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

2 juin 2026 mis à jour par: 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.

Aperçu de l'étude

Statut

Complété

Les conditions

Intervention / Traitement

Description détaillée

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.

Type d'étude

Observationnel

Inscription (Réel)

70

Contacts et emplacements

Cette section fournit les coordonnées de ceux qui mènent l'étude et des informations sur le lieu où cette étude est menée.

Lieux d'étude

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

Critères de participation

Les chercheurs recherchent des personnes qui correspondent à une certaine description, appelée critères d'éligibilité. Certains exemples de ces critères sont l'état de santé général d'une personne ou des traitements antérieurs.

Critère d'éligibilité

Âges éligibles pour étudier

  • Adulte
  • Adulte plus âgé

Accepte les volontaires sains

Oui

Méthode d'échantillonnage

Échantillon non probabiliste

Population étudiée

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)

La description

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

Plan d'étude

Cette section fournit des détails sur le plan d'étude, y compris la façon dont l'étude est conçue et ce que l'étude mesure.

Comment l'étude est-elle conçue ?

Détails de conception

Cohortes et interventions

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

Que mesure l'étude ?

Principaux critères de jugement

Mesure des résultats
Description de la mesure
Délai
Change in Regional Cerebral Oxygen Saturation (rSO2)
Délai: 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.

Mesures de résultats secondaires

Mesure des résultats
Description de la mesure
Délai
Change in Mean Arterial Pressure (MAP)
Délai: 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)
Délai: 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)
Délai: 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)
Délai: 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

Collaborateurs et enquêteurs

C'est ici que vous trouverez les personnes et les organisations impliquées dans cette étude.

Parrainer

Ankara Etlik City Hospital

Dates d'enregistrement des études

Ces dates suivent la progression des dossiers d'étude et des soumissions de résultats sommaires à ClinicalTrials.gov. Les dossiers d'étude et les résultats rapportés sont examinés par la Bibliothèque nationale de médecine (NLM) pour s'assurer qu'ils répondent à des normes de contrôle de qualité spécifiques avant d'être publiés sur le site Web public.

Dates principales de l'étude

Début de l'étude (Réel)

6 mars 2026

Achèvement primaire (Réel)

18 mai 2026

Achèvement de l'étude (Réel)

18 mai 2026

Dates d'inscription aux études

Première soumission

18 mai 2026

Première soumission répondant aux critères de contrôle qualité

2 juin 2026

Première publication (Réel)

8 juin 2026

Mises à jour des dossiers d'étude

Dernière mise à jour publiée (Réel)

8 juin 2026

Dernière mise à jour soumise répondant aux critères de contrôle qualité

2 juin 2026

Dernière vérification

1 juin 2026

Plus d'information

Termes liés à cette étude

Mots clés

Termes MeSH pertinents supplémentaires

Autres numéros d'identification d'étude

  • AEŞH-EK-2026-048

Plan pour les données individuelles des participants (IPD)

Prévoyez-vous de partager les données individuelles des participants (DPI) ?

NON

Description du régime IPD

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.

Informations sur les médicaments et les dispositifs, documents d'étude

Étudie un produit pharmaceutique réglementé par la FDA américaine

Non

Étudie un produit d'appareil réglementé par la FDA américaine

Non

Ces informations ont été extraites directement du site Web clinicaltrials.gov sans aucune modification. Si vous avez des demandes de modification, de suppression ou de mise à jour des détails de votre étude, veuillez contacter register@clinicaltrials.gov. Dès qu'un changement est mis en œuvre sur clinicaltrials.gov, il sera également mis à jour automatiquement sur notre site Web .

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