Laparoscopic HysterectomyNCT07467200
Effect of Trendelenburg Position on Patient State Index
An observational study of Laparoscopic Hysterectomy, run by Sakarya University at 1 site in Turkey (Türkiye).
Trial summary
The goal of this observational study is to evaluate whether the Trendelenburg position affects electroencephalography-based depth of anesthesia monitoring and cerebral oxygenation during general anesthesia. Read more about this study
- Who is it for?
- Ages 18 to 65 years, women only
- Conditions the study is for
- Laparoscopic Hysterectomy
- How many people
- 60 participants
- Where
- 1 siteTurkey (Türkiye)
- Study dates
- 1 May 2026to 1 Dec 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 to 65 years
- Women only
- No healthy volunteers
- Adult, Older adult
Study population: The study population consists of adult female patients undergoing elective laparoscopic hysterectomy under general anesthesia at a tertiary care university-affiliated hospital. Eligible patients will be recruited consecutively among those scheduled for surgery who meet the inclusion criteria and provide written informed consent.
Who may be able to join
- Female patients aged 18-65 years
- American Society of Anesthesiologists (ASA) physical status I-III
- Scheduled for elective laparoscopic hysterectomy under general anesthesia
- Ability to provide written informed consent
Who cannot join
- History of neurological disease (e.g., stroke, epilepsy)
- Known cerebrovascular disease, glaucoma, or retinal disease
- Severe cardiac or pulmonary disease
- Contraindication to near-infrared spectroscopy sensor placement
- Obesity (Body Mass Index > 35 kg/m²)
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Ahmet R Dogan, M.D. contact
Turkey (Türkiye)1 site, 1 recruiting
- Recruiting
Sakarya University Training and Research Hospital, Department of Anesthesiology and Reanimation
Sakarya
Ahmet Ridvan Dogan, a.ridvandogan@gmail.com
About this study
Official title: Effect of the Trendelenburg Position on Patient State Index and Frontal Cerebral Oxygenation: A Prospective Observational Study
The goal of this observational study is to evaluate whether the Trendelenburg position affects electroencephalography-based depth of anesthesia monitoring and cerebral oxygenation during general anesthesia.
The main questions it aims to answer are:
Read more
- Does the Trendelenburg position cause a change in the Patient State Index (PSI), an Electroensephalography (EEG)-derived indicator of anesthetic depth?
- Are changes in PSI associated with changes in frontal cerebral oxygen saturation (rSO₂) and hemodynamic parameters?
The study will include adult female patients undergoing elective laparoscopic gynecologic surgery under general anesthesia.
Participants will receive standard anesthesia and routine intraoperative monitoring. In addition to standard monitoring, Patient State Index (PSI) and frontal cerebral oxygen saturation (rSO₂) will be recorded using non-invasive sensors. No additional intervention will be performed for research purposes.
Physiological parameters including PSI, cerebral oxygen saturation, mean arterial pressure, heart rate, oxygen saturation, and end-tidal carbon dioxide will be recorded at predefined intraoperative time points before and after the Trendelenburg position.
The study aims to determine whether position-related physiological changes influence EEG-based anesthesia depth indices and to improve the interpretation of intraoperative brain monitoring.
Read the detailed description
Electroencephalography (EEG)-based depth of anesthesia monitors are widely used to assess the hypnotic component of general anesthesia. The Patient State Index (PSI) is a processed EEG parameter derived from frontal EEG signals and provides a numerical estimate of anesthetic depth ranging from 0 to 100. Although these indices are primarily designed to reflect the pharmacologic effects of anesthetic agents, physiological factors that influence cerebral hemodynamics may also affect EEG-derived parameters.
The Trendelenburg position is frequently used during laparoscopic pelvic surgery to improve surgical exposure. This position can alter venous return, increase cerebral venous pressure, and influence intracranial dynamics. When combined with pneumoperitoneum, these physiological changes may modify cerebral blood flow and cerebral oxygenation. Such alterations may potentially influence EEG-based indices of anesthetic depth independently of anesthetic drug concentration.
Previous studies have demonstrated that body position can influence processed EEG indices such as the bispectral index (BIS), particularly in the beach-chair position. However, the response of the Patient State Index to the Trendelenburg position has not been clearly established.
This prospective observational study aims to evaluate whether the Trendelenburg position affects PSI values during general anesthesia and to investigate the relationship between PSI changes and cerebral oxygenation measured by near-infrared spectroscopy (NIRS).
Adult female patients undergoing elective laparoscopic hysterectomy under general anesthesia will be included. Standard intraoperative monitoring will be applied, including electrocardiography, non-invasive blood pressure, pulse oximetry, end-tidal carbon dioxide, and anesthetic gas monitoring. In addition, EEG-based depth of anesthesia monitoring will be performed using the PSI monitor (Masimo SedLine), and frontal cerebral oxygen saturation (rSO₂) will be measured using near-infrared spectroscopy sensors.
Physiological parameters including PSI, cerebral oxygen saturation, mean arterial pressure, heart rate, oxygen saturation, and end-tidal carbon dioxide will be recorded at predefined intraoperative time points: before induction of anesthesia, after tracheal intubation in the supine position, after pneumoperitoneum, and at several intervals following the Trendelenburg position.
No intervention will be performed for research purposes. Anesthetic management and surgical positioning will follow routine clinical practice. The study will analyze whether position-related physiological changes are associated with variations in PSI and whether these changes correlate with cerebral oxygenation or hemodynamic parameters.
Understanding the influence of patient positioning on EEG-based anesthesia depth indices may improve the interpretation of intraoperative brain monitoring and help prevent unnecessary adjustments of anesthetic drug dosing.
- Conditions
- Laparoscopic Hysterectomy
- Keywords
- Trendelenburg Position, Patient State Index, Processed EEG, Depth of Anesthesia Monitoring, Cerebral Oxygenation, Near-Infrared Spectroscopy, General Anesthesia, Intraoperative Monitoring
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 |
|---|---|---|
| Patients Undergoing Laparoscopic Hysterectomy in Trendelenburg Position | This cohort includes adult female patients undergoing elective laparoscopic hysterectomy under general anesthesia. All participants receive standard intraoperative monitoring as part of routine clinical care. In addition to routine monitoring, depth of anesthesia is assessed using the Patient State Index (PSI), and frontal cerebral oxygen saturation (rSO₂) is measured using near-infrared spectroscopy sensors. Physiological parameters including PSI, cerebral oxygen saturation, mean arterial pressure, heart rate, oxygen saturation, and end-tidal carbon dioxide are recorded at predefined intraoperative time points before and after pneumoperitoneum and Trendelenburg positioning. No intervention is performed for research purposes. Surgical positioning and anesthetic management follow routine clinical practice, and the study involves only the observational recording of physiological parameters. |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change in Patient State Index (ΔPSI) After Trendelenburg Position
The primary outcome is the change in Patient State Index (PSI), an Electroensephalography(EEG)-derived indicator of anesthetic depth, between the supine position after tracheal intubation and the early Trendelenburg position following pneumoperitoneum. PSI values will be recorded using the Masimo SedLine monitoring system. The analysis will evaluate whether Trendelenburg positioning is associated with a significant change in PSI independent of anesthetic drug concentration.
Measured: From Post-intubation (Supine) to Trendelenburg Positioning
Secondary outcomes (3)
Change in Frontal Cerebral Oxygen Saturation (rSO₂)
Frontal cerebral oxygen saturation (rSO₂) measured using near-infrared spectroscopy sensors will be recorded to evaluate changes in cerebral oxygenation associated with pneumoperitoneum and Trendelenburg positioning. The analysis will assess whether changes in rSO₂ occur during Trendelenburg positioning and whether these changes are associated with variations in Patient State Index (PSI).
Measured: Intraoperative period (recorded at predefined time points before and after Trendelenburg positioning)
Mean Arterial Pressure Changes During Trendelenburg Position
Mean arterial pressure (MAP) will be recorded to evaluate hemodynamic changes associated with pneumoperitoneum and Trendelenburg positioning and to explore its relationship with changes in Patient State Index and cerebral oxygen saturation.
Measured: Intraoperative period (recorded at predefined time points before and after Trendelenburg positioning)
Heart Rate Changes During Trendelenburg Position
Heart rate will be monitored to evaluate intraoperative hemodynamic responses associated with pneumoperitoneum and Trendelenburg positioning and to assess its relationship with changes in Patient State Index and cerebral oxygen saturation.
Measured: Intraoperative period (recorded at predefined time points before and after Trendelenburg positioning)
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted12 Mar 2026
- Study start1 May 2026
- Primary completion1 Aug 2026 (estimated)
- Study completion1 Dec 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (2)Papers the sponsor has linked to this study.
- Other trials for Laparoscopic HysterectomyStudies 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
- 60 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Sakarya University
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Ayça Taş Tuna, Sakarya University
- Investigators
- Ayca Tas Tuna, Professor, M.D., Principal investigator, Sakarya University Faculty of Medicine
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07467200
- Sponsor's protocol ID
- SEAH-TrendelenburgPsi-2026
- Status last verified
- Jun 2026
- First submitted
- 9 Mar 2026
- Last updated
- 4 Jun 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No: Individual participant data will not be publicly shared because the dataset contains clinical perioperative monitoring data collected at a single center. De-identified data may be made available from the corresponding investigator upon reasonable request and subject to institutional and ethical approval.
Publications
Buget MI, Atalar AC, Edipoglu IS, Sungur Z, Sivrikoz N, Karadeniz M, Saka E, Kucukay S, Senturk MN. Patient state index and cerebral blood flow changes during shoulder arthroscopy in beach chair position. Braz J Anesthesiol. 2016 Sep-Oct;66(5):470-4. doi: 10.1016/j.bjane.2015.02.002. Epub 2015 Oct 1.
PubMed 27591460Chen W, Wang J, Wang L, Hu W, Chen X, Jin L. Effect of patient position on the EEG bispectral index and entropy index under general anaesthesia. Technol Health Care. 2025;33(1):311-319. doi: 10.3233/THC-241026.
PubMed 39302400
Study at a glance
From the registry record, last updated by the sponsor on 4 Jun 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Effect of the Trendelenburg Position on Patient State Index and Frontal Cerebral Oxygenation: A Prospective Observational Study
- ClinicalTrials.gov ID
- NCT07467200
- Acronym / sponsor ID
- SEAH-TrendelenburgPsi-2026
- Conditions
- Laparoscopic Hysterectomy
- Keywords
- Trendelenburg Position, Patient State Index, Processed EEG, Depth of Anesthesia Monitoring, Cerebral Oxygenation, Near-Infrared Spectroscopy, General Anesthesia, Intraoperative Monitoring
- Study type
- Observational
- Recruitment status
- Recruiting
- Enrolment
- 60 participants (estimated)
- Lead sponsor
- Sakarya UniversityUniversity, hospital or other
- Study start
- 1 May 2026 (actual)
- Primary completion
- 1 Aug 2026 (estimated)
- Study completion
- 1 Dec 2026 (estimated)
- First posted
- 12 Mar 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.
The goal of this observational study is to evaluate whether the Trendelenburg position affects electroencephalography-based depth of anesthesia monitoring and cerebral oxygenation during general anesthesia.
The main questions it aims to answer are:
- Does the Trendelenburg position cause a change in the Patient State Index (PSI), an Electroensephalography (EEG)-derived indicator of anesthetic depth?
- Are changes in PSI associated with changes in frontal cerebral oxygen saturation (rSO₂) and hemodynamic parameters?
The study will include adult female patients undergoing elective laparoscopic gynecologic surgery under general anesthesia.
Participants will receive standard anesthesia and routine intraoperative monitoring. In addition to standard monitoring, Patient State Index (PSI) and frontal cerebral oxygen saturation (rSO₂) will be recorded using non-invasive sensors. No additional intervention will be performed for research purposes.
Physiological parameters including PSI, cerebral oxygen saturation, mean arterial pressure, heart rate, oxygen saturation, and end-tidal carbon dioxide will be recorded at predefined intraoperative time points before and after the Trendelenburg position.
The study aims to determine whether position-related physiological changes influence EEG-based anesthesia depth indices and to improve the interpretation of intraoperative brain monitoring.
Detailed description
Electroencephalography (EEG)-based depth of anesthesia monitors are widely used to assess the hypnotic component of general anesthesia. The Patient State Index (PSI) is a processed EEG parameter derived from frontal EEG signals and provides a numerical estimate of anesthetic depth ranging from 0 to 100. Although these indices are primarily designed to reflect the pharmacologic effects of anesthetic agents, physiological factors that influence cerebral hemodynamics may also affect EEG-derived parameters.
The Trendelenburg position is frequently used during laparoscopic pelvic surgery to improve surgical exposure. This position can alter venous return, increase cerebral venous pressure, and influence intracranial dynamics. When combined with pneumoperitoneum, these physiological changes may modify cerebral blood flow and cerebral oxygenation. Such alterations may potentially influence EEG-based indices of anesthetic depth independently of anesthetic drug concentration.
Previous studies have demonstrated that body position can influence processed EEG indices such as the bispectral index (BIS), particularly in the beach-chair position. However, the response of the Patient State Index to the Trendelenburg position has not been clearly established.
This prospective observational study aims to evaluate whether the Trendelenburg position affects PSI values during general anesthesia and to investigate the relationship between PSI changes and cerebral oxygenation measured by near-infrared spectroscopy (NIRS).
Adult female patients undergoing elective laparoscopic hysterectomy under general anesthesia will be included. Standard intraoperative monitoring will be applied, including electrocardiography, non-invasive blood pressure, pulse oximetry, end-tidal carbon dioxide, and anesthetic gas monitoring. In addition, EEG-based depth of anesthesia monitoring will be performed using the PSI monitor (Masimo SedLine), and frontal cerebral oxygen saturation (rSO₂) will be measured using near-infrared spectroscopy sensors.
Physiological parameters including PSI, cerebral oxygen saturation, mean arterial pressure, heart rate, oxygen saturation, and end-tidal carbon dioxide will be recorded at predefined intraoperative time points: before induction of anesthesia, after tracheal intubation in the supine position, after pneumoperitoneum, and at several intervals following the Trendelenburg position.
No intervention will be performed for research purposes. Anesthetic management and surgical positioning will follow routine clinical practice. The study will analyze whether position-related physiological changes are associated with variations in PSI and whether these changes correlate with cerebral oxygenation or hemodynamic parameters.
Understanding the influence of patient positioning on EEG-based anesthesia depth indices may improve the interpretation of intraoperative brain monitoring and help prevent unnecessary adjustments of anesthetic drug dosing.
Study design
- Observational model
- Cohort
- Time perspective
- Prospective
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| Patients Undergoing Laparoscopic Hysterectomy in Trendelenburg Position | – | –This cohort includes adult female patients undergoing elective laparoscopic hysterectomy under general anesthesia. All participants receive standard intraoperative monitoring as part of routine clinical care. In addition to routine monitoring, depth of anesthesia is assessed using the Patient State Index (PSI), and frontal cerebral oxygen saturation (rSO₂) is measured using near-infrared spectroscopy sensors. Physiological parameters including PSI, cerebral oxygen saturation, mean arterial pressure, heart rate, oxygen saturation, and end-tidal carbon dioxide are recorded at predefined intraoperative time points before and after pneumoperitoneum and Trendelenburg positioning. No intervention is performed for research purposes. Surgical positioning and anesthetic management follow routine clinical practice, and the study involves only the observational recording of physiological parameters. |
Who may qualify
- Ages
- 18 to 65 years
- Sex
- Female only
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
- Study population
- The study population consists of adult female patients undergoing elective laparoscopic hysterectomy under general anesthesia at a tertiary care university-affiliated hospital. Eligible patients will be recruited consecutively among those scheduled for surgery who meet the inclusion criteria and provide written informed consent.
Key inclusion criteria (4 listed)
- Female patients aged 18-65 years
- American Society of Anesthesiologists (ASA) physical status I-III
- Scheduled for elective laparoscopic hysterectomy under general anesthesia
- Ability to provide written informed consent
Key exclusion criteria (5 listed)
- History of neurological disease (e.g., stroke, epilepsy)
- Known cerebrovascular disease, glaucoma, or retinal disease
- Severe cardiac or pulmonary disease
- Contraindication to near-infrared spectroscopy sensor placement
- Obesity (Body Mass Index > 35 kg/m²)
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
Change in Patient State Index (ΔPSI) After Trendelenburg Position
Time frame: From Post-intubation (Supine) to Trendelenburg Positioning
The primary outcome is the change in Patient State Index (PSI), an Electroensephalography(EEG)-derived indicator of anesthetic depth, between the supine position after tracheal intubation and the early Trendelenburg position following pneumoperitoneum. PSI values will be recorded using the Masimo SedLine monitoring system. The analysis will evaluate whether Trendelenburg positioning is associated with a significant change in PSI independent of anesthetic drug concentration.
3 secondary outcomes
Change in Frontal Cerebral Oxygen Saturation (rSO₂)
Time frame: Intraoperative period (recorded at predefined time points before and after Trendelenburg positioning)
Mean Arterial Pressure Changes During Trendelenburg Position
Time frame: Intraoperative period (recorded at predefined time points before and after Trendelenburg positioning)
Heart Rate Changes During Trendelenburg Position
Time frame: Intraoperative period (recorded at predefined time points before and after Trendelenburg positioning)
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 4 Jun 2026.
- Background: PubMed 27591460Buget MI, Atalar AC, Edipoglu IS, Sungur Z, Sivrikoz N, Karadeniz M, Saka E, Kucukay S, Senturk MN. Patient state index and cerebral blood flow changes during shoulder arthroscopy in beach chair position. Braz J Anesthesiol. 2016 Sep-Oct;66(5):470-4. doi: 10.1016/j.bjane.2015.02.002. Epub 2015 Oct 1.
- Background: PubMed 39302400Chen W, Wang J, Wang L, Hu W, Chen X, Jin L. Effect of patient position on the EEG bispectral index and entropy index under general anaesthesia. Technol Health Care. 2025;33(1):311-319. doi: 10.3233/THC-241026.
- Individual participant dataSharing planned: No. Individual participant data will not be publicly shared because the dataset contains clinical perioperative monitoring data collected at a single center. De-identified data may be made available from the corresponding investigator upon reasonable request and subject to institutional and ethical approval.
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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.
Ahmet R Dogan, M.D. contact
Ayca Tas Tuna, Professor, M.D. principal investigator
Sakarya University Faculty of Medicine
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 Laparoscopic Hysterectomy, run by Sakarya 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 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 4 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?
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 Ayca Tas Tuna, Professor, M.D. (+90 532 300 48 26, aycatas@yahoo.com), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Change in Patient State Index (ΔPSI) After Trendelenburg Position (time frame: From Post-intubation (Supine) to Trendelenburg Positioning). 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 NCT07467200, which also lists 2 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 4 Jun 2026.