Mechanical VentilationDeXFLoWNCT06024993
Dead Space in Mechanical Ventilation With Constant Expiratory Flow
A study of Mechanical Ventilation and Artificial Respiration, run by University Hospital, Antwerp at 1 site in Belgium.
Trial summary
Conventional continuous mandatory mechanical ventilation relies on the passive recoil of the chest wall for expiration. This results in an exponentially decreasing expiratory flow. Read more about this study
- Who is it for?
- Ages 18 to 70 years
- Conditions the study is for
- Mechanical Ventilation, Artificial Respiration
- Type of treatment
- Medical device
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 13 participants
- Where
- 1 siteBelgium
- Study dates
- 22 Jul 2024to 30 Apr 2026
- Phase
- Interventional
- 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 to 70 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Adults [18-70] yrs
- General anaesthesia for elective surgery
- Arterial line, central venous line and endotracheal tube as part of standard of care
- Expected duration of controlled mechanical ventilation ≥ 60 minutes
- Supine position (0±10°)
Who cannot join
- One lung ventilation
- Known pregnancy
- Increased intra-abdominal pressure (pneumoperitoneum or obesity (BMI > 30kg/m2))
- COPD GOLD IV or home oxygen dependence
- Cardiac pacemaker, implantable cardioverter-defibrillator (ICD) or thoracic neurostimulator
- Skin lesions (e.g. injury, inflammation) at the level where the Electrical Impedance Tomography (EIT) band is to be applied
Show all 9Show fewer
- Clinical signs of raised intracranial pressure
- Potential interference with the surgery due to the setup of the study instruments.
- Patient refusal to participate
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Belgium1 site, 1 recruiting
- Recruiting
Antwerp University Hospital (UZA)
Edegem, Antwerp, 2650
Carine Smitz, +323 821 49 30, carine.smitz@uza.be
Tom Schepens, M.D., Ph.D.
About this study
Conventional continuous mandatory mechanical ventilation relies on the passive recoil of the chest wall for expiration. This results in an exponentially decreasing expiratory flow.
Flow controlled ventilation (FCV), a new ventilation mode with constant, continuous, controlled expiratory flow, has recently become clinically available and is increasingly being adopted for complex mechanical ventilation during surgery.
Read more
In both clinical and pre-clinical settings, an improvement in ventilation (CO2 clearance) has been observed during FCV compared to conventional ventilation. Recently, Schranc et al. compared flow-controlled ventilation with pressure-regulated volume control in both double lung ventilation and one-lung ventilation in pigs. They report differences in dead space ventilation that may explain the improved CO2 clearance, although their study was not designed to compare dead space ventilation within the group of double lung ventilation.
Dead space ventilation, or "wasted ventilation", is the ventilation of hypoperfused lung zones, and is clinically relevant, as it is a strong predictor of mortality in patients with the acute respiratory distress syndrome (ARDS) and is correlated with higher airway driving pressures which are thought to be injurious to the lung (lung stress).
This trial aims to study the difference in dead space ventilation between conventional mechanical ventilation in volume-controlled mode and flow controlled-ventilation.
- Conditions
- Mechanical Ventilation, Artificial Respiration
- Being tested
- Flow-controlled ventilation (FCV), Conventional volume-controlled ventilation (VCV)
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Flow-controlled ventilation (FCV)Device
20 minutes of FCV, delivered with the CE-marked Evone ventilator (Ventinova medical, the Netherlands)
Conventional volume-controlled ventilation (VCV)Device
20 minutes of conventional VCV, delivered with the CE-marked Aisys CS3 (GE Healthcare, USA) or Flow-i (Getinge, Sweden) ventilators.
| Study group | Role | What they receive |
|---|---|---|
| FCV-VCV | Experimental | After titration of ventilation in baseline VCV (all arms), participants will first receive 20 min of baseline-matched FCV and subsequently 20 min of baseline-matched VCV. Receives: Device: Flow-controlled ventilation (FCV); Device: Conventional volume-controlled ventilation (VCV) |
| VCV-FCV | Experimental | After titration of ventilation in baseline VCV (all arms), participants will first receive 20 min of baseline-matched VCV and subsequently 20 min of baseline-matched FCV. Receives: Device: Flow-controlled ventilation (FCV); Device: Conventional volume-controlled ventilation (VCV) |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change in Bohr dead space ventilation (VDBr/VT)
Quantified by the Bohr approach with volumetric capnography
Measured: During FCV and VCV measurements (20 minutes)
Secondary outcomes (34)
Change in Enghoff dead space ventilation (VDEng/VT)
Quantified by the Enghoff approach with volumetric capnography
Measured: During FCV and VCV measurements (20 minutes)
Change in physiological dead space volume (Vdfys)
Measured with volumetric capnography and Enghoff's approach
Measured: During FCV and VCV measurements (20 minutes)
Change in airway dead space volume (Vdaw)
Measured with volumetric capnography and Fletcher's approach
Measured: During FCV and VCV measurements (20 minutes)
Change in alveolar dead space volume (Vdalv)
As measured with volumetric capnography and Fletcher's approach
Measured: During FCV and VCV measurements (20 minutes)
Ventilatory efficiency (VE/VCO2)
Ratio of minute ventilation to carbon dioxide output
Measured: During FCV and VCV measurements (20 minutes)
Change in airway driving pressure (∆Paw)
Calculated as the difference between the plateau pressure (Pplat) during an inspiratory pause and the dynamic positive end-expiratory pressure (PEEP), as no expiratory hold is possible on the Evone.
Measured: During FCV and VCV measurements (20 minutes)
Change in transpulmonary shunt fraction (Qs/Qt)
calculated with the modified Berggren equation
Measured: During FCV and VCV measurements (20 minutes)
Change in global lung hyperdistention (hyperdistentionEIT)
Calculated from electric impedance tomography
Measured: During FCV and VCV measurements (20 minutes)
Change in anterio-posterior distribution of ventilation on EIT (AP)
% anterior / % posterior
Measured: During FCV and VCV measurements (20 minutes)
Change in right-left distribution of ventilation on EIT (RL)
% right / % left
Measured: During FCV and VCV measurements (20 minutes)
Change in 4-layered distribution of ventilation on EIT
Measured: During FCV and VCV measurements (20 minutes)
Change in centre of ventilation on EIT
Measured: During FCV and VCV measurements (20 minutes)
Change in cardiac index (CI)
Calculated from the arterial waveform (pulse contour analysis) by the HemoSphere monitor
Measured: During FCV and VCV measurements (20 minutes)
Change in mean arterial pressure (MAP)
Measured on a radial artery line
Measured: During FCV and VCV measurements (20 minutes)
Change in partial pressure of arterial CO2 (PaCO2)
Measured on an arterial blood gas
Measured: During FCV and VCV measurements (20 minutes)
Change in peak expiratory flow (PEF)
As measured by the citrex respiratory monitor
Measured: During FCV and VCV measurements (20 minutes)
Change in peak inspiratory flow (PIF)
As measured by the citrex respiratory monitor
Measured: During FCV and VCV measurements (20 minutes)
Change in mean airway pressure (MPaw)
As measured by the citrex respiratory monitor
Measured: During FCV and VCV measurements (20 minutes)
Change in tidal volume (TV)
As measured by the citrex respiratory monitor
Measured: During FCV and VCV measurements (20 minutes)
Change in respiratory rate (RR)
As measured by the citrex respiratory monitor
Measured: During FCV and VCV measurements (20 minutes)
Change in minute ventilation (MV)
As measured by the citrex respiratory monitor
Measured: During FCV and VCV measurements (20 minutes)
Change in inspiratory time (Ti)
As measured by the citrex respiratory monitor
Measured: During FCV and VCV measurements (20 minutes)
Change in expiratory time (Te)
As measured by the citrex respiratory monitor
Measured: During FCV and VCV measurements (20 minutes)
Change in ratio of inspiratory time to total breath time (Ti / Tt)
As measured by the citrex respiratory monitor
Measured: During FCV and VCV measurements (20 minutes)
Change in positive end-expiratory pressure (PEEP)
As measured by the citrex respiratory monitor
Measured: During FCV and VCV measurements (20 minutes)
Change in peak inspiratory pressure (PIP)
As measured by the citrex respiratory monitor
Measured: During FCV and VCV measurements (20 minutes)
Change in plateau pressure (Pplat)
As measured by the citrex respiratory monitor
Measured: During FCV and VCV measurements (20 minutes)
Change in static airway compliance (Caw)
Calculated as tidal volume / airway driving pressure
Measured: During FCV and VCV measurements (20 minutes)
Change in end-tidal CO2 (ETCO2)
As measured by the citrex respiratory monitor
Measured: During FCV and VCV measurements (20 minutes)
Change in global airway resistance (Raw)
As measured by the citrex respiratory monitor
Measured: During FCV and VCV measurements (20 minutes)
Change in global airway time constant (TAUaw)
Calculated as global airway resistance x global airway compliance
Measured: During FCV and VCV measurements (20 minutes)
Change in total energy
As calculated from monitoring data
Measured: During FCV and VCV measurements (20 minutes)
Change in dissipated energy
As calculated from monitoring data
Measured: During FCV and VCV measurements (20 minutes)
Change in P/F ratio
Calculated as partial pressure of arterial oxygen divided by inspiratory fraction of oxygen
Measured: During FCV and VCV measurements (20 minutes)
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted6 Sep 2023
- Study start22 Jul 2024
- Primary completion30 Dec 2025 (estimated)
- Study completion30 Apr 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.
- 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
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Model description
- Crossover volume-controlled ventilation and flow-controlled ventilation
- Masking
- Double blind
- Who is masked
- Participant, Outcomes assessor
- Enrolment
- 13 participants (estimated)
Sponsor and investigators
- Lead sponsor
- University Hospital, Antwerp
- Sponsor type
- University, hospital or other
- Collaborators
- Universiteit Antwerpen
- Responsible party
- Sponsor
- Investigators
- Vera Saldien, M.D., Ph.D., Principal investigator, Antwerp University Hospital / University of Antwerp
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06024993
- Sponsor's protocol ID
- 003029
- Acronym
- DeXFLoW
- Status last verified
- Jan 2025
- First submitted
- 3 Apr 2023
- Last updated
- 22 Jan 2025
- Results posted
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
Study at a glance
From the registry record, last updated by the sponsor on 22 Jan 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Dead Space in Mechanical Ventilation With Constant Expiratory Flow
- ClinicalTrials.gov ID
- NCT06024993
- Acronym / sponsor ID
- DeXFLoW / 003029
- Conditions
- Mechanical Ventilation, Artificial Respiration
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 13 participants (estimated)
- Lead sponsor
- University Hospital, AntwerpUniversity, hospital or other
- Collaborators
- Universiteit Antwerpen
- Study start
- 22 Jul 2024 (actual)
- Primary completion
- 30 Dec 2025 (estimated)
- Study completion
- 30 Apr 2026 (estimated)
- First posted
- 6 Sep 2023 (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.
Conventional continuous mandatory mechanical ventilation relies on the passive recoil of the chest wall for expiration. This results in an exponentially decreasing expiratory flow.
Flow controlled ventilation (FCV), a new ventilation mode with constant, continuous, controlled expiratory flow, has recently become clinically available and is increasingly being adopted for complex mechanical ventilation during surgery.
In both clinical and pre-clinical settings, an improvement in ventilation (CO2 clearance) has been observed during FCV compared to conventional ventilation. Recently, Schranc et al. compared flow-controlled ventilation with pressure-regulated volume control in both double lung ventilation and one-lung ventilation in pigs. They report differences in dead space ventilation that may explain the improved CO2 clearance, although their study was not designed to compare dead space ventilation within the group of double lung ventilation.
Dead space ventilation, or "wasted ventilation", is the ventilation of hypoperfused lung zones, and is clinically relevant, as it is a strong predictor of mortality in patients with the acute respiratory distress syndrome (ARDS) and is correlated with higher airway driving pressures which are thought to be injurious to the lung (lung stress).
This trial aims to study the difference in dead space ventilation between conventional mechanical ventilation in volume-controlled mode and flow controlled-ventilation.
Study design
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Double blind (participant, outcomes assessor)
- Number of arms
- 2
- Model description
- Crossover volume-controlled ventilation and flow-controlled ventilation
| Arm | Type | Receives |
|---|---|---|
| FCV-VCV | Experimental | Device: Flow-controlled ventilation (FCV), Device: Conventional volume-controlled ventilation (VCV)After titration of ventilation in baseline VCV (all arms), participants will first receive 20 min of baseline-matched FCV and subsequently 20 min of baseline-matched VCV. |
| VCV-FCV | Experimental | Device: Flow-controlled ventilation (FCV), Device: Conventional volume-controlled ventilation (VCV)After titration of ventilation in baseline VCV (all arms), participants will first receive 20 min of baseline-matched VCV and subsequently 20 min of baseline-matched FCV. |
Who may qualify
- Ages
- 18 to 70 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (5 listed)
- Adults [18-70] yrs
- General anaesthesia for elective surgery
- Arterial line, central venous line and endotracheal tube as part of standard of care
- Expected duration of controlled mechanical ventilation ≥ 60 minutes
- Supine position (0±10°)
Key exclusion criteria (9 listed)
- One lung ventilation
- Known pregnancy
- Increased intra-abdominal pressure (pneumoperitoneum or obesity (BMI > 30kg/m2))
- COPD GOLD IV or home oxygen dependence
- Cardiac pacemaker, implantable cardioverter-defibrillator (ICD) or thoracic neurostimulator
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 |
|---|---|---|
| Flow-controlled ventilation (FCV)20 minutes of FCV, delivered with the CE-marked Evone ventilator (Ventinova medical, the Netherlands) | Device | FCV-VCV, VCV-FCV |
| Conventional volume-controlled ventilation (VCV)20 minutes of conventional VCV, delivered with the CE-marked Aisys CS3 (GE Healthcare, USA) or Flow-i (Getinge, Sweden) ventilators. | Device | FCV-VCV, VCV-FCV |
Primary outcome
Change in Bohr dead space ventilation (VDBr/VT)
Time frame: During FCV and VCV measurements (20 minutes)
Quantified by the Bohr approach with volumetric capnography
34 secondary outcomes
Change in Enghoff dead space ventilation (VDEng/VT)
Time frame: During FCV and VCV measurements (20 minutes)
Change in physiological dead space volume (Vdfys)
Time frame: During FCV and VCV measurements (20 minutes)
Change in airway dead space volume (Vdaw)
Time frame: During FCV and VCV measurements (20 minutes)
Change in alveolar dead space volume (Vdalv)
Time frame: During FCV and VCV measurements (20 minutes)
Ventilatory efficiency (VE/VCO2)
Time frame: During FCV and VCV measurements (20 minutes)
Change in airway driving pressure (∆Paw)
Time frame: During FCV and VCV measurements (20 minutes)
Change in transpulmonary shunt fraction (Qs/Qt)
Time frame: During FCV and VCV measurements (20 minutes)
Change in global lung hyperdistention (hyperdistentionEIT)
Time frame: During FCV and VCV measurements (20 minutes)
Change in anterio-posterior distribution of ventilation on EIT (AP)
Time frame: During FCV and VCV measurements (20 minutes)
Change in right-left distribution of ventilation on EIT (RL)
Time frame: During FCV and VCV measurements (20 minutes)
Change in 4-layered distribution of ventilation on EIT
Time frame: During FCV and VCV measurements (20 minutes)
Change in centre of ventilation on EIT
Time frame: During FCV and VCV measurements (20 minutes)
Change in cardiac index (CI)
Time frame: During FCV and VCV measurements (20 minutes)
Change in mean arterial pressure (MAP)
Time frame: During FCV and VCV measurements (20 minutes)
Change in partial pressure of arterial CO2 (PaCO2)
Time frame: During FCV and VCV measurements (20 minutes)
Change in peak expiratory flow (PEF)
Time frame: During FCV and VCV measurements (20 minutes)
Change in peak inspiratory flow (PIF)
Time frame: During FCV and VCV measurements (20 minutes)
Change in mean airway pressure (MPaw)
Time frame: During FCV and VCV measurements (20 minutes)
Change in tidal volume (TV)
Time frame: During FCV and VCV measurements (20 minutes)
Change in respiratory rate (RR)
Time frame: During FCV and VCV measurements (20 minutes)
Change in minute ventilation (MV)
Time frame: During FCV and VCV measurements (20 minutes)
Change in inspiratory time (Ti)
Time frame: During FCV and VCV measurements (20 minutes)
Change in expiratory time (Te)
Time frame: During FCV and VCV measurements (20 minutes)
Change in ratio of inspiratory time to total breath time (Ti / Tt)
Time frame: During FCV and VCV measurements (20 minutes)
Change in positive end-expiratory pressure (PEEP)
Time frame: During FCV and VCV measurements (20 minutes)
Change in peak inspiratory pressure (PIP)
Time frame: During FCV and VCV measurements (20 minutes)
Change in plateau pressure (Pplat)
Time frame: During FCV and VCV measurements (20 minutes)
Change in static airway compliance (Caw)
Time frame: During FCV and VCV measurements (20 minutes)
Change in end-tidal CO2 (ETCO2)
Time frame: During FCV and VCV measurements (20 minutes)
Change in global airway resistance (Raw)
Time frame: During FCV and VCV measurements (20 minutes)
Change in global airway time constant (TAUaw)
Time frame: During FCV and VCV measurements (20 minutes)
Change in total energy
Time frame: During FCV and VCV measurements (20 minutes)
Change in dissipated energy
Time frame: During FCV and VCV measurements (20 minutes)
Change in P/F ratio
Time frame: During FCV and VCV measurements (20 minutes)
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 22 Jan 2025.
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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.
Vera Saldien, M.D., Ph.D. principal investigator
Antwerp University Hospital / University of Antwerp
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study of Mechanical Ventilation and Artificial Respiration, run by University Hospital, Antwerp at 1 site in Belgium.
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 5 inclusion and 9 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: looking for participants now, as of the sponsor's last update on 22 Jan 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 Belgium. 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?
Contact Carine Smitz (+32 3 821 49 30, carine.smitz@uza.be), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Change in Bohr dead space ventilation (VDBr/VT) (time frame: During FCV and VCV measurements (20 minutes)). 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 22 Jan 2025; AzTrials last refreshed its copy on 26 Oct 2026.