OPTIC NERVE SHEATH DIAMETER – A MARKER FOR ASSESSING AND PREDICTING INTRACRANIAL PRESSURE IN HEAD INJURY PATIENTS

Background: Elevated intracranial pressure (ICP) is a life-threatening complication of head trauma requiring prompt diagnosis. This study evaluates the utility of optic nerve sheath diameter (ONSD) measurement via ultrasonography (ONUS) as a non-invasive bedside method to predict elevated ICP in comparison to cranial CT. Methods: In this prospective observational study at a tertiary hospital, 120 adult head injury patients underwent ONUS and cranial CT. ONSD measurements ≥5 mm were considered indicative of raised ICP. Clinical signs, CT findings, and neurosurgical interventions were analysed. Sensitivity, specificity, and predictive values of ONUS for raised ICP and surgical necessity were determined. Results:CTidentified elevated ICPin 87 patients. Mean ONSD was significantly higher in patients with CT-confirmed raised ICP(5.6 ± 0.54 mm) compared to those without (3.3 ± 0.74 mm, p < 0.0001). ONUS demonstrated high sensitivity (97.7%) and specificity (96.8%) for raised ICP, with a positive predictive value (PPV) of 98.8% and a negative predictive value (NPV) of 93.9%. Among 75 patients requiring surgical intervention for intracranial hematomas, ONUS accurately predicted 85.2% of cases, with a PPV of 98.6%. Conclusion: ONUS provides a reliable, non-invasive alternative to CT for predicting elevated ICP and guiding surgical decisions in trauma patients. Its portability, rapidity, and cost-effectiveness make it particularly valuable in resource-limited and emergency settings. ONUS holds potential as a critical tool for triaging and monitoring head injury patients.