Optic Nerve Sheath Diameter by Point of Care Ultrasound to Detect Raised Intracranial Pressure in Children.

Objectives: The primary objective was to determine the area under the curve of optic nerve sheath diameter >4.5 mm for detection of raised intracranial pressure in children aged 1 year to 12 years admitted to PICU with neurological signs and symptoms. Our secondary objectives were to compare optic nerve sheath values in study population with age and sex-matched controls and determine change after 30 minutes of osmotherapy.

Methods: One hundred twenty-five children (40 with raised intracranial pressure, 45 without raised intracranial pressure, and 40 non-neurological controls) were enrolled. Optic nerve sheath diameter using point of care ultrasound was measured at admission and 30 minutes after initiation of osmotherapy in patients who received osmotherapy.

Results: Mean optic nerve sheath diameter in children with raised intracranial pressure was 5.48 ± 0.48 mm, while that without raised intracranial pressure was 5.14 ± 0.57 mm and non-neurological controls was 4.54 ± 0.24 mm. A diameter of >4.5 mm was able to detect raised intracranial pressure with sensitivity of 100%, with area under the curve of 0.53. Best cutoff was determined to be 4.92 mm, with sensitivity of 90%, specificity of 46.67% and area under the curve of 0.68. Higher optic nerve sheath diameter was observed with increase in Friesen grading of papilledema. Also, a significant decrease in values was found after 30 minutes of osmotherapy, with no difference between 3% saline and 20% mannitol.

Conclusion: Optic nerve sheath diameter using ultrasound was able to detect raised intracranial pressure with high sensitivity, but low specificity, with optimal cutoff observed as 4.92 mm.