Lung Response to a Higher PEEP During Severe Pneumonia: a CT Study

NCT07112976 | Completed

• 1 other identifier: Studio retrospettivo n. 28/25
• Study Type: observational
• Target: 47
• Locations: 1 country
• Sites: 1

Brief Summary

At their institution, the investigators routinely assess the individual response of mechanically ventilated patients with acute respiratory failure to higher positive end-expiratory pressure (PEEP) by examining changes in lung aeration through lung computed tomography (CT). They typically obtain two lung CT scans during an end-expiratory hold, one at a PEEP of 10 cmH2O and another at 15 cmH2O. Recruitment and hyperinflation are measured by assessing the decrease in the volume of non-aerated lung regions (with a density greater than -100 HU) and the increase in the volume of hyperinflated lung regions (with a density of less than -900 HU) between the two CT scans. If recruitment exceeds hyperinflation, the response to higher PEEP is considered "positive", and medical doctors are encouraged to treat that patient with a higher PEEP. Conversely, if hyperinflation exceeds recruitment, the response is deemed "negative", and a higher PEEP is discouraged. This assessment is further complemented by a "PEEP test," during which gas exchange (specifically arterial oxygen and carbon dioxide tension) and respiratory system mechanics (including compliance) are evaluated while ventilating with PEEP levels of 10 and 15 cmH2O. In this retrospective analysis, the investigators will focus on patients with severe pneumonia who underwent the two lung CTs as part of their routine clinical practice. They will retrieve data on primary demographic characteristics, significant comorbidities, causes of pneumonia, severity of acute illness, and treatments delivered. Additionally, they will review the results of the quantitative analysis of the lung CT scans taken at 10 and 15 cmH2O, and the PEEP tests. The primary aim of this study is to determine the proportion of patients with net hyperinflation in response to higher PEEP.

Conditions

Severe Pneumonia

Keywords

Mechanical ventilation; Positive end-expiratory pressure; Hyperinflation; Recruitment; Computed tomography

Outcome Measures

Primary Outcomes (1)

• Lung response to a higher PEEP

  The primary study objective is to evaluate the effects of higher PEEP with quantitative analysis of lung CT scans in patients with severe pneumonia. We hypothesize that 50% of these patients will exhibit more hyperinflation than recruitment. We measure recruitment and hyperinflation by assessing the change in the volume of non-aerated lung regions (with a density greater than -100 HU) and hyperinflated lung regions (with a density of less than -900 HU) between the two CT scans.

  The effects of a higher PEEP will be assessed by comparing the CT scans taken at ICU admission, with a PEEP of 10 or 15 cmH2O, within the same subject. Usually, the interval between the two CT scans is a few minutes.

Eligibility Criteria

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

Study Population

Adults admitted to the ICU with severe pneumonia, treated with mechanical ventilation

You may qualify if:

• adult (≥18 years of age) patients
• admitted to ICU from 1/10/2022 to 31/12/2024
• with severe pneumonia
• treated with mechanical ventilation
• who underwent the two lung CTs at 10 and 15 cmH2O

You may not qualify if:

• pneumothorax
• pneumomediastinum
• lung CT was obtained with contrast medium to rule out pulmonary embolism

Sponsors & Collaborators

• Istituto Clinico Humanitas: lead

Study Sites (1)

IRCCS Humanitas Research Hospital

Milan, Italy

Location

Related Publications (1)

• 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

MeSH Terms

Conditions

Pneumonia

Condition Hierarchy (Ancestors)

Respiratory Tract Infections; Infections; Lung Diseases; Respiratory Tract Diseases

Study Design

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

Study Record Dates

• First Submitted: July 3, 2025
• First Posted: August 8, 2025
• Study Start: October 1, 2022
• Primary Completion: December 31, 2024
• Study Completion: December 31, 2024
• Last Updated: August 13, 2025

Record last verified: 2025-08

Data Sharing

• IPD Sharing: Will not share

Locations

IT (1)