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Bariatric Surgery (Sleeve Gastrectomy )NCT06835166

Effect of Intraoperative Position Change on Hemodynamics and Electrocardiography

An observational study of Bariatric Surgery (Sleeve Gastrectomy ) and Hemodynamics, run by Firat University at 1 site in Turkey (Türkiye).

Completed

Finished. The study has ended and is not enrolling. Results may be posted on the official record.

Official record
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Trial summary

The combined effects of obesity-related cardiac structure and function changes, comorbidities, pneumoperitoneum technique, and reverse Trendelenburg position may complicate anesthesia management by affecting intraoperative hemodynamics and cardiac function. Read more about this study

Who is it for?
Ages 18 to 65 years
What is being tested?
12-lead electrocardiography measurement
Type of treatment
Surgery or procedure
How many people
80 participants
Where
1 siteTurkey (Türkiye)
Study dates
10 Feb 2025to 20 May 2025
Phase
Observational
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 65 years
  • All sexes
  • No healthy volunteers
  • Adult, Older adult

Study population: Morbidly obese patients undergoing laparoscopic sleeve gastrectomy

Who may be able to join

  • Adult patient planned for elective primary laparoscopic sleeve gastrectomy surgery
  • Body Mass Index (BMI) ≥ 40 kg/ / m²
  • Age ≥ 18
  • ASA physical health class II-III.

Who cannot join

  • Patient refusal to participate in the study
  • Those who underwent revision laparoscopic sleeve gastrectomy
  • Emergency laparoscopic sleeve gastrectomy surgery (stump leakage, etc.)
  • Secondary surgery in addition to elective laparoscopic sleeve gastrectomy
  • Patients with previous recurrent abdominal surgery
  • Patients with electrolyte imbalance
Show all 11Show fewer
  • Direct laryngoscopy in ramp position
  • Multiple intubation attempts due to difficult intubation
  • Preoperative arrhythmia and heart failure (ejection fraction < 30%)
  • Renal and liver failure
  • Patients who require > 8 ml/kg for tidal volume

Trial locations and contacts

1 site in 1 country.

Turkey (Türkiye)1 site
  • Firat University Hospital, Department of Anesthesiology and Reanimation

    Elâzığ, 23200

Other trials in Turkey (Türkiye)

About this study

Official title: Effect of Intraoperative Position Change on Hemodynamics and Cardiac Electrophysiological Balance Index in Morbidly Obese Patients Undergoing Laparoscopic Sleeve Gastrectomy

The combined effects of obesity-related cardiac structure and function changes, comorbidities, pneumoperitoneum technique, and reverse Trendelenburg position may complicate anesthesia management by affecting intraoperative hemodynamics and cardiac function. Increased intra-abdominal pressure leads to various physiological changes through mechanical and neurohormonal responses. Furthermore, pneumoperitoneum and reverse Trendelenburg position are reported to stimulate the sympathetic nervous system and increase the risk of cardiac arrhythmia.

Obesity-related changes in cardiac structure and function have been shown to predispose to cardiac conduction and repolarization disorders. It has also been stated that obesity directly affects cardiac electrophysiology.

Read more

Moreover, obese patients may have hidden risks associated with the development of cardiac arrhythmias due to the adverse contributions of the cardiovascular effects of anesthesia, pneumoperitoneum, and patient positioning during laparoscopic intervention.

The index of cardiac electrophysiological balance (iCEB) is a non-invasive marker calculated by the QT/QRS ratio that can predict malignant ventricular arrhythmias.

The aim of this study was to investigate the effects of intraoperative patient positions on hemodynamics and the index of cardiac electrophysiological balance (iCEB) during laparoscopic sleeve gastrectomy in morbidly obese patients.

Read the detailed description

Morbidly obese patients who will undergo laparoscopic sleeve gastrectomy will be included in the study.

Patients will be taken to the operating room without premedication after a minimum of 8 hours of fasting. Venous access will be established with a 22 G angiocatheter on the operating table. Routine heart rate, arterial blood pressure, peripheral oxygen saturation (SpO₂), body temperature, bispectral index (BIS) (Bispectral Drager Vista 120 system, Covidien, USA) monitoring will be performed. BIS will be kept between 40 - 60. In addition, 12-lead ECG (Cardioline®) will be used for electrocardiogram (ECG) measurements.

Mechanical ventilation will be provided with a tidal volume of 8 mL/kg (IBW) and a positive end expiratory pressure (PEEP) of 8 cmH₂O. The respiratory rate will be adjusted to maintain end-tidal carbon dioxide (EtCO2) at 35 to 45 mmHg.

Targeted Fluid Management (GDFM) will be provided by continuous Pleth Variability Index (PVI) monitoring by placing a Pulse CO-Oximeter sensor system (Masimo rainbow set® Masimo Corporation, Irvine, CA, USA) on the patients' 4th finger. Hemodynamic targets are both PVI and mean arterial pressure. Fluid loading prescription is based on a PVI value greater than 13%, and vasopressor use is based on a mean arterial pressure < 65 mmHg. If necessary, additional fluids and norepinephrine will be given to maintain mean arterial pressure > 65 mmHg.

A 12-lead ECG will be taken at five intraoperative position measurement points (1. Supine-monitored; 2. After induction; 3. Under general anesthesia-Supine-abdominal inflated; 4. Abdominal inflated-(30% upright) Reverse Trendelenburg; 5. Abdominal deflated-(30% upright) Reverse Trendelenburg). Hemodynamic monitoring [systolic blood pressure (SBP), diastolic blood pressure (DAB), mean arterial pressure (MAP), heart rate (HR)] will be recorded at 5 simultaneous measurement points. All hemodynamic measurements and ECG recordings will be made 3 minutes after the position change to ensure standardization, allow the response to settle after the position change, and prevent the possibility of exaggerated or false data.

All patients will have their surgeries performed by the same surgical team and intra-abdominal pressure will be kept below 15 mmHg.

Demographic data (age, gender, height, weight, BMI), American Society of Anesthesiologists (ASA) physical status classification, preoperative assessment information (comorbidities, medications used), duration of surgery and anesthesia, amount of fluid administered, and amount of norepinephrine to be used when needed will be recorded.

Power analysis was calculated as follows:

Repeated measures, within factors Options: Pillai V, O'Brien-Shieh Algorithm Analysis: A priori: Compute required sample size Input: Effect size f = 0.25 α = 0.05 Power (1-β ) = 0.95 Number of groups = 1 Number of measurements = 5 Corr among rep measures = 0 Output: Noncentrality parameter λ = 20.3125000 Critical F = 2.5226149 Numerator df = 4.0000000 Denominator df = 61.0000000 Total sample size = 65 Actual power = 0.9523977 Pillai V = 0.2380952 Considering that there may be data loss in ECG measurements and evaluations, the number of cases was determined as 80 patients.

Intraoperative hemodynamic and ECG (Heart-electrophysiological balance index (iCEB = QT/QRS ratio) changes in 5 positions will be evaluated.

Being tested
12-lead electrocardiography measurement
Keywords
Bariatric Surgery, Laparoscopic sleeve gastrectomy

What participants receive

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

  • 12-lead electrocardiography measurementProcedure or surgery

    Intraoperative 12-lead electrocardiography (EKG) measurement during laparoscopic sleeve gastrectomy in morbidly obese patients:

    In all patients, pneumoperitoneum CO₂ intraabdominal pressure will be studied as 15 cmH₂O.

    Intraoperatively, 12-lead ECG will be obtained at five position measurement points:

    Procedure1. Supine-monitored; Procedure 2. After induction; Procedure 3. Under general anesthesia-Supine-abdominal inflated; Procedure 4. Abdominal inflated-(30% vertical) Reverse Trendelenburg; Procedure 5. Abdominal deflated-(30% vertical) Reverse Trendelenburg.

    Hemodynamic monitoring [systolic blood pressure, diastolic blood pressure, mean arterial pressure, heart rate ] was recorded at 5 simultaneous measurement points.

    All hemodynamic measurements and ECG recordings will be performed 3 minutes after the position change to ensure standardization, to allow the response to settle after the position change, and to prevent the possibility of exaggerated-incorrect data.

What is being measured

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

  1. Evaluation of the QT (ms) interval in morbidly obese patients undergoing laparoscopic sleeve gastrectomy.

    Electrocardiograms will be recorded in the following predefined positions:

    1. Supine - monitored; 2. Post-anesthesia; 3. Under general anesthesia - Supine - abdominal distension; 4. Abdominal distension - (30% vertical) Reverse Trendelenburg; 5. Abdominal distension reduced - (30% vertical) Reverse Trendelenburg)

    Measured: The operation takes approximately 2 hours to complete.

  2. Evaluation of QRS (ms) interval in morbidly obese patients undergoing laparoscopic sleeve gastrectomy.

    Electrocardiograms will be recorded in the following predefined positions:

    (1. Supine - monitored; 2. Post-anesthesia; 3. Under general anesthesia - Supine - abdominal distension; 4. Abdominal distension - (30% vertical) Reverse Trendelenburg; 5. Abdominal distension reduced - (30% vertical) Reverse Trendelenburg)

    Measured: The operation takes approximately 2 hours to complete.

  3. Evaluation of the cardiac electrophysiological balance index (QT/QRS) in morbidly obese patients undergoing laparoscopic sleeve gastrectomy.

    The QT interval will be measured from the beginning of the QRS complex to the end of the T wave, and the QT/QRS (iCEB) ratio will be calculated.

    Measured: The operation takes approximately 2 hours to complete.

  4. Patient height measurement (in meters)

    All patients' heights will be measured (in meters).

    Measured: Height measurement for each patient takes approximately 10 minutes.

  5. Patients' body weight measurement (kilograms)

    Patients' body weights will also be measured (in kilograms).

    Measured: Body weight measurement takes approximately 10 minutes for each patient.

  6. Calculation of body mass index (BMI = kg/m²).

    Body Mass Index (BMI) is calculated by dividing body weight (kg) by the square of height (m) (BMI = kg/m²).

    Measured: This will take approximately 10 minutes for each patient.

Secondary outcomes (2)
  1. Evaluation of patients' blood pressure measurements (mmHg)

    Patients' blood pressure will be recorded as systolic, diastolic, and mean blood pressure.

    Measurement time points are indicated below:

    (1. Supine - monitored; 2. Post-anesthesia; 3. Under general anesthesia - Supine - abdominal distension; 4. Abdominal distension - (30% vertical) Reverse Trendelenburg; 5. Abdominal distension reduced - (30% vertical) Reverse Trendelenburg)

    Measured: The operation takes approximately 2 hours to complete.

  2. measurement of patients' heart rates (beats/min)

    Measurement time points are indicated below:

    (1. Supine - monitored; 2. Post-anesthesia; 3. Under general anesthesia - Supine - abdominal distension; 4. Abdominal distension - (30% vertical) Reverse Trendelenburg; 5. Abdominal distension reduced - (30% vertical) Reverse Trendelenburg)

    Measured: The operation takes approximately 2 hours to complete.

Timeline

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

  1. First posted19 Feb 2025
  2. Study start10 Feb 2025
  3. Primary completion25 Apr 2025
  4. Study completion20 May 2025

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
Other
Time perspective
Prospective
Enrolment
80 participants (actual)
IDs, dates and publications
ClinicalTrials.gov ID
NCT06835166
Sponsor's protocol ID
FiratU-ANEST-FC-01
Status last verified
Jan 2026
First submitted
6 Feb 2025
Last updated
16 Jan 2026
Results posted
No
Data monitoring committee
Yes
FDA-regulated drug
No
FDA-regulated device
No
Individual data sharing
Undecided: We have not yet decided whether to share the IPDs of our study.

Publications

  • Atkinson TM, Giraud GD, Togioka BM, Jones DB, Cigarroa JE. Cardiovascular and Ventilatory Consequences of Laparoscopic Surgery. Circulation. 2017 Feb 14;135(7):700-710. doi: 10.1161/CIRCULATIONAHA.116.023262.

    PubMed 28193800

Questions about this trial

What is this clinical trial studying?

An observational study of Bariatric Surgery (Sleeve Gastrectomy ) and Hemodynamics, run by Firat University 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 11 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 16 Jan 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?

Evaluation of the QT (ms) interval in morbidly obese patients undergoing laparoscopic sleeve gastrectomy. (time frame: The operation takes approximately 2 hours to complete.). The study lists 6 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 NCT06835166, 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 16 Jan 2026.

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