Abstract W MP83: Use of Optic Nerve Sheath Diameter in Emergency Department to Predict Stroke Outcome

Abstract

Introduction: Elevated intracranial pressure (ICP) reflects long-term neurologic deficit and death in patients with stroke. Deterioration in neurologic exam is an early indicator of increasing ICP, however has limitations enabling accurate detection of elevated ICP due to confounding factors including fluctuations in mental status and sedation/ paralysis as part of the acute management. Optic ultrasound (OUS) represents a non-invasive technique that can be used to measure the optic nerve sheath dimension providing valuable ICP monitoring data. Hypothesis: Optic ultrasound (OUS) can measure optic nerve sheath size and may be used as a screening tool to identify patients at risk of mortality from increased ICP. Methods: In a prospective convenience sample study, 86 stroke patients were studied at a tertiary care center. On the day of admission and following day, bedside OUS was performed to measure Optic nerve sheath diameter (ONSD). A longitudinal and transverse measurement were taken on both eyes of each patient. Data analysis includes paired t- tests and Chi-Square to compare means and proportions as appropriate. Regression analysis assessed ONSD and patient outcome relationships. Results: There was a significant difference in mean ONSD between patients who died in comparison with those who survived in both ischemic stroke category (0.582 vs 0.533; p=0.0092), and intracerebral hemorrhage category (0.623 vs 0.572; p=0.0187) respectively. Overall, for every 0.1 cm increase in ONSD, the mortality odds were 4.239 times the odds of no death among ischemic stroke patients (95% CI 1.317, 13.642 p=0.0155), and 6.222 times the odds of no death among intracerebral hemorrhage patients (95% CI 1.160, 33.382 p=0.0329). Increased ONSD measurements show a moderately strong correlation (r=0.44 p<0.0001) with poorer Modified Rankin Scale scores at 6 months. Conclusions: Increased ONSD measurements correlated with poor short term (in-hospital) and long term (6 months) mortality. OUS may be used as a screening tool to identify patients at risk of poor outcome from increased ICP. OUS in the future may enable the treating physician to utilize this reliable non-invasive monitoring technique to predict elevated ICP and initiate early therapeutics to improve patient care.