Optic Nerve Sheath Diameter MeasurementONSD ETDNCT07784361
Assessment of Optic Sheat Diameter (ONSD) and Eyeball Transverse Diameter (ETD) Ratio Measurement From Ocular Ultrasound
An observational study of Optic Nerve Sheath Diameter Measurement and Intracranial Pressure Increase, run by Gaziantep City Hospital.
Trial summary
The aim of this study is to evaluate the effects of different carbon dioxide gas insufflation pressures on the ultrasound-guided optic nerve sheath diameter in patients undergoing laparoscopic cholecystectomy and to determine the possible relationship between these changes and intracranial pressure. Read more about this study
- Who is it for?
- Ages 18 to 80 years
- Conditions the study is for
- Optic Nerve Sheath Diameter Measurement, Intracranial Pressure Increase, Laparoscopic Cholecystectomy Surgery
- What is being tested?
- Low Pressure Group and High Pressure Group
- Type of treatment
- Surgery or procedure
- How many people
- 68 participants
- Where
- No sites listed yet
- Study dates
- 30 Nov 2026to 15 Feb 2027
- Phase
- Observational
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 80 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Study population: The study population consists of adult patients aged 18-80 years, classified as ASA I-II physical status, who are scheduled to undergo elective laparoscopic cholecystectomy in a tertiary care hospital setting. Patients are observed within the routine clinical workflow of the anesthesia and general surgery departments.
Who may be able to join
- Patients aged between 18 and 80 years.
- Patients scheduled for laparoscopic cholecystectomy.
- ASA (American Society of Anesthesiologists) physical status I or II.
Who cannot join
- History of intracranial space-occupying lesion or high intracranial pressure (ICP).
- History of abdominal trauma.
- History of orbital/ocular trauma.
Trial locations and contacts
No sites are listed yet. Contact the study team or a site near you to ask about taking part.
About this study
Official title: Assessment of Increased Intracranial Pressure by Optic Nerve Sheath Diameter (ONSD), Eyeball Transverse Diameter (ETD) and ONSD/ETD Ratio Measurement From Ocular Ultrasound
The aim of this study is to evaluate the effects of different carbon dioxide gas insufflation pressures on the ultrasound-guided optic nerve sheath diameter in patients undergoing laparoscopic cholecystectomy and to determine the possible relationship between these changes and intracranial pressure. The study aims to gain a better understanding of the neurophysiological effects of gas pressures used during laparoscopic surgery and to obtain scientific data aimed at improving patient safety.
Read the detailed description
Laparoscopic surgeries are now widely preferred in the treatment of gallbladder diseases. Carbon dioxide (CO₂) pneumoperitoneum created during laparoscopic surgery and the surgical positions applied can lead to temporary physiological changes in intracranial pressure (ICP). Increased intra-abdominal pressure can trigger an increase in ICP by reducing venous return, increasing intrathoracic pressure, and causing hypercapnia. Since direct measurement of increased intracranial pressure requires invasive methods, it is not applicable to every patient in clinical practice. Optic nerve sheath diameter (ONSD) measurement, performed with transorbital ultrasonography, is a non-invasive, bedside method that can indirectly reflect changes in ICP. Literature shows that an increase in ONSD correlates with increased ICP and can be a reliable monitoring method during laparoscopic surgeries. Furthermore, to reduce the impact of inter-individual ocular anatomical differences on measurement results, the ratio of optic nerve sheath diameter to eyeball transverse diameter (ONSD/ETD) will be calculated. The literature reports that the ONSD/ETD ratio exhibits lower variability compared to ONSD measurement alone and may be a more reliable parameter for reflecting intracranial pressure changes. However, studies comparing the effects of different gas insufflation pressures on ONSD/ETD in laparoscopic cholecystectomy surgeries are limited.
Measurements of ONSD (On-Surgery Pressure) have shown that pneumoperitoneum created during these surgeries can increase intracranial pressure in both the early and late stages. Literature reports that ONSD values in the range of 5.0-5.9 mm may be associated with increased ICP. While current studies reveal the effects of pneumoperitoneum duration, surgical position, and hypercapnia on ICP, data on the comparative effects of different gas insufflation pressures are limited. Therefore, evaluating the effects of low and standard insufflation pressures on ONSD during laparoscopic cholecystectomy aims to fill this gap in the current literature. This study has the potential to contribute to determining safer pressure ranges in laparoscopic surgical procedures.
- Conditions
- Optic Nerve Sheath Diameter Measurement, Intracranial Pressure Increase, Laparoscopic Cholecystectomy Surgery
- Being tested
- Low Pressure Group, High Pressure Group
- Keywords
- ONSD, ETD, Laparoscopic Cholecystectomy, intracranial pressure increase
- Medical subject headings
- Intracranial Hypertension
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Low Pressure GroupProcedure or surgery
Data will be collected on patients who underwent surgery within a pressure range of 10-14, depending on the surgeon's preference.
High Pressure GroupProcedure or surgery
Data will be collected on patients who underwent surgery within a pressure range of 14-18, depending on the surgeon's preference.
| Study group | Role | What they receive |
|---|---|---|
| Laparoscopic Cholecystectomy | Observation of patients undergoing laparoscopic cholecystectomy under either low or high gas insufflation pressure determined by the clinical routine. Optic nerve sheath diameter (ONSD) and eyeball transverse diameter (ETD) will be measured via non-invasive transorbital ultrasonography. Receives: Procedure: Low Pressure Group; Procedure: High Pressure Group |
What is being measured
The primary outcome is the main question the study is designed to answer.
ONSD/ETD
Optic nerve sheath diameter (ONSD) eyeball transverse diameter (ETD) ratio: The ONSD/ETD ratio will be calculated by dividing the mean ONSD value by the mean ETD value for each participant. This dimensionless ratio will be utilized as a standardized surrogate marker to evaluate changes in intracranial pressure (ICP), effectively minimizing confounding individual variations in eyeball size and ocular anatomy
Measured: T1(Baseline):Before the induction of anesthesia T2(Post-Intubation):5 minutes after endotracheal intubation T3(Intra-Pneumoperitoneum):15 minutes after the establishment of pneumoperitoneum T4(Post-Exsufflation):10 minutes after complete Exsufflation
Secondary outcomes (2)
ONSD
Optic Nerve Sheat Diameter during surgery: Optic nerve sheath diameter (ONSD) will be evaluated using high-resolution transbulbar ultrasonography to monitor real-time changes in intracranial pressure during the surgical procedure. A linear ultrasound probe will be placed gently over the closed eyelid using acoustic gel, ensuring minimal pressure on the globe.ONSD measurements will be performed bilaterally at a depth of 3 mm posterior to the retina, perpendicular to the optic nerve axis. The mean value of three consecutive measurements from each eye will be recorded for analysis.
Measured: T1(Baseline):Before the induction of anesthesia T2(Post-Intubation):5 minutes after endotracheal intubation T3(Intra-Pneumoperitoneum):15 minutes after the establishment of pneumoperitoneum T4(Post-Exsufflation):10 minutes after complete Exsufflation
MAP
Recording Measurement of Mean Arterial Pressure (MAP) in mmHg during surgery
Measured: T1(Baseline):Before the induction of anesthesia T2(Post-Intubation):5 minutes after endotracheal intubation T3(Intra-Pneumoperitoneum):15 minutes after the establishment of pneumoperitoneum T4(Post-Exsufflation):10 minutes after complete Exsufflation
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted25 Aug 2026
- Study start30 Nov 2026 (estimated)
- Primary completion15 Feb 2027 (estimated)
- Study completion15 Feb 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (2)Papers the sponsor has linked to this study.
- Other trials for Optic Nerve Sheath Diameter MeasurementStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Cohort
- Time perspective
- Prospective
- Enrolment
- 68 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Gaziantep City Hospital
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Gamze Nur Teke, Gaziantep City Hospital
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07784361
- Sponsor's protocol ID
- 2024-KAEK-39
- Acronym
- ONSD ETD
- Status last verified
- Nov 2026
- First submitted
- 18 Aug 2026
- Last updated
- 4 Nov 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No: Individual participant data will not be shared outside the primary research team to protect patient privacy and maintain strict confidentiality in accordance with local personal data protection laws (KVKK) and the approved institutional review board protocol.
Publications
Huang Y, Cai Y, Peng MQ, Yi TT. Evaluation of the effect of fluid management on intracranial pressure in patients undergoing laparoscopic gynaecological surgery based on the ratio of the optic nerve sheath diameter to the eyeball transverse diameter as measured by ultrasound: a randomised controlled trial. BMC Anesthesiol. 2024 Sep 7;24(1):319. doi: 10.1186/s12871-024-02683-7.
PubMed 39244545Kim EJ, Koo BN, Choi SH, Park K, Kim MS. Ultrasonographic optic nerve sheath diameter for predicting elevated intracranial pressure during laparoscopic surgery: a systematic review and meta-analysis. Surg Endosc. 2018 Jan;32(1):175-182. doi: 10.1007/s00464-017-5653-3. Epub 2017 Jun 21.
PubMed 28639043
Study at a glance
From the registry record, last updated by the sponsor on 4 Nov 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Assessment of Increased Intracranial Pressure by Optic Nerve Sheath Diameter (ONSD), Eyeball Transverse Diameter (ETD) and ONSD/ETD Ratio Measurement From Ocular Ultrasound
- ClinicalTrials.gov ID
- NCT07784361
- Acronym / sponsor ID
- ONSD ETD / 2024-KAEK-39
- Conditions
- Optic Nerve Sheath Diameter Measurement, Intracranial Pressure Increase, Laparoscopic Cholecystectomy Surgery
- Keywords
- ONSD, ETD, Laparoscopic Cholecystectomy, intracranial pressure increase
- Study type
- Observational
- Recruitment status
- Not yet recruiting
- Enrolment
- 68 participants (estimated)
- Lead sponsor
- Gaziantep City HospitalUniversity, hospital or other
- Study start
- 30 Nov 2026 (estimated)
- Primary completion
- 15 Feb 2027 (estimated)
- Study completion
- 15 Feb 2027 (estimated)
- First posted
- 25 Aug 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The aim of this study is to evaluate the effects of different carbon dioxide gas insufflation pressures on the ultrasound-guided optic nerve sheath diameter in patients undergoing laparoscopic cholecystectomy and to determine the possible relationship between these changes and intracranial pressure. The study aims to gain a better understanding of the neurophysiological effects of gas pressures used during laparoscopic surgery and to obtain scientific data aimed at improving patient safety.
Detailed description
Laparoscopic surgeries are now widely preferred in the treatment of gallbladder diseases. Carbon dioxide (CO₂) pneumoperitoneum created during laparoscopic surgery and the surgical positions applied can lead to temporary physiological changes in intracranial pressure (ICP). Increased intra-abdominal pressure can trigger an increase in ICP by reducing venous return, increasing intrathoracic pressure, and causing hypercapnia. Since direct measurement of increased intracranial pressure requires invasive methods, it is not applicable to every patient in clinical practice. Optic nerve sheath diameter (ONSD) measurement, performed with transorbital ultrasonography, is a non-invasive, bedside method that can indirectly reflect changes in ICP. Literature shows that an increase in ONSD correlates with increased ICP and can be a reliable monitoring method during laparoscopic surgeries. Furthermore, to reduce the impact of inter-individual ocular anatomical differences on measurement results, the ratio of optic nerve sheath diameter to eyeball transverse diameter (ONSD/ETD) will be calculated. The literature reports that the ONSD/ETD ratio exhibits lower variability compared to ONSD measurement alone and may be a more reliable parameter for reflecting intracranial pressure changes. However, studies comparing the effects of different gas insufflation pressures on ONSD/ETD in laparoscopic cholecystectomy surgeries are limited.
Measurements of ONSD (On-Surgery Pressure) have shown that pneumoperitoneum created during these surgeries can increase intracranial pressure in both the early and late stages. Literature reports that ONSD values in the range of 5.0-5.9 mm may be associated with increased ICP. While current studies reveal the effects of pneumoperitoneum duration, surgical position, and hypercapnia on ICP, data on the comparative effects of different gas insufflation pressures are limited. Therefore, evaluating the effects of low and standard insufflation pressures on ONSD during laparoscopic cholecystectomy aims to fill this gap in the current literature. This study has the potential to contribute to determining safer pressure ranges in laparoscopic surgical procedures.
Study design
- Observational model
- Cohort
- Time perspective
- Prospective
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| Laparoscopic Cholecystectomy | – | Procedure: Low Pressure Group, Procedure: High Pressure GroupObservation of patients undergoing laparoscopic cholecystectomy under either low or high gas insufflation pressure determined by the clinical routine. Optic nerve sheath diameter (ONSD) and eyeball transverse diameter (ETD) will be measured via non-invasive transorbital ultrasonography. |
Who may qualify
- Ages
- 18 to 80 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
- Study population
- The study population consists of adult patients aged 18-80 years, classified as ASA I-II physical status, who are scheduled to undergo elective laparoscopic cholecystectomy in a tertiary care hospital setting. Patients are observed within the routine clinical workflow of the anesthesia and general surgery departments.
Key inclusion criteria (3 listed)
- Patients aged between 18 and 80 years.
- Patients scheduled for laparoscopic cholecystectomy.
- ASA (American Society of Anesthesiologists) physical status I or II.
Key exclusion criteria (3 listed)
- History of intracranial space-occupying lesion or high intracranial pressure (ICP).
- History of abdominal trauma.
- History of orbital/ocular trauma.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Low Pressure GroupData will be collected on patients who underwent surgery within a pressure range of 10-14, depending on the surgeon's preference. | Procedure or surgery | Laparoscopic Cholecystectomy |
| High Pressure GroupData will be collected on patients who underwent surgery within a pressure range of 14-18, depending on the surgeon's preference. | Procedure or surgery | Laparoscopic Cholecystectomy |
Primary outcome
ONSD/ETD
Time frame: T1(Baseline):Before the induction of anesthesia T2(Post-Intubation):5 minutes after endotracheal intubation T3(Intra-Pneumoperitoneum):15 minutes after the establishment of pneumoperitoneum T4(Post-Exsufflation):10 minutes after complete Exsufflation
Optic nerve sheath diameter (ONSD) eyeball transverse diameter (ETD) ratio: The ONSD/ETD ratio will be calculated by dividing the mean ONSD value by the mean ETD value for each participant. This dimensionless ratio will be utilized as a standardized surrogate marker to evaluate changes in intracranial pressure (ICP), effectively minimizing confounding individual variations in eyeball size and ocular anatomy
2 secondary outcomes
ONSD
Time frame: T1(Baseline):Before the induction of anesthesia T2(Post-Intubation):5 minutes after endotracheal intubation T3(Intra-Pneumoperitoneum):15 minutes after the establishment of pneumoperitoneum T4(Post-Exsufflation):10 minutes after complete Exsufflation
MAP
Time frame: T1(Baseline):Before the induction of anesthesia T2(Post-Intubation):5 minutes after endotracheal intubation T3(Intra-Pneumoperitoneum):15 minutes after the establishment of pneumoperitoneum T4(Post-Exsufflation):10 minutes after complete Exsufflation
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 4 Nov 2026.
- Results publication: PubMed 39244545Huang Y, Cai Y, Peng MQ, Yi TT. Evaluation of the effect of fluid management on intracranial pressure in patients undergoing laparoscopic gynaecological surgery based on the ratio of the optic nerve sheath diameter to the eyeball transverse diameter as measured by ultrasound: a randomised controlled trial. BMC Anesthesiol. 2024 Sep 7;24(1):319. doi: 10.1186/s12871-024-02683-7.
- Results publication: PubMed 28639043Kim EJ, Koo BN, Choi SH, Park K, Kim MS. Ultrasonographic optic nerve sheath diameter for predicting elevated intracranial pressure during laparoscopic surgery: a systematic review and meta-analysis. Surg Endosc. 2018 Jan;32(1):175-182. doi: 10.1007/s00464-017-5653-3. Epub 2017 Jun 21.
- Individual participant dataSharing planned: No. Individual participant data will not be shared outside the primary research team to protect patient privacy and maintain strict confidentiality in accordance with local personal data protection laws (KVKK) and the approved institutional review board protocol.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Questions about this trial
What is this clinical trial studying?
An observational study of Optic Nerve Sheath Diameter Measurement and Intracranial Pressure Increase, run by Gaziantep City Hospital.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 3 inclusion and 3 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: opening soon, as of the sponsor's last update on 4 Nov 2026. Status can change between updates, so confirm with the study contact before making plans.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Gamze Nur Teke, medical doctor (+905546694389, gamzenur.koca@gmail.com), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
ONSD/ETD (time frame: T1(Baseline):Before the induction of anesthesia T2(Post-Intubation):5 minutes after endotracheal intubation T3(Intra-Pneumoperitoneum):15 minutes after the establishment of pneumoperitoneum T4(Post-Exsufflation):10 minutes after complete Exsufflation). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT07784361, which also lists 2 linked publications.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 4 Nov 2026.