Assessment of Sevoflurane Consumption During General Anesthesia With a Low Fresh Gas Flow Rate of 0.3 L/Min (FGF 03)

June 3, 2026 updated by: Centre Hospitalier Universitaire de Nīmes

Driven by industry demands and the need for anesthesia that consumes fewer resources ("green anesthesia"), manufacturers of anesthesia ventilators have developed closed-circuit ventilators. In a closed-circuit system, during the exhalation phase, gases are not released outside the ventilator into the atmosphere but are injected into the inspiratory limb of the circuit after being warmed and having CO2 removed. It is a closed loop. However, the loop is not completely closed because a very small stream of air is additionally injected into the inspiratory limb to limit the risk of hypoxia. This small stream of air is called "Fresh Gas Flow" or FGF.

To optimize this closed-loop recirculation, manufacturers have designed machines capable of minimizing the fresh gas flow. In the 2000s, machines operated with FGFs of 2 L/min, dropping to flows as low as 0.5 L/min by 2010. This low-flow regime allows for an 80% reduction in halogenated gas (sevoflurane) consumption while maintaining the same efficiency. Recently, even more sophisticated machines have been designed with FGFs of 0.3 L/min. Some of these new machines will be commercially available on a large scale in 2026. As part of an industrial partnership, the Nîmes University Hospital has validated the post-CE marking of these machines for certain manufacturers (including General Electric); the post-CE marking allows the manufacturer to have access to usage data Given that this product has only recently been introduced to the market, very little data has been published on the use of sevoflurane in daily practice at very low FGF flow rates (0.3 to 0.5 L/min).

For the past four months, the Nîmes University Hospital has had two CE-marked machines (GE, CS 850) capable of ventilating at flow rates of 0.3 L/min. These machines are connected to software (Carestation Insight) that allows all anonymized ventilator data to be recorded independently of the users. This software has been in continuous use in 12 operating rooms since 2024 within our institution and has been the subject of numerous publications (see Ref. 19). All ventilation and sevoflurane data are continuously recorded and stored in a secure, anonymous cloud (Ref. 19).

The objective of this retrospective study is to analyze the database of sevoflurane consumption derived from the Carestation Insight software for patients who underwent general anesthesia with ventilation at FGF flow rates of 0.3 L/min and to compare these data with our database of patients under anesthesia at flow rates of 0.5 to 2 L/min, also derived from this same cloud.

Study Overview

Status

Status

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Not yet recruiting

Conditions

Conditions

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Intervention / Treatment

Intervention / Treatment

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Study Type

Study Type

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Observational

Enrollment (Estimated)

Enrollment

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30

Contacts and Locations

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Study Contact

Study Contact

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Participation Criteria

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Eligibility Criteria

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Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Sampling Method

Probability Sample

Study Population

Patients who underwent general anesthesia with ventilation at a minute volume of 0.3 L/min at the Nîmes University Hospital

Description

Inclusion Criteria:

  • Adult patients undergoing surgery under general anesthesia with mechanical ventilation

    • Connected to a ventilator linked to the Carestaion software
    • No refusal as indicated by a letter of consent

Exclusion Criteria:

  • Refusal to participate
  • Minor patients

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

Cohorts and Interventions

Group / Cohort

Group / Cohort

A group or subgroup of participants in an observational study that is assessed for biomedical or health outcomes.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
FGF flow rates of 0.3
Patients who underwent general anesthesia with mechanical ventilation at a minute ventilation of 0.3
Other: None, Pure observatinal study
None, Pure observatinal study

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
sevoflurane consumption
Time Frame: Perioperative
Measurement of sevoflurane consumption (in liters) per minute of anesthesia
Perioperative
FGF
Time Frame: Perioperative
Measurement of gas flow rate (FGF) (L/minute).
Perioperative

Collaborators and Investigators

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Sponsor

Sponsor

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Centre Hospitalier Universitaire de Nīmes

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Study Director: Anissa MEGZARI, Centre Hospitalier Universitaire de Nīmes

Study record dates

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Study Major Dates

Study Start (Estimated)

Study Start

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June 1, 2026

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
December 1, 2027

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
December 1, 2027

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
May 28, 2026

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
June 3, 2026

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
June 4, 2026

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
June 4, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
June 3, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
May 1, 2026

More Information

Terms related to this study

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • Local/2026/PC-01

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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