Effect of Trendelenburg Position on Patient State Index

NCT07467200 | Recruiting

• 1 other identifier: SEAH-TrendelenburgPsi-2026
• Study Type: observational
• Target: 60
• Locations: 1 country
• Sites: 1

Brief 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. 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.

Conditions

Laparoscopic Hysterectomy

Keywords

Trendelenburg Position; Patient State Index; Processed EEG; Depth of Anesthesia Monitoring; Cerebral Oxygenation; Near-Infrared Spectroscopy; General Anesthesia; Intraoperative Monitoring

Outcome Measures

Primary Outcomes (1)

• 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.

  From Post-intubation (Supine) to Trendelenburg Positioning

Secondary Outcomes (3)

• Change in Frontal Cerebral Oxygen Saturation (rSO₂)

  Intraoperative period (recorded at predefined time points before and after Trendelenburg positioning)

• Mean Arterial Pressure Changes During Trendelenburg Position

  Intraoperative period (recorded at predefined time points before and after Trendelenburg positioning)

• Heart Rate Changes During Trendelenburg Position

  Intraoperative period (recorded at predefined time points before and after Trendelenburg positioning)

Study Arms (1)

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.

Eligibility Criteria

• Age: 18 Years - 65 Years
• Sex: female
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)
• Sampling Method: Non-Probability Sample

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.

You may qualify if:

• 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

You may not qualify if:

• 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)

Sponsors & Collaborators

• Sakarya University: lead

Study Sites (1)

Sakarya University Training and Research Hospital, Department of Anesthesiology and Reanimation

Sakarya, Turkey (Türkiye)

RECRUITING

Related Publications (2)

• 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.

  PMID: 27591460 BACKGROUND

• Chen 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.

  PMID: 39302400 BACKGROUND

Study Officials

• Ayca Tas Tuna, Professor, M.D.

  Sakarya University Faculty of Medicine

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Ayca Tas Tuna, Professor, M.D.

CONTACT

+90 532 300 48 26; aycatas@yahoo.com

Ahmet R Dogan, M.D.

CONTACT

+905427988070

Study Design

• Study Type: observational
• Observational Model: COHORT
• Time Perspective: PROSPECTIVE
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Prof.Dr.

Study Record Dates

• First Submitted: March 9, 2026
• First Posted: March 12, 2026
• Study Start: May 1, 2026
• Primary Completion (Estimated): August 1, 2026
• Study Completion (Estimated): December 1, 2026
• Last Updated: June 4, 2026

Record last verified: 2026-06

Data Sharing

• IPD Sharing: Will not share

Locations

TU (1)