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DOI: DOI: http://dx.doi.org/10.21088/ijnns.0975.0223.10318.9

Abstract

 Patients suffering Brain injury commonly develop Elevated intracranial pressure (EICP) . We need an easy,  reproducible method to detect EICP earlier. Objectives: Measurement of optic nerve sheath diameter (ONSD) to identify earlier, the development of EICP. Methods: We did a prospective, blinded observational study in our Institute emergency department (ED) on patients with possible EICP due to brain injury over a 6 months period. ONSD was measured 3mm behind the globe by using a 10 MHz linear probe on both the eyelids of supine patients. An upper limit value of above 4.5 mm was taken as abnormally high. Brain Computed tomography (BCT) indicative of EICP were a midline shift of 3 mm or more, effacement of sulci, presence of significant edema, and effaced cisterns. Student’s t test analyzed ONSDs in the normal and EICP groups and necessary values were documented separately for each patient. Results: Forty four patients in total were included in the study group. CT Brain showed features of raised ICP in 24 of them. All these patients were correctly identified by ONSD measurement with over 4.5 mm on USG. The sensitivity was 100%. Specificity was 95%. The positive predictive values were 93%. Negative prediction was 100%. Conclusions: USG measurement of ONSD is good and a possible bedside alternative in the early identification of EICP. 

Keywords: Brain Injury; Computerized Tomography; Intracranial Pressure; Ultrasonography.

Corresponding Author : Balamurugan S., Associate Professor, Department of Neurosurgery, Institute of Neurosurgery, Madras Medical college and Rajiv Gandhi Government General Hospital, Chennai­600003 India.