Obesity, MorbidNCT07641829
Flow-Controlled vs Volume-Controlled Ventilation in Morbidly Obese Patients Undergoing Laparoscopic Bariatric Surgery
An observational study of Obesity, Morbid and Bariatric Surgery (Sleeve Gastrectomy ), run by Ankara Training and Research Hospital at 1 site in Turkey (Türkiye).
Trial summary
The goal of this clinical trial is to compare the effects of flow-controlled ventilation (FCV) and volume-controlled ventilation (VCV) on hemodynamic and respiratory parameters in obese patients undergoing elective laparoscopic bariatric surgery. Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Obesity, Morbid, Bariatric Surgery (Sleeve Gastrectomy ), Mechanical Ventilation
- Type of treatment
- Medical device
- How many people
- 34 participants
- Where
- 1 siteTurkey (Türkiye)
- Study dates
- 15 Mar 2026to 21 Jul 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: Adult morbidly obese patients (BMI ≥40 kg/m²) aged 18-65 years, classified as ASA I-III, scheduled for elective laparoscopic bariatric surgery at Ankara Training and Research Hospital.
Who may be able to join
- Age between 18 and 65 years
- American Society of Anesthesiologists (ASA) physical status I, II, or III
- Body Mass Index (BMI) ≥ 40 kg/m²
- Scheduled for elective laparoscopic bariatric surgery
- Willing to participate in the study
Who cannot join
- ASA physical status IV or V
- Emergency surgical procedures
- Pregnant patients
- Patients requiring vasopressor support to maintain mean arterial pressure above 65 mmHg intraoperatively
- Patients with advanced pulmonary disease
- Patients who decline to participate in the study
Trial locations and contacts
1 site in 1 country.
Turkey (Türkiye)1 site
Ankara Education and Research Hospital
Ankara, 06230
About this study
Official title: Investigation of the Effects of Flow-Controlled Ventilation and Volume-Controlled Ventilation on Pulmonary Dynamics and Hemodynamics in Morbidly Obese Patients Undergoing Laparoscopic Bariatric Surgery
The goal of this clinical trial is to compare the effects of flow-controlled ventilation (FCV) and volume-controlled ventilation (VCV) on hemodynamic and respiratory parameters in obese patients undergoing elective laparoscopic bariatric surgery. The main questions it aims to answer are:
Does FCV provide better intraoperative hemodynamic and respiratory stability compared to VCV during laparoscopic bariatric surgery? Is FCV a safe and feasible ventilation strategy under high intraabdominal pressure and position changes required in bariatric surgery?
Read more
Researchers will compare FCV group to VCV group to see if FCV improves intraoperative respiratory mechanics and hemodynamic parameters.
Participants will:
Undergo elective laparoscopic bariatric surgery with BMI >40 kg/m² (ASA I-III) Receive either flow-controlled or volume-controlled ventilation with individualized PEEP and tidal volume of 6-8 ml/kg predicted body weight Have intraoperative hemodynamic and respiratory parameters monitored at regular intervals, including arterial blood gas analysis Be followed postoperatively for oxygen therapy requirement and intensive care need
Read the detailed description
Laparoscopic surgery is associated with significant physiological changes due to pneumoperitoneum, which adversely affects hemodynamic and respiratory parameters, thereby complicating intraoperative anesthetic management. These challenges are particularly pronounced in obese patients, who present with reduced functional residual capacity and other physiological alterations that impact both intraoperative and postoperative outcomes.
Although bariatric surgery has conventionally been managed with volume-controlled ventilation (VCV), recent studies have highlighted the potential benefits of flow-controlled ventilation (FCV) in terms of safety and contribution to lung-protective ventilation strategies.
This study primarily aims to compare the effects of FCV and VCV on intraoperative hemodynamic and respiratory function dynamics in patients undergoing bariatric surgery. Secondarily, the study evaluates the clinical feasibility and safety of FCV under the high intraabdominal pressures and position changes required during bariatric procedures.
Study Design:
This study includes 34 patients with BMI >40 kg/m² classified as ASA I-III scheduled for elective laparoscopic bariatric surgery. Seventeen patients were prospectively managed with FCV, while data from 17 patients managed with VCV were retrospectively reviewed. All patients received standard monitoring plus intra-arterial blood pressure monitoring. Anesthesia induction and maintenance protocols were identical across both groups.
Ventilation Protocol:
In the FCV group, a tidal volume (VT) of 6-8 ml/kg predicted body weight was targeted, and positive end-expiratory pressure (PEEP) was individualized based on compliance following CO₂ insufflation. The same tidal volume strategy was applied in the VCV group with PEEP titration performed in eligible patients.
Measurements:
The following parameters were recorded after intubation, after insufflation, and at 30-minute intervals intraoperatively: mean arterial pressure (MAP), heart rate, peripheral oxygen saturation (SpO₂), plateau airway pressure (Pplat), peak airway pressure (Ppeak), driving pressure, end-tidal CO₂ (EtCO₂), minute volume, respiratory rate (RR), airway resistance (Raw), and static compliance (Cstatic) calculated as VT/(Pplat-PEEP). Arterial blood gas parameters including pH, PaCO₂, PaO₂, SaO₂, hemoglobin, and lactate were also recorded. Postoperative oxygen therapy requirement and intensive care unit admission were monitored.
- Being tested
- Flow-Controlled Ventilation (FCV), Volume-Controlled Ventilation (VCV)
- Keywords
- Flow-controlled ventilation, Volume-controlled ventilation, Respiratory mechanics, Lung-protective ventilation, Bariatric surgery
- Medical subject headings
- Obesity, Morbid
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Flow-Controlled Ventilation (FCV)Device
Also called FCV
Patients were ventilated using flow-controlled ventilation with a tidal volume of 6-8 ml/kg predicted body weight. PEEP was individualized based on respiratory compliance following CO₂ insufflation.
Volume-Controlled Ventilation (VCV)Device
Patients were ventilated using volume-controlled ventilation with a tidal volume of 6-8 ml/kg predicted body weight. PEEP titration was performed in eligible patients.
| Study group | Role | What they receive |
|---|---|---|
| FCV Group | Patients undergoing elective laparoscopic bariatric surgery managed with flow-controlled ventilation (FCV) with tidal volume of 6-8 ml/kg predicted body weight and individualized PEEP based on compliance following CO₂ insufflation. Receives: Device: Flow-Controlled Ventilation (FCV) | |
| VCV Group | Patients undergoing elective laparoscopic bariatric surgery managed with volume-controlled ventilation (VCV) with tidal volume of 6-8 ml/kg predicted body weight and PEEP titration performed in eligible patients. Data collected retrospectively. Receives: Device: Volume-Controlled Ventilation (VCV) |
What is being measured
The primary outcome is the main question the study is designed to answer.
Intraoperative Respiratory Mechanics
Comparison of driving pressure between FCV and VCV groups at defined intraoperative time points.
Measured: From intubation to end of surgery, measured after intubation, after insufflation, and at 30-minute intervals intraoperatively
Mean Arterial Pressure
Comparison of mean arterial pressure (MAP) between FCV and VCV groups at defined intraoperative time points.
Measured: From preoperative baseline to end of surgery, measured before surgery, after intubation, after insufflation, at 30-minute intervals intraoperatively, and at end of surgery
Secondary outcomes (4)
Pa02/Fi02 ratio
Comparison of Horowitz index between FCV and VCV groups.
Measured: From intubation to end of surgery, measured after intubation, after insufflation, at 30-minute intervals intraoperatively and at the end of the surgery.
Postoperative Oxygen Theraphy Need
Comparison of percentage of participants requiring postoperative oxygen therapy requirement between FCV and VCV groups.
Measured: Within 24 hours after surgery
Postoperative Intensive Unit Admission
Comparison of the number of patients requiring admission to the intensive care unit between the FCV and VCV groups.
Measured: Within 24 hours after surgery
Arterial Partial Pressure of Carbon Dioxide (PaCO2)
Comparison of arterial partial pressure of carbon dioxide (PaCO2) between the FCV and VCV groups to evaluate efficiency of carbon dioxide elimination at defined time points.
Measured: From intubation to the end of surgery, measured after intubation, after insufflation, and at 30-minute intervals intraoperatively and at the end of the operation
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted11 Jun 2026
- Study start15 Mar 2026
- Primary completion20 Jul 2026
- Study completion21 Jul 2026
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Obesity, MorbidStudies 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
- Observational
- Observational model
- Cohort
- Time perspective
- Other
- Enrolment
- 34 participants (actual)
Sponsor and investigators
- Lead sponsor
- Ankara Training and Research Hospital
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, MD, Tugce Ozdogan, Ankara Training and Research Hospital
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07641829
- Sponsor's protocol ID
- E-25-418
- Status last verified
- Jul 2026
- First submitted
- 1 Jun 2026
- Last updated
- 23 Jul 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Yes: Individual participant data will be shared upon reasonable request.
Study at a glance
From the registry record, last updated by the sponsor on 23 Jul 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Investigation of the Effects of Flow-Controlled Ventilation and Volume-Controlled Ventilation on Pulmonary Dynamics and Hemodynamics in Morbidly Obese Patients Undergoing Laparoscopic Bariatric Surgery
- ClinicalTrials.gov ID
- NCT07641829
- Acronym / sponsor ID
- E-25-418
- Keywords
- Flow-controlled ventilation, Volume-controlled ventilation, Respiratory mechanics, Lung-protective ventilation, Bariatric surgery
- Study type
- Observational
- Recruitment status
- Completed
- Enrolment
- 34 participants (actual)
- Lead sponsor
- Ankara Training and Research HospitalUniversity, hospital or other
- Study start
- 15 Mar 2026 (actual)
- Primary completion
- 20 Jul 2026 (actual)
- Study completion
- 21 Jul 2026 (actual)
- First posted
- 11 Jun 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.
The goal of this clinical trial is to compare the effects of flow-controlled ventilation (FCV) and volume-controlled ventilation (VCV) on hemodynamic and respiratory parameters in obese patients undergoing elective laparoscopic bariatric surgery. The main questions it aims to answer are:
Does FCV provide better intraoperative hemodynamic and respiratory stability compared to VCV during laparoscopic bariatric surgery? Is FCV a safe and feasible ventilation strategy under high intraabdominal pressure and position changes required in bariatric surgery?
Researchers will compare FCV group to VCV group to see if FCV improves intraoperative respiratory mechanics and hemodynamic parameters.
Participants will:
Undergo elective laparoscopic bariatric surgery with BMI >40 kg/m² (ASA I-III) Receive either flow-controlled or volume-controlled ventilation with individualized PEEP and tidal volume of 6-8 ml/kg predicted body weight Have intraoperative hemodynamic and respiratory parameters monitored at regular intervals, including arterial blood gas analysis Be followed postoperatively for oxygen therapy requirement and intensive care need
Detailed description
Laparoscopic surgery is associated with significant physiological changes due to pneumoperitoneum, which adversely affects hemodynamic and respiratory parameters, thereby complicating intraoperative anesthetic management. These challenges are particularly pronounced in obese patients, who present with reduced functional residual capacity and other physiological alterations that impact both intraoperative and postoperative outcomes.
Although bariatric surgery has conventionally been managed with volume-controlled ventilation (VCV), recent studies have highlighted the potential benefits of flow-controlled ventilation (FCV) in terms of safety and contribution to lung-protective ventilation strategies.
This study primarily aims to compare the effects of FCV and VCV on intraoperative hemodynamic and respiratory function dynamics in patients undergoing bariatric surgery. Secondarily, the study evaluates the clinical feasibility and safety of FCV under the high intraabdominal pressures and position changes required during bariatric procedures.
Study Design:
This study includes 34 patients with BMI >40 kg/m² classified as ASA I-III scheduled for elective laparoscopic bariatric surgery. Seventeen patients were prospectively managed with FCV, while data from 17 patients managed with VCV were retrospectively reviewed. All patients received standard monitoring plus intra-arterial blood pressure monitoring. Anesthesia induction and maintenance protocols were identical across both groups.
Ventilation Protocol:
In the FCV group, a tidal volume (VT) of 6-8 ml/kg predicted body weight was targeted, and positive end-expiratory pressure (PEEP) was individualized based on compliance following CO₂ insufflation. The same tidal volume strategy was applied in the VCV group with PEEP titration performed in eligible patients.
Measurements:
The following parameters were recorded after intubation, after insufflation, and at 30-minute intervals intraoperatively: mean arterial pressure (MAP), heart rate, peripheral oxygen saturation (SpO₂), plateau airway pressure (Pplat), peak airway pressure (Ppeak), driving pressure, end-tidal CO₂ (EtCO₂), minute volume, respiratory rate (RR), airway resistance (Raw), and static compliance (Cstatic) calculated as VT/(Pplat-PEEP). Arterial blood gas parameters including pH, PaCO₂, PaO₂, SaO₂, hemoglobin, and lactate were also recorded. Postoperative oxygen therapy requirement and intensive care unit admission were monitored.
Study design
- Observational model
- Cohort
- Time perspective
- Other
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| FCV Group | – | Device: Flow-Controlled Ventilation (FCV)Patients undergoing elective laparoscopic bariatric surgery managed with flow-controlled ventilation (FCV) with tidal volume of 6-8 ml/kg predicted body weight and individualized PEEP based on compliance following CO₂ insufflation. |
| VCV Group | – | Device: Volume-Controlled Ventilation (VCV)Patients undergoing elective laparoscopic bariatric surgery managed with volume-controlled ventilation (VCV) with tidal volume of 6-8 ml/kg predicted body weight and PEEP titration performed in eligible patients. Data collected retrospectively. |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
- Study population
- Adult morbidly obese patients (BMI ≥40 kg/m²) aged 18-65 years, classified as ASA I-III, scheduled for elective laparoscopic bariatric surgery at Ankara Training and Research Hospital.
Key inclusion criteria (5 listed)
- Age between 18 and 65 years
- American Society of Anesthesiologists (ASA) physical status I, II, or III
- Body Mass Index (BMI) ≥ 40 kg/m²
- Scheduled for elective laparoscopic bariatric surgery
- Willing to participate in the study
Key exclusion criteria (6 listed)
- ASA physical status IV or V
- Emergency surgical procedures
- Pregnant patients
- Patients requiring vasopressor support to maintain mean arterial pressure above 65 mmHg intraoperatively
- Patients with advanced pulmonary disease
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)Also: FCVPatients were ventilated using flow-controlled ventilation with a tidal volume of 6-8 ml/kg predicted body weight. PEEP was individualized based on respiratory compliance following CO₂ insufflation. | Device | FCV Group |
| Volume-Controlled Ventilation (VCV)Patients were ventilated using volume-controlled ventilation with a tidal volume of 6-8 ml/kg predicted body weight. PEEP titration was performed in eligible patients. | Device | VCV Group |
Primary outcome
Intraoperative Respiratory Mechanics
Time frame: From intubation to end of surgery, measured after intubation, after insufflation, and at 30-minute intervals intraoperatively
Comparison of driving pressure between FCV and VCV groups at defined intraoperative time points.
Mean Arterial Pressure
Time frame: From preoperative baseline to end of surgery, measured before surgery, after intubation, after insufflation, at 30-minute intervals intraoperatively, and at end of surgery
Comparison of mean arterial pressure (MAP) between FCV and VCV groups at defined intraoperative time points.
4 secondary outcomes
Pa02/Fi02 ratio
Time frame: From intubation to end of surgery, measured after intubation, after insufflation, at 30-minute intervals intraoperatively and at the end of the surgery.
Postoperative Oxygen Theraphy Need
Time frame: Within 24 hours after surgery
Postoperative Intensive Unit Admission
Time frame: Within 24 hours after surgery
Arterial Partial Pressure of Carbon Dioxide (PaCO2)
Time frame: From intubation to the end of surgery, measured after intubation, after insufflation, and at 30-minute intervals intraoperatively and at the end of the operation
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 23 Jul 2026.
- Individual participant dataSharing planned: Yes. Individual participant data will be shared upon reasonable request.
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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.
The record lists no contact. Use the official record to reach the sponsor.
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 Obesity, Morbid and Bariatric Surgery (Sleeve Gastrectomy ), run by Ankara Training and Research 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 5 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: finished, as of the sponsor's last update on 23 Jul 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?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
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?
Intraoperative Respiratory Mechanics (time frame: From intubation to end of surgery, measured after intubation, after insufflation, and at 30-minute intervals intraoperatively). 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 23 Jul 2026.