Evaluation of Optic Nerve Sheath Diameter Changes During Cardiopulmonary Bypass in Open Heart Surgery

November 26, 2025 updated by: Burak Omur, Medipol University

A Prospective Evaluation of Optic Nerve Sheath Diameter Changes Measured by Ultrasonography During Cardiopulmonary Bypass in Patients Undergoing Open Heart Surgery

During cardiopulmonary bypass (CPB) in open-heart surgery, direct measurement of intracranial pressure is not feasible. Evaluation of the optic nerve sheath diameter (ONSD) by ultrasonography is considered a reliable method for predicting increases in intracranial pressure. This study aims to investigate changes in ONSD in patients undergoing open-heart surgery with CPB.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

Several mechanisms during CPB-including inflammatory response, hemodilution, reperfusion injury, hypothermia-rewarming imbalances, and microembolism formation-can lead to increased intracranial pressure and cerebral edema. Ultrasonographic measurement of ONSD provides a noninvasive means of monitoring these changes. In this study, ONSD will be measured at different time points, while hemodynamic parameters, NIRS values, and arterial blood gas analyses will be recorded simultaneously. The primary objective is to evaluate changes in ONSD, and the secondary objective is to determine the potential impact of these changes on intracranial pressure.

Study Type

Observational

Enrollment (Actual)

40

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

N/A

Sampling Method

Non-Probability Sample

Study Population

Adult patients (18-85 years) undergoing elective open-heart surgery with cardiopulmonary bypass at Istanbul Medipol University Hospital, who meet inclusion criteria and provide written informed consent.

Description

Inclusion Criteria:

  • Adults aged 18-85 years
  • Scheduled for elective open-heart surgery with cardiopulmonary bypass
  • Provided written informed consent

Exclusion Criteria:

  • Ocular or neurological complications related to diabetes
  • History of previous eye, brain, or thoracic surgery
  • Diagnosis of hydrocephalus, glaucoma, intracranial mass, or stroke

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
Study Cohort
Adult patients (18-85 years) undergoing elective open-heart surgery with cardiopulmonary bypass. Optic nerve sheath diameter (ONSD) will be measured by ultrasonography at predefined time points, along with hemodynamic parameters, NIRS values, and arterial blood gas analyses.
Procedure: Ultrasonography of the Optic Nerve Sheath
Ultrasonographic measurement of the optic nerve sheath diameter (ONSD) will be performed using a 7.5 MHz linear probe. Measurements will be taken 3 mm behind the globe in both transverse and sagittal planes, three times for each eye, and the average value will be recorded at predefined time points during cardiopulmonary bypass.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change in Optic Nerve Sheath Diameter (ONSD)
Time Frame: From tracheal intubation (baseline) until the end of surgery (approximately 4-6 hours); measurements at six predefined time points (post-intubation, CPB initiation, 15 min, 45 min, 15 min after CPB termination, end of surgery).
Evaluation of ONSD changes measured by ultrasonography to assess potential alterations in intracranial pressure during cardiopulmonary bypass.
From tracheal intubation (baseline) until the end of surgery (approximately 4-6 hours); measurements at six predefined time points (post-intubation, CPB initiation, 15 min, 45 min, 15 min after CPB termination, end of surgery).

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Mean Arterial Pressure (MAP)
Time Frame: From induction of anesthesia until the end of surgery, recorded simultaneously with OSD measurements.
Measurement of mean arterial pressure.
From induction of anesthesia until the end of surgery, recorded simultaneously with OSD measurements.
Central Venous Pressure (CVP)
Time Frame: From induction of anesthesia until the end of surgery, recorded simultaneously with OSD measurements.
Measurement of central venous pressure.
From induction of anesthesia until the end of surgery, recorded simultaneously with OSD measurements.
Arterial Blood pH
Time Frame: From tracheal intubation (baseline) until the end of surgery (approximately 4-6 hours); measurements at six predefined time points (post-intubation, CPB initiation, 15 min, 45 min, 15 min after CPB termination, end of surgery).
Analysis of arterial blood pH values
From tracheal intubation (baseline) until the end of surgery (approximately 4-6 hours); measurements at six predefined time points (post-intubation, CPB initiation, 15 min, 45 min, 15 min after CPB termination, end of surgery).
Partial Pressure of Arterial Carbon Dioxide (PaCO₂)
Time Frame: From tracheal intubation (baseline) until the end of surgery (approximately 4-6 hours); measurements at six predefined time points (post-intubation, CPB initiation, 15 min, 45 min, 15 min after CPB termination, end of surgery).
Analysis of partial pressure of arterial carbon dioxide.
From tracheal intubation (baseline) until the end of surgery (approximately 4-6 hours); measurements at six predefined time points (post-intubation, CPB initiation, 15 min, 45 min, 15 min after CPB termination, end of surgery).
Lactate
Time Frame: From tracheal intubation (baseline) until the end of surgery (approximately 4-6 hours); measurements at six predefined time points (post-intubation, CPB initiation, 15 min, 45 min, 15 min after CPB termination, end of surgery).
Analysis of blood lactate levels.
From tracheal intubation (baseline) until the end of surgery (approximately 4-6 hours); measurements at six predefined time points (post-intubation, CPB initiation, 15 min, 45 min, 15 min after CPB termination, end of surgery).
partial Pressure of Arterial Oxygen (PaO₂)
Time Frame: From tracheal intubation (baseline) until the end of surgery (approximately 4-6 hours); measurements at six predefined time points (post-intubation, CPB initiation, 15 min, 45 min, 15 min after CPB termination, end of surgery).
Analysis of partial pressure of arterial oxygen.
From tracheal intubation (baseline) until the end of surgery (approximately 4-6 hours); measurements at six predefined time points (post-intubation, CPB initiation, 15 min, 45 min, 15 min after CPB termination, end of surgery).

Collaborators and Investigators

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

Sponsor

Medipol University

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

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)

June 10, 2025

Primary Completion (Actual)

October 10, 2025

Study Completion (Actual)

November 25, 2025

Study Registration Dates

First Submitted

August 22, 2025

First Submitted That Met QC Criteria

November 26, 2025

First Posted (Actual)

November 28, 2025

Study Record Updates

Last Update Posted (Actual)

November 28, 2025

Last Update Submitted That Met QC Criteria

November 26, 2025

Last Verified

November 1, 2025

More Information

Terms related to this study

Other Study ID Numbers

  • Medipol-OSKC-2025

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

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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