Optic Nerve Sheath Diameter Changes in Laparoscopic Cholecystectomy

Purpose The aim of this clinical trial is to investigate how different intra-abdominal pressures applied during laparoscopic cholecystectomy affect the optic nerve sheath diameter (ONSD), which serves as a reliable, non-invasive marker of intracranial pressure. The study also seeks to determine whether perioperative ONSD changes are associated with postoperative symptoms such as headache, nausea, and disorientation, as well as with recovery parameters and hemodynamic stability.

Study Design

This is a prospective, randomized, double-blind, interventional clinical trial. Eligible patients scheduled for elective laparoscopic cholecystectomy will be randomized into two groups based on pneumoperitoneum pressure:

Group 1 (Low-pressure group): pneumoperitoneum maintained at 8 mmHg Group 2 (High-pressure group): pneumoperitoneum maintained at 14 mmHg

ONSD will be measured via transorbital ultrasonography at standardized perioperative time points:

T0: Before induction of anesthesia

T1: 30 minutes after initiation of pneumoperitoneum

T2: 5 minutes after extubation

T3: 1 hour postoperatively

T4: 2 hours postoperatively

All ultrasonographic assessments will be performed by a trained investigator blinded to the patient's group allocation.

Participation Patients will receive anesthesia and undergo laparoscopic cholecystectomy according to standard surgical protocols.

Each participant will be randomly assigned to one of the two pneumoperitoneum pressure groups (8 mmHg or 14 mmHg).

After surgery, patients will be observed in the recovery unit. Postoperative symptoms including headache, nausea and vomiting will be recorded.

Inclusion criteria

• 18-65 years of age
• ASA physical status I-II
• BMI < 30 kg/m²
• Scheduled for elective laparoscopic cholecystectomy

Exclusion criteria

• Known neurological diseases
• Ocular pathology
• History of elevated intracranial pressure (ICP)
• Pregnancy
• Need for emergency surgery