Flow-Controlled Versus Volume-Controlled Ventilation in Bariatric Surgery
For patients and families
In plain language
An automatic summary of structured registry data. It is an orientation aid, not a substitute for the official protocol or a physician assessment.
- What is being studied
- The protocol lists: FCV Group, VCV Group.
- Who it may be relevant to
- Registry conditions: Obesity, Bariatric Surgery, Mechanical Ventilation. Basic parameters: 18 years — 65 years · All.
- What needs checking
- Age, condition and sex are only basic indicators. Prior treatment, laboratory values and other mandatory requirements appear in the eligibility criteria below.
- Where it takes place
- Turkey (Türkiye)
- Next step
- Save the trial, show it to the treating physician, and confirm current recruitment with the study center. Costs, documents and travel →
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Official title
Comparison of Flow-Controlled and Volume-Controlled Ventilation During Bariatric Surgery: A Prospective Randomized Trial
Overview
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.
Interventions
- Procedure FCV Group
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. - Procedure VCV Group
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.
Primary outcome measures
- The PaO₂ value 20 minutes after insufflation. [Time frame: At 20 minutes after insufflation in the intraoperative period.]
Secondary outcome measures (3)
- 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.]
Eligibility criteria
Inclusion criteria
- Age between 18 and 65 years
- Body mass index (BMI) ≥ 30 kg/m²
- ASA physical status II-III
Exclusion criteria
- 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
Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.
Healthy volunteers: No
Study design
- Allocation
- Randomized
- Model
- Parallel assignment
- Masking
- Single blind
- Primary purpose
- Treatment
Study locations
Turkey (Türkiye) · 1 center
- Ankara Etlik City Hospital — Ankara
Identifiers
NCT: NCT07430111 · AEŞH-EK-2026-011