The Application of Ultrasonic Measurement of Optic Nerve Sheath Diameter in Liposuction Surgery

The main purpose of this study is to investigate the effect of changes in Optic Nerve Sheath Diameter (ONSD) measured at different operating position during Liposuction Surgery. Optic nerve sheath diameter (ONSD) has been shown to be a noninvasive indicator for monitoring intracranial pressure changes. The use of anesthetic drugs will reduce the intracranial pressure. However, prone position and large fluid infusion can still lead to increased intracranial pressure. The investigators hypothesized that during sedation and analgesia anesthesia, patients in prone position had higher ONSD.