 PEEP levels tested: 15, 12, 10, 8, 5 and 2 cmH2O. Each PEEP step will last 30 minutes, and measurements will be collected recording the last 10 minutes of each step.]

Secondary outcome measures (12)

• PEEP-induced changes in inspiratory effort [Time frame: Measurements will be conducted throughout the protocol at each of the 6 PEEP levels tested: 15, 12, 10, 8, 5 and 2 cmH2O. Each PEEP step will last 30 minutes, and measurements will be collected recording the last 10 minutes of each step.]
• PEEP-induced changes in neural respiratory drive [Time frame: Measurements will be conducted throughout the protocol at each of the 6 PEEP levels tested: 15, 12, 10, 8, 5 and 2 cmH2O. Each PEEP step will last 30 minutes, and measurements will be collected recording the last 10 minutes of each step.]
• PEEP-induced effects on partitioned respiratory system mechanics [Time frame: Measurements will be conducted throughout the protocol at each of the 6 PEEP levels tested: 15, 12, 10, 8, 5 and 2 cmH2O. Each PEEP step will last 30 minutes, and measurements will be collected recording the last 10 minutes of each step.]
• PEEP induced effects on tidal volume [Time frame: Measurements will be conducted throughout the protocol at each of the 6 PEEP levels tested: 15, 12, 10, 8, 5 and 2 cmH2O. Each PEEP step will last 30 minutes, and measurements will be collected recording the last 10 minutes of each step.]
• PEEP-induced effects on end-expiratory lung impedance [Time frame: Measurements will be conducted throughout the protocol at each of the 6 PEEP levels tested: 15, 12, 10, 8, 5 and 2 cmH2O. Each PEEP step will last 30 minutes, and measurements will be collected recording the last 10 minutes of each step.]
• PEEP-induced effects on amount of pendelluft [Time frame: Measurements will be conducted throughout the protocol at each of the 6 PEEP levels tested: 15, 12, 10, 8, 5 and 2 cmH2O. Each PEEP step will last 30 minutes, and measurements will be collected recording the last 10 minutes of each step.]
• PEEP-induced changes in diaphragm thickening fraction assessed through ultrasound [Time frame: Measurements will be conducted throughout the protocol at each of the 6 PEEP levels tested: 15, 12, 10, 8, 5 and 2 cmH2O. Each PEEP step will last 30 minutes, and measurements will be collected once within the last 10 minutes of each step.]
• PEEP-induced effects on internal oblique muscle thickening fraction [Time frame: Measurements will be conducted throughout the protocol at each of the 6 PEEP levels tested: 15, 12, 10, 8, 5 and 2 cmH2O. Each PEEP step will last 30 minutes, and measurements will be collected once within the last 10 minutes of each step.]
• PEEP-induced changes in gastric pressure during expiration [Time frame: Measurements will be conducted throughout the protocol at each of the 6 PEEP levels tested: 15, 12, 10, 8, 5 and 2 cmH2O. Each PEEP step will last 30 minutes, and measurements will be collected recording the last 10 minutes of each step.]
• PEEP-induced changes in abdominal wall muscles expiratory activity [Time frame: Measurements will be conducted throughout the protocol at each of the 6 PEEP levels tested: 15, 12, 10, 8, 5 and 2 cmH2O. Each PEEP step will last 30 minutes, and measurements will be collected recording the last 10 minutes of each step.]
• PEEP-induced effects on gas exchange [Time frame: Measurements will be conducted throughout the protocol at baseline and at each of the 6 PEEP levels tested: 15, 12, 10, 8, 5 and 2 cmH2O. Each PEEP step will last 30 minutes, and measurements will be collected once in the last 10 minutes of each step.]
• PEEP-induced effects on arterial blood pressure [Time frame: Measurements will be conducted throughout the protocol at baseline and at each of the 6 PEEP levels tested: 15, 12, 10, 8, 5 and 2 cmH2O. Each PEEP step will last 30 minutes, and measurements will be collected once in the last 10 minutes of each step.]

Eligibility criteria

Inclusion criteria

• Age > 18 years
• Acute hypoxemic respiratory failure (AHRF) with a PaO2/FiO2-ratio ≤ 200
• Patient on invasive assisted mechanical ventilation in pressure support mode exhibiting valid inspiratory efforts (occlusion pressure > 5 cmH2O).

Exclusion criteria

• Pre-existent neuromuscular disease
• History of chronic respiratory failure requiring long-term oxygen therapy
• Muscle paralysis
• Pneumothorax
• Contra-indication to EIT monitoring (e.g. burns, pacemaker, thoracic wounds limiting electrode placement)
• Contra-indications for EAdi or oesophageal balloon catheter placement (e.g. history of gastric bypass surgery, gastro-oesophageal junction surgery, oesophageal stricture, recent upper gastrointestinal hemorrhage or known/suspected varices).

Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.

Healthy volunteers: No

Study design

Allocation

N/A

Model

Single group

Masking

Open label

Primary purpose

Other

Study locations

Netherlands · 1 center

• Radboudumc — Nijmegen

Identifiers

NCT: NCT07203781 · NL-009995

Primary sources (government registries)

• ClinicalTrials.gov (US NIH)

View this study on ClinicalTrials.gov ↗