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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 uppdaterad av: 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.

Studieöversikt

Status

Avslutad

Betingelser

Intervention / Behandling

Detaljerad beskrivning

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.

Studietyp

Observationell

Inskrivning (Faktisk)

70

Kontakter och platser

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Studieorter

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

Deltagandekriterier

Forskare letar efter personer som passar en viss beskrivning, så kallade behörighetskriterier. Några exempel på dessa kriterier är en persons allmänna hälsotillstånd eller tidigare behandlingar.

Urvalskriterier

Åldrar som är berättigade till studier

  • Vuxen
  • Äldre vuxen

Tar emot friska volontärer

Ja

Testmetod

Icke-sannolikhetsprov

Studera befolkning

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)

Beskrivning

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

Studieplan

Det här avsnittet ger detaljer om studieplanen, inklusive hur studien är utformad och vad studien mäter.

Hur är studien utformad?

Designdetaljer

Kohorter och interventioner

Grupp / Kohort
Intervention / Behandling
Standard Trendelenburg Cohort
Patients undergoing elective laparoscopic surgery placed in the standard straight Trendelenburg position.
Procedur: 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).
Procedur: Modified Z-Trendelenburg Position
Placement of the patient in a modified head-down tilt position combined with leg flexion

Vad mäter studien?

Primära resultatmått

Resultatmått
Åtgärdsbeskrivning
Tidsram
Change in Regional Cerebral Oxygen Saturation (rSO2)
Tidsram: 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.

Sekundära resultatmått

Resultatmått
Åtgärdsbeskrivning
Tidsram
Change in Mean Arterial Pressure (MAP)
Tidsram: 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)
Tidsram: 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)
Tidsram: 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)
Tidsram: 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

Samarbetspartners och utredare

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Sponsor

Ankara Etlik City Hospital

Studieavstämningsdatum

Dessa datum spårar framstegen för inlämningar av studieposter och sammanfattande resultat till ClinicalTrials.gov. Studieposter och rapporterade resultat granskas av National Library of Medicine (NLM) för att säkerställa att de uppfyller specifika kvalitetskontrollstandarder innan de publiceras på den offentliga webbplatsen.

Studera stora datum

Studiestart (Faktisk)

6 mars 2026

Primärt slutförande (Faktisk)

18 maj 2026

Avslutad studie (Faktisk)

18 maj 2026

Studieregistreringsdatum

Först inskickad

18 maj 2026

Först inskickad som uppfyllde QC-kriterierna

2 juni 2026

Första postat (Faktisk)

8 juni 2026

Uppdateringar av studier

Senaste uppdatering publicerad (Faktisk)

8 juni 2026

Senaste inskickade uppdateringen som uppfyllde QC-kriterierna

2 juni 2026

Senast verifierad

1 juni 2026

Mer information

Termer relaterade till denna studie

Nyckelord

Ytterligare relevanta MeSH-villkor

Andra studie-ID-nummer

  • AEŞH-EK-2026-048

Plan för individuella deltagardata (IPD)

Planerar du att dela individuella deltagardata (IPD)?

NEJ

IPD-planbeskrivning

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.

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