Flow-Controlled Versus Volume-Controlled Ventilation During Balloon Dilatation Under Direct Laryngoscopy

February 24, 2026 updated by: Atakan Sezgi, Ankara Etlik City Hospital

Comparison of Flow-Controlled and Volume-Controlled Ventilation During Balloon Dilatation Under Direct Laryngoscopy: A Prospective Randomized Trial

This prospective trial aims to compare the effects of flow-controlled ventilation (FCV) and volume-controlled ventilation (VCV) on airway pressures and oxygenation in adult patients undergoing balloon dilatation under direct laryngoscopy. Airway procedures performed under general anesthesia are associated with unique respiratory mechanics and limited ventilation conditions, making the choice of an optimal ventilation strategy particularly important.

Adult patients aged 18-65 years with American Society of Anesthesiologists (ASA) physical status I-III will be allocated to receive either FCV or VCV during surgery. Ventilatory parameters, airway pressures, pulmonary compliance, and arterial blood gas values will be recorded at predefined intraoperative time points. The primary outcome is the PaO₂ measured 20 minutes under an FiO₂ of 0.8-1.0 after starting the ventilation under general anesthesia, reflecting early intraoperative oxygenation under stable conditions.

By providing comparative data on respiratory mechanics and oxygenation, this study aims to contribute to the identification of lung-protective ventilation strategies in patients undergoing balloon dilatation under direct laryngoscopy.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Estimated)

40

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Age between 18 and 65 years
  • ASA physical status I-III

Exclusion Criteria:

  • Age < 18 years or > 65 years
  • 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
  • ASA physical status IV or higher
  • Refusal or inability to provide informed consent

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Single

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Active Comparator: FCV Group

Patients allocated to the FCV group will receive intraoperative mechanical ventilation using a flow-controlled ventilation mode during surgery under general anesthesia. 80-100% FiO₂ will be applied, and a driving pressure of 12 cmH₂O will be used. After the 20th minute, the patient's FiO₂ will be adjusted according to the clinical condition.

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 was further titrated to maintain ETCO₂ between 35 and 40 mmHg.
Procedure: FCV Group
Patients allocated to the FCV group will receive mechanical ventilation using a flow-controlled ventilation mode throughout the surgical procedure performed under general anesthesia. Ventilation will be managed according to routine clinical practice, with standardized anesthetic induction and monitoring. Ventilatory parameters, airway pressures, pulmonary compliance, and arterial blood gas values will be recorded at predefined intraoperative time points, including after starting the ventilation under general anesthesia and 20 minutes after intubation. This group aims to evaluate the effects of FCV on airway pressures and early intraoperative oxygenation during balloon dilatation performed under direct laryngoscopy.
Active Comparator: 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 80-100% FiO₂, 7 ml/ideal body weight tidal volume, PEEP 5, 12 breaths per minute frequency, and a 1:2 inspiration/expiration ratio. After the 20th minute, the patient's FiO₂ will be adjusted according to the clinical condition.
Procedure: VCV Group
Patients allocated to the VCV group will receive mechanical ventilation using a conventional volume-controlled ventilation mode throughout the surgical procedure under general anesthesia. Anesthetic management and monitoring will follow standard clinical protocols identical to those applied in the FCV group. Ventilatory parameters, airway pressures, pulmonary compliance, and arterial blood gas measurements will be recorded at the same predefined intraoperative time points, including after starting the ventilation under general anesthesia and 20 minutes after intubation. This group serves as the comparator arm to assess the effects of volume-controlled ventilation on airway pressures and oxygenation during balloon dilatation under direct laryngoscopy.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
The PaO₂ measured 20 minutes after intubation.
Time Frame: 20 minutes after intubation in the intraoperative period
The primary outcome measure will be the PaO₂ derived from arterial blood gas analysis at 20 minutes after intubation.
20 minutes after intubation in the intraoperative period

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
The PaO₂ measured during perioperative period
Time Frame: At the initiation of mechanical ventilation following intubation and at the first postoperative hour after extubation
The PaO₂ values will be measured and recorded using arterial blood gas analysis.
At the initiation of mechanical ventilation following intubation and at the first postoperative hour after extubation
Peak airway pressure (Ppeak) values during perioperative period.
Time Frame: At the initiation of mechanical ventilation following intubation and 20 minutes after intubation
Ppeak will be measured and recorded.
At the initiation of mechanical ventilation following intubation and 20 minutes after intubation
Plateau airway pressure (Pplateau) values during perioperative period
Time Frame: At the initiation of mechanical ventilation following intubation and 20 minutes after intubation
Pplateau will be measured and recorded.
At the initiation of mechanical ventilation following intubation and 20 minutes after intubation

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Ankara Etlik City Hospital

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

February 24, 2026

Primary Completion (Estimated)

August 7, 2026

Study Completion (Estimated)

August 20, 2026

Study Registration Dates

First Submitted

February 18, 2026

First Submitted That Met QC Criteria

February 18, 2026

First Posted (Actual)

February 24, 2026

Study Record Updates

Last Update Posted (Actual)

February 25, 2026

Last Update Submitted That Met QC Criteria

February 24, 2026

Last Verified

February 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • AEŞH-EK-2026-012

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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