Effect of Optic Nerve Sheath Diameter in Paediatric patients undergoing laparoscopic surgeries

In laparoscopic surgeries carbon dioxide and pneumoperitoneum result in various events such as the potential to increase cerebral blood flow, intracranial pressure and intraocular pressure. Pneumoperitoneum elevates ICP because of the increased abdominal pressure and ICP increases even further in the Trendelenberg position. Pneumoperitoneum also increases cerebral blood flow resulting in an acute rise in ICP that may be harmful to patients with head injury or unrecognized intracranial mass lesion. Direct ICP measurement using a small pressure sensitive probe inserted through the skull is the gold standard for monitoring ICP. For routine surgeries the risks of such an invasive test outweigh the benefits. A new non invasive method the Optic Nerve Sheath Diameter(ONSD) measurement via ultrasonography detects the raised ICP and is reliable and inexpensive and can be repeated many a time. Due to elastic subarachnoid trabecular anatomy, the optic nerve sheath is most distensible at 3mm behind the globe thus making it the best point for ONSD interpretation. ONSD was reported to increase between 15 and 30 mm Hg. Ultrasound based ONSD measurement have been extensively used quickly and non invasively to assess ICP  both at clinical and research levels. Hence our study aimed to measure ONSD to assess ICP in paediatric patient