Optic Nerve Sheath Diameter in Retrobulbar Ultrasound as a Surrogate Measure for Intracranial Pressure Before and After Non-invasive Strategies

Measurement of the diameter of the sheath of the optic nerve in patients hospitalized in intensive care, with increased intracranial pressure (\> 20mmHg) as a substitute measure for diagnosis and follow-up before and after different non-invasive strategies. Three groups were created in which, through strategies already proven and non-invasive (mannitol, hypertonic solution 7.5% NaCl, reverse trendelenburg) to decrease the intracranial pressure, the optic nerve diameter measurement was performed and simultaneously the investigators monitored intracranial pressure through an intraventricular catheter continuously to determine if both correspond