Impact of patient position and intraabdominal gas used in laparoscopic hysterectomy on optic nerve sheath diameter which reflects intracranial pressure

We hypothesized that pneumoperitoneum and Trendelenburg position applied during laparoscopic hysterectomy would impact intracranial pressure. Optic nerve sheath diameter measured with USG reflects intracranial pressure. Therefore we are enrolling patients undergoing a laparoscopic hysterectomy in our institute and measuring optic nerve sheath diameter with a linear 13-6 megahertz probe during different stages of the surgery (eg. before and after pneumoperitoneum, before and after Trendelenburg position). The primary outcome is the change in optic nerve sheath diameter with pneumoperitoneum and Trendelenburg position. The secondary outcome is postoperative nausea and vomiting and postoperative headache.