Clinical Research Directory

Effect Of Trendelenburg Position And Pneumoperitoneum On Optic Nerve Sheath Diameter In Robot-Assisted Prostatectomy

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.

Effect of Carbon Dioxide Pressure on Optic Nerve Sheath Diameter in Laparoscopic Transperitoneal Nephrectomy

Nephrectomy is a surgical procedure performed for various indications, and with the development and increasing availability of advanced diagnostic techniques, its incidence has been rising. Today, in appropriate cases, laparoscopic surgery is recommended due to its minimally invasive nature and its surgical success rates being comparable to those of open surgery. In laparoscopic surgery, to achieve optimal visualization, a 45° lateral decubitus position is applied, followed by the creation of a pneumoperitoneum using carbon dioxide gas. While the cardiopulmonary effects of this procedure have been shown to be minimal, studies on its intracranial effects are limited. Cerebral perfusion pressure is defined as the difference between mean arterial pressure and either central venous pressure or intracranial pressure, whichever is higher. Intracranial pressure can be assessed non-invasively using ultrasonographic measurement of the Optic Nerve Sheath Diameter (ONSD). The retrobulbar segment of the optic nerve is surrounded by a distensible subarachnoid space, which expands in response to increased intracranial pressure. The effect of increased intra-abdominal pressure during laparoscopic surgery on intracranial pressure, and its impact on ONSD, will be evaluated non-invasively. In patients scheduled for laparoscopic kidney surgery, the Optic Nerve Sheath Diameter will be measured transorbitally using ultrasonography by the investigator at various stages of the surgery (before anesthesia, after anesthesia, in the lateral decubitus position, during pneumoperitoneum, and at routine intraoperative pressure levels). Additionally, standard monitoring parameters such as pulse rate, blood pressure, oxygen saturation, and End-Tidal CO₂ will be recorded. The Optic Nerve Sheath Diameter, which serves as an indicator of increased intracranial pressure, will be compared with variables such as surgical positioning, BMI, ASA score, and other relevant factors.

Early WAKE-up Predictors After Out-of-Hospital Cardiac Arrest

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.

Comparison of the Effects of Endotracheal Intubation and Laryngeal Mask Applications on Optic Nerve Diameter in Pediatric Patients

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.

The Effects of Positive End-expiratory Pressure (PEEP) on Optic Nerve Sheath Diameter in Laparoscopic Cholecystectomy

This prospective interventional study will evaluate the effects of applying positive end-expiratory pressure (PEEP) at 10 cmH₂O on optic nerve sheath diameter (ONSD) in patients undergoing elective laparoscopic cholecystectomy under general anesthesia. A total of approximately 80 adult patients (ASA physical status I-III) will be included following informed consent. ONSD will be measured using a high-frequency linear ultrasound probe at three predefined intraoperative time points: (T0) 10 minutes after initiation of mechanical ventilation, (T1) 10 minutes after pneumoperitoneum creation, and (T2) 30 minutes after pneumoperitoneum creation. Dynamic lung compliance, peak airway pressure (Ppeak), end-tidal CO₂ (EtCO₂), heart rate, mean arterial pressure, and SpO₂ will also be recorded. The aim is to assess whether the application of PEEP influences intracranial pressure indicators, particularly ONSD, during laparoscopic procedures. The study may provide valuable insights into the neurophysiological effects of intra-abdominal pressure and mechanical ventilation strategies in surgical patients.

Lidocaine, Dexmedetomidine, Esmolol and Magnesium Effect on Optic Nerve Sheath Diameter After Laryngoscopy

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.

Oropharyngeal Vs Intravenous Lidocaine Effects on Optic Nerve Sheath Diameter After Intubation

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.

Effect of Spinal Needle Type on Optic Nerve Sheath Diameter

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.