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Effects of Standard and Modified Z-Trendelenburg Positions on Cerebral Oxygenation and Optic Nerve Sheath Diameter (MOD-TREND)

2 juni 2026 bijgewerkt door: Neriman Doğan, Ankara Etlik City Hospital

Comparison of the Effects of Standard Trendelenburg and Modified Z Trendelenburg Positions on Cerebral Oxygenation (NIRS) and Optic Nerve Sheath Diameter in Laparoscopic Gynecological Cases

The purpose of this study is to compare the effects of the standard Trendelenburg position and the modified Z-Trendelenburg position on cerebral oxygenation and optic nerve sheath diameter (ONSD) in patients undergoing laparoscopic surgery. The prolonged use of the standard Trendelenburg position combined with pneumoperitoneum can increase intracranial pressure and affect cerebral blood flow. In this study, researchers will use non-invasive methods, including Near-Infrared Spectroscopy (NIRS) to monitor regional cerebral oxygenation, and ocular ultrasonography to measure ONSD as an indicator of intracranial pressure changes. The main goal is to determine whether the modified Z-Trendelenburg position serves as a safer physiological alternative by reducing these potential adverse effects compared to the standard position.

Studie Overzicht

Toestand

Voltooid

Conditie

Interventie / Behandeling

Gedetailleerde beschrijving

Laparoscopic surgeries frequently require patients to be placed in a steep Trendelenburg position with pneumoperitoneum to provide optimal surgical exposure. However, this combination induces significant physiological alterations, most notably an increase in intracranial pressure (ICP) and a potential compromise in cerebral venous drainage and regional cerebral oxygen saturation (rSO2). Non-invasive monitoring techniques, such as measuring the optic nerve sheath diameter (ONSD) via ultrasonography, provide reliable, real-time estimates of ICP changes. Additionally, Near-Infrared Spectroscopy (NIRS) allows for the continuous monitoring of cerebral oxygenation.

This prospective clinical study is designed to evaluate and compare the cerebral and hemodynamic impacts of the standard straight Trendelenburg position versus a modified Z-Trendelenburg position. Participants scheduled for elective laparoscopic procedures will be divided into specific positioning groups. Hemodynamic parameters, NIRS values, and ONSD measurements will be recorded at predefined time points throughout the surgery: at baseline, post-induction, after the establishment of pneumoperitoneum and positioning, at specific intervals during the surgery, and post-operatively in the recovery room. The primary hypothesis is that the modified Z-Trendelenburg position will attenuate the rise in ICP (reflected by a smaller increase in ONSD) and provide better cerebral oxygenation stability compared to the traditional standard position.

Studietype

Observationeel

Inschrijving (Werkelijk)

70

Contacten en locaties

In dit gedeelte vindt u de contactgegevens van degenen die het onderzoek uitvoeren en informatie over waar dit onderzoek wordt uitgevoerd.

Studie Locaties

  • Turkije (Türkiye)
    • Ankara
      • Ankara, Ankara, Turkije (Türkiye), 06010
        • Ankara Etlik City Hospital

Deelname Criteria

Onderzoekers zoeken naar mensen die aan een bepaalde beschrijving voldoen, de zogenaamde geschiktheidscriteria. Enkele voorbeelden van deze criteria zijn iemands algemene gezondheidstoestand of eerdere behandelingen.

Geschiktheidscriteria

Leeftijden die in aanmerking komen voor studie

  • Volwassen
  • Oudere volwassene

Accepteert gezonde vrijwilligers

Ja

Bemonsteringsmethode

Niet-waarschijnlijkheidssteekproef

Studie Bevolking

The study population consists of adult patients up to 80 years of age who [are admitted to the intensive care unit / are undergoing elective surgery / present to the emergency department]. The population excludes patients with known increased intracranial pressure, severe cerebrovascular, cardiovascular, or pulmonary diseases, morbid obesity (BMI > 35 kg/m^2), pregnancy, and any pre-existing ocular pathologies that could affect optic nerve sheath diameter (ONSD)

Beschrijving

Inclusion Criteria:

Patients aged between 18 and 70 years

American Society of Anesthesiologists (ASA) physical status I or II

Scheduled for elective laparoscopic surgery requiring Trendelenburg position

Provided written informed consent

Exclusion Criteria:

Patient refusal to participate

History of severe cerebrovascular disease

Known increased intracranial pressure

Pre-existing ocular pathology that could affect optic nerve sheath diameter (ONSD) measurements (e.g., glaucoma, optic neuritis, ocular trauma)

Severe cardiovascular or pulmonary disease Body Mass Index (BMI) greater than 35 kg/m^2 Pregnancy

Studie plan

Dit gedeelte bevat details van het studieplan, inclusief hoe de studie is opgezet en wat de studie meet.

Hoe is de studie opgezet?

Ontwerpdetails

Cohorten en interventies

Groep / Cohort
Interventie / Behandeling
Standard Trendelenburg Cohort
Patients undergoing elective laparoscopic surgery placed in the standard straight Trendelenburg position.
Procedure: Standard Trendelenburg Position
Placement of the patient in the traditional straight head-down tilt position required for laparoscopic surgical access and pneumoperitoneum
Modified Z-Trendelenburg Cohort
Patients undergoing elective laparoscopic surgery placed in the modified Z-Trendelenburg position (head-down tilt combined with leg flexion).
Procedure: Modified Z-Trendelenburg Position
Placement of the patient in a modified head-down tilt position combined with leg flexion

Wat meet het onderzoek?

Primaire uitkomstmaten

Uitkomstmaat
Maatregel Beschrijving
Tijdsspanne
Change in Regional Cerebral Oxygen Saturation (rSO2)
Tijdsspanne: Baseline (before anesthesia induction), at 10, 45, 60, and 90 minutes after establishing pneumoperitoneum and surgical positioning, and 10 minutes after returning to the supine position.
Regional cerebral oxygen saturation (rSO2) will be measured bilaterally using Near-Infrared Spectroscopy (NIRS) sensors placed on the patient's forehead. This non-invasive monitoring will be used to evaluate cerebral oxygenation changes during different surgical positions and pneumoperitoneum. Values will be recorded as percentages (%).
Baseline (before anesthesia induction), at 10, 45, 60, and 90 minutes after establishing pneumoperitoneum and surgical positioning, and 10 minutes after returning to the supine position.

Secundaire uitkomstmaten

Uitkomstmaat
Maatregel Beschrijving
Tijdsspanne
Change in Mean Arterial Pressure (MAP)
Tijdsspanne: Baseline ( 10 minutes after anesthesia induction), at 10,45, 60, and 90 minutes after establishing pneumoperitoneum and surgical positioning, and 10 minutes after returning to the supine position.
Mean Arterial Pressure (MAP) will be continuously monitored and recorded to evaluate the cardiovascular effects of the pneumoperitoneum and modified positioning. Values will be reported in mmHg.
Baseline ( 10 minutes after anesthesia induction), at 10,45, 60, and 90 minutes after establishing pneumoperitoneum and surgical positioning, and 10 minutes after returning to the supine position.
Change in Optic Nerve Sheath Diameter (ONSD)
Tijdsspanne: Baseline ( 10 minutes after anesthesia induction), at 10, 45, 60, and 90 minutes after establishing pneumoperitoneum and surgical positioning, and 10 minutes after returning to the supine position.
Intracranial pressure changes will be evaluated indirectly by measuring the optic nerve sheath diameter (ONSD) using ocular ultrasonography. Measurements will be taken bilaterally and recorded in millimeters (mm).
Baseline ( 10 minutes after anesthesia induction), at 10, 45, 60, and 90 minutes after establishing pneumoperitoneum and surgical positioning, and 10 minutes after returning to the supine position.
Change in Peak Airway Pressure (Ppeak)
Tijdsspanne: Baseline (10 minutes after anesthesia induction), at 10,45, 60, and 90 minutes after establishing pneumoperitoneum and surgical positioning, and 10 minutes after returning to the supine posi
Peak airway pressure will be monitored continuously and recorded to evaluate the effects of pneumoperitoneum and different surgical positions on respiratory mechanics. Values will be reported in centimeters of water (cmH2O).
Baseline (10 minutes after anesthesia induction), at 10,45, 60, and 90 minutes after establishing pneumoperitoneum and surgical positioning, and 10 minutes after returning to the supine posi
Change in End-tidal Carbon Dioxide (EtCO2)
Tijdsspanne: Baseline (10 minutes after anesthesia induction), at 10, 45, 60, and 90 minutes after establishing pneumoperitoneum and surgical positioning, and 10 minutes after returning to the supine positi
End-tidal carbon dioxide levels will be monitored continuously via capnography to evaluate ventilation status during pneumoperitoneum and different positioning. Values will be reported in millimeters of mercury (mmHg).
Baseline (10 minutes after anesthesia induction), at 10, 45, 60, and 90 minutes after establishing pneumoperitoneum and surgical positioning, and 10 minutes after returning to the supine positi

Medewerkers en onderzoekers

Hier vindt u mensen en organisaties die betrokken zijn bij dit onderzoek.

Sponsor

Ankara Etlik City Hospital

Studie record data

Deze datums volgen de voortgang van het onderzoeksdossier en de samenvatting van de ingediende resultaten bij ClinicalTrials.gov. Studieverslagen en gerapporteerde resultaten worden beoordeeld door de National Library of Medicine (NLM) om er zeker van te zijn dat ze voldoen aan specifieke kwaliteitscontrolenormen voordat ze op de openbare website worden geplaatst.

Bestudeer belangrijke data

Studie start (Werkelijk)

6 maart 2026

Primaire voltooiing (Werkelijk)

18 mei 2026

Studie voltooiing (Werkelijk)

18 mei 2026

Studieregistratiedata

Eerst ingediend

18 mei 2026

Eerst ingediend dat voldeed aan de QC-criteria

2 juni 2026

Eerst geplaatst (Werkelijk)

8 juni 2026

Updates van studierecords

Laatste update geplaatst (Werkelijk)

8 juni 2026

Laatste update ingediend die voldeed aan QC-criteria

2 juni 2026

Laatst geverifieerd

1 juni 2026

Meer informatie

Termen gerelateerd aan deze studie

Trefwoorden

Aanvullende relevante MeSH-voorwaarden

Andere studie-ID-nummers

  • AEŞH-EK-2026-048

Plan Individuele Deelnemersgegevens (IPD)

Bent u van plan om gegevens van individuele deelnemers (IPD) te delen?

NEE

Beschrijving IPD-plan

The study population consists of adult female patients, aged 18 to 80 years, classified with an American Society of Anesthesiologists (ASA) physical status of I or II, who are scheduled to undergo elective laparoscopic gynecological surgery under general anesthesia at Ankara Etlik City Hospital. Eligible participants must have a Body Mass Index (BMI) between 18 and 30 kg/m2 and require the Trendelenburg position during surgery. Patients are excluded from the study population if they have a history of intracranial pathology, neurological disorders, severe ophthalmologic conditions (such as glaucoma), cerebrovascular diseases, severe cardiac or pulmonary diseases, profound anemia (Hb < 10 g/dL), or if they are pregnant.

Informatie over medicijnen en apparaten, studiedocumenten

Bestudeert een door de Amerikaanse FDA gereguleerd geneesmiddel

Nee

Bestudeert een door de Amerikaanse FDA gereguleerd apparaatproduct

Nee

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