Low-flow AnesthesiaNCT07040735
Low-Flow Anesthesia and Open-Heart Surgery
An observational study of Low-flow Anesthesia and Hemodynamics, run by Çağrı Özdemir at 1 site in Turkey (Türkiye).
Trial summary
Low-flow anesthesia (LFA) is a technique in which at least 50% of the exhaled air, after carbon dioxide absorption, is mixed with a certain amount of fresh gas and returned to the patient during the next inspiration. In 1974, R. Virtue defined minimal flow anesthesia (MFA) as 0.5 L/min. Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Low-flow Anesthesia, Hemodynamics, Open-heart Surgery
- How many people
- 80 participants
- Where
- 1 siteTurkey (Türkiye)
- Study dates
- 1 Jul 2025to 23 Sep 2026
- Phase
- Observational
- Are there results?
- Not yet: the study is under way
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 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Study population: ≥18 years and scheduled for open-heart surgery patients
Who may be able to join
- -≥18 years and scheduled for open-heart surgery patients
- -ASA I-II-III-IV physical class
Who cannot join
- Emergency cases
- Patients under 18 years of age
- Patients who have had open heart surgery before
- Patients for whom the use of inhaled anesthetic agents is contraindicated
- Patients who do not sign a voluntary consent form
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Turkey (Türkiye)1 site, 1 recruiting
- Recruiting
Gazi University Faculty of Medicine
Ankara
About this study
Official title: The Effect of Low-Flow Anesthesia on Hemodynamics in Open-Heart Surgery
Low-flow anesthesia (LFA) is a technique in which at least 50% of the exhaled air, after carbon dioxide absorption, is mixed with a certain amount of fresh gas and returned to the patient during the next inspiration. In 1974, R. Virtue defined minimal flow anesthesia (MFA) as 0.5 L/min. In 1984, Baker and Simionescu classified LFA as 0.5-1 L/min and MFA as 0.25-0.5 L/min. The aim of this study is to investigate whether there are hemodynamic differences between open-heart surgery cases performed with LFA at different fresh gas flow rates.
- Conditions
- Low-flow Anesthesia, Hemodynamics, Open-heart Surgery
- Keywords
- Low-flow anesthesia, Hemodynamics, Open-heart surgery
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
| Study group | Role | What they receive |
|---|---|---|
| Group 1 | Followed using Bispectral Index (BIS) with 4% Sevoflurane and fresh gas flow set at 0.5 L/min | |
| Group 2 | Followed using Minimum Alveolar Concentration (MAC) with 4% Sevoflurane and fresh gas flow set at 0.5 L/min | |
| Group 3 | Followed using BIS with 4% Sevoflurane and fresh gas flow set at 1 L/min | |
| Group 4 | Followed using MAC with 4% Sevoflurane and fresh gas flow set at 1 L/min |
What is being measured
The primary outcome is the main question the study is designed to answer.
physiological parameter ; heart rate
Heart rate will be recorded every 10 minutes, expressed as beats per minute, starting before induction and including the sternotomy and pericardiotomy periods.
Measured: Intraoperatively
physiological parameter; systolic/diastolic blood pressure
Systolic and diastolic blood pressure will be recorded every 10 minutes in mmHg, starting before induction and including the sternotomy and pericardiotomy periods.
Measured: Intraoperatively
physiological parameter; SpO2
SpO2 will be recorded as a percentage every 10 minutes, starting before induction and including the sternotomy and pericardiotomy periods.
Measured: Intraoperatively
Monitoring parameter; Bispectral Index (BIS)
The BIS value will be recorded numerically every 10 minutes, starting from before induction and including the sternotomy and pericardiotomy periods.
Measured: Intraoperatively
Monitoring parameter; Minimum alveolar concentration (MAC)
The MAC value will be recorded numerically every 10 minutes, starting from before induction and including the sternotomy and pericardiotomy periods.
Measured: Intraoperatively
Secondary outcomes (3)
Preoperative data; ASA (American Society of Anesthesiologists) classification
During the preoperative period, preoperative data, including the American Society of Anesthesiologists (ASA) Physical Status Classification, will be recorded. The ASA classification is used to assess the patient's preoperative physical status and perioperative risk, with higher ASA classes (I-IV) indicating increased systemic disease severity and perioperative risk.
Measured: 24 hours before surgery
Preoperative data
In the preoperative period, the degree of valve dysfunction (such as I.degree TY, II.degree MY) of the patients will be recorded.
Measured: 24 hours before surgery
Preoperaitive data
In the preoperative period, the patient's ejection fraction will be recorded as a percentage.
Measured: 24 hours before surgery
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted27 Jun 2025
- Study start1 Jul 2025
- Primary completion2 Sep 2026 (estimated)
- Study completion23 Sep 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- 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
- Observational
- Observational model
- Cohort
- Time perspective
- Prospective
- Enrolment
- 80 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Çağrı Özdemir
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor-investigator, Çağrı Özdemir, Gazi University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07040735
- Sponsor's protocol ID
- 2025-146
- Status last verified
- May 2026
- First submitted
- 6 Jun 2025
- Last updated
- 27 May 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 27 May 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- The Effect of Low-Flow Anesthesia on Hemodynamics in Open-Heart Surgery
- ClinicalTrials.gov ID
- NCT07040735
- Acronym / sponsor ID
- 2025-146
- Conditions
- Low-flow Anesthesia, Hemodynamics, Open-heart Surgery
- Keywords
- Low-flow anesthesia, Hemodynamics, Open-heart surgery
- Study type
- Observational
- Recruitment status
- Recruiting
- Enrolment
- 80 participants (estimated)
- Lead sponsor
- Çağrı ÖzdemirUniversity, hospital or other
- Study start
- 1 Jul 2025 (actual)
- Primary completion
- 2 Sep 2026 (estimated)
- Study completion
- 23 Sep 2026 (estimated)
- First posted
- 27 Jun 2025 (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.
Low-flow anesthesia (LFA) is a technique in which at least 50% of the exhaled air, after carbon dioxide absorption, is mixed with a certain amount of fresh gas and returned to the patient during the next inspiration. In 1974, R. Virtue defined minimal flow anesthesia (MFA) as 0.5 L/min. In 1984, Baker and Simionescu classified LFA as 0.5-1 L/min and MFA as 0.25-0.5 L/min. The aim of this study is to investigate whether there are hemodynamic differences between open-heart surgery cases performed with LFA at different fresh gas flow rates.
Study design
- Observational model
- Cohort
- Time perspective
- Prospective
- Number of arms
- 4
| Arm | Type | Receives |
|---|---|---|
| Group 1 | – | –Followed using Bispectral Index (BIS) with 4% Sevoflurane and fresh gas flow set at 0.5 L/min |
| Group 2 | – | –Followed using Minimum Alveolar Concentration (MAC) with 4% Sevoflurane and fresh gas flow set at 0.5 L/min |
| Group 3 | – | –Followed using BIS with 4% Sevoflurane and fresh gas flow set at 1 L/min |
| Group 4 | – | –Followed using MAC with 4% Sevoflurane and fresh gas flow set at 1 L/min |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
- Study population
- ≥18 years and scheduled for open-heart surgery patients
Key inclusion criteria (2 listed)
- -≥18 years and scheduled for open-heart surgery patients
- -ASA I-II-III-IV physical class
Key exclusion criteria (5 listed)
- Emergency cases
- Patients under 18 years of age
- Patients who have had open heart surgery before
- Patients for whom the use of inhaled anesthetic agents is contraindicated
- Patients who do not sign a voluntary consent form
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Primary outcome
physiological parameter ; heart rate
Time frame: Intraoperatively
Heart rate will be recorded every 10 minutes, expressed as beats per minute, starting before induction and including the sternotomy and pericardiotomy periods.
physiological parameter; systolic/diastolic blood pressure
Time frame: Intraoperatively
Systolic and diastolic blood pressure will be recorded every 10 minutes in mmHg, starting before induction and including the sternotomy and pericardiotomy periods.
physiological parameter; SpO2
Time frame: Intraoperatively
SpO2 will be recorded as a percentage every 10 minutes, starting before induction and including the sternotomy and pericardiotomy periods.
Monitoring parameter; Bispectral Index (BIS)
Time frame: Intraoperatively
The BIS value will be recorded numerically every 10 minutes, starting from before induction and including the sternotomy and pericardiotomy periods.
Monitoring parameter; Minimum alveolar concentration (MAC)
Time frame: Intraoperatively
The MAC value will be recorded numerically every 10 minutes, starting from before induction and including the sternotomy and pericardiotomy periods.
3 secondary outcomes
Preoperative data; ASA (American Society of Anesthesiologists) classification
Time frame: 24 hours before surgery
Preoperative data
Time frame: 24 hours before surgery
Preoperaitive data
Time frame: 24 hours before surgery
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 27 May 2026.
- Individual participant dataSharing planned: No
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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.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Low-flow Anesthesia and Hemodynamics, run by Çağrı Özdemir 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 2 inclusion and 5 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: looking for participants now, as of the sponsor's last update on 27 May 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?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Çağrı Özdemir (+905544239196, cagriozdemir@gazi.edu.tr), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
physiological parameter ; heart rate (time frame: Intraoperatively). The study lists 5 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
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 27 May 2026; AzTrials last refreshed its copy on 29 Oct 2026.