Effects of Different PEEP Levels on Work of Breathing in Morbidly Obese Patients Prior to and After Extubation

February 18, 2026 updated by: Lorenzo Berra, MD, Massachusetts General Hospital

The main purpose of this study is to define at the bedside the "Titrated-PEEP" level for obese patients that increases the likelihood of extubation and ventilator liberation.

The investigators hypothesized that a titrated level of PEEP ("Titrated-PEEP") during SBT will keep the lung recruited, maintain oxygenation, and decrease the work of breathing resulting in successful ventilator liberation. In addition, post-extubation the investigators hypothesize that these patients will require noninvasive ventilatory support in the form of CPAP at the level of "titrated-PEEP" used during the SBT.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Withdrawn

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

The high WOB of morbidly obese patients is associated with respiratory muscle fatigue and failure in extubation. The investigators hypothesized that the use of a titrated PEEP level prior to and after extubation might improve successful extubation rates and avoid re-intubation.

In this study, patients will be awake and ventilated in the pressure support ventilation (PSV) mode. The investigators will apply different PEEP levels to measure WOB, transpulmonary pressure and characterize the response of the respiratory system to increasing or decreasing PEEP. The "Titrated-PEEP" will be identified as the PEEP level associated with the lowest value of respiratory system elastance and an end expiratory transpulmonary pressure of 2 cmH2O. Then the participants will have two spontaneous breathing trials; one at PEEP 0-5 cmH2O, and the other at the "Titrated-PEEP" level, with PSV=0 and FiO2 unchanged. After extubation, the participants will first receive CPAP set at "Titrated-PEEP", then spontaneous breathing. Electrical impedance tomography (EIT), respiratory system mechanics and gas exchange will be recorded during the study.

The investigators believe that the real-time determination of "Titrated-PEEP" can guide the treatment of mechanical ventilation and give us a better understanding of the physiology and pathophysiology of morbidly obese patients. As a result, this study will improve patient safety; reduce the duration of mechanical ventilation, complications and healthcare costs.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • United States
    • Massachusetts
      • Boston, Massachusetts, United States, 02114
        • Massachussets General Hospital

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

14 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Intubated and mechanically ventilated;
  • Weaning from mechanical ventilation;
  • BMI ≥ 35 kg/m2 with waist circumference > 88 cm for women; waist circumference > 102 cm for men.
  • A well functioning arterial line.

Exclusion Criteria:

  • Known presence of esophageal varices
  • Recent esophageal trauma or surgery
  • Severe thrombocytopenia (PTL ≤ 5,000/mm3)
  • Severe coagulopathy (INR ≥ 4)
  • Presence of pneumothorax
  • Pregnancy
  • Pacemaker and/or internal cardiac defibrillator

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: N/A
  • Interventional Model: Single Group Assignment

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: Patients with BMI > 35

ICU patients with a BMI > 35, on pressure support ventilation, scheduled for spontaneous breathing trial for evaluation of extubation

After recruitment maneuver and decremental PEEP trial, the "Titrated-PEEP" is identified. Patients will have two spontaneous breathing trials (SBTs) in randomized order. Either the patient will receive SBT at PEEP = 0-5 cmH2O, with PSV=0 and FiO2 unchanged; or the patient will perform an SBT at "Titrated-PEEP", with the PSV=0 and FiO2 unchanged.
Procedure: Positive end-expiratory pressure (PEEP)
"Titrated-PEEP". After recruitment maneuver and decremental PEEP trial, the "Titrated-PEEP" is identified. Patients will have two spontaneous breathing trials (SBTs). In this arm, patients will have SBT at "Titrated-PEEP", with the PSV=0 and FiO2 unchanged.
Procedure: ZEEP
After recruitment maneuver and decremental PEEP trial, the "Titrated-PEEP" is identified. Patients will have two spontaneous breathing trials (SBTs). In this arm, patients will have SBT at PEEP = 0-5 cmH2O, with the PSV=0 and FiO2 unchanged.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Differences in WOB at titrated PEEP levels vs. ZEEP level
Time Frame: 24 hours
Work Of Breathing measured as J/L and J/min during a Spontaneous Breathing Trial at titrated PEEP vs. Work Of Breathing measured as J/L and J/min during a Spontaneous Breathing Trial at zero PEEP
24 hours

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Gas Exchange - Oxygenation
Time Frame: 24 hours
Difference in oxygenation as measured in mmHg of PaO2/FiO2 during a Spontaneous Breathing Trial at titrated PEEP and at zero PEEP.
24 hours
Gas Exchange - Arterial carbon dioxide
Time Frame: 24 hours
Difference in arterial carbon dioxide as measured in mmHg (PaCO2) during a Spontaneous Breathing Trial at titrated PEEP and at zero PEEP.
24 hours
Respiratory Mechanics - Compliance
Time Frame: 24 hours
Difference in Compliance, measured as ml/cmH2O, of the respiratory system, lungs and chest wall during a Spontaneous Breathing Trial at titrated PEEP and at zero PEEP.
24 hours
Gas Volume Distribution
Time Frame: 24 hours
Difference in the images of Electric Impedance Tomography measured as relative variation of regional impedance (deltaZ) (i.e. distribution of ventilation) during a Spontaneous Breathing Trial at titrated PEEP and at zero PEEP.
24 hours
Hemodynamics - Blood pressure
Time Frame: 24 hours
Changes in arterial blood pressures (BP, mmHg) during a Spontaneous Breathing Trial at titrated PEEP and at zero PEEP.
24 hours
Hemodynamics - Heart rate
Time Frame: 24 hours
Changes in heart rate (HR, bpm) during a Spontaneous Breathing Trial at titrated PEEP and at zero PEEP.
24 hours

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Massachusetts General Hospital

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Lorenzo Berra, MD, Massachusetts General Hospital
  • Principal Investigator: Robert Kacmarek, RRT, PhD, Massachusetts General Hospital

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
November 1, 2015

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
November 24, 2025

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
November 24, 2025

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
June 12, 2015

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
July 2, 2015

First Posted (Estimated)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
July 8, 2015

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
February 20, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
February 18, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
February 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • WOBTRIAL

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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