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NCT Number: NCT07253922

Evaluation of Optic Nerve Sheath Diameter Changes During Cardiopulmonary Bypass in 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.

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Key information

Conditions

Open Heart Surgery Cardiopulmonary Bypass Intracranial Pressure Optic Nerve Sheath Diameter

Age range

18 year–85 year

Sex eligibility

All sexes

Study type

Observational

Primary location

Medipol University

Istanbul, Turkey (Türkiye)

About this study

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.

Who can participate

Only the study team can determine whether someone qualifies for participation.

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

Treatment and study plan

Ultrasonography of the Optic Nerve Sheath

Procedure

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.

Primary outcomes

  1. 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.

Secondary outcomes

  1. 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.

  2. 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.

  3. 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

  4. 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.

  5. 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.

  6. 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.

Sponsors and collaborators

Lead sponsor

Medipol University

Other

Registry information

Official study title

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

Important dates

Study start
2025
Primary completion
2025
Study completion
2025
First posted
Nov 28, 2025
Registry last updated
Nov 28, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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