Acute Hypoxemic Respiratory FailurePUMANCT06494085
Pressure Muscle Index and Threshold of Over-assistance During Pressure Support Ventilation
An observational study of Acute Hypoxemic Respiratory Failure, run by Unity Health Toronto at 1 site in Canada.
Trial summary
Pressure support ventilation (PSV) is used to assist the breathing of the intubated patient with some pressure from the ventilator. This support aims at avoiding excessive inspiratory effort, while ensuring a certain degree of training of the patient's inspiratory muscle. Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Acute Hypoxemic Respiratory Failure
- What is being tested?
- Measuring Respiratory Mechanics and Randomized Pressure Support
- How many people
- 20 participants
- Where
- 1 siteCanada
- Study dates
- 4 Oct 2024to 28 Feb 2026
- Phase
- Observational
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Study population: The Study population will include patients mechanically ventilated in the St. Michael's Intensive Care Unit. Patients who are younger than 18 years of age will be excluded from this study on the basis that the ICUs at St. Michael's Hospital are intended for adults; individuals aged less than 18 years are rarely, if ever, admitted.
Who may be able to join
- >18 y.o.
- Invasively ventilated in Intensive Care Unit.
- Diagnosed with acute hypoxemic respiratory failure (P/F<300 mmHg).
- Breathing on pressure support ventilation.
Who cannot join
- <18 y.o.
- Contraindication for Electrical Impedence Tomography monitoring (e.g. pacemaker, burns, or - wounds limiting electrode placement).
- Severe and previously diagnosed neurological and neuromuscular disease.
- Psychomotor agitation (Sedation Agitation Scale > 4).
Trial locations and contacts
1 site in 1 country.
Canada1 site, 1 recruiting
- Recruiting
St. Michael's Hospital
Toronto, Ontario, M5B 1W8
Laurent Brochard, MD, laurent.brochard@unityhealth.to
About this study
Official title: PressUre-Muscle-index to Identify Patient's Desired Tidal Volume and the Threshold of Over-Assistance During Pressure Support Ventilation
Pressure support ventilation (PSV) is used to assist the breathing of the intubated patient with some pressure from the ventilator. This support aims at avoiding excessive inspiratory effort, while ensuring a certain degree of training of the patient's inspiratory muscle. Avoiding both minimal and excessive assistance is thus important for the optimal care of the intubated patient ensuring a lung and diaphragm protective ventilation with the goal to liberate the patient from the ventilator as soon as possible.
Recently pressure-muscle-index (PMI), an index of inspiratory effort easy to be measured on the ventilator screen, has been proposed to avoid excessive assistance in PSV. This will be the first prospective study testing the effects of setting pressure support based on PMI to avoid excessive assistance on patients recovering from acute lung injury (acute hypoxemic respiratory failure).
Read the detailed description
First, for each patient enrolled the investigators will perform 1 inspiratory and 3 expiratory occlusions separated at least by 30 seconds at clinical PSV to measure respiratory mechanics (plateau pressure [Pplat] and respiratory system compliance [Crs] and elastance [Ers]) and inspiratory effort and drive (Pocc, P0.1, PMI) and Vt expressed in ml/Kg of predicted body weight.
Second, if PMI≥0 at baseline, the investigators will set Pressure Support (PS) so that positive end-expiratory pressure (PEEP) +PS (i.e. Peak pressure [Ppeak]) equals Pplat measured at baseline, in order to make PMI=0. If PMI<0 at baseline, the investigators will set PS so that PEEP+PS equals Pplat measured at baseline, then the investigators will perform an inspiratory occlusion and repeat the procedure until PMI=0. The PS level at which PMI=0 (PSPMI=0) and the corresponding breathing pattern (tial volume [Vt] and respiratory rate [RR]) will be used as reference for the study protocol. After 5 minutes at PSPMI=0 the investigators will perform 3 inspiratory and 3 expiratory occlusions separated at least by 30 seconds.
Third, each patient will undergo 3 steps of PS above (+2, +4, +6 cmH2O) and 3 below (-2, -4, -6 cmH2O) PSPMI=0 in a randomized order. Steps will be randomized using a simple sequence written within envelopes opened blindly by the investigators. Each step will last 5 minutes or less if poorly tolerated (see tolerance rules below). At the end of each step the investigators will perform 1 inspiratory occlusion and 3 expiratory occlusions. Each of the expiratory occlusion will be separated by 30 seconds in order to restore the patient's breathing pattern. The investigators will resume a 3-minutes clinical PS in between each step to minimize changes in PaCO2. If not yet comprised by the study steps each patient will undergo an adjunctive 5 minutes step at PS 0 (zero) cmH2O.
The study protocol will last approximately 60 minutes. The patient will be continuously monitored by a physician and a respiratory therapist.
At the end of the study, if different from clinically set PS, the investigators will propose clinicians to adjust the PS to target PMI>0 and a lung and diaphragm protective ventilation strategy following current literature. Data about PS setting at the end of the study will be recorded in the case report form.
Tolerance rules:
Protocol will be stopped if: heart rate >140 beats/min; increase in respiratory rate by 50% or more if not explained by ineffective effort; hypotension [systolic blood pressure <90 mmHg] or hypertension [systolic blood pressure >180 mmHg]; peripheral arterial oxygen saturation <90% for 5 minutes; excessive use of accessory respiratory muscles, diaphoresis, agitation, and the appearance of major abdominal or thoracic paradoxical movements. If apnea would appear at high PS levels (as described as overassistance), the PS will be decreased to the next lower level. PS will be set to not exceed a Ppeak of 30 cmH2O or a Vt of 12 mL/kg of predicted bodyweight
- Conditions
- Acute Hypoxemic Respiratory Failure
- Being tested
- Measuring Respiratory Mechanics, Randomized Pressure Support
- Keywords
- Mechanical Ventilation, Intensive Care Unit, Pendelluft, Pressure Support Ventilation
- Medical subject headings
- Respiratory Insufficiency
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Measuring Respiratory MechanicsOther
First, for each patient enrolled we will perform inspiratory and expiratory occlusions - routinely performed diagnostic maneuvers to measure patient's breathing effort - at the clinically set level of breathing assistance by the mechanical ventilator. Importantly, we will measure pressure-muscle-index (PMI).
Second, we will set the level of assistance (i.e. pressure support, PS) in order to make PMI=0. The PS level at which PMI=0 (PS PMI=0) will be used as reference for the study protocol. After 5 minutes at PS PMI=0 we will perform inspiratory and expiratory occlusions.
Randomized Pressure SupportOther
3 steps of PS above (+2, +4, +6 cmH2O) and 3 below (-2, -4, -6 cmH2O) PSPMI=0 done in a randomized order (sequence in envelopes opened blindly by the investigators). Each step will last ≤5 minutes if poorly tolerated (see tolerance rule in description). At the end of each step we will perform 1 inspiratory occlusion and 3 expiratory occlusions. Each of the expiratory occlusion will be separated by 30 seconds in order to restore the patient's breathing pattern. We will resume a 3-minutes clinical PS in between each step to minimize changes in PaCO2. If not yet comprised by the study steps each patient will undergo an adjunctive 5 minutes step at PS 0 (zero) cmH2O.
What is being measured
The primary outcome is the main question the study is designed to answer.
Inspiratory Occlusion
To investigate the role of the inspiratory occlusion as a diagnostic tool to understand the patient's desired tidal volume and minute ventilation in Pressure Support Ventilation (PSV),
Measured: 60 minutes
Pressure Muscle Index (PMI)
To investigate the role of a PMI>0 strategy to avoid over-assistance in Pressure Support Ventilation
Measured: 60 minutes
Secondary outcomes (2)
Pendelluft
To investigate the relationship between "active" and "passive" pendelluft measured over different levels of assistance in PSV.
Measured: 60 minutes
Lung and Diaphragm Protective Ventilation
To measure indexes proposed by current literature to target a lung and diaphragm protective ventilation strategy with both inspiratory and expiratory occlusions in PSV, while applying a PMI>0 strategy.
Measured: 60 minutes
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted10 Jul 2024
- Study start4 Oct 2024
- Primary completion28 Feb 2026 (estimated)
- Study completion28 Feb 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Acute Hypoxemic Respiratory FailureStudies of the same condition, open and under way.
- More trials run by Unity Health TorontoThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Case crossover
- Time perspective
- Prospective
- Enrolment
- 20 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Unity Health Toronto
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
- Investigators
- Laurent Brochard, Principal investigator, Unity Health Toronto - St. Michael's Hospital
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06494085
- Sponsor's protocol ID
- 24-105
- Acronym
- PUMA
- Status last verified
- Aug 2024
- First submitted
- 2 Jul 2024
- Last updated
- 20 May 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 20 May 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- PressUre-Muscle-index to Identify Patient's Desired Tidal Volume and the Threshold of Over-Assistance During Pressure Support Ventilation
- ClinicalTrials.gov ID
- NCT06494085
- Acronym / sponsor ID
- PUMA / 24-105
- Conditions
- Acute Hypoxemic Respiratory Failure
- Keywords
- Mechanical Ventilation, Intensive Care Unit, Pendelluft, Pressure Support Ventilation
- Study type
- Observational
- Recruitment status
- Unknown status
- Enrolment
- 20 participants (estimated)
- Lead sponsor
- Unity Health TorontoUniversity, hospital or other
- Study start
- 4 Oct 2024 (actual)
- Primary completion
- 28 Feb 2026 (estimated)
- Study completion
- 28 Feb 2026 (estimated)
- First posted
- 10 Jul 2024 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Pressure support ventilation (PSV) is used to assist the breathing of the intubated patient with some pressure from the ventilator. This support aims at avoiding excessive inspiratory effort, while ensuring a certain degree of training of the patient's inspiratory muscle. Avoiding both minimal and excessive assistance is thus important for the optimal care of the intubated patient ensuring a lung and diaphragm protective ventilation with the goal to liberate the patient from the ventilator as soon as possible.
Recently pressure-muscle-index (PMI), an index of inspiratory effort easy to be measured on the ventilator screen, has been proposed to avoid excessive assistance in PSV. This will be the first prospective study testing the effects of setting pressure support based on PMI to avoid excessive assistance on patients recovering from acute lung injury (acute hypoxemic respiratory failure).
Detailed description
First, for each patient enrolled the investigators will perform 1 inspiratory and 3 expiratory occlusions separated at least by 30 seconds at clinical PSV to measure respiratory mechanics (plateau pressure [Pplat] and respiratory system compliance [Crs] and elastance [Ers]) and inspiratory effort and drive (Pocc, P0.1, PMI) and Vt expressed in ml/Kg of predicted body weight.
Second, if PMI≥0 at baseline, the investigators will set Pressure Support (PS) so that positive end-expiratory pressure (PEEP) +PS (i.e. Peak pressure [Ppeak]) equals Pplat measured at baseline, in order to make PMI=0. If PMI<0 at baseline, the investigators will set PS so that PEEP+PS equals Pplat measured at baseline, then the investigators will perform an inspiratory occlusion and repeat the procedure until PMI=0. The PS level at which PMI=0 (PSPMI=0) and the corresponding breathing pattern (tial volume [Vt] and respiratory rate [RR]) will be used as reference for the study protocol. After 5 minutes at PSPMI=0 the investigators will perform 3 inspiratory and 3 expiratory occlusions separated at least by 30 seconds.
Third, each patient will undergo 3 steps of PS above (+2, +4, +6 cmH2O) and 3 below (-2, -4, -6 cmH2O) PSPMI=0 in a randomized order. Steps will be randomized using a simple sequence written within envelopes opened blindly by the investigators. Each step will last 5 minutes or less if poorly tolerated (see tolerance rules below). At the end of each step the investigators will perform 1 inspiratory occlusion and 3 expiratory occlusions. Each of the expiratory occlusion will be separated by 30 seconds in order to restore the patient's breathing pattern. The investigators will resume a 3-minutes clinical PS in between each step to minimize changes in PaCO2. If not yet comprised by the study steps each patient will undergo an adjunctive 5 minutes step at PS 0 (zero) cmH2O.
The study protocol will last approximately 60 minutes. The patient will be continuously monitored by a physician and a respiratory therapist.
At the end of the study, if different from clinically set PS, the investigators will propose clinicians to adjust the PS to target PMI>0 and a lung and diaphragm protective ventilation strategy following current literature. Data about PS setting at the end of the study will be recorded in the case report form.
Tolerance rules:
Protocol will be stopped if: heart rate >140 beats/min; increase in respiratory rate by 50% or more if not explained by ineffective effort; hypotension [systolic blood pressure <90 mmHg] or hypertension [systolic blood pressure >180 mmHg]; peripheral arterial oxygen saturation <90% for 5 minutes; excessive use of accessory respiratory muscles, diaphoresis, agitation, and the appearance of major abdominal or thoracic paradoxical movements. If apnea would appear at high PS levels (as described as overassistance), the PS will be decreased to the next lower level. PS will be set to not exceed a Ppeak of 30 cmH2O or a Vt of 12 mL/kg of predicted bodyweight
Study design
- Observational model
- Case crossover
- Time perspective
- Prospective
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
- Study population
- The Study population will include patients mechanically ventilated in the St. Michael's Intensive Care Unit. Patients who are younger than 18 years of age will be excluded from this study on the basis that the ICUs at St. Michael's Hospital are intended for adults; individuals aged less than 18 years are rarely, if ever, admitted.
Key inclusion criteria (4 listed)
- >18 y.o.
- Invasively ventilated in Intensive Care Unit.
- Diagnosed with acute hypoxemic respiratory failure (P/F<300 mmHg).
- Breathing on pressure support ventilation.
Key exclusion criteria (4 listed)
- <18 y.o.
- Contraindication for Electrical Impedence Tomography monitoring (e.g. pacemaker, burns, or - wounds limiting electrode placement).
- Severe and previously diagnosed neurological and neuromuscular disease.
- Psychomotor agitation (Sedation Agitation Scale > 4).
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Measuring Respiratory MechanicsFirst, for each patient enrolled we will perform inspiratory and expiratory occlusions - routinely performed diagnostic maneuvers to measure patient's breathing effort - at the clinically set level of breathing assistance by the mechanical ventilator. Importantly, we will measure pressure-muscle-index (PMI). Second, we will set the level of assistance (i.e. pressure support, PS) in order to make PMI=0. The PS level at which PMI=0 (PS PMI=0) will be used as reference for the study protocol. After 5 minutes at PS PMI=0 we will perform inspiratory and expiratory occlusions. | Other | – |
| Randomized Pressure Support3 steps of PS above (+2, +4, +6 cmH2O) and 3 below (-2, -4, -6 cmH2O) PSPMI=0 done in a randomized order (sequence in envelopes opened blindly by the investigators). Each step will last ≤5 minutes if poorly tolerated (see tolerance rule in description). At the end of each step we will perform 1 inspiratory occlusion and 3 expiratory occlusions. Each of the expiratory occlusion will be separated by 30 seconds in order to restore the patient's breathing pattern. We will resume a 3-minutes clinical PS in between each step to minimize changes in PaCO2. If not yet comprised by the study steps each patient will undergo an adjunctive 5 minutes step at PS 0 (zero) cmH2O. | Other | – |
Primary outcome
Inspiratory Occlusion
Time frame: 60 minutes
To investigate the role of the inspiratory occlusion as a diagnostic tool to understand the patient's desired tidal volume and minute ventilation in Pressure Support Ventilation (PSV),
Pressure Muscle Index (PMI)
Time frame: 60 minutes
To investigate the role of a PMI>0 strategy to avoid over-assistance in Pressure Support Ventilation
2 secondary outcomes
Pendelluft
Time frame: 60 minutes
Lung and Diaphragm Protective Ventilation
Time frame: 60 minutes
Results and safety
Results are not available in the source record.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 20 May 2025.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Laurent Brochard principal investigator
Unity Health Toronto - St. Michael's Hospital
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Acute Hypoxemic Respiratory Failure, run by Unity Health Toronto at 1 site in Canada.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 4 inclusion and 4 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: status not confirmed, as of the sponsor's last update on 20 May 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Canada. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
Results are not available in the source record.
How can a doctor refer a patient or contact the research team?
Contact Laurent Brochard, MD, PhD (4168645686, laurent.brochard@unityhealth.to), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Inspiratory Occlusion (time frame: 60 minutes). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 20 May 2025.