Low Flow AnesthesiaNCT07313969
Ultra-Low-Flow Anesthesia and Carbon Footprint
A study testing ultra low flow anesthesia and normal flow anesthesia in people with Low Flow Anesthesia and Sevoflurane Anesthesia, run by Dr Abdurrahman Yurtaslan Ankara Oncology Training and Research Hospital at 1 site in Turkey (Türkiye).
Trial summary
This is a prospective, randomized controlled clinical trial evaluating the effects of ultra-low fresh gas flow (0.5 L/min) versus normal fresh gas flow (2.0 L/min) sevoflurane anesthesia in adult patients undergoing on-pump cardiac surgery. Read more about this study
- Who is it for?
- Ages 18 to 80 years
- Conditions the study is for
- Low Flow Anesthesia, Sevoflurane Anesthesia, Cardiac Surgery
- What is being tested?
- ultra low flow anesthesia and normal flow anesthesia
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 92 participants
- Where
- 1 siteTurkey (Türkiye)
- Study dates
- 30 Dec 2025to 15 May 2026
- Phase
- Interventional
- 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 to 80 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Adult patients aged 18-80 years
- Scheduled for elective on-pump CABG or valve surgery
- ASA physical status II-III
- Written informed consent obtained
Who cannot join
- Emergency surgery
- Severe hepatic or renal dysfunction
- Known allergy to volatile anesthetics
- Significant pulmonary disease (e.g., COPD with GOLD III-IV)
Trial locations and contacts
1 site in 1 country.
About this study
Official title: The Impact of Ultra-Low-Flow Sevoflurane Anesthesia on Carbon Footprint and Cost: A Randomized Controlled Study in Cardiac Surgery Patients
This is a prospective, randomized controlled clinical trial evaluating the effects of ultra-low fresh gas flow (0.5 L/min) versus normal fresh gas flow (2.0 L/min) sevoflurane anesthesia in adult patients undergoing on-pump cardiac surgery. The study aims to determine whether ultra-low-flow anesthesia can be used safely to reduce volatile anesthetic consumption and environmental emissions without compromising hemodynamic stability or anesthetic depth.
Eligible adult patients scheduled for elective coronary artery bypass grafting (CABG) or valve surgery under general anesthesia will be randomized in a 1:1 ratio to one of two groups: ultra-low-flow (0.5 L/min) or normal-flow (2.0 L/min). All other anesthetic techniques, including induction drugs, ventilation parameters, temperature management, and perfusion strategies, will be standardized.
Read more
The primary outcome is the total amount of sevoflurane consumed per case. Secondary outcomes include intraoperative hemodynamic parameters (heart rate, mean arterial pressure), depth of anesthesia (BIS/MAC values), postoperative recovery times, and estimated carbon dioxide equivalent (CO₂e) emissions.
Outcome assessors and data analysts will remain blinded to group allocation. The findings of this study are expected to provide new evidence regarding the safety, efficiency, and environmental benefits of ultra-low-flow anesthesia techniques in cardiac surgery.
Read the detailed description
This randomized controlled trial investigates the impact of ultra-low-flow (0.5 L/min) versus normal-flow (2.0 L/min) sevoflurane anesthesia on anesthetic consumption, intraoperative hemodynamics, and environmental footprint during on-pump cardiac surgery. Although low-flow anesthesia is known to reduce anesthetic agent use and greenhouse gas emissions, evidence regarding its safety and efficiency during cardiopulmonary bypass procedures remains limited.
Adult patients scheduled for elective CABG or valve surgery will be randomly assigned to either an ultra-low-flow or normal-flow group. Randomization will be performed using a computer-generated sequence with variable block sizes and allocation concealment via sequentially numbered, opaque, sealed envelopes. All participants will receive standardized induction, perfusion, and maintenance techniques according to institutional cardiac anesthesia protocols.
The primary outcome measure is total sevoflurane consumption per patient, assessed through vaporizer readings and anesthetic gas analyzer data. Secondary outcomes include intraoperative mean arterial pressure, heart rate, BIS/MAC values, body temperature, recovery characteristics, and calculated CO₂ equivalent emissions. Outcome assessors and data analysts will remain blinded to group allocation.
This study is designed to evaluate both clinical and ecological aspects of anesthetic practice. It aims to determine whether ultra-low-flow anesthesia can provide equivalent anesthetic quality while offering substantial reductions in agent consumption and environmental impact. The findings may contribute to establishing safer and more sustainable anesthesia standards for cardiac surgery.
- Conditions
- Low Flow Anesthesia, Sevoflurane Anesthesia, Cardiac Surgery
- Being tested
- ultra low flow anesthesia, normal flow anesthesia
- Keywords
- low flow anesthesia, ultra low flow anesthesia, carbon footprint
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
ultra low flow anesthesiaDrug
General anesthesia will be maintained with sevoflurane at a fresh gas flow rate of 0.5 L/min using oxygen and air mixture. The flow rate will be kept constant from post-induction stabilization until the end of cardiopulmonary bypass.
normal flow anesthesiaDrug
General anesthesia will be maintained with sevoflurane at a fresh gas flow rate of 2.0 L/min using oxygen and air mixture. The flow rate will be kept constant from post-induction stabilization until the end of cardiopulmonary bypass.
| Study group | Role | What they receive |
|---|---|---|
| Ultra-Low-Flow Group (0.5 L/min) | Active comparator | Sevoflurane anesthesia with fresh gas flow maintained at 0.5 L/min throughout the maintenance period. A 2 lt/min fresh gas flow will be used in the preoxygenation and intubation phase.
General anesthesia will be maintained with sevoflurane at a fresh gas flow rate of 0.5 L/min using an oxygen and air mixture. The flow rate will be kept constant from post-induction stabilization until the end of the surgery. Ventilation will be paused during cardiopulmonary bypass. Receives: Drug: ultra low flow anesthesia |
| Normal-Flow Group (2.0 L/min) | Active comparator | Sevoflurane anesthesia with fresh gas flow maintained at 2.0 L/min throughout maintenance period. The flow rate will be kept constant from post-induction stabilization until the end of surgery. Ventilation will be paused during cardiopulmonary bypass Receives: Drug: normal flow anesthesia |
What is being measured
The primary outcome is the main question the study is designed to answer.
Total sevoflurane consumption (mL per case), measured at the end of surgery.
Measured: throughout the surgery
Secondary outcomes (1)
carbon footprint
Estimated CO₂e emissions (calculated from anesthetic use)
Measured: throughout the surgery
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted2 Jan 2026
- Study start30 Dec 2025
- Primary completion15 Mar 2026
- Study completion15 May 2026
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for Low Flow AnesthesiaStudies 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
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Double blind
- Who is masked
- Participant, Outcomes assessor
- Enrolment
- 92 participants (actual)
Sponsor and investigators
- Lead sponsor
- Dr Abdurrahman Yurtaslan Ankara Oncology Training and Research Hospital
- Sponsor type
- University, hospital or other
- Collaborators
- Ankara Etlik City Hospital
- Responsible party
- Principal investigator, Ekin Guran, MD, Ankara Etlik City Hospital
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07313969
- Sponsor's protocol ID
- Ultra_low_flow
- Status last verified
- Jun 2026
- First submitted
- 10 Dec 2025
- Last updated
- 18 Jun 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- No
- FDA-regulated device
- No
Publications
McGain F, Sheridan N, Wickramarachchi K, Yates S, Chan B, McAlister S. Carbon Footprint of General, Regional, and Combined Anesthesia for Total Knee Replacements. Anesthesiology. 2021 Dec 1;135(6):976-991. doi: 10.1097/ALN.0000000000003967.
PubMed 34529033
Study at a glance
From the registry record, last updated by the sponsor on 18 Jun 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- The Impact of Ultra-Low-Flow Sevoflurane Anesthesia on Carbon Footprint and Cost: A Randomized Controlled Study in Cardiac Surgery Patients
- ClinicalTrials.gov ID
- NCT07313969
- Acronym / sponsor ID
- Ultra_low_flow
- Conditions
- Low Flow Anesthesia, Sevoflurane Anesthesia, Cardiac Surgery
- Keywords
- low flow anesthesia, ultra low flow anesthesia, carbon footprint
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 92 participants (actual)
- Lead sponsor
- Dr Abdurrahman Yurtaslan Ankara Oncology Training and Research HospitalUniversity, hospital or other
- Collaborators
- Ankara Etlik City Hospital
- Study start
- 30 Dec 2025 (actual)
- Primary completion
- 15 Mar 2026 (actual)
- Study completion
- 15 May 2026 (actual)
- First posted
- 2 Jan 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.
This is a prospective, randomized controlled clinical trial evaluating the effects of ultra-low fresh gas flow (0.5 L/min) versus normal fresh gas flow (2.0 L/min) sevoflurane anesthesia in adult patients undergoing on-pump cardiac surgery. The study aims to determine whether ultra-low-flow anesthesia can be used safely to reduce volatile anesthetic consumption and environmental emissions without compromising hemodynamic stability or anesthetic depth.
Eligible adult patients scheduled for elective coronary artery bypass grafting (CABG) or valve surgery under general anesthesia will be randomized in a 1:1 ratio to one of two groups: ultra-low-flow (0.5 L/min) or normal-flow (2.0 L/min). All other anesthetic techniques, including induction drugs, ventilation parameters, temperature management, and perfusion strategies, will be standardized.
The primary outcome is the total amount of sevoflurane consumed per case. Secondary outcomes include intraoperative hemodynamic parameters (heart rate, mean arterial pressure), depth of anesthesia (BIS/MAC values), postoperative recovery times, and estimated carbon dioxide equivalent (CO₂e) emissions.
Outcome assessors and data analysts will remain blinded to group allocation. The findings of this study are expected to provide new evidence regarding the safety, efficiency, and environmental benefits of ultra-low-flow anesthesia techniques in cardiac surgery.
Detailed description
This randomized controlled trial investigates the impact of ultra-low-flow (0.5 L/min) versus normal-flow (2.0 L/min) sevoflurane anesthesia on anesthetic consumption, intraoperative hemodynamics, and environmental footprint during on-pump cardiac surgery. Although low-flow anesthesia is known to reduce anesthetic agent use and greenhouse gas emissions, evidence regarding its safety and efficiency during cardiopulmonary bypass procedures remains limited.
Adult patients scheduled for elective CABG or valve surgery will be randomly assigned to either an ultra-low-flow or normal-flow group. Randomization will be performed using a computer-generated sequence with variable block sizes and allocation concealment via sequentially numbered, opaque, sealed envelopes. All participants will receive standardized induction, perfusion, and maintenance techniques according to institutional cardiac anesthesia protocols.
The primary outcome measure is total sevoflurane consumption per patient, assessed through vaporizer readings and anesthetic gas analyzer data. Secondary outcomes include intraoperative mean arterial pressure, heart rate, BIS/MAC values, body temperature, recovery characteristics, and calculated CO₂ equivalent emissions. Outcome assessors and data analysts will remain blinded to group allocation.
This study is designed to evaluate both clinical and ecological aspects of anesthetic practice. It aims to determine whether ultra-low-flow anesthesia can provide equivalent anesthetic quality while offering substantial reductions in agent consumption and environmental impact. The findings may contribute to establishing safer and more sustainable anesthesia standards for cardiac surgery.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Double blind (participant, outcomes assessor)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Ultra-Low-Flow Group (0.5 L/min) | Active comparator | Drug: ultra low flow anesthesiaSevoflurane anesthesia with fresh gas flow maintained at 0.5 L/min throughout the maintenance period. A 2 lt/min fresh gas flow will be used in the preoxygenation and intubation phase. General anesthesia will be maintained with sevoflurane at a fresh gas flow rate of 0.5 L/min using an oxygen and air mixture. The flow rate will be kept constant from post-induction stabilization until the end of the surgery. Ventilation will be paused during cardiopulmonary bypass. |
| Normal-Flow Group (2.0 L/min) | Active comparator | Drug: normal flow anesthesiaSevoflurane anesthesia with fresh gas flow maintained at 2.0 L/min throughout maintenance period. The flow rate will be kept constant from post-induction stabilization until the end of surgery. Ventilation will be paused during cardiopulmonary bypass |
Who may qualify
- Ages
- 18 to 80 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (4 listed)
- Adult patients aged 18-80 years
- Scheduled for elective on-pump CABG or valve surgery
- ASA physical status II-III
- Written informed consent obtained
Key exclusion criteria (4 listed)
- Emergency surgery
- Severe hepatic or renal dysfunction
- Known allergy to volatile anesthetics
- Significant pulmonary disease (e.g., COPD with GOLD III-IV)
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 |
|---|---|---|
| ultra low flow anesthesiaGeneral anesthesia will be maintained with sevoflurane at a fresh gas flow rate of 0.5 L/min using oxygen and air mixture. The flow rate will be kept constant from post-induction stabilization until the end of cardiopulmonary bypass. | Drug | Ultra-Low-Flow Group (0.5 L/min) |
| normal flow anesthesiaGeneral anesthesia will be maintained with sevoflurane at a fresh gas flow rate of 2.0 L/min using oxygen and air mixture. The flow rate will be kept constant from post-induction stabilization until the end of cardiopulmonary bypass. | Drug | Normal-Flow Group (2.0 L/min) |
Primary outcome
Total sevoflurane consumption (mL per case), measured at the end of surgery.
Time frame: throughout the surgery
1 secondary outcome
carbon footprint
Time frame: throughout the surgery
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 18 Jun 2026.
- Background: PubMed 34529033McGain F, Sheridan N, Wickramarachchi K, Yates S, Chan B, McAlister S. Carbon Footprint of General, Regional, and Combined Anesthesia for Total Knee Replacements. Anesthesiology. 2021 Dec 1;135(6):976-991. doi: 10.1097/ALN.0000000000003967.
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Anesthesia
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?
A study testing ultra low flow anesthesia and normal flow anesthesia in people with Low Flow Anesthesia and Sevoflurane Anesthesia, run by Dr Abdurrahman Yurtaslan Ankara Oncology 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 4 inclusion and 4 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 18 Jun 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?
Total sevoflurane consumption (mL per case), measured at the end of surgery. (time frame: throughout the surgery). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT07313969, which also lists 1 linked publication.
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 18 Jun 2026.