Q: How ocular sonography can be of help in Neuro-Critical-Care?
Answer: Biggest advantage of ocular sonography is that it is non-invasive. It can measure the diameter of optic nerve sheath, which correlates with intracranial pressure (ICP). Literature is conflicting in establishing the cutoff point but diameter above 5.5 mm is found to have a high sensitivity and specificity for ICP of >20 cm H2O.
1. Amini A, Kariman H, Arhami Dolatabadi A, Hatamabadi HR, Derakhshanfar H, Mansouri B, et al. Use of the sonographic diameter of optic nerve sheath to estimate intracranial pressure. Am J Emerg Med. 2013;31:236–9.
2. Soldatos T, Karakitsos D, Chatzimichail K, et al. Optic nerve sonography in the diagnostic evaluation of adult brain injury. Crit Care 2008; 12:R67.
3. Dubourg J, Javouhey E, Geeraerts T, et al. Ultrasonography of optic nerve sheath diameter for detection of raised intracranial pressure: a systematic review and meta-analysis. Intensive Care Med 2011; 37:1059.