Estimation of P0.1 Using Ultrasound Indexes of Diaphragm Function (PoccUS)

April 27, 2026 updated by: Assistance Publique - Hôpitaux de Paris

Estimation of Airway Occlusion Pressure at 100 ms Using Ultrasound Indexes of Diaphragm Function

Occlusion pressure at 100 ms (P0.1) is a reliable and non-invasive index of inspiratory drive that can be measured easily on most ventilator. Unfortunately, P0.1 cannot be measured reliably in non-intubated patients. In those receiving non-invasive ventilation, the measurement of P0.1 might be inaccurate due to leaks. P0.1 cannot be measured at all in patients receiving high-flow nasal canulae (HFNC).

Ultrasound indices of diaphragm contractile function, namely diaphragm excursion, velocity and thickening fraction, could be reliable and non-invasive proxies of respiratory drive in non-intubated patient.

Our hypothesis is that ultrasound indices of diaphragm function may reliably estimate P0.1. To validate this hypothesis, theses indices will be measured simultaneously with P0.1 in intubated patients, during diaphragm loading conditions similar to spontaneous breathing: the spontaneous breathing trial (SBT). The SBT is used to evaluate if patients can breathe without the assistance provided by the ventilator, and thus, be weaned from mechanical ventilation.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Not yet recruiting

Conditions

Conditions

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Intervention / Treatment

Intervention / Treatment

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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.
Observational

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
40

Participation Criteria

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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

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Sampling Method

Non-Probability Sample

Study Population

Patients admitted to the intensive care unit who are intubated or have undergone a tracheostomy.

Description

Inclusion Criteria:

  • - Age ≥ 18 years old
  • Patient intubated or tracheostomized
  • Decision by the clinician in charge to initiate a SBT
  • After information, the patient or next of kind did not refuse to participate (according to the French law, written informed consent is waived)

Exclusion Criteria:

  • - Suspicion of diaphragmatic nerves injury
  • Preexisting neuromuscular disease
  • Spinal cord injury above C5
  • Neuromuscular blockade within last 24 hours
  • Body mass index > 40 kg/m2
  • Pregnancy or breast feeding
  • Patient under legal protection

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

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
P0.1 and Peak contraction velocity 5 minutes after the initiation of the SBT
Time Frame: 5 minutes after the initiation of the SBT
Airway occlusion pressure measured 100 ms after the initiation of the inspiration, compared to peak contraction velocity of the diaphragm, measured by subcostal ultrasound in TDI-mode
5 minutes after the initiation of the SBT

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
P0.1 and EXdi
Time Frame: Immediately after the initiation of the SBT then 5, 10, 15, 20, 25 and 30 minutes after the initiation of the SBT
Airway occlusion pressure measured 100 ms after the initiation of the inspiration, compared to maximal excursion of the diaphragm, measured by subcostal ultrasound in M-mode
Immediately after the initiation of the SBT then 5, 10, 15, 20, 25 and 30 minutes after the initiation of the SBT
P0.1 and Peak contraction velocity
Time Frame: Immediately after the initiation of the SBT then 10, 15, 20, 25 and 30 minutes after the initiation of the SBT
Airway occlusion pressure measured 100 ms after the initiation of the inspiration, compared to peak contraction velocity of the diaphragm, measured by subcostal ultrasound in TDI-mode
Immediately after the initiation of the SBT then 10, 15, 20, 25 and 30 minutes after the initiation of the SBT
P0.1 and EXdi,0.1
Time Frame: Immediately after the initiation of the SBT then 10, 15, 20, 25 and 30 minutes after the initiation of the SBT
Airway occlusion pressure measured 100 ms after the initiation of the inspiration, compared to excursion of the diaphragm measured 100 ms after the beginning of the inspiration, measured by subcostal ultrasound in M-mode
Immediately after the initiation of the SBT then 10, 15, 20, 25 and 30 minutes after the initiation of the SBT
P0.1 and Velocity Time Integral
Time Frame: Immediately after the initiation of the SBT then 10, 15, 20, 25 and 30 minutes after the initiation of the SBT
Airway occlusion pressure measured 100 ms after the initiation of the inspiration, compared to velocity time integral of the diaphragm, measured by subcostal ultrasound in TDI-mode
Immediately after the initiation of the SBT then 10, 15, 20, 25 and 30 minutes after the initiation of the SBT
P0.1 and Peak relaxation velocity
Time Frame: Immediately after the initiation of the SBT then 10, 15, 20, 25 and 30 minutes after the initiation of the SBT
Airway occlusion pressure measured 100 ms after the initiation of the inspiration, compared to peak relaxation velocity of the diaphragm, measured by subcostal ultrasound in TDI-mode
Immediately after the initiation of the SBT then 10, 15, 20, 25 and 30 minutes after the initiation of the SBT
P0.1 and Peak relaxation rate
Time Frame: Immediately after the initiation of the SBT then 10, 15, 20, 25 and 30 minutes after the initiation of the SBT
Airway occlusion pressure measured 100 ms after the initiation of the inspiration, compared to peak relaxation rate of the diaphragm, measured by subcostal ultrasound in TDI-mode
Immediately after the initiation of the SBT then 10, 15, 20, 25 and 30 minutes after the initiation of the SBT
P0.1 and TFdi
Time Frame: Immediately after the initiation of the SBT then 10, 15, 20, 25 and 30 minutes after the initiation of the SBT
Airway occlusion pressure measured 100 ms after the initiation of the inspiration, compared to thickening fraction of the diaphragm, measured by intercostal ultrasound in M-mode.
Immediately after the initiation of the SBT then 10, 15, 20, 25 and 30 minutes after the initiation of the SBT
P0.1 and mean thickening velocity
Time Frame: Immediately after the initiation of the SBT then 10, 15, 20, 25 and 30 minutes after the initiation of the SBT
Airway occlusion pressure measured 100 ms after the initiation of the inspiration, compared to mean thickening velocity of the diaphragm, measured by intercostal ultrasound in M-mode.
Immediately after the initiation of the SBT then 10, 15, 20, 25 and 30 minutes after the initiation of the SBT

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.
Assistance Publique - Hôpitaux de Paris

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 (Estimated)

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.
July 1, 2026

Primary Completion (Estimated)

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.
January 1, 2027

Study Completion (Estimated)

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.
January 1, 2027

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).
April 27, 2026

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.
April 27, 2026

First Posted (Actual)

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.
May 4, 2026

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.
May 4, 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.
April 27, 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.
April 1, 2026

More Information

Terms related to this study

Keywords

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.
  • APHP260589

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

IPD Plan Description

The procedures carried out with the French data privacy authority (CNIL, Commission nationale de l'informatique et des libertés) do not provide for the transmission of the database, nor do the information and consent documents signed by the patients.

Consultation by the editorial board or interested researchers of individual participant data that underlie the results reported in the article after deidentification may nevertheless be considered, subject to prior determination of the terms and conditions of such consultation and in respect for compliance with the applicable regulations.

IPD Sharing Time Frame

Beginning 3 months and ending 3 years following article publication. Requests out of these time frame can also be submitted to the sponsor

IPD Sharing Access Criteria

Researchers who provide a methodologically sound proposal.

IPD Sharing Supporting Information Type

  • STUDY_PROTOCOL
  • ICF

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

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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