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Cardiac ArrhythmiaNCT07571980

The Effects of Low-Flow and Normal-Flow Sevoflurane Anesthesia on Frontal QRS-T Angle and TP-e Interval

An observational study of Cardiac Arrhythmia and Anesthesia, run by Istanbul University.

Not yet recruiting

Opening soon. The study is approved but enrolment has not started yet. Sites may already take enquiries.

Official record
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Trial summary

Laparoscopic cholecystectomy procedures involve pneumoperitoneum and volatile anesthetics, both of which can significantly influence cardiovascular physiology and autonomic balance. Read more about this study

Who is it for?
Ages 18 years and olderHealthy volunteers can take part
Conditions the study is for
Cardiac Arrhythmia, Anesthesia
What is being tested?
low flow anesthesia
Type of treatment
Surgery or procedure
How many people
128 participants
Where
No sites listed yet
Study dates
15 May 2026to 15 Aug 2027
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
  • Healthy volunteers accepted
  • Adult, Older adult

Study population: The study population consists of adult patients (aged 18 years and older) scheduled for elective or semi-elective laparoscopic cholecystectomy at a tertiary care training and research hospital.

Who may be able to join

  • Patients aged 18 years and older.
  • Patients scheduled for elective or semi-elective laparoscopic cholecystectomy.
  • Patients who provide written voluntary informed consent.
  • Patients with a predicted surgical duration between 60 and 180 minutes.

Who cannot join

  • Patients with heart failure.
  • Patients with valvular heart disease or pathology.
  • Patients with hemodynamic instability.
  • Patients requiring blood transfusion.
  • Patients with a preoperative corrected QT (QTc) interval > 450 ms.
  • Patients with a known history of cardiac arrhythmia.
Show all 9Show fewer
  • Patients scheduled for emergency surgery.
  • Patients with a known risk or family history of malignant hyperthermia.
  • Use of medications associated with QT interval prolongation (e.g., ketamine, 5-HT3 antagonists, quetiapine, etc.).

About this study

Official title: The Effects of Low-Flow and Normal-Flow Sevoflurane Anesthesia on Frontal QRS-T Angle and TP-e Interval in Patients Undergoing Elective Laparoscopic Cholecystectomy

Laparoscopic cholecystectomy procedures involve pneumoperitoneum and volatile anesthetics, both of which can significantly influence cardiovascular physiology and autonomic balance. While volatile anesthetics are known to affect myocardial repolarization, the specific impact of Low-Flow Anesthesia (LFA)-a cost-effective and environmentally friendly technique-on these cardiac markers remains under-researched.

This prospective observational study aims to compare the effects of low-flow versus normal-flow sevoflurane anesthesia on two critical non-invasive biomarkers of ventricular repolarization: the Frontal QRS-T angle and the Tp-e interval. These parameters are essential for predicting electrical instability and the risk of malignant arrhythmias. The study will evaluate a total of 128 patients to determine whether different fresh gas flow rates lead to significant changes in cardiac electrophysiological stability during the perioperative and early postoperative periods.

Read the detailed description

This prospective observational study is designed to investigate the electrophysiological effects of different fresh gas flow rates during sevoflurane anesthesia in patients undergoing elective laparoscopic cholecystectomy. Laparoscopic procedures involving pneumoperitoneum and volatile anesthetics are known to influence autonomic nervous system balance and cardiovascular stability. While the impact of inhalation agents on myocardial repolarization is documented, the specific effects of Low-Flow Anesthesia (LFA)-an environmentally and economically favorable technique-on markers of electrical instability remain to be fully elucidated. The primary objective is to evaluate and compare the effects of low-flow and normal-flow sevoflurane techniques on the Frontal QRS-T angle and the Tp-e interval, which serve as critical non-invasive biomarkers for predicting malignant arrhythmia risk and reflecting the transmural distribution of ventricular repolarization.

The study protocol involves 128 patients, a sample size determined by power analysis (80% power, 0.05 alpha) to account for a predicted 35% difference between groups and potential dropouts. Patients are observationally assigned to either the Low-Flow Group (LFG) or the Normal-Flow Group (NFG) according to routine clinical practice. Following a standardized induction and an initial stabilization phase at 4-6 L/min, flow rates are adjusted once the target concentration (MACage +1) is reached: the LFG is reduced to 0.5 L/min, while the NFG is maintained at 2 L/min. Ventilation is managed to keep EtCO2 between 35-45 mmHg. Data collection is performed via high-resolution ECG recordings at four time points: preoperative baseline (T1), 5 minutes post-intubation (T2), 15 minutes post-intubation (T3), and 15 minutes postoperatively (T4).

Another key focus of this research is the detailed analysis of secondary outcomes, including the monitoring of hemodynamic stability (mean arterial pressure and heart rate) across all time points. Furthermore, the study aims to characterize the electrophysiological profile of each technique by analyzing the Tp-e/QT ratio and calculating time-dependent variations in repolarization parameters, specifically the delta changes from baseline to intraoperative stages (ΔT1-T2 and ΔT1-T3). Additionally, a cost-effectiveness analysis will be conducted by determining the total volume of volatile anesthetic consumed in both techniques. Statistical analysis will involve independent samples t-tests for inter-group comparisons, while repeated measures ANOVA with Bonferroni correction will evaluate time-dependent changes. Pearson correlation analysis will be utilized to assess the relationships between continuous variables, providing a comprehensive assessment of the safety and efficacy of low-flow versus normal-flow anesthesia management.

Being tested
low flow anesthesia
Medical subject headings
Arrhythmias, Cardiac

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • low flow anesthesiaProcedure or surgery

    Fresh Gas Flow (FGF) reduced to 0.5 L/min after the target concentration (MACage +1) is reached.

Study groups in NCT07571980
Study groupRoleWhat they receive
Low-Flow Group (LFG)Anesthesia induction and initial stabilization (first 6-8 minutes at 4-6 L/min) follow standard hospital protocols. Fresh Gas Flow (FGF) reduced to 0.5 L/min after the target concentration (MACage +1) is reached. Ventilation parameters are adjusted to maintain end-tidal carbon dioxide (EtCO2) between 35-45 mmHg with a minimum FiO2 of 0.30. Volatile anesthetics are discontinued 15 minutes before the estimated end of surgery. Pre-oxygenation and wash-out are performed at 5-6 L/min with 80% oxygen prior to extubation.
Receives: Procedure: low flow anesthesia
Normal-Flow Group (NFG)Anesthesia induction and initial stabilization (first 6-8 minutes at 4-6 L/min) follow standard hospital protocols. Fresh Gas Flow (FGF) maintained at 2 L/min during anesthesia maintenance. Ventilation parameters are adjusted to maintain end-tidal carbon dioxide (EtCO2) between 35-45 mmHg with a minimum FiO2 of 0.30. Volatile anesthetics are discontinued 15 minutes before the estimated end of surgery. Pre-oxygenation and wash-out are performed at 5-6 L/min with 80% oxygen prior to extubation.

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. Frontal QRS-T angle

    electrocardiogram

    Measured: Pre-operative period, 5 minutes after induction, 15 minutes after induction, post operative 15th minute

  2. Tp-e interval

    electrocardiogram

    Measured: Pre-operative period, 5 minutes after induction, 15 minutes after induction, post-operative 15th minute

Secondary outcomes (5)

  1. blood pressure

    Non-invasive blood pressure (NIBP) monitor

    Measured: during peri-operative period

  2. heart rate

    electrocardiogram

    Measured: during peri-operative period

  3. Tp-e/QT ratio

    electrocardiogram

    Measured: Pre-operative period, 5 minutes after induction, 15 minutes after induction, post-operative 15th minute

  4. Total amount of volatile anesthetic consumed

    Mindray anesthesia machine

    Measured: end of operation

  5. Total amount of Remifentanil consumed

    infusion pump

    Measured: end of operation

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted7 May 2026
  2. Study start15 May 2026 (estimated)
  3. Primary completion15 May 2027 (estimated)
  4. Study completion15 Aug 2027 (estimated)

Resources

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
128 participants (estimated)
IDs, dates and publications
ClinicalTrials.gov ID
NCT07571980
Sponsor's protocol ID
96-2026
Status last verified
Apr 2026
First submitted
30 Apr 2026
Last updated
7 May 2026
Results posted
No
FDA-regulated drug
No
FDA-regulated device
No

Publications

  • Yildirim H, Adanir T, Atay A, Katircioglu K, Savaci S. The effects of sevoflurane, isoflurane and desflurane on QT interval of the ECG. Eur J Anaesthesiol. 2004 Jul;21(7):566-70. doi: 10.1017/s0265021504007112.

    PubMed 15318470

  • Kim NY, Han DW, Koh JC, Rha KH, Hong JH, Park JM, Kim SY. Effect of Dexmedetomidine on Heart Rate-Corrected QT and Tpeak-Tend Intervals During Robot-Assisted Laparoscopic Prostatectomy With Steep Trendelenburg Position: A Prospective, Randomized, Double-Blinded, Controlled Study. Medicine (Baltimore). 2016 May;95(19):e3645. doi: 10.1097/MD.0000000000003645.

    PubMed 27175685

  • Bingol Tanriverdi T, Tercan M, Patmano G, Tanriverdi Z, Gusun Halitoglu A, Kaya A. The Effect of Low-Flow and Normal-Flow Desflurane Anesthesia on the Frontal QRS-T Angle in Patients Undergoing Rhinoplasty Operation: A Randomized Prospective Study. Cureus. 2022 Sep 8;14(9):e28920. doi: 10.7759/cureus.28920. eCollection 2022 Sep.

    PubMed 36225439

Questions about this trial

What is this clinical trial studying?

An observational study of Cardiac Arrhythmia and Anesthesia, run by Istanbul University.

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 9 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: opening soon, as of the sponsor's last update on 7 May 2026. Status can change between updates, so confirm with the study contact before making plans.

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?

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?

Frontal QRS-T angle (time frame: Pre-operative period, 5 minutes after induction, 15 minutes after induction, post operative 15th minute). The study lists 2 primary outcomes in all. 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 NCT07571980, which also lists 3 linked publications.

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 7 May 2026.

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