Perioperative Noninvasive Assessment of Intracranial Tension by Ultrasonographic Monitoring of Optic Nerve Sheath Diameter: Our Experience

Intracranial hypertension occurs with significant regularity during general anaesthesia. Although majority of times it goes unrecognised and does not cause significant perioperative morbidity, its importance cannot be ignored especially in patients with intracranial pathologies. The intracranial tension can rise significantly during prolonged extreme positioning like steep trendelenburg position for pelvic surgeries. This might have serious impact on the recovery characteristics and can cause reduced cerebral perfusion pressure, delayed awakening, need for post operative ventilatory support, etc. We started using sonoimaging guided estimation of the optic nerve sheath diameter to get an estimate of the intracranial tension. Although limited by observer variations and subjectivity, in the hands of a single trained personal, it provides a reproducible yet non invasive, simple real time assessment of intracranial tension. This brief communication is based on our experience over the last 6 months in 60 patients. Although reports of monitoring optic nerve sheath diameter with ultrasound in ICU patients are plenty in the literature, no report is available stating its utility in monitoring intraoperative intracranial tension to the best of our knowledge and search results using the keywords ‘ultrasonography’, ‘optic nerve sheath diameter’, ‘intraoperative’, ‘intracranial tension’, and ‘anaesthesia’.