Non-invasive Assessment of Inspiratory Effort and Tidal Distension During Non-invasive Ventilation (INSPIRE) (INSPIRE)

January 8, 2026 updated by: Salvatore Grasso, University of Bari

Noninvasive Assessment of Inspiratory Effort and Tidal Distension During Noninvasive Ventilation. The INSPIRE Study.

The goal of this observational study is to evaluate whether the airway occlusion pressure recorded during a sudden end-expiratory breath-hold (ΔPocc) is correlated with esophageal swing in pressure and the reliability of P0.1, driving pressure, plateau pressure, pressure-muscle index, and diaphragm ultrasound as noninvasive estimates of inspiratory effort and lung distension in hypoxemic patients undergoing NIV.

The main questions this trial aims to answer are:

- Primary Outcome: whether the airway occlusion pressure recorded during a sudden end-expiratory breath-hold (ΔPocc) is correlated with esophageal swing in pressure and the reliability of various noninvasive estimates of inspiratory effort and lung distension in hypoxemic patients undergoing NIV.

Secondary outcomes will include:

  • Statistic metric of association between P0.1, ΔP, PMI and ΔPes
  • Statistic metric of association between P0.1, ΔPocc, ΔP, PMI and PaO2/FiO2 ratio
  • Statistic metric of association between P0.1, ΔPocc, ΔP, PMI and tidal volume
  • Statistic metric of association between P0.1, ΔPocc, ΔP, PMI and DTF%
  • Statistic metric of association between P0.1, ΔPocc, ΔP, PMI and Ex/DTF%
  • Statistic metric of association between P0.1, ΔPocc, ΔP, PMI and respiratory rate, VAS dyspnea and VAS discomfort.

Participants will undergo the following tasks and treatments:

  • Complete written informed consent before enrollment.
  • Post-extubation noninvasive ventilation via nose-to-mouth and full-face masks.
  • Monitoring of esophageal pressure (in all patients the catheter will be placed before extubation, according to clinical judgment, and its correct position will be verified through a positive pressure occlusion test)
  • Continuous recording of airway pressure, flow, and esophageal pressure (Pes), using a dedicated pneumotachograph and pressure transducer.
  • Sudden end-inspiratory and end-expiratory occlusion maneuvers, to measure plateau pressure (Pplat) and end-expiratory airway occlusion pressure (ΔPocc), respectively.
  • Collection of hemodynamic and arterial blood-gas parameters, performed according to clinical judgment, along with assessments of dyspnea and discomfort using a modified visual analogue scale (VAS).
  • Diaphragm ultrasound during occlusion maneuvers, measuring diaphragm displacement, diaphragm thickening fraction (DTF%), and diaphragmatic excursion (Ex) under various conditions.

Study Overview

Status

Active, not recruiting

Conditions

Intervention / Treatment

Study Type

Observational

Enrollment (Actual)

60

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

  • Italy
    • Bari
      • Bari, Bari, Italy, 70124
        • Azienda Ospedaliero-Universitaria Consorziale Policlinico di Bari

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

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Sampling Method

Non-Probability Sample

Study Population

All hypoxemic patients with a PaO2/FiO2 ratio equal or lower than 300, receiving post-extubation noninvasive ventilation via an nose-to-mouth or a full-face mask, will be screened for eligibility.

Description

Inclusion Criteria:

  • Age greater than or equal to 18 years.
  • Non-pregnant and non-lactating.
  • Monitored through esophageal pressure for clinical decision before extubation.
  • Able to provide written informed consent to participate in the study.

Exclusion Criteria:

  • Patients with severe facial trauma or deformity that precludes the placement of a facemask or esophageal catheter.
  • Patients with neuromuscular disorders that may impair inspiratory drive and effort.
  • Patients with acute exacerbation of COPD
  • Patients with esophageal or tracheal abnormalities that impede esophageal manometry.
  • Patients with a known hypersensitivity or allergy to any of the materials used in the study.
  • Excessive air leak (difference between inspiratory and expiratory tidal volume major or equal to 30% [prot. n 1136947]).

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

Cohorts and Interventions

Group / Cohort
Intervention / Treatment
Cohort (n=60)

All hypoxemic patients with a PaO2/FiO2 ratio equal or lower than 300, receiving post-extubation noninvasive ventilation.

Participants will undergo the following tasks and treatments:

  • Complete written informed consent before enrollment.
  • Post-extubation noninvasive ventilation via nose-to-mouth and full-face masks.
  • Monitoring of esophageal pressure
  • Continuous recording of airway pressure, flow, and esophageal pressure (Pes), using a dedicated pneumotachograph and pressure transducer.
  • Sudden end-inspiratory and end-expiratory occlusion maneuvers.
  • Collection of hemodynamic and arterial blood-gas parameters, performed according to clinical judgment, along with assessments of dyspnea and discomfort using a modified visual analogue scale (VAS).
  • Diaphragm ultrasound during occlusion maneuvers, measuring diaphragm displacement, diaphragm thickening fraction (DTF%), and diaphragmatic excursion (Ex) under various conditions.
Diagnostic test: End-inspiratory Maneuvers
Airway pressure, flow, and esophageal pressure will be continuously recorded in all patients using a dedicated pneumotachograph and pressure transducer: all signals will be acquired and stored. Once a stable ventilation pattern is observed NIV will be administered by setting ventilator in invasive-pressure support ventilation. PEEP and PS-level will by kept constant while expiratory trigger will be adjusted to optimize patient-ventilatory synchrony. Immediately after, sudden end-inspiratory and end-expiratory occlusion maneuvers will be performed to measure plateau pressure and end-expiratory airway occlusion pressure (ΔPocc), respectively. Invasive PSV will be used only to perform the occlusion maneuvers, subsequently, PSV will be delivered in non-invasive PSV mode. Patient's blood-gas parameters and vital signs will be collected, including discomfort assessment. During the occlusion maneuvers, diaphragm ultrasound will be performed, and images will be recorded.
Other Names:
  • End-Expiratory Occlusion Maneuvers
  • Esophageal pressure monitoring
  • Diaphragmatic ultrasounds

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Statistic metric of association between ΔPocc and ΔPes
Time Frame: 24 hours
to evaluate whether the airway occlusion pressure recorded during a sudden end-expiratory breath-hold (ΔPocc) is correlated with esophageal swing in pressure
24 hours

Secondary Outcome Measures

Outcome Measure
Time Frame
Statistic metric of association between P0.1, ΔP, PMI and ΔPes
Time Frame: 24 hours
24 hours
Statistic metric of association between P0.1, ΔPocc, ΔP, PMI and PaO2/FiO2 ratio
Time Frame: 24 hours
24 hours
Statistic metric of association between P0.1, ΔPocc, ΔP, PMI and tidal volume
Time Frame: 24 hours
24 hours
Statistic metric of association between P0.1, ΔPocc, ΔP, PMI and DTF%
Time Frame: 24 hours
24 hours
Statistic metric of association between P0.1, ΔPocc, ΔP, PMI and Ex/DTF%
Time Frame: 24 hours
24 hours
Statistic metric of association between P0.1, ΔPocc, ΔP, PMI and respiratory rate, VAS dyspnea and VAS discomfort
Time Frame: 24 hours
24 hours

Other Outcome Measures

Outcome Measure
Measure Description
Time Frame
Reliability of various noninvasive estimates of inspiratory effort and lung distension in hypoxemic patients undergoing NIV
Time Frame: 24 hours
To investigate the reliability of P0.1, driving pressure, plateau pressure, pressure-muscle index, and diaphragm ultrasound as noninvasive estimates of inspiratory effort and lung distension in hypoxemic patients undergoing NIV
24 hours

Collaborators and Investigators

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

Sponsor

University of Bari

Investigators

  • Study Chair: Salvatore Grasso, Prof, Azienda Ospedaliero-Universitaria "Consorziale Policlinico" Bari

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

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 (Actual)

November 1, 2023

Primary Completion (Estimated)

May 1, 2026

Study Completion (Estimated)

June 1, 2026

Study Registration Dates

First Submitted

March 27, 2024

First Submitted That Met QC Criteria

March 27, 2024

First Posted (Actual)

April 3, 2024

Study Record Updates

Last Update Posted (Estimated)

January 12, 2026

Last Update Submitted That Met QC Criteria

January 8, 2026

Last Verified

November 1, 2025

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 0049191

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

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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