Flow-Controlled Versus Volume-Controlled Ventilation in Lumbar Disc Herniation Surgery

May 27, 2026 updated by: Atakan Sezgi, Ankara Etlik City Hospital

Comparison of Flow-Controlled and Volume-Controlled Ventilation During Lumbar Disc Herniation Surgery: A Prospective Randomized Trial

This prospective randomized trial aims to compare the effects of flow-controlled ventilation (FCV) and volume-controlled ventilation (VCV) on intraoperative airway pressures and oxygenation in patients undergoing lumbar disc herniation surgery under general anesthesia.

Adult patients aged 18-65 years, with ASA physical status I-III and a body mass index of 18-30 kg/m², will be allocated to receive either FCV or VCV during routine intraoperative mechanical ventilation. Ventilatory parameters, including peak airway pressure, plateau pressure, pulmonary compliance, EtCO₂, SpO₂, and arterial blood gas variables, will be recorded at predefined time points after intubation.

The primary endpoint is the PaO₂ value measured after 20 minutes in the prone position.

By comparing respiratory mechanics and oxygenation between the two ventilation modes, this study aims to contribute to the optimization of intraoperative ventilatory management in lumbar disc herniation surgery.

Study Overview

Status

Not yet recruiting

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Estimated)

80

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 Contact

Study Contact Backup

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
  • Body Mass Index between 18 and 30 kg/m²

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: 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. 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.
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.
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. %50 FiO₂ will be applied, and a driving pressure of 12 cmH₂O will be used.

After intubation, the patient will be placed in the prone position. Following the prone position, 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.
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.

What is the study measuring?

Primary Outcome Measures

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

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
The PaO₂ measured during perioperative period
Time Frame: Day 1
The PaO₂ values will be measured and recorded using arterial blood gas analysis.
Day 1
Peak airway pressure (Ppeak) values during perioperative period
Time Frame: Day 1
Ppeak will be measured and recorded.
Day 1
Plateau airway pressure (Pplateau) values during perioperative period
Time Frame: Day 1
Pplateau will be measured and recorded.
Day 1

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 (Estimated)

June 1, 2026

Primary Completion (Estimated)

November 12, 2026

Study Completion (Estimated)

November 26, 2026

Study Registration Dates

First Submitted

May 18, 2026

First Submitted That Met QC Criteria

May 27, 2026

First Posted (Actual)

May 29, 2026

Study Record Updates

Last Update Posted (Actual)

May 29, 2026

Last Update Submitted That Met QC Criteria

May 27, 2026

Last Verified

May 1, 2026

More Information

Terms related to this study

Keywords

Other Study ID Numbers

  • AEŞH-EK-2026-096

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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