ObesityNCT07430111
Flow-Controlled Versus Volume-Controlled Ventilation in Bariatric Surgery
A study testing FCV Group and VCV Group in people with Obesity and Bariatric Surgery, run by Ankara Etlik City Hospital at 1 site in Turkey (Türkiye).
Trial summary
This prospective trial aims to compare the effects of flow-controlled ventilation (FCV) and volume-controlled ventilation (VCV) on intraoperative airway pressures and oxygenation in bariatric surgery under general anesthesia. Read more about this study
- Who is it for?
- Ages 18 to 65 years
- Conditions the study is for
- Obesity, Bariatric Surgery, Mechanical Ventilation
- What is being tested?
- FCV Group and VCV Group
- Type of treatment
- Surgery or procedure
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 40 participants
- Where
- 1 siteTurkey (Türkiye)
- Study dates
- 24 Feb 2026to 18 Feb 2027
- 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 65 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Age between 18 and 65 years
- Body mass index (BMI) ≥ 30 kg/m²
- ASA physical status II-III
Who cannot join
- ASA physical status I or IV and above
- Known or previously diagnosed pulmonary disease
- Patients with severe preoperative pulmonary function impairment (e.g., FEV₁ < 50% predicted, severe restrictive or obstructive pathology)
- Patients with markedly altered lung anatomy or function due to prior major thoracic surgery
- Patients who were dependent on supplemental oxygen therapy in the preoperative period
- Refusal to participate in the study or inability to comply with study procedures
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Turkey (Türkiye)1 site, 1 recruiting
- Recruiting
Ankara Etlik City Hospital
Ankara, 06000
Atakan Sezgi, M.D., 00905323327000, kansezgi@gmail.com
Musa Zengin, Associate Professor, 00905307716235, musazengin@gmail.com
About this study
Official title: Comparison of Flow-Controlled and Volume-Controlled Ventilation During Bariatric Surgery: A Prospective Randomized Trial
This prospective trial aims to compare the effects of flow-controlled ventilation (FCV) and volume-controlled ventilation (VCV) on intraoperative airway pressures and oxygenation in bariatric surgery under general anesthesia. Obesity is associated with altered respiratory mechanics, reduced functional residual capacity, and increased airway pressures, making the selection of an optimal ventilation strategy particularly important in this patient population.
Adult patients aged 18-65 years with a body mass index ≥30 kg/m² and American Society of Anesthesiologists (ASA) physical status II-III will be allocated to receive either FCV or VCV as part of routine intraoperative mechanical ventilation. Ventilatory parameters, including peak and plateau airway pressures, pulmonary compliance, will be recorded at predefined intraoperative time points.
Read more
The primary endpoint of the study is the PaO₂ value measured at the 20th minute under an FiO₂ of 0.8-1.0.
By providing comparative data on respiratory mechanics and oxygenation, this study aims to contribute to the identification of lung-protective ventilation strategies and to optimize intraoperative ventilatory management in bariatric surgery.
- Conditions
- Obesity, Bariatric Surgery, Mechanical Ventilation
- Being tested
- FCV Group, VCV Group
- Keywords
- Obesity, Flow-Controlled Ventilation, Volume-Controlled Ventilation
- Medical subject headings
- Obesity
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
FCV GroupProcedure or surgery
Patients allocated to the FCV group will receive intraoperative mechanical ventilation using a flow-controlled ventilation mode during surgery under general anesthesia. Patients will be started on ventilation after intubation with 50% oxygen, driving pressure 12, PEEP 5, and a 1:1 inspiration/expiratory ratio.
VCV GroupProcedure or surgery
Patients allocated to the VCV group will receive intraoperative mechanical ventilation using a conventional volume-controlled ventilation mode throughout surgery under general anesthesia. Patients will be started on ventilation after intubation with 50% oxygen, 7 ml/ideal body weight tidal volume, PEEP 5, 12 breaths per minute frequency, and a 1:2 inspiration/expiration ratio.
| Study group | Role | What they receive |
|---|---|---|
| FCV Group | Active comparator | Patients allocated to the FCV group will receive intraoperative mechanical ventilation using a flow-controlled ventilation mode during surgery under general anesthesia. %50 FiO₂ will be applied, and a driving pressure of 12 cmH₂O will be used.
Following insufflation, the patient's FiO₂ will be maintained between 0.8 and 1.0 for 20 minutes.
After the 20th minute, ventilator settings will be returned to the baseline values.
Tidal volume will be generated and recorded by the ventilator according to the driving pressure and the patient's lung mechanics.
Minute ventilation will be adjusted based on the target tidal volume. The target tidal volume will be set at 6-8 mL/kg (7 mL/kg) with a respiratory rate of 12 breaths/min.
Positive end-expiratory pressure (PEEP) will be maintained at 5 cmH₂O. The respiratory rate will be further titrated to maintain ETCO₂ between 35 and 40 mmHg. Receives: Procedure: FCV Group |
| VCV Group | Active comparator | Patients allocated to the VCV group will receive intraoperative mechanical ventilation using a conventional volume-controlled ventilation mode throughout surgery under general anesthesia. Anesthetic induction, monitoring, and perioperative management will follow the same standardized clinical protocols as those used in the FCV group. Ventilatory parameters, including peak and plateau airway pressures and arterial blood gas measurements, will be collected at identical predefined intraoperative time points. This group serves as the comparator arm for evaluating the effects of volume-controlled ventilation on airway pressures and oxygenation in these patients. Receives: Procedure: VCV Group |
What is being measured
The primary outcome is the main question the study is designed to answer.
The PaO₂ value 20 minutes after insufflation.
The primary endpoint of the study is the PaO₂ value measured at the 20th minute under an FiO₂ of 0.8-1.0. Following insufflation, the patient's FiO₂ will be maintained between 0.8 and 1.0 for 20 minutes.
The primary endpoint of the study is the PaO₂ value measured at the 20th minute under an FiO₂ of 1.0.
After the 20th minute, ventilator settings will be returned to the baseline values.
Measured: At 20 minutes after insufflation in the intraoperative period.
Secondary outcomes (3)
The PaO₂ value during perioperative period
The PaO₂ values will be measured and recorded using arterial blood gas analysis.
Measured: At the beginning of the insufflation, 60 minutes after insufflation, before extubation, 1 hour after extubation.
Peak airway pressure (Ppeak) values during perioperative period.
Ppeak will be measured and recorded.
Measured: At the beginning of the insufflation, 20 minutes after insufflation, 60 minutes after insufflation, before extubation, 1 hour after extubation.
Plateau airway pressure (Pplateau) values during perioperative period
Pplateau will be measured and recorded.
Measured: At the beginning of the insufflation, 20 minutes after insufflation, 60 minutes after insufflation, before extubation, 1 hour after extubation.
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted24 Feb 2026
- Study start24 Feb 2026
- Primary completion5 Feb 2027 (estimated)
- Study completion18 Feb 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for ObesityStudies 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
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Single blind
- Who is masked
- Participant
- Enrolment
- 40 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Ankara Etlik City Hospital
- Sponsor type
- Other government
- Responsible party
- Principal investigator, Atakan Sezgi, Ankara Etlik City Hospital
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07430111
- Sponsor's protocol ID
- AEŞH-EK-2026-011
- Status last verified
- Feb 2026
- First submitted
- 18 Feb 2026
- Last updated
- 25 Feb 2026
- 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 25 Feb 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Comparison of Flow-Controlled and Volume-Controlled Ventilation During Bariatric Surgery: A Prospective Randomized Trial
- ClinicalTrials.gov ID
- NCT07430111
- Acronym / sponsor ID
- AEŞH-EK-2026-011
- Conditions
- Obesity, Bariatric Surgery, Mechanical Ventilation
- Keywords
- Obesity, Flow-Controlled Ventilation, Volume-Controlled Ventilation
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 40 participants (estimated)
- Lead sponsor
- Ankara Etlik City HospitalOther government
- Study start
- 24 Feb 2026 (actual)
- Primary completion
- 5 Feb 2027 (estimated)
- Study completion
- 18 Feb 2027 (estimated)
- First posted
- 24 Feb 2026 (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.
This prospective trial aims to compare the effects of flow-controlled ventilation (FCV) and volume-controlled ventilation (VCV) on intraoperative airway pressures and oxygenation in bariatric surgery under general anesthesia. Obesity is associated with altered respiratory mechanics, reduced functional residual capacity, and increased airway pressures, making the selection of an optimal ventilation strategy particularly important in this patient population.
Adult patients aged 18-65 years with a body mass index ≥30 kg/m² and American Society of Anesthesiologists (ASA) physical status II-III will be allocated to receive either FCV or VCV as part of routine intraoperative mechanical ventilation. Ventilatory parameters, including peak and plateau airway pressures, pulmonary compliance, will be recorded at predefined intraoperative time points.
The primary endpoint of the study is the PaO₂ value measured at the 20th minute under an FiO₂ of 0.8-1.0.
By providing comparative data on respiratory mechanics and oxygenation, this study aims to contribute to the identification of lung-protective ventilation strategies and to optimize intraoperative ventilatory management in bariatric surgery.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Single blind (participant)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| FCV Group | Active comparator | Procedure: FCV GroupPatients allocated to the FCV group will receive intraoperative mechanical ventilation using a flow-controlled ventilation mode during surgery under general anesthesia. %50 FiO₂ will be applied, and a driving pressure of 12 cmH₂O will be used. Following insufflation, the patient's FiO₂ will be maintained between 0.8 and 1.0 for 20 minutes. After the 20th minute, ventilator settings will be returned to the baseline values. Tidal volume will be generated and recorded by the ventilator according to the driving pressure and the patient's lung mechanics. Minute ventilation will be adjusted based on the target tidal volume. The target tidal volume will be set at 6-8 mL/kg (7 mL/kg) with a respiratory rate of 12 breaths/min. Positive end-expiratory pressure (PEEP) will be maintained at 5 cmH₂O. The respiratory rate will be further titrated to maintain ETCO₂ between 35 and 40 mmHg. |
| VCV Group | Active comparator | Procedure: VCV GroupPatients allocated to the VCV group will receive intraoperative mechanical ventilation using a conventional volume-controlled ventilation mode throughout surgery under general anesthesia. Anesthetic induction, monitoring, and perioperative management will follow the same standardized clinical protocols as those used in the FCV group. Ventilatory parameters, including peak and plateau airway pressures and arterial blood gas measurements, will be collected at identical predefined intraoperative time points. This group serves as the comparator arm for evaluating the effects of volume-controlled ventilation on airway pressures and oxygenation in these patients. |
Who may qualify
- Ages
- 18 to 65 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (3 listed)
- Age between 18 and 65 years
- Body mass index (BMI) ≥ 30 kg/m²
- ASA physical status II-III
Key exclusion criteria (6 listed)
- ASA physical status I or IV and above
- Known or previously diagnosed pulmonary disease
- Patients with severe preoperative pulmonary function impairment (e.g., FEV₁ < 50% predicted, severe restrictive or obstructive pathology)
- Patients with markedly altered lung anatomy or function due to prior major thoracic surgery
- Patients who were dependent on supplemental oxygen therapy in the preoperative period
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 |
|---|---|---|
| FCV GroupPatients allocated to the FCV group will receive intraoperative mechanical ventilation using a flow-controlled ventilation mode during surgery under general anesthesia. Patients will be started on ventilation after intubation with 50% oxygen, driving pressure 12, PEEP 5, and a 1:1 inspiration/expiratory ratio. | Procedure or surgery | FCV Group |
| VCV GroupPatients allocated to the VCV group will receive intraoperative mechanical ventilation using a conventional volume-controlled ventilation mode throughout surgery under general anesthesia. Patients will be started on ventilation after intubation with 50% oxygen, 7 ml/ideal body weight tidal volume, PEEP 5, 12 breaths per minute frequency, and a 1:2 inspiration/expiration ratio. | Procedure or surgery | VCV Group |
Primary outcome
The PaO₂ value 20 minutes after insufflation.
Time frame: At 20 minutes after insufflation in the intraoperative period.
The primary endpoint of the study is the PaO₂ value measured at the 20th minute under an FiO₂ of 0.8-1.0. Following insufflation, the patient's FiO₂ will be maintained between 0.8 and 1.0 for 20 minutes. The primary endpoint of the study is the PaO₂ value measured at the 20th minute under an FiO₂ of 1.0. After the 20th minute, ventilator settings will be returned to the baseline values.
3 secondary outcomes
The PaO₂ value during perioperative period
Time frame: At the beginning of the insufflation, 60 minutes after insufflation, before extubation, 1 hour after extubation.
Peak airway pressure (Ppeak) values during perioperative period.
Time frame: At the beginning of the insufflation, 20 minutes after insufflation, 60 minutes after insufflation, before extubation, 1 hour after extubation.
Plateau airway pressure (Pplateau) values during perioperative period
Time frame: At the beginning of the insufflation, 20 minutes after insufflation, 60 minutes after insufflation, before extubation, 1 hour after extubation.
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 25 Feb 2026.
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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.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing FCV Group and VCV Group in people with Obesity and Bariatric Surgery, run by Ankara Etlik City Hospital at 1 site in Turkey (Türkiye).
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 3 inclusion and 6 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 25 Feb 2026. 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 Turkey (Türkiye). 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?
Each site lists its own contact: choose the nearest one under Trial locations. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
The PaO₂ value 20 minutes after insufflation. (time frame: At 20 minutes after insufflation in the intraoperative period.). 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 25 Feb 2026.