Optic Nerve Sheath Diameter

This observational study aims to evaluate the effect of menstrual cycle phase on optic nerve sheath diameter (ONSD) in women undergoing elective laparoscopic gynecologic surgery. Patients will be grouped according to menstrual cycle phase as follicular or luteal. ONSD measurements will be performed perioperatively, and postoperative nausea and vomiting as well as postoperative cognitive function will also be assessed. The study is designed to investigate whether hormonal variations during the menstrual cycle are associated with differences in intracranial pressure reflected by ONSD measurements and postoperative outcomes

This prospective study aims to evaluate the effect of steep Trendelenburg position and pneumoperitoneum on optic nerve sheath diameter in patients undergoing robot-assisted laparoscopic radical prostatectomy and open radical prostatectomy under general anesthesia. Increased intracranial pressure may occur during robotic surgery due to pneumoperitoneum and head-down positioning. Optic nerve sheath diameter measured by ocular ultrasonography is a non-invasive method used to assess intracranial pressure changes. Hemodynamic and respiratory parameters will also be recorded during surgery. The results of this study may help to better understand the physiological effects of surgical position and pneumoperitoneum during prostatectomy procedures.

WAKE-OHCA is a prospective observational substudy of the Danish Out-of-Hospital Cardiac Arrest (DANOHCA) trial, identifier NCT05895838. The aim is to collect early neuromonitoring data to identify key predictors of successful wake-up.

This clinical study aims to investigate the effects of breathing tubes, which we use to connect children aged 1-11 to a respiratory device under general anesthesia in the operating room, on intracranial pressure after they are inserted. No changes will be made to routine anesthesia practices for this purpose, and eye examinations will be performed with an USG device. This study has no undesirable effects or risks. This study does not include any invasive procedures. You have the right to refuse to participate in the study. You have the right to withdraw from the study at any time. If you decide not to participate in the study for any reason, there will be no disruption to your treatment. You will not be liable for any financial loss if you participate in the study, and you will not be paid. Your identity will be kept confidential if you participate in the study.

This clinical trial aims to compare the effects of lidocaine, dexmedetomidine, esmolol, and magnesium on optic nerve sheath diameter and hemodynamic response to laryngoscopy. The participants will be patients determined to need intubation and general anesthesia for any elective surgery. Each participant will receive either lidocaine, dexmedetomidine, esmolol, magnesium, or none before anesthesia induction, according to randomization. The investigator will measure the optic nerve sheath diameter by ultrasonography before and after intubation. Researchers will compare the difference between optic nerve sheath diameter, systolic blood pressure, and heart rate before and after laryngoscopy and search for the most stable group. The trial aims to determine a general anesthesia induction protocol for patients sensitive to intracranial pressure changes reflected as optic nerve sheath diameter for easy monitoring.

This study aims to evaluate the effects of pre-intubation oropharyngeal topical lidocaine on optic nerve sheath diameter (ONSD) post-endotracheal intubation. The study will measure the ONSD using ultrasonography before intubation, and at 1, 5, and 10 minutes post-intubation. The results will be compared between patients receiving %10 lidocaine topically and %2 intravenous lidocaine.

The optic nerve sheath is a continuation of the dura mater, extending along the subarachnoid space surrounding the optic nerve. Consequently, changes in intracranial pressure cause an augmentation or contraction in the diameter of the optic nerve sheath, which is coreleted with intracranial pressure. Participants undergoing lower extremity operations (ankle, distal tibia and fibula surgeries) using a tourniquet under spinal anesthesia will be investigated. Spinal anesthesia will be performed with a 25 G Whitacre, 25 G Quincke, or 27 G Quincke needle, depending on the study group. Optic nerve sheath diameter (ONSD) measurements will be performed before spinal anesthesia; and 5 minutes, 15 minutes,,24 hours after spinal block, respectively.The 4th measurement will be performed after tourniquet is opened. Measurements will be done with 15 MHz linear ultrasound (US) probe in B mode, 3 mm behind the posterior globe in the transverse plane from both eyes, on upper eyelid. Values will be recorded numerically. The impact of spinal anesthesia administered using various needle designs (Quincke and Whitacre) and sizes (25G-27G) on intracranial pressure will be investigated.