Trendelenburg Angle and Upper Airway Ultrasound Findings in Laparoscopic Hysterectomy (TAU-LH)

August 27, 2026 updated by: Izmir City Hospital

Evaluation of the Effect of Trendelenburg Position on Upper Airway Edema by Ultrasonography and Its Relationship With Postoperative Clinical Airway Findings in Patients Undergoing Laparoscopic Hysterectomy

This observational study was designed to evaluate whether the Trendelenburg position used during laparoscopic hysterectomy is associated with swelling of the upper airway.

Women scheduled for elective laparoscopic hysterectomy under general anesthesia were included. During surgery, the angle of the operating table in the Trendelenburg position was measured. The upper airway was assessed with bedside ultrasound by measuring the distance from the skin to the epiglottis and the thickness of the tongue at different time points before and during surgery.

The study did not assign participants to any treatment or intervention. All participants received standard surgical and anesthetic care. After surgery, participants were monitored for early airway-related findings such as noisy breathing after extubation, need for extra oxygen, low oxygen saturation, or need for reintubation.

Study Overview

Detailed Description

Laparoscopic hysterectomy often requires carbon dioxide pneumoperitoneum and Trendelenburg positioning to improve surgical exposure. This position may shift fluid toward the head and neck region and may contribute to swelling of upper airway soft tissues.

This single-center prospective observational study included adult female participants scheduled for elective laparoscopic hysterectomy under general anesthesia. No study-related intervention was assigned. The Trendelenburg angle was determined by the surgical team according to routine clinical need and was recorded using a digital inclinometer.

Upper airway ultrasound measurements were performed at three perioperative time points: before anesthesia induction in the supine position, after Trendelenburg positioning, and at the end of surgery before return to the supine position. The measured ultrasound parameters were distance from skin to epiglottis and tongue thickness.

After extubation, participants were monitored in the post-anesthesia care unit and during the first 24 postoperative hours for clinical airway findings, including postextubation stridor, supplemental oxygen requirement, oxygen saturation below 94% on room air, and reintubation. The study aimed to assess the relationship between Trendelenburg angle, ultrasound-measured upper airway soft tissue changes, and early postoperative clinical airway findings.

Study Type

Observational

Enrollment (Actual)

68

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Sampling Method

Non-Probability Sample

Study Population

Adult female patients scheduled for elective laparoscopic hysterectomy under general anesthesia at Izmir City Hospital, University of Health Sciences, Izmir, Turkey.

Description

Inclusion Criteria:

  • Female patients aged 18 to 65 years
  • Scheduled for elective laparoscopic hysterectomy
  • Planned surgery under general anesthesia
  • American Society of Anesthesiologists physical status I to III
  • Body mass index 35 kg/m² or lower
  • Provided written informed consent for study participation

Exclusion Criteria:

  • Known history of difficult airway or expected difficult airway on preoperative evaluation
  • Mallampati class III or IV
  • Congenital or acquired upper airway pathology
  • Neck mass or previous neck surgery
  • Body mass index greater than 35 kg/m²
  • Pregnancy
  • Emergency surgery
  • Known chronic respiratory disease, such as chronic obstructive pulmonary disease or advanced asthma
  • Upper respiratory tract infection within the previous three weeks
  • Inability to communicate in Turkish
  • Lack of cooperation
  • Conversion to open surgery
  • Requirement for blood transfusion or additional fluid resuscitation beyond the standard protocol
  • Significant hypotension requiring vasopressor support
  • Persistent high peak airway pressures with ventilatory difficulty
  • More than two intubation attempts
  • Withdrawal from the study

Exclusion Criteria:

-

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

Cohorts and Interventions

Group / Cohort
Intervention / Treatment
Laparoscopic Hysterectomy Cohort
Adult female participants scheduled for elective laparoscopic hysterectomy under general anesthesia. Participants received standard surgical and anesthetic care. No study-related intervention was assigned. Trendelenburg angle was determined according to routine surgical need and recorded during surgery. Upper airway ultrasound measurements were obtained perioperatively, and participants were monitored for postoperative clinical airway findings during the first 24 hours.
Participants underwent elective laparoscopic hysterectomy under general anesthesia as part of standard clinical care. Trendelenburg positioning was applied according to routine surgical need and was not assigned by the study protocol. The Trendelenburg angle was measured and recorded during surgery. Upper airway ultrasound measurements were obtained before and during surgery, and participants were monitored for postoperative clinical airway findings during the first 24 hours.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change in distance from skin to epiglottis
Time Frame: From before anesthesia induction to the end of surgery before return to the supine position
Distance from skin to epiglottis was measured using point-of-care upper airway ultrasonography before anesthesia induction, after Trendelenburg positioning, and at the end of surgery before return to the supine position. The outcome was the change from baseline to the end of surgery, expressed in centimeters.
From before anesthesia induction to the end of surgery before return to the supine position

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change in tongue thickness
Time Frame: From before anesthesia induction to the end of surgery before return to the supine position
Tongue thickness was measured using point-of-care upper airway ultrasonography before anesthesia induction, after Trendelenburg positioning, and at the end of surgery before return to the supine position. The outcome was the change in tongue thickness from baseline to the end of surgery, expressed in centimeters.
From before anesthesia induction to the end of surgery before return to the supine position

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

February 5, 2026

Primary Completion (Actual)

May 5, 2026

Study Completion (Actual)

May 5, 2026

Study Registration Dates

First Submitted

August 27, 2026

First Submitted That Met QC Criteria

August 27, 2026

First Posted (Actual)

August 31, 2026

Study Record Updates

Last Update Posted (Actual)

August 31, 2026

Last Update Submitted That Met QC Criteria

August 27, 2026

Last Verified

August 1, 2026

More Information

Terms related to this study

Other Study ID Numbers

  • IZMIR-USG-TREND-2026-57
  • 2026/57 (Registry Identifier: Izmir City Hospital Non-Interventional Clinical Research Ethics Committee)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

IPD Plan Description

De-identified individual participant data underlying the results reported in this study may be shared upon reasonable request. Shared data will not include any direct personal identifiers. Access will be subject to approval by the corresponding author and applicable institutional and ethics committee requirements.

IPD Sharing Time Frame

Data may become available after publication of the main study results and may be available for 5 years after publication.

IPD Sharing Access Criteria

Data may be made available to qualified researchers who submit a methodologically sound proposal for scientific purposes related to perioperative airway management, airway ultrasonography, or postoperative airway outcomes. Requests should be directed to the corresponding author. Data sharing will require appropriate institutional and ethics committee approval when applicable.

IPD Sharing Supporting Information Type

  • STUDY_PROTOCOL

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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