An observational study in Optic Nerve Sheath Diameter Measurement, Intracranial Pressure Increase and Laparoscopic Cholecystectomy Surgery, sponsored by Gaziantep City Hospital. Not yet recruiting. Open to participants aged 18 Years to 80 Years. Per ClinicalTrials.gov, last updated 2026-11-04.
Sponsored by Gaziantep City Hospital · Observational
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.
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.
165 studies on the registry are indexed under Intracranial Hypertension; 36 are open to participants now.
This study's planned enrollment of 68 is above the median of 60 across 76 observational studies indexed under Intracranial Hypertension.
Browse Intracranial Hypertension studies →Gaziantep City Hospital is the lead sponsor of 21 studies on the registry; 14 are open to participants now.
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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.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
The anaesthetists’ scale of health before surgery: I is healthy, II has a mild illness that is under control, III a severe one, IV a severe illness that is a constant threat to life. V and VI are used for the critically ill and for organ donors.
ASA physical status
The anaesthetists’ scale of health before surgery: I is healthy, II has a mild illness that is under control, III a severe one, IV a severe illness that is a constant threat to life. V and VI are used for the critically ill and for organ donors.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
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.
Procedure: Low Pressure Group · Procedure: High Pressure Group
Data will be collected on patients who underwent surgery within a pressure range of 10-14, depending on the surgeon's preference.
Data will be collected on patients who underwent surgery within a pressure range of 14-18, depending on the surgeon's preference.
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
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
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.
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
Recording Measurement of Mean Arterial Pressure (MAP) in mmHg during surgery
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
No study locations are listed for this record.
Plan to share: 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.
Start is estimated for Nov 2026; primary completion for Feb 2027, 2 months later.
Of 42 non-industry observational studies under Intracranial Hypertension, half reached primary completion within 31 months of starting (the median), counting those still running; a quarter within 11 and three quarters within 62. This study's planned 2 months is below that.
Counting every sponsor, half of 44 studies reached it within 31 months; a quarter within 11 and three quarters within 62.
Since we started tracking on Sep 25, 2026, the dates moved once, on Nov 4, 2026: start Aug 2026 → Nov 2026, primary completion Oct 2026 → Feb 2027 and completion Oct 2026 → Feb 2027.
Earlier changes are on the record history on ClinicalTrials.gov ↗
How these figures are worked out, and which studies are left out of them.
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
This study is not yet recruiting, as verified in Nov 2026. You cannot join it, but the record below documents what was studied.
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Gaziantep City Hospital