2. OPTIC NERVE SHEATH DIAMETER (ONSD) MEASUREMENT WITH OPTIC NERVE ULTRASOUND (ONUS) IN THE EVALUATION OF ELEVATED INTRACRANIAL PRESSURE: A COMPARATIVE STUDY WITH CT SCAN IN HEAD TRAUMA PATIENTS.

Shreyas Patel, Krunalkumar Pancholi, Rahulkumar Humbal, Rina Parikh, A.K. Saxena

ABSTRACT

BACKGROUND & OBJECTIVE: Elevated intracranial pressure (ICP) is a challenging and potentially fatal complication of acute head trauma in patients who present to the emergency department. Although computed tomography scanners are the most common diagnostic tests for these patients in hospital, there are situations in which a rapid bedside means of evaluating intracranial pressure would be advantageous. These situations include unstable multiorgan-system trauma patients, remote settings with prolonged transport time, or mass casualty occurrences. The optic nerve sheath diameter has been suggested as a possible indicator of elevated intracranial pressure.1-9 Optic Nerve Ultrasonography (ONUS) may help us to identify raised intracranial pressure. Our objective is to determine whether a bedside ultrasonographic measurement of optic nerve sheath diameter can accurately predict elevated intracranial pressure in adult head injury patients in the emergency department (ED),taking CT scan as gold standard test. Methods: We conducted a prospective, blinded observational study on adult patients in ED patients with suspected intracranial injury. Using a 7.5-MHz ultrasonographic probe on the closed eyelids, a single optic nerve sheath diameter was measured 3 mm behind the globe in each eye. Cranial CT findings of midline shift, edema, or effacement suggestive of elevated intracranial pressure were used to evaluate the accuracy of optic nerve sheath diameter. RESULTS: The sensitivity of mean binocular ONSD >5mm measured by ONUS for raised ICP was found to be 100% with specificity of 89%.The Positive predictive value was 68% & the negative predictive value was 100%. CONCLUSION: Bedside ONSD measurement, performed by ED physicians can provide accurate, non-invasive method to identify raised ICP in patients with acute brain injury.

KEY-WORDS: ONSD, ONUS, Elevated ICP, Head Trauma, Emergency Department.

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