Mechanical VentilationDIAVOLANCT07206459
DIAPHRAGM STRENGTH AND LUNG VOLUMES
An observational study of Mechanical Ventilation, run by Unity Health Toronto at 1 site in Canada.
Trial summary
Diaphragm dysfunction (loss of diaphragm strength) is common in the intensive care unit (ICU) patients using ventilators. The diaphragm is the main muscle of respiration and its dysfunction can prolong mechanical ventilation and increase mortality risk. Read more about this study
- Who is it for?
- Ages 18 years and olderHealthy volunteers can take part
- Conditions the study is for
- Mechanical Ventilation
- What is being tested?
- Healthy Patients and Critically Care Patients
- How many people
- 30 participants
- Where
- 1 siteCanada
- Study dates
- 1 Dec 2024to 1 Dec 2026
- Phase
- Observational
- Are there results?
- Not yet: the study is under way
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
- Healthy volunteers accepted
- Adult, Older adult
Study population: 15 healthy adults and 15 critically ill adult patients admitted to St. Michael's Hospital ICU, Unity Health Toronto, Ontario, Canada. Healthy participants will be recruited by work of mouth from the Grand Toronto Area.
Who may be able to join
- Inclusion criteria for the healthy participants will be age ≥18 years, no acute or chronic condition impacting respiratory, musculoskeletal or neurological system or that would interfere with the performance of the tests; body mass index <35 kg/m2 and sufficient English fluency to provide informed consent and to follow the study protocols.
- Inclusion criteria for patients will be intubation for more than 6 hours, triggering or not the ventilator (any mode of ventilation).
Who cannot join
- Exclusion criteria for the healthy participants will be contraindication for PNS (e.g., cardiac pacemaker or implanted defibrillator, cervical implants), contraindication for a nasogastric tube (e.g., esophageal varices, recent nasal bleeding)and pregnancy.
- Exclusion criteria for patients will be primary contraindication for magnetic PNS, severe neurological disorders, pregnancy, current use of continuous neuromuscular blocking agents at the time of the study procedure, P/F ratio <120, unstable hemodynamics (2 vasopressors), monitored ICP.
Trial locations and contacts
1 site in 1 country.
About this study
Official title: Diaphragm Strength and Lung Volumes
Diaphragm dysfunction (loss of diaphragm strength) is common in the intensive care unit (ICU) patients using ventilators. The diaphragm is the main muscle of respiration and its dysfunction can prolong mechanical ventilation and increase mortality risk. The ventilator settings determine how much air and pressure the patient gets every breath and how much air is left on the lungs after they breathe out. The amount of air left on the lungs influence diaphragm strength measurements which can affect clinical decisions, such as weaning patients off ventilators. This research aims to explore the relationship between the amount of air left in the lungs and diaphragm strength to create a method of correcting measurements of diaphragm strength according to how much air the patients have in the lungs after they breath out. The investigators will test healthy individuals to understand this relationship, then verify if it holds true for ventilated patients by comparing results from both groups.
Read the detailed description
Our ultimate objective is to create a correction factor for adjusting values of diaphragm strength obtained from measurements of pressure generated by PNS performed at various EELV induced by different levels of PEEP. This correction factor will be derived from the slope of the relationship between PEEP/EELV and diaphragm strength. The initial development of the correction factor will be conducted in healthy individuals, and its applicability will be assessed in mechanically ventilated patients. To achieve this, the investigators will compare the relationship between PEEP/EELV and diaphragm strength, measured through PNS, between both healthy subjects and individuals undergoing mechanical ventilation.
RESEARCH DESIGN AND METHODS This will be a physiological observational study
Study design. Healthy participants and patients will breathe on CPAP with a ventilator. The investigators will deliver the PNS at PEEP levels of zero cmH2O (baseline EELV), zero cmH2O + an abdominal binder (to reduce lung volume), five cmH2O and ten cmH2O. The abdominal binder will be used to achieve an EELV lower than at baseline. At the end of the protocol another PNS at zero cmH2O (baseline EELV) will be performed. Healthy participants will be exposed to the different levels of PEEP from 2 to 5 minutes before each PNS is performed.
At every PEEP level, relative changes in EELV (∆z) will be measured with Electrical Impedance Tomography (EIT) to record relative changes in EELV and the electrical activity of the costal diaphragm will be measured using surface electromyography . The (potentiated) PNS will be performed by bilateral anterior magnetic stimulation. Potentiation will be achieved by performing a maximum inspiratory pressure maneuver (MIP; healthy volunteers).
For patients. The investigators will perform PNS at the patients own mode of ventilation at their clinical level of PEEP (baseline EELV), PEEP of zero cmH2O (if acceptable for 5 minutes), clinical PEEP ± 2 - 4 cmH2O. At the end of the protocol, another stimulation at the clinical level of PEEP (baseline EELV) will be performed. Patients will be exposed to the different levels of PEEP from 2 to 5 minutes before each PNS is performed. At every PEEP level, relative changes in EELV (∆z) will be measured with Electrical Impedance Tomography (EIT) to record relative changes in EELV and the electrical activity of the costal diaphragm will be measured using surface electromyography . The PNS will be performed by bilateral anterior magnetic stimulation. Potentiation, when possible (patients triggering the ventilator), will be achieved by performing an end-expiratory occlusion maneuver on the ventilator for up to 30 sec or at least 3 inspiratory efforts.
- Conditions
- Mechanical Ventilation
- Being tested
- Healthy Patients, Critically Care Patients
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Healthy PatientsOther
RESEARCH DESIGN AND METHODS This will be a physiological observational study
Study design. Participants will breathe on CPAP with a ventilator. The investigators will deliver the PNS at PEEP levels of zero cmH2O (baseline EELV), zero cmH2O + an abdominal binder (to reduce lung volume), five cmH2O and ten cmH2O. The abdominal binder will be used to achieve an EELV lower than at baseline. At the end of the protocol another PNS at zero cmH2O (baseline EELV) will be performed. Healthy participants will be exposed to the different levels of PEEP from 2 to 5 minutes before each PNS is performed.
At every PEEP level, relative changes in EELV (∆z) will be measured with Electrical Impedance Tomography (EIT) to record relative changes in EELV and the electrical activity of the costal diaphragm will be measured using surface electromyography
Critically Care PatientsOther
RESEARCH DESIGN AND METHODS This will be a physiological observational study
Study design. For patients. The investigators will perform PNS at the patients own mode of ventilation at their clinical level of PEEP (baseline EELV), PEEP of zero cmH2O (if acceptable for 5 minutes), clinical PEEP ± 2 - 4 cmH2O. At the end of the protocol, another stimulation at the clinical level of PEEP (baseline EELV) will be performed. Patients will be exposed to the different levels of PEEP from 2 to 5 minutes before each PNS is performed.
| Study group | Role | What they receive |
|---|---|---|
| Healthy Adults | Healthy participants will be recruited by work of mouth from the Grand Toronto Area.
Inclusion criteria for the healthy participants will be age ≥18 years, no acute or chronic condition impacting respiratory, musculoskeletal or neurological system or that would interfere with the performance of the tests; body mass index <35 kg/m2 and sufficient English fluency to provide informed consent and to follow the study protocols.
Exclusion criteria for the healthy participants will be contraindication for PNS (e.g., cardiac pacemaker or implanted defibrillator, cervical implants), contraindication for a nasogastric tube (e.g., esophageal varices, recent nasal bleeding)and pregnancy. Receives: Other: Healthy Patients | |
| Critical Care Patients | Adult patients admitted to St. Michael's Hospital ICU, Unity Health Toronto, Ontario, Canada, Inclusion criteria for patients will be intubation for more than 6 hours, triggering or not the ventilator (any mode of ventilation).
Exclusion criteria for patients will be primary contraindication for magnetic PNS, severe neurological disorders, pregnancy, current use of continuous neuromuscular blocking agents at the time of the study procedure, P/F ratio <120, unstable hemodynamics (2 vasopressors), monitored ICP. Receives: Other: Critically Care Patients |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change in diaphragm strength
Change in the pressure generated by the diaphragm (cmH₂O), assessed during end-expiratory occlusion on mechanical ventilation while applying phrenic nerve stimulation. Measurement will be obtained repeatedly on Day 1, between 3-5 minutes after each PEEP adjustment.
Measured: Day 1 (within 5 minutes at each PEEP level during the intervention)
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted3 Oct 2025
- Study start1 Dec 2024
- Primary completion1 Dec 2026 (estimated)
- Study completion1 Dec 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Mechanical VentilationStudies 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
- Other
- Time perspective
- Prospective
- Enrolment
- 30 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Unity Health Toronto
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
- Investigators
- Laurent Brochard, MD, PhD, Principal investigator, Unity Health Toronto - St. Michael's Hospital
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07206459
- Sponsor's protocol ID
- 24-170
- Acronym
- DIAVOLA
- Status last verified
- Nov 2024
- First submitted
- 15 Sep 2025
- Last updated
- 3 Oct 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No: The datasets generated and/or analyzed during the current study are not publicly available due participant confidentiality.
Study at a glance
From the registry record, last updated by the sponsor on 3 Oct 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Diaphragm Strength and Lung Volumes
- ClinicalTrials.gov ID
- NCT07206459
- Acronym / sponsor ID
- DIAVOLA / 24-170
- Conditions
- Mechanical Ventilation
- Study type
- Observational
- Recruitment status
- Active, not recruiting
- Enrolment
- 30 participants (estimated)
- Lead sponsor
- Unity Health TorontoUniversity, hospital or other
- Study start
- 1 Dec 2024 (actual)
- Primary completion
- 1 Dec 2026 (estimated)
- Study completion
- 1 Dec 2026 (estimated)
- First posted
- 3 Oct 2025 (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.
Diaphragm dysfunction (loss of diaphragm strength) is common in the intensive care unit (ICU) patients using ventilators. The diaphragm is the main muscle of respiration and its dysfunction can prolong mechanical ventilation and increase mortality risk. The ventilator settings determine how much air and pressure the patient gets every breath and how much air is left on the lungs after they breathe out. The amount of air left on the lungs influence diaphragm strength measurements which can affect clinical decisions, such as weaning patients off ventilators. This research aims to explore the relationship between the amount of air left in the lungs and diaphragm strength to create a method of correcting measurements of diaphragm strength according to how much air the patients have in the lungs after they breath out. The investigators will test healthy individuals to understand this relationship, then verify if it holds true for ventilated patients by comparing results from both groups.
Detailed description
Our ultimate objective is to create a correction factor for adjusting values of diaphragm strength obtained from measurements of pressure generated by PNS performed at various EELV induced by different levels of PEEP. This correction factor will be derived from the slope of the relationship between PEEP/EELV and diaphragm strength. The initial development of the correction factor will be conducted in healthy individuals, and its applicability will be assessed in mechanically ventilated patients. To achieve this, the investigators will compare the relationship between PEEP/EELV and diaphragm strength, measured through PNS, between both healthy subjects and individuals undergoing mechanical ventilation.
RESEARCH DESIGN AND METHODS This will be a physiological observational study
Study design. Healthy participants and patients will breathe on CPAP with a ventilator. The investigators will deliver the PNS at PEEP levels of zero cmH2O (baseline EELV), zero cmH2O + an abdominal binder (to reduce lung volume), five cmH2O and ten cmH2O. The abdominal binder will be used to achieve an EELV lower than at baseline. At the end of the protocol another PNS at zero cmH2O (baseline EELV) will be performed. Healthy participants will be exposed to the different levels of PEEP from 2 to 5 minutes before each PNS is performed.
At every PEEP level, relative changes in EELV (∆z) will be measured with Electrical Impedance Tomography (EIT) to record relative changes in EELV and the electrical activity of the costal diaphragm will be measured using surface electromyography . The (potentiated) PNS will be performed by bilateral anterior magnetic stimulation. Potentiation will be achieved by performing a maximum inspiratory pressure maneuver (MIP; healthy volunteers).
For patients. The investigators will perform PNS at the patients own mode of ventilation at their clinical level of PEEP (baseline EELV), PEEP of zero cmH2O (if acceptable for 5 minutes), clinical PEEP ± 2 - 4 cmH2O. At the end of the protocol, another stimulation at the clinical level of PEEP (baseline EELV) will be performed. Patients will be exposed to the different levels of PEEP from 2 to 5 minutes before each PNS is performed. At every PEEP level, relative changes in EELV (∆z) will be measured with Electrical Impedance Tomography (EIT) to record relative changes in EELV and the electrical activity of the costal diaphragm will be measured using surface electromyography . The PNS will be performed by bilateral anterior magnetic stimulation. Potentiation, when possible (patients triggering the ventilator), will be achieved by performing an end-expiratory occlusion maneuver on the ventilator for up to 30 sec or at least 3 inspiratory efforts.
Study design
- Observational model
- Other
- Time perspective
- Prospective
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Healthy Adults | – | Other: Healthy PatientsHealthy participants will be recruited by work of mouth from the Grand Toronto Area. Inclusion criteria for the healthy participants will be age ≥18 years, no acute or chronic condition impacting respiratory, musculoskeletal or neurological system or that would interfere with the performance of the tests; body mass index <35 kg/m2 and sufficient English fluency to provide informed consent and to follow the study protocols. Exclusion criteria for the healthy participants will be contraindication for PNS (e.g., cardiac pacemaker or implanted defibrillator, cervical implants), contraindication for a nasogastric tube (e.g., esophageal varices, recent nasal bleeding)and pregnancy. |
| Critical Care Patients | – | Other: Critically Care PatientsAdult patients admitted to St. Michael's Hospital ICU, Unity Health Toronto, Ontario, Canada, Inclusion criteria for patients will be intubation for more than 6 hours, triggering or not the ventilator (any mode of ventilation). Exclusion criteria for patients will be primary contraindication for magnetic PNS, severe neurological disorders, pregnancy, current use of continuous neuromuscular blocking agents at the time of the study procedure, P/F ratio <120, unstable hemodynamics (2 vasopressors), monitored ICP. |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
- Study population
- 15 healthy adults and 15 critically ill adult patients admitted to St. Michael's Hospital ICU, Unity Health Toronto, Ontario, Canada. Healthy participants will be recruited by work of mouth from the Grand Toronto Area.
Key inclusion criteria (2 listed)
- Inclusion criteria for the healthy participants will be age ≥18 years, no acute or chronic condition impacting respiratory, musculoskeletal or neurological system or that would interfere with the performance of the tests; body mass index <35 kg/m2 and sufficient English fluency to provide informed consent and to follow the study protocols.
- Inclusion criteria for patients will be intubation for more than 6 hours, triggering or not the ventilator (any mode of ventilation).
Key exclusion criteria (2 listed)
- Exclusion criteria for the healthy participants will be contraindication for PNS (e.g., cardiac pacemaker or implanted defibrillator, cervical implants), contraindication for a nasogastric tube (e.g., esophageal varices, recent nasal bleeding)and pregnancy.
- Exclusion criteria for patients will be primary contraindication for magnetic PNS, severe neurological disorders, pregnancy, current use of continuous neuromuscular blocking agents at the time of the study procedure, P/F ratio <120, unstable hemodynamics (2 vasopressors), monitored ICP.
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 |
|---|---|---|
| Healthy PatientsRESEARCH DESIGN AND METHODS This will be a physiological observational study Study design. Participants will breathe on CPAP with a ventilator. The investigators will deliver the PNS at PEEP levels of zero cmH2O (baseline EELV), zero cmH2O + an abdominal binder (to reduce lung volume), five cmH2O and ten cmH2O. The abdominal binder will be used to achieve an EELV lower than at baseline. At the end of the protocol another PNS at zero cmH2O (baseline EELV) will be performed. Healthy participants will be exposed to the different levels of PEEP from 2 to 5 minutes before each PNS is performed. At every PEEP level, relative changes in EELV (∆z) will be measured with Electrical Impedance Tomography (EIT) to record relative changes in EELV and the electrical activity of the costal diaphragm will be measured using surface electromyography | Other | Healthy Adults |
| Critically Care PatientsRESEARCH DESIGN AND METHODS This will be a physiological observational study Study design. For patients. The investigators will perform PNS at the patients own mode of ventilation at their clinical level of PEEP (baseline EELV), PEEP of zero cmH2O (if acceptable for 5 minutes), clinical PEEP ± 2 - 4 cmH2O. At the end of the protocol, another stimulation at the clinical level of PEEP (baseline EELV) will be performed. Patients will be exposed to the different levels of PEEP from 2 to 5 minutes before each PNS is performed. | Other | Critical Care Patients |
Primary outcome
Change in diaphragm strength
Time frame: Day 1 (within 5 minutes at each PEEP level during the intervention)
Change in the pressure generated by the diaphragm (cmH₂O), assessed during end-expiratory occlusion on mechanical ventilation while applying phrenic nerve stimulation. Measurement will be obtained repeatedly on Day 1, between 3-5 minutes after each PEEP adjustment.
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 3 Oct 2025.
- Individual participant dataSharing planned: No. The datasets generated and/or analyzed during the current study are not publicly available due participant confidentiality.
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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, MD, PhD 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 Mechanical Ventilation, 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 2 inclusion and 2 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: under way, not looking for participants, as of the sponsor's last update on 3 Oct 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?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Change in diaphragm strength (time frame: Day 1 (within 5 minutes at each PEEP level during the intervention)). 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 3 Oct 2025.