Retrospective Evaluation of Optic Nerve Sheath Diameters of Patients Diagnosed with Brain Death

Abstract

Purpose: Purpose of this study is to reveal the relationship between optic nerve sheath diameter (ONSD) and the etiology of brain death and to investigate whether there is a correlation between ONSD and blood gas parameters before and after the apnea test in patients diagnosed with brain death. Materıals and Methods: The data of 92 patients with brain death diagnoses were retrospectively analyzed for ONSD measurements for each eye, partial carbon dioxide pressure (pCO2), and blood gas parameters before and after the apnea test. Results: Subarachnoidal and intracerebral hemorrhages were the two most common brain death etiology. The mean ONSD for the right eye was 6.37±1.03 mm. The mean ONSD for the left eye was 6.43±1.02 mm. Only 8 patients had ONSD below 5.00 mm. There was no statistically significant correlation between the percent change of pCO2 and ONSD change (p>0.05). Conclusion: The present study shows that ONSD values are very high regardless of the partial pressure of carbon dioxide in patients with brain death diagnoses. We can suggest that ONSD can find a place for evaluating comatose patients for brain death diagnosis.

Keywords

• optic nerve sheath diameter
• brain death
• apnea test
• blood gas analysis