Association Between EIT and CT During PEEP Titration in Patients With Acute Respiratory Failure

NCT07175194 | Not Yet Recruiting

• 1 other identifier: TAC-EIT-20-5
• Study Type: observational
• Target: 30
• Locations: 0 countries
• Sites: N/A

Brief Summary

This observational study will analyze data already collected by the investigators as part of their routine clinical practice from patients with acute respiratory failure (ARF) treated with mechanical ventilation. The study itself does not require any specific intervention. Mechanical ventilation can save the lives of patients with ARF. However, if used improperly, it can exacerbate lung disease and worsen outcomes (Slutsky et al.). Despite decades of animal and clinical research, it remains unclear how to establish the positive end-expiratory pressure (PEEP) during mechanical ventilation to reduce the risk of lung damage. Several methods have been suggested, but none have consistently proven superior to the others (Sahetya et al.). As part of their routine clinical practice, the investigators study the responses to different PEEP levels of patients with ARF undergoing mechanical ventilation by integrating information from various techniques, each examining different aspects of lung morphology and physiology. The methods the investigators use include lung computed tomography (CT) and electrical impedance tomography (EIT). Lung CT is the reference technique for measuring the morphological response to PEEP (Gattinoni et al.). It quantifies the volume of the hyperinflated and non-aerated lung, both of which are related to the risk of mechanical ventilation causing damage (Slutsky et al.). Lung EIT monitors the functional response to PEEP in terms of changes in regional compliance across different PEEP levels. Allegedly, an increase in compliance when PEEP is decreased reveals overdistention, the functional correlate of (worrisome) hyperinflation, at the higher PEEP. A decrease in compliance when PEEP is decreased signals new collapse, the functional correlate of (worrisome) loss of aeration (Franchineau et al.). In the Unit where the investigators work, patients with ARF treated with mechanical ventilation are routinely studied as follows. First, a lung CT with a PEEP of 20 cmH2O and then of 5 cmH2O is obtained. Thereafter, a decremental PEEP test is performed with the EIT, where PEEP is decreased from 20 cmH2O down to 5 cmH2O in steps of 2 or 3 cmH2O. Finally, results are analyzed and compared offline. At the lung CT, decreasing PEEP from 20 to 5 cmH2O is always associated with some decrease in the volume of the hyperinflated lung and some increase in the volume of the non-aerated lung. However, the magnitude of these two effects varies among individuals, and the net response may be defined as the difference between those two competing effects. If the decrease in the volume of the hyperinflated lung is greater than the increase in the volume of the non-aerated lung, the overall response (i.e., less hyperinflation) can be considered positive. PEEP should then be set closer to 5 than to 20 cmH2O. Diversely, if the decrease in the volume of the hyperinflated lung is smaller than the increase in the volume of the non-aerated lung, the overall response (i.e., more loss of aeration) can be considered negative. PEEP should then be set closer to 20 cmH2O (Protti et al.). Similarly, at the lung EIT, decreasing PEEP from 20 to 5 cmH2O is always associated with compliance improvement in some regions (i.e., less overdistension) and worsening in others (i.e., more collapse). Again, the magnitude of these two opposite effects varies among individuals. According to most experts on lung EIT, PEEP should be set at the level where both overdistension and collapse are minimized (the so-called "best" PEEP) (Jonkman et al.). Lung CT requires transfer to the radiology unit, exposure of the patient to radiation, and complex analysis offline. By contrast, lung EIT is virtually risk-free, and analysis can be performed using an automatic algorithm. Nevertheless, lung EIT is less well validated than lung CT. For instance, the assumption that a decrease in compliance in response to a decrease in PEEP is due to new collapse has been questioned (Protti et al., Chiumello et al., Menga et al.). So far, lung CT remains the reference technique for studying individual responses to PEEP, while lung EIT requires further validation. This study aims to verify whether the "best" PEEP identified using lung EIT is strongly associated with the net response assessed using lung CT, when PEEP is decreased from 20 to 5 cmH2O in patients with ARF treated with mechanical ventilation. If so, this would strengthen the rationale for using the lung EIT (which is safer and simpler than the lung CT) to set PEEP.

Conditions

Acute Hypoxemic Respiratory Failure; Ventilation, Mechanical

Keywords

Positive End-Expiratory Pressure; Computed Tomography; Electrical Impedance Tomography

Outcome Measures

Primary Outcomes (1)

• Association Between Lung EIT and CT Findings During PEEP Titration

  The investigators will use the Spearman's correlation coefficient (rho) to measure the strength of the linear association between these two continuous variables: Y: the "best" PEEP identified with the EIT, as the PEEP level between 20 and 5 cmH2O where overdistension and collapse are minimal. This variable is measured in cmH2O. X: the overall net response to decreasing PEEP from 20 to 5 cmH2O, as assessed with the lung CT. This variable is the difference between the decrease in the volume of the hyperinflated lung and the increase in the volume of the non-aerated lung across the two PEEP levels and is measured in ml.

  Within 72 hours from the start of mechanical ventilation

Eligibility Criteria

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

Study Population

Adults admitted to the Intensive Care Unit of the IRCCS Humanitas Research Hospital, in Rozzano (Milan, Italy), with acute respiratory failure treated with mechanical ventilation

You may qualify if:

• Adults (≥18 years of age) admitted to our Unit with ARF treated with mechanical ventilation
• The patient undergoes a lung CT and EIT to guide the setting of PEEP as part of our routine clinical practice

You may not qualify if:

• The patient cannot undergo a lung CT and/or EIT as judged by the attending physician (for instance, transport to the radiology unit may be considered too risky if the patient is extremely severe, or using EIT may be contraindicated because of the presence of a pacemaker)
• Pregnancy (as this condition alters the respiratory physiology)

Sponsors & Collaborators

• Istituto Clinico Humanitas: lead

Related Publications (8)

• Slutsky AS, Ranieri VM. Ventilator-induced lung injury. N Engl J Med. 2013 Nov 28;369(22):2126-36. doi: 10.1056/NEJMra1208707. No abstract available.

  PMID: 24283226 BACKGROUND

• Sahetya SK, Goligher EC, Brower RG. Fifty Years of Research in ARDS. Setting Positive End-Expiratory Pressure in Acute Respiratory Distress Syndrome. Am J Respir Crit Care Med. 2017 Jun 1;195(11):1429-1438. doi: 10.1164/rccm.201610-2035CI.

  PMID: 28146639 BACKGROUND

• Gattinoni L, Caironi P, Cressoni M, Chiumello D, Ranieri VM, Quintel M, Russo S, Patroniti N, Cornejo R, Bugedo G. Lung recruitment in patients with the acute respiratory distress syndrome. N Engl J Med. 2006 Apr 27;354(17):1775-86. doi: 10.1056/NEJMoa052052.

  PMID: 16641394 BACKGROUND

• Franchineau G, Jonkman AH, Piquilloud L, Yoshida T, Costa E, Roze H, Camporota L, Piraino T, Spinelli E, Combes A, Alcala GC, Amato M, Mauri T, Frerichs I, Brochard LJ, Schmidt M. Electrical Impedance Tomography to Monitor Hypoxemic Respiratory Failure. Am J Respir Crit Care Med. 2024 Mar 15;209(6):670-682. doi: 10.1164/rccm.202306-1118CI.

  PMID: 38127779 BACKGROUND

• Protti A, Santini A, Pennati F, Chiurazzi C, Cressoni M, Ferrari M, Iapichino GE, Carenzo L, Lanza E, Picardo G, Caironi P, Aliverti A, Cecconi M. Lung Response to a Higher Positive End-Expiratory Pressure in Mechanically Ventilated Patients With COVID-19. Chest. 2022 Apr;161(4):979-988. doi: 10.1016/j.chest.2021.10.012. Epub 2021 Oct 16.

  PMID: 34666011 BACKGROUND

• Jonkman AH, Alcala GC, Pavlovsky B, Roca O, Spadaro S, Scaramuzzo G, Chen L, Dianti J, Sousa MLA, Sklar MC, Piraino T, Ge H, Chen GQ, Zhou JX, Li J, Goligher EC, Costa E, Mancebo J, Mauri T, Amato M, Brochard LJ; Pleural Pressure Working Group (PLUG). Lung Recruitment Assessed by Electrical Impedance Tomography (RECRUIT): A Multicenter Study of COVID-19 Acute Respiratory Distress Syndrome. Am J Respir Crit Care Med. 2023 Jul 1;208(1):25-38. doi: 10.1164/rccm.202212-2300OC.

  PMID: 37097986 BACKGROUND

• Chiumello D, Marino A, Brioni M, Cigada I, Menga F, Colombo A, Crimella F, Algieri I, Cressoni M, Carlesso E, Gattinoni L. Lung Recruitment Assessed by Respiratory Mechanics and Computed Tomography in Patients with Acute Respiratory Distress Syndrome. What Is the Relationship? Am J Respir Crit Care Med. 2016 Jun 1;193(11):1254-63. doi: 10.1164/rccm.201507-1413OC.

  PMID: 26699672 BACKGROUND

• Menga LS, Subira C, Wong A, Sousa M, Brochard LJ. Setting positive end-expiratory pressure: does the 'best compliance' concept really work? Curr Opin Crit Care. 2024 Feb 1;30(1):20-27. doi: 10.1097/MCC.0000000000001121. Epub 2023 Nov 29.

  PMID: 38085857 BACKGROUND

MeSH Terms

Conditions

Respiratory Insufficiency; Respiratory Aspiration

Condition Hierarchy (Ancestors)

Respiration Disorders; Respiratory Tract Diseases; Pathologic Processes; Pathological Conditions, Signs and Symptoms

Central Study Contacts

Alessandro Protti

CONTACT

+39 02 82244135; alessandro.protti@hunimed.eu

Study Design

• Study Type: observational
• Observational Model: COHORT
• Time Perspective: PROSPECTIVE
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: September 9, 2025
• First Posted: September 16, 2025
• Study Start: December 1, 2025
• Primary Completion (Estimated): March 1, 2027
• Study Completion (Estimated): June 1, 2027
• Last Updated: September 19, 2025

Record last verified: 2025-09

Data Sharing

• IPD Sharing: Will not share