Comparison of propofol and propofol–ketamine anesthesia on optic nerve sheath diameter in endovascular cerebral aneurysm procedures: a prospective randomized study

Abstract

Endovascular treatment of unruptured intracranial aneurysms requires anesthetic strategies that maintain cerebral perfusion and hemodynamic stability while avoiding increases in intracranial pressure (ICP). Optic nerve sheath diameter (ONSD) measured by ultrasonography is commonly used as a noninvasive surrogate marker of ICP. This study compared propofol and propofol–ketamine anesthesia with respect to perioperative ONSD, cerebral oxygenation, and hemodynamic parameters during endovascular aneurysm procedures. In this prospective, randomized, single-center, observer-blinded trial, 40 adults undergoing elective endovascular treatment of unruptured intracranial aneurysms were allocated to a propofol group (P, n = 20) or a propofol–ketamine group (KP, n = 20). Standardized anesthetic protocols and ventilation targeting normocapnia were used in both groups. ONSD, regional cerebral oxygen saturation (rSO₂), bispectral index (BIS), and hemodynamic variables were recorded at predefined perioperative time points. The primary outcome was the temporal change in mean ONSD. Mean ONSD was analyzed using a linear mixed-effects model including group, time, and group × time interaction. Secondary longitudinal outcomes were analyzed using exploratory mixed-effects models. Baseline demographic and clinical characteristics were comparable between groups. Total propofol consumption was significantly lower in the KP group, whereas remifentanil use showed a non-significant trend toward reduction. In the primary mixed-effects analysis, the group × time interaction for mean ONSD was not statistically significant, indicating that the temporal trajectory of ONSD did not differ between groups. The main effect of group was also not significant, whereas the main effect of time was significant. Exploratory analyses of secondary longitudinal outcomes showed significant group × time interactions for selected hemodynamic, ventilation-related, anesthetic depth, and cerebral oxygenation parameters, including DBP, MAP, EtCO₂, BIS, and mean rSO₂. Heart rate and SpO₂ trajectories were comparable between groups. In this small randomized cohort of patients undergoing elective endovascular treatment of unruptured intracranial aneurysms, propofol and propofol–ketamine anesthesia showed comparable ONSD trajectories over time. The propofol–ketamine regimen was associated with reduced propofol consumption and exploratory evidence of differential perioperative hemodynamic and cerebral oxygenation profiles. However, the study was not powered to evaluate safety outcomes or rare adverse events. Larger neurosurgical trials are required before firm conclusions regarding safety and clinical feasibility can be drawn. The study was registered at ClinicalTrials.gov (identifier NCT07542015) on April 14, 2026. Retrospectively registered.